Alaska

@article{crocker1955soil1,
    author = "Crocker, R. and Major, J",
    title = "Soil development in relation to vegetation and surface age at Glacier Bay, Alaska",
    year = "1955",
    journal = "Journal of Ecology, v. 43, p. 427-448",
    note = "talkorigins\_source = {true}; raw\_reference = {Crocker, R., and Major, J., 1955, Soil development in relation to vegetation and surface age at Glacier Bay, Alaska: Journal of Ecology, v. 43, p. 427-448.}"
}

@article{openalexw1558206756,
    author = "Kulten, E.",
    title = "Flora of Alaska and neighboring territories.",
    year = "1968",
    url = "https://openalex.org/W1558206756",
    openalex = "W1558206756"
}

Late Cretaceous dinosaur eggshells from southern France and the Spanish Pyrenees, presumably belonging to the sauropod Hypselosaurus priscus Matheron, are almost exclusively composed of primary calcite. Besides normal development of these eggshells, there appear two kinds of pathologic tendencies: bi- or multi-shells (infrequent), and shells with a reduced thickness (increasing in frequency until, in the uppermost horizon, they represent more than 90% of the sample). The extinction of the species is attributed primarily to the consequences of thinning of the eggshells. The physiological mechanisms producing pathologic dinosaur eggshells are evaluated in the light of homologous phenomena occurring in living birds and reptiles. On this basis, it is concluded that in the late Maastrichtian populations of “Hypselosaurus,” pathologic eggshells were caused by hormonal imbalances of the vasotocin and of the estrogen levels. On the same basis it is postulated that the teratological shell repetition led to embryo suffocation and that the pathological reduction in shell thickness caused shell breakage and dehydration of the embryo. The lethal results are evident from the frequent absence of “resorption craters” in the mammillary knobs of pathologic shells, a fact which indicates either lack of fertilization of the eggs or the perishing of the embryo prior to the calcification of its skeletal bones. A change in environmental conditions is the ultimate factor which caused hormonal imbalances and extinction. Such a change is indicated by a shift of the mean oxygen isotopic composition (δ 18 O) of eggshell carbonates from −0.6% o to −5.3% o, and by changes in Sr. Information of palaeo-climate is primarily derived from eggshells of living birds and reptiles. The correlation between temperature and oxygen isotopic composition of waters (and related carbonates) is less distinct than for marine carbonates. δ 13 C ranges from −16.5 to −4.5 of eggshells of extant species indicate food from “normal” C 3 metabolism and from C 4 metabolism of plants in a dry climate. “Hypselosaurus” populations probably consumed “normal” C 3 plants. Using isotopic calibration of eggshell carbonates for the interpretation of δ 13 C and δ 18 O values of dinosaur eggshells, a slight change from higher to lower temperatures or a change from a dry to a more humid climate during the time from Lower (and Middle) to Late Maastrichtian can be assumed. The latter explanation is favored because the exceptionally high Sr in the Early Maastrichtian eggshells could be a potential indicator of co-existing evaporites.

@article{doi101017s0094837300016900,
    author = "Erben, H. K. and Hoefs, J. and Wedepohl, K. H.",
    title = "Paleobiological and isotopic studies of eggshells from a declining dinosaur species",
    year = "1979",
    journal = "Paleobiology",
    abstract = "Late Cretaceous dinosaur eggshells from southern France and the Spanish Pyrenees, presumably belonging to the sauropod Hypselosaurus priscus Matheron, are almost exclusively composed of primary calcite. Besides normal development of these eggshells, there appear two kinds of pathologic tendencies: bi- or multi-shells (infrequent), and shells with a reduced thickness (increasing in frequency until, in the uppermost horizon, they represent more than 90\% of the sample). The extinction of the species is attributed primarily to the consequences of thinning of the eggshells. The physiological mechanisms producing pathologic dinosaur eggshells are evaluated in the light of homologous phenomena occurring in living birds and reptiles. On this basis, it is concluded that in the late Maastrichtian populations of “Hypselosaurus,” pathologic eggshells were caused by hormonal imbalances of the vasotocin and of the estrogen levels. On the same basis it is postulated that the teratological shell repetition led to embryo suffocation and that the pathological reduction in shell thickness caused shell breakage and dehydration of the embryo. The lethal results are evident from the frequent absence of “resorption craters” in the mammillary knobs of pathologic shells, a fact which indicates either lack of fertilization of the eggs or the perishing of the embryo prior to the calcification of its skeletal bones. A change in environmental conditions is the ultimate factor which caused hormonal imbalances and extinction. Such a change is indicated by a shift of the mean oxygen isotopic composition (δ 18 O) of eggshell carbonates from −0.6\% o to −5.3\% o, and by changes in Sr. Information of palaeo-climate is primarily derived from eggshells of living birds and reptiles. The correlation between temperature and oxygen isotopic composition of waters (and related carbonates) is less distinct than for marine carbonates. δ 13 C ranges from −16.5 to −4.5 of eggshells of extant species indicate food from “normal” C 3 metabolism and from C 4 metabolism of plants in a dry climate. “Hypselosaurus” populations probably consumed “normal” C 3 plants. Using isotopic calibration of eggshell carbonates for the interpretation of δ 13 C and δ 18 O values of dinosaur eggshells, a slight change from higher to lower temperatures or a change from a dry to a more humid climate during the time from Lower (and Middle) to Late Maastrichtian can be assumed. The latter explanation is favored because the exceptionally high Sr in the Early Maastrichtian eggshells could be a potential indicator of co-existing evaporites.",
    url = "https://doi.org/10.1017/s0094837300016900",
    doi = "10.1017/s0094837300016900",
    openalex = "W1774427581",
    references = "doi1010160016703758900334, doi1010160016703764900225, doi1010160016703778901990, doi1010160016703781902441, doi101016s0016703760800063, doi101104pp473380, doi101111j1474919x1962tb08690x, doi101111j155856461968tb03995x, doi101111j215334901964tb00181x, doi101126science13334651702, doi103402tellusav16i48993"
}

Abundant skeletal remains demonstrate that lambeosaurine hadrosaurid, tyrannosaurid, and troodontid dinosaurs lived on the Alaskan North Slope during late Campanian—early Maestrichtian time (about 66 to 76 million years ago) in a deltaic environment dominated by herbaceous vegetation. The high ground terrestrial plant community was a mild- to cold-temperate forest composed of coniferous and broad leaf trees. The high paleolatitude (about 70° to 85° North) implies extreme seasonal variation in solar insolation, temperature, and herbivore food supply. Great distances of migration to contemporaneous evergreen floras and the presence of both juvenile and adult hadrosaurs suggest that they remained at high latitudes year-round. This challenges the hypothesis that short-term periods of darkness and temperature decrease resulting from a bolide impact caused dinosaurian extinction.

@article{brouwers1987dinosaurs,
    author = "Brouwers, Elisabeth M. and Clemens, William A. and Spicer, Robert A. and Ager, Thomas A. and Carter, L. David and Sliter, William V.",
    title = "Dinosaurs on the North Slope, Alaska: High Latitude, Latest Cretaceous Environments",
    year = "1987",
    journal = "Science",
    abstract = "Abundant skeletal remains demonstrate that lambeosaurine hadrosaurid, tyrannosaurid, and troodontid dinosaurs lived on the Alaskan North Slope during late Campanian—early Maestrichtian time (about 66 to 76 million years ago) in a deltaic environment dominated by herbaceous vegetation. The high ground terrestrial plant community was a mild- to cold-temperate forest composed of coniferous and broad leaf trees. The high paleolatitude (about 70° to 85° North) implies extreme seasonal variation in solar insolation, temperature, and herbivore food supply. Great distances of migration to contemporaneous evergreen floras and the presence of both juvenile and adult hadrosaurs suggest that they remained at high latitudes year-round. This challenges the hypothesis that short-term periods of darkness and temperature decrease resulting from a bolide impact caused dinosaurian extinction.",
    url = "https://doi.org/10.1126/science.237.4822.1608",
    doi = "10.1126/science.237.4822.1608",
    number = "4822",
    pages = "1608-1610",
    volume = "237"
}

@article{davies1987duckbill2,
    author = "Davies, K. L",
    title = "Duckbill dinosaurs from the North Slope of Alaska",
    year = "1987",
    journal = "Journal of Paleontology, v. 61, p. 198-200",
    note = "talkorigins\_source = {true}; raw\_reference = {Davies, K. L., 1987, Duckbill dinosaurs from the North Slope of Alaska: Journal of Paleontology, v. 61, p. 198-200.}"
}

Hadrosaur Bones have been found on the Colville River north of Umiat on the North Slope of Alaska. This find represents the first report of dinosaur bones in Alaska and their northernmost reported occurrence. The remains are not determinable below family level but are important, nonetheless, for interpretations of the paleoclimatology and paleobiogeography of the Late Cretaceous.

@article{doi101017s0022336000028341,
    author = "Davies, Kyle L.",
    title = "Duck-bill dinosaurs (Hadrosauridae, Ornithischia) from the North Slope of Alaska",
    year = "1987",
    journal = "Journal of Paleontology",
    abstract = "Hadrosaur Bones have been found on the Colville River north of Umiat on the North Slope of Alaska. This find represents the first report of dinosaur bones in Alaska and their northernmost reported occurrence. The remains are not determinable below family level but are important, nonetheless, for interpretations of the paleoclimatology and paleobiogeography of the Late Cretaceous.",
    url = "https://www.semanticscholar.org/paper/f55b1039b83338550eb77ee878676518aae8f885",
    doi = "10.1017/S0022336000028341",
    is_oa = "true",
    number = "1",
    pages = "198-200",
    semanticscholar_citation_count = "40",
    semanticscholar_id = "f55b1039b83338550eb77ee878676518aae8f885",
    volume = "61"
}

@misc{parrish1987cretaceous3,
    author = "Parrish, J. T. et al",
    title = "Cretaceous vertebrates from Alaska - implications for dinosaur ecology",
    year = "1987",
    howpublished = "Geological Society of America, Abstracts with Programs, v. 19, no. 5, p. 326; Abstracts, 40th Annual Meeting, Rocky Mountain Section, GSA",
    note = "talkorigins\_source = {true}; raw\_reference = {Parrish, J. T. et al., 1987, Cretaceous vertebrates from Alaska - implications for dinosaur ecology: Geological Society of America, Abstracts with Programs, v. 19, no. 5, p. 326; Abstracts, 40th Annual Meeting, Rocky Mountain Section, GSA.}"
}

@article{parrish1987late,
    author = "Parrish, J. Michael and Parrish, Judith Totman and Hutchison, J. Howard and Spicer, Robert A.",
    title = "Late Cretaceous Vertebrate Fossils from the North Slope of Alaska and Implications for Dinosaur Ecology",
    year = "1987",
    journal = "PALAIOS",
    url = "https://doi.org/10.2307/3514763",
    doi = "10.2307/3514763",
    number = "4",
    openalex = "W2317865496",
    pages = "377",
    volume = "2",
    references = "davies1987duckbill, doi1010160012825283900016, doi101038274661a0, doi101038324148a0, doi101086284369, doi101086284406, doi101130spe40p1, doi101146annurevea05050177001535, doi1023071444927, doi1023072937268, doi102475ajs2628975, doi104095105049, doi105479si00963801361666197, openalexw2204429280"
}

@article{doi1010160198014989901441,
    author = "Martin, John H. and Gordon, R. Michael and Fitzwater, Steve E. and Broenkow, William W.",
    title = "Vertex: phytoplankton/iron studies in the Gulf of Alaska",
    year = "1989",
    journal = "Deep Sea Research Part A Oceanographic Research Papers",
    url = "https://doi.org/10.1016/0198-0149(89)90144-1",
    doi = "10.1016/0198-0149(89)90144-1",
    openalex = "W2030534042",
    references = "doi1010160016703764901292, doi1010160198014987900860, doi101038282677a0, doi101038316591a0, doi101038326655a0, doi101038329408a0, doi101038331341a0, doi1023072484419, doi1023073875, doi104319lo19671220196, openalexw1552913007"
}

@article{paul1989late,
    author = "Paul, Gregory S. and Parrish, J. T. and Parrish, J. M. and Hutchison, J. H. and Spicer, R. A.",
    title = "Late Cretaceous Vertebrate Fossils from the North Slope of Alaska and Implications for Dinosaur Ecology: Comment \& Reply",
    year = "1989",
    journal = "PALAIOS",
    url = "https://doi.org/10.2307/3514779",
    doi = "10.2307/3514779",
    number = "3",
    openalex = "W2330431635",
    pages = "298",
    volume = "4",
    references = "brouwers1987dinosaurs, doi101017s0022336000018862, doi101038333547a0, doi101126science23547931156, doi101126science239483510b, doi101126science239483511, doi10113000917613198614703pefcnp20co2, doi1011300091761319880160022lctvan23co2, doi1023071563593"
}

In primary succession following deglaciation at Glacier Bay, Alaska, we tested the hypothesis that the major effect of initial nitrogen—fixing colonizers is to facilitate establishment of late—successional dominants and that other possible causes of successional change (e.g., life history factors governing seed rain and competitive interactions among species) need not be invoked. Environment changed dramatically through the first 200 yr of succession. Soil organic matter increased 10—fold in the upper mineral soil with corresponding increases in soil moisture, total nitrogen (N), and capacity to support plant growth and declines in bulk density, pH, and total phosphorus (P). Plant growth in pioneer soils tended to be simultaneously limited by both N and P, as well as by unknown factors (perhaps lack of mycorrhizae), whereas only P limited growth in older soils. Light availability to seedlings declined through succession. Early—successional species (Epilobium latifolium, Dryas drummondii) had smaller seeds, younger age at first reproduction, shorter life—span, and shorter height at maturity than did mid—successional (alder, Alnus sinuata) and late—successional species (sitka spruce, Picea sitchensis). Seed rain of alder and spruce was negligible in the pioneer stage, increased prior to the stage in which a species was dominant, and was greatest in the stage in which a species dominated. Vegetation in each successional stage inhibited germination and initial establishment of sown alder and spruce seeds (except a tendency of the "black—crust") algal/microbial community in the pioneer stage to enhance survivorship). Removal of the surface litter layer generally enhanced germination and survivorship, particularly of alder. Comparisons of germination in the greenhouse and the field indicated that climatic or indirect vegetation effects (e.g., differential seed predation) and allelopathy also reduced germination and establishment in vegetated communities. Naturally occurring spruce seedlings grew most rapidly in the Dryas and alder stages and most slowly in the spruce stage. Similarly, growth of spruce seedlings transplanted into each successional stage was facilitated by the Dryas (nonsignificantly) and alder stages but inhibited by the spruce stage, relative to earlier successional stages. Facilitation of growth of natural and transplanted spruce seedlings by Dryas and alder stages was associated with higher N and P uptake and tissue nutrient concentrations, whereas nutrient uptake and concentration in spruce seedlings declined in the spruce stage. By contrast, transplanted alder seedlings grew rapidly and accumulated most nutrients in the pioneer stage and were strongly inhibited by subsequent stages. The facilitative effect of Dryas and alder comes primarily from inputs of organic matter and associated N. Addition of alder litter stimulated nutrient uptake and growth of transplanted spruce seedlings in the pioneer and Dryas stages, whereas shading had no effect on growth of spruce seedlings. Root trenching and planting of spruce near isolated alders indicated that, although the net effect of alder is facilitative, alder also inhibits growth of spruce seedlings through competition for soil resources. Strong root competition also occurs in the spruce stage. Alder competitively inhibits Dryas, primarily by shading but also through the physical and allelopathic effects of its litter. In general, both at Glacier Bay and elsewhere, life history traits determine the pattern of succession. Changes in competitive balance accompanying successional changes in environment provide the mechanism for changes in species dominance. Initial site conditions (and facilitation, where present) influence the rate of change and final state of community composition and productivity. We conclude that no single factor or mechanism fully accounts for primary succession at Glacier Bay.

@article{doi1023072937039,
    author = "Chapin, F. Stuart and Walker, Lawrence R. and Fastie, Christopher L. and Sharman, Lewis C.",
    title = "Mechanisms of Primary Succession Following Deglaciation at Glacier Bay, Alaska",
    year = "1994",
    journal = "Ecological Monographs",
    abstract = {In primary succession following deglaciation at Glacier Bay, Alaska, we tested the hypothesis that the major effect of initial nitrogen—fixing colonizers is to facilitate establishment of late—successional dominants and that other possible causes of successional change (e.g., life history factors governing seed rain and competitive interactions among species) need not be invoked. Environment changed dramatically through the first 200 yr of succession. Soil organic matter increased 10—fold in the upper mineral soil with corresponding increases in soil moisture, total nitrogen (N), and capacity to support plant growth and declines in bulk density, pH, and total phosphorus (P). Plant growth in pioneer soils tended to be simultaneously limited by both N and P, as well as by unknown factors (perhaps lack of mycorrhizae), whereas only P limited growth in older soils. Light availability to seedlings declined through succession. Early—successional species (Epilobium latifolium, Dryas drummondii) had smaller seeds, younger age at first reproduction, shorter life—span, and shorter height at maturity than did mid—successional (alder, Alnus sinuata) and late—successional species (sitka spruce, Picea sitchensis). Seed rain of alder and spruce was negligible in the pioneer stage, increased prior to the stage in which a species was dominant, and was greatest in the stage in which a species dominated. Vegetation in each successional stage inhibited germination and initial establishment of sown alder and spruce seeds (except a tendency of the "black—crust") algal/microbial community in the pioneer stage to enhance survivorship). Removal of the surface litter layer generally enhanced germination and survivorship, particularly of alder. Comparisons of germination in the greenhouse and the field indicated that climatic or indirect vegetation effects (e.g., differential seed predation) and allelopathy also reduced germination and establishment in vegetated communities. Naturally occurring spruce seedlings grew most rapidly in the Dryas and alder stages and most slowly in the spruce stage. Similarly, growth of spruce seedlings transplanted into each successional stage was facilitated by the Dryas (nonsignificantly) and alder stages but inhibited by the spruce stage, relative to earlier successional stages. Facilitation of growth of natural and transplanted spruce seedlings by Dryas and alder stages was associated with higher N and P uptake and tissue nutrient concentrations, whereas nutrient uptake and concentration in spruce seedlings declined in the spruce stage. By contrast, transplanted alder seedlings grew rapidly and accumulated most nutrients in the pioneer stage and were strongly inhibited by subsequent stages. The facilitative effect of Dryas and alder comes primarily from inputs of organic matter and associated N. Addition of alder litter stimulated nutrient uptake and growth of transplanted spruce seedlings in the pioneer and Dryas stages, whereas shading had no effect on growth of spruce seedlings. Root trenching and planting of spruce near isolated alders indicated that, although the net effect of alder is facilitative, alder also inhibits growth of spruce seedlings through competition for soil resources. Strong root competition also occurs in the spruce stage. Alder competitively inhibits Dryas, primarily by shading but also through the physical and allelopathic effects of its litter. In general, both at Glacier Bay and elsewhere, life history traits determine the pattern of succession. Changes in competitive balance accompanying successional changes in environment provide the mechanism for changes in species dominance. Initial site conditions (and facilitation, where present) influence the rate of change and final state of community composition and productivity. We conclude that no single factor or mechanism fully accounts for primary succession at Glacier Bay.},
    url = "https://doi.org/10.2307/2937039",
    doi = "10.2307/2937039",
    openalex = "W2068028745",
    references = "doi101007bf00002772, doi1010160016706176900665, doi101086283241, doi101126science1643877262, doi101146annureves10110179002031, doi1023071942484, doi1023071942661, doi1023071943075, doi1023072258728, doi1023074549, doi105962bhltitle56234"
}

The fine particle (<2.5 μm) composition data from seven National Park Service locations in Alaska for the period from 1986 to 1995 was performed using a new type of factor analysis, positive matrix factorization (PMF). This method uses the estimates of the error in the data to provide optimum data point scaling and permits a better treatment of missing and below detection limit values. Eight source components were obtained for data sets from the Northwest Alaska Areas and the Bering Land Bridge sites. Five to seven components were obtained for the other Alaskan sites. The solutions were normalized by using aerosol fine mass concentration data. Squared correlation coefficients between the reconstructed mass obtained from aerosol composition data for the sites and the measured mass were in the range of 0.74–0.95. Two factors identified as soils were obtained for all of the sites. Concentrations for these factors for most of the sites have maxima in the summer and minima in the winter. A sea‐salt component was found at five locations. A factor with the highest concentrations of black carbon (BC), H +, and K identified as forest fire smoke was obtained for all data sets except at Katmai. Factors with high concentrations of S, BC‐Na‐S, and Zn‐Cu were obtained at all sites. At three sites, the solutions also contained a factor with high Pb and Br values. The factors with the high S, Pb, and BC‐Na‐S values at most sites show an annual cycle with maxima during the winter‐spring season and minima in the summer. The seasonal variations and elemental compositions of these factors suggest anthropogenic origins with the spatial pattern suggesting that the sources are distant from the receptor sites. The seasonal maxima/minima ratios of these factors were higher for more northerly locations. Four main sources contribute to the observed concentrations at these locations: long‐range transported anthropogenic aerosol (Arctic haze aerosol), sea‐salt aerosol, local soil dust, and aerosol with high BC concentrations from regional forest fires or local wood smoke. A northwest to southeast negative gradient suggesting long‐range transport of air masses from regions north or northwest of Alaska dominated the spatial distribution of the high S factor concentrations.

@article{doi10102998jd01212,
    author = "Polissar, Alexandr V. and Hopke, Philip K. and Paatero, Pentti and Malm, William C. and Sisler, James F.",
    title = "Atmospheric aerosol over Alaska: 2. Elemental composition and sources",
    year = "1998",
    journal = "Journal of Geophysical Research Atmospheres",
    abstract = "The fine particle (<2.5 μm) composition data from seven National Park Service locations in Alaska for the period from 1986 to 1995 was performed using a new type of factor analysis, positive matrix factorization (PMF). This method uses the estimates of the error in the data to provide optimum data point scaling and permits a better treatment of missing and below detection limit values. Eight source components were obtained for data sets from the Northwest Alaska Areas and the Bering Land Bridge sites. Five to seven components were obtained for the other Alaskan sites. The solutions were normalized by using aerosol fine mass concentration data. Squared correlation coefficients between the reconstructed mass obtained from aerosol composition data for the sites and the measured mass were in the range of 0.74–0.95. Two factors identified as soils were obtained for all of the sites. Concentrations for these factors for most of the sites have maxima in the summer and minima in the winter. A sea‐salt component was found at five locations. A factor with the highest concentrations of black carbon (BC), H +, and K identified as forest fire smoke was obtained for all data sets except at Katmai. Factors with high concentrations of S, BC‐Na‐S, and Zn‐Cu were obtained at all sites. At three sites, the solutions also contained a factor with high Pb and Br values. The factors with the high S, Pb, and BC‐Na‐S values at most sites show an annual cycle with maxima during the winter‐spring season and minima in the summer. The seasonal variations and elemental compositions of these factors suggest anthropogenic origins with the spatial pattern suggesting that the sources are distant from the receptor sites. The seasonal maxima/minima ratios of these factors were higher for more northerly locations. Four main sources contribute to the observed concentrations at these locations: long‐range transported anthropogenic aerosol (Arctic haze aerosol), sea‐salt aerosol, local soil dust, and aerosol with high BC concentrations from regional forest fires or local wood smoke. A northwest to southeast negative gradient suggesting long‐range transport of air masses from regions north or northwest of Alaska dominated the spatial distribution of the high S factor concentrations.",
    url = "https://doi.org/10.1029/98jd01212",
    doi = "10.1029/98jd01212",
    openalex = "W2090680793",
    references = "doi101002env3170050203, doi1010160004698176902110, doi101016016974399380055m, doi1010160960168693901047, doi101016135223109400367t, doi101016s0169743996000445, doi101021es60162a006, doi10102993jd02916, doi1011751520047719950762403tahp20co2, openalexw1552913007"
}

We mapped the minimum magnitude of complete reporting, M c, for Alaska, the western United States, and for the JUNEC earthquake catalog of Japan. Mc was estimated based on its departure from the linear frequency-magnitude relation of the 250 closest earthquakes to grid nodes, spaced 10 km apart. In all catalogs studied, Mc was strongly heterogeneous. In offshore areas the Mc was typically one unit of magnitude higher than onshore. On land also, Mc can vary by one order of magnitude over distance less than 50 km. We recommend that seismicity studies that depend on complete sets of small earthquakes should be limited to areas with similar Mc, or the minimum magnitude for the analysis has to be raised to the highest com- mon value of Mc. We believe that the data quality, as reflected by the Mc level, should be used to define the spatial extent of seismicity studies where Mc plays a role. The method we use calculates the goodness of fit between a power law fit to the data and the observed frequency-magnitude distribution as a function of a lower cutoff of the magnitude data. Mc is defined as the magnitude at which 90% of the data can be modeled by a power law fit. Mc in the 1990s is approximately 1.2 0.4 in most parts of California, 1.8 0.4 in most of Alaska (Aleutians and Panhandle excluded), and at a higher level in the JUNEC catalog for Japan. Various sources, such as ex- plosions and earthquake families beneath volcanoes, can lead to distributions that cannot be fit well by power laws. For the Hokkaido region we demonstrate how neglecting the spatial variability of M c can lead to erroneous assumptions about deviations from self-similarity of earthquake scaling.

@article{doi1017850119990114,
    author = "Wiemer, Stefan",
    title = "Minimum Magnitude of Completeness in Earthquake Catalogs: Examples from Alaska, the Western United States, and Japan",
    year = "2000",
    journal = "Bulletin of the Seismological Society of America",
    abstract = "We mapped the minimum magnitude of complete reporting, M c, for Alaska, the western United States, and for the JUNEC earthquake catalog of Japan. Mc was estimated based on its departure from the linear frequency-magnitude relation of the 250 closest earthquakes to grid nodes, spaced 10 km apart. In all catalogs studied, Mc was strongly heterogeneous. In offshore areas the Mc was typically one unit of magnitude higher than onshore. On land also, Mc can vary by one order of magnitude over distance less than 50 km. We recommend that seismicity studies that depend on complete sets of small earthquakes should be limited to areas with similar Mc, or the minimum magnitude for the analysis has to be raised to the highest com- mon value of Mc. We believe that the data quality, as reflected by the Mc level, should be used to define the spatial extent of seismicity studies where Mc plays a role. The method we use calculates the goodness of fit between a power law fit to the data and the observed frequency-magnitude distribution as a function of a lower cutoff of the magnitude data. Mc is defined as the magnitude at which 90\% of the data can be modeled by a power law fit. Mc in the 1990s is approximately 1.2 0.4 in most parts of California, 1.8 0.4 in most of Alaska (Aleutians and Panhandle excluded), and at a higher level in the JUNEC catalog for Japan. Various sources, such as ex- plosions and earthquake families beneath volcanoes, can lead to distributions that cannot be fit well by power laws. For the Hokkaido region we demonstrate how neglecting the spatial variability of M c can lead to erroneous assumptions about deviations from self-similarity of earthquake scaling.",
    url = "https://doi.org/10.1785/0119990114",
    doi = "10.1785/0119990114",
    openalex = "W2163379050",
    references = "doi101007s000240050275, doi101007s000240050276, doi10102992jb01891, doi10102997jb00726, doi101038337251a0, doi10150830000033631, doi101785bssa0340040185, doi101785bssa0720051677, doi101785bssa0730030831, openalexw2908218553"
}

We have used airborne laser altimetry to estimate volume changes of 67 glaciers in Alaska from the mid-1950s to the mid-1990s. The average rate of thickness change of these glaciers was -0.52 m/year. Extrapolation to all glaciers in Alaska yields an estimated total annual volume change of -52 +/- 15 km3/year (water equivalent), equivalent to a rise in sea level (SLE) of 0.14 +/- 0.04 mm/year. Repeat measurements of 28 glaciers from the mid-1990s to 2000-2001 suggest an increased average rate of thinning, -1.8 m/year. This leads to an extrapolated annual volume loss from Alaska glaciers equal to -96 +/- 35 km3/year, or 0.27 +/- 0.10 mm/year SLE, during the past decade. These recent losses are nearly double the estimated annual loss from the entire Greenland Ice Sheet during the same time period and are much higher than previously published loss estimates for Alaska glaciers. They form the largest glaciological contribution to rising sea level yet measured.

@article{doi101126science1072497,
    author = "Arendt, A. A. and Echelmeyer, Κ. A. and Harrison, William D. and Lingle, Craig S. and Valentine, V. B.",
    title = "Rapid Wastage of Alaska Glaciers and Their Contribution to Rising Sea Level",
    year = "2002",
    journal = "Science",
    abstract = "We have used airborne laser altimetry to estimate volume changes of 67 glaciers in Alaska from the mid-1950s to the mid-1990s. The average rate of thickness change of these glaciers was -0.52 m/year. Extrapolation to all glaciers in Alaska yields an estimated total annual volume change of -52 +/- 15 km3/year (water equivalent), equivalent to a rise in sea level (SLE) of 0.14 +/- 0.04 mm/year. Repeat measurements of 28 glaciers from the mid-1990s to 2000-2001 suggest an increased average rate of thinning, -1.8 m/year. This leads to an extrapolated annual volume loss from Alaska glaciers equal to -96 +/- 35 km3/year, or 0.27 +/- 0.10 mm/year SLE, during the past decade. These recent losses are nearly double the estimated annual loss from the entire Greenland Ice Sheet during the same time period and are much higher than previously published loss estimates for Alaska glaciers. They form the largest glaciological contribution to rising sea level yet measured.",
    url = "https://doi.org/10.1126/science.1072497",
    doi = "10.1126/science.1072497",
    openalex = "W1995028739",
    references = "doi101017s0022143000002410, doi101017s002214300000928x, doi10103835119, doi101073pnas9741406, doi101126science1063556, doi101126science22646811418, doi101126science2895478428, doi1011751520044219980112161cvacim20co2, doi1023071551986, openalexw3162929933"
}

Synopsis The dinosaurs of the Hateg Basin of Transylvania (late Maastrichtian; western Romania) include Theropoda, Sauropoda, Ornithopoda and Ankylosauria. Of these, one of the most enigmatic taxa is the ornithopod that Franz Baron Nopcsa originally described as Mochlodon suessi and M. robustus in 1902. These two species have come to be regarded as a single species of Rhabdodon, R. robustus, which is distinct from R. priscus from the Late Cretaceous of southern France and northern Spain. This study provides a detailed anatomical revision of the Rhabdodon material that was described originally by Nopcsa during the early decades of the 20th century. It also adds information on material discovered in the Hateg area of Romania since the 1930s. A phylogenetic analysis of basal euornithopods indicates that the non‐hadrosaurid material from Hateg comprises two distinct, but congeneric, species. These two species can be distinguished unambiguously from R. priscus. A new genus Zalmoxes is established for the Romanian ornithopod, comprising Z. robustus comb. nov. (the type‐species of the genus) and Z. shqiperorum sp. nov. Phylogenetic analysis indicates that the two species of Zalmoxes and R. priscus are united in the monophyletic clade Rhabdodontidae (nov.). Rhabdodontidae constitutes the sibling clade to Iguanodontia. R. septimanicus, M. suessi, and the Villeveyrac Rhabdodon also appear to be members of Rhabdodontidae. The evolutionary implications of this phylogenetic analysis include the recognition of a ghost lineage, extending from the most recent common ancestor of Rhabdodontidae and Iguanodontia, which extends for 73 million years. This extraordinarily long ghost lineage duration may reflect considerable gaps in the history of this group or the geographical isolation of Rhabdodontidae in Europe during much of the Cretaceous period. The area of origin of the Rhabdodontidae + Iguanodontia clade may be North America, while the common ancestor of Rhabdodontidae dispersed to Europe, at that time a marine‐dominated region with tectonically‐active terrestrial habitats. Adult individuals of Z. robustus are smaller than either of its two closest relatives, Z. shqiperorum and R. priscus, within the Rhabdodontidae, or with many species of Iguanodontia and, therefore, is considered a possible paedomorphic dwarf.

@article{doi101017s1477201903001032,
    author = "Weishampel, David B. and Jianu, Coralia‐Maria and Csiki‐Sava, Zoltán and Norman, David",
    title = "Osteology and phylogeny of Zalmoxes (n. g.), an unusual Euornithopod dinosaur from the latest Cretaceous of Romania",
    year = "2003",
    journal = "Journal of Systematic Palaeontology",
    abstract = "Synopsis The dinosaurs of the Hateg Basin of Transylvania (late Maastrichtian; western Romania) include Theropoda, Sauropoda, Ornithopoda and Ankylosauria. Of these, one of the most enigmatic taxa is the ornithopod that Franz Baron Nopcsa originally described as Mochlodon suessi and M. robustus in 1902. These two species have come to be regarded as a single species of Rhabdodon, R. robustus, which is distinct from R. priscus from the Late Cretaceous of southern France and northern Spain. This study provides a detailed anatomical revision of the Rhabdodon material that was described originally by Nopcsa during the early decades of the 20th century. It also adds information on material discovered in the Hateg area of Romania since the 1930s. A phylogenetic analysis of basal euornithopods indicates that the non‐hadrosaurid material from Hateg comprises two distinct, but congeneric, species. These two species can be distinguished unambiguously from R. priscus. A new genus Zalmoxes is established for the Romanian ornithopod, comprising Z. robustus comb. nov. (the type‐species of the genus) and Z. shqiperorum sp. nov. Phylogenetic analysis indicates that the two species of Zalmoxes and R. priscus are united in the monophyletic clade Rhabdodontidae (nov.). Rhabdodontidae constitutes the sibling clade to Iguanodontia. R. septimanicus, M. suessi, and the Villeveyrac Rhabdodon also appear to be members of Rhabdodontidae. The evolutionary implications of this phylogenetic analysis include the recognition of a ghost lineage, extending from the most recent common ancestor of Rhabdodontidae and Iguanodontia, which extends for 73 million years. This extraordinarily long ghost lineage duration may reflect considerable gaps in the history of this group or the geographical isolation of Rhabdodontidae in Europe during much of the Cretaceous period. The area of origin of the Rhabdodontidae + Iguanodontia clade may be North America, while the common ancestor of Rhabdodontidae dispersed to Europe, at that time a marine‐dominated region with tectonically‐active terrestrial habitats. Adult individuals of Z. robustus are smaller than either of its two closest relatives, Z. shqiperorum and R. priscus, within the Rhabdodontidae, or with many species of Iguanodontia and, therefore, is considered a possible paedomorphic dwarf.",
    url = "https://doi.org/10.1017/s1477201903001032",
    doi = "10.1017/s1477201903001032",
    openalex = "W2167550757",
    references = "doi10100797836426953391, doi10103835059070, doi10108002724634199010011815, doi101086284406, doi101098rspl18870117, doi101111j109636421998tb02533x, doi101126science27352791204, doi102307jctvxkn7tk, doi102475ajss321125417, doi105479si00963801361666197, openalexw51761775, openalexw575814759"
}

@article{fiorillo2004the,
    author = "Fiorillo, Anthony R.",
    title = "The Dinosaurs of Arctic Alaska",
    year = "2004",
    journal = "Scientific American",
    url = "https://doi.org/10.1038/scientificamerican1204-84",
    doi = "10.1038/scientificamerican1204-84",
    number = "6",
    openalex = "W2001396577",
    pages = "84-91",
    volume = "291"
}

@article{doi101007s1058400553522,
    author = "Hinzman, L. D. and Bettez, Neil D. and Bolton, William and Chapin, F. Stuart and Dyurgerov, Mark B. and Fastie, Chris L. and Griffith, Brad and Hollister, Robert D. and Hope, Allen and Huntington, Henry P. and Jensen, Anne M. and Jia, Gensuo and Jorgenson, T. and Kane, D. L. and Klein, David R. and Kofinas, Gary P. and Lynch, Amanda H. and Lloyd, Andrea H. and McGuire, A. David and Nelson, Frederick E. and Oechel, Walter C. and Osterkamp, Thomas E. and Racine, Charles H. and Romanovsky, V. E. and Stone, Robert S. and Stow, Douglas A. and Sturm, Matthew and Tweedie, C. E. and Vourlitis, George L. and Walker, Marilyn D. and Walker, Donald A. and Webber, Patrick J. and Welker, J. M. and Winker, Kevin and Yoshikawa, Kenji",
    title = "Evidence and Implications of Recent Climate Change in Northern Alaska and Other Arctic Regions",
    year = "2005",
    journal = "Climatic Change",
    url = "https://doi.org/10.1007/s10584-005-5352-2",
    doi = "10.1007/s10584-005-5352-2",
    openalex = "W2109692532",
    references = "doi101023a1005504031923, doi101023a1005667424292, doi1010292000jd000115, doi10103835079180, doi101038361520a0, doi101038386698a0, doi10108001431168608948945, doi101126science1072497, doi101126science1077445, doi101126science2344777689, doi101126science27853411251, doi101126science28954851743, doi1023071939337, doi102307210739, openalexw158363710"
}

Drawing on experiences across Fourth World contexts, with an emphasis on the Alaska context, this article seeks to extend our understandings of the learning processes within and at the intersection of diverse worldviews and knowledge systems. We outline the rationale for a comprehensive program of educational initiatives closely articulated with the emergence of a new generation of Indigenous scholars who seek to move the role of Indigenous knowledge and learning from the margins to the center of educational research, thereby confronting some of the most intractable and salient educational issues of our times.

@article{doi101525aeq2005361008,
    author = "Barnhardt, Ray and Kawagley, Angayuqaq Oscar",
    title = "Indigenous Knowledge Systems and Alaska Native Ways of Knowing",
    year = "2005",
    journal = "Anthropology \& Education Quarterly",
    abstract = "Drawing on experiences across Fourth World contexts, with an emphasis on the Alaska context, this article seeks to extend our understandings of the learning processes within and at the intersection of diverse worldviews and knowledge systems. We outline the rationale for a comprehensive program of educational initiatives closely articulated with the emergence of a new generation of Indigenous scholars who seek to move the role of Indigenous knowledge and learning from the margins to the center of educational research, thereby confronting some of the most intractable and salient educational issues of our times.",
    url = "https://doi.org/10.1525/aeq.2005.36.1.008",
    doi = "10.1525/aeq.2005.36.1.008",
    openalex = "W1981410738",
    references = "doi101177003172170208300806, doi1015159780822390831023, doi10218329781800418868012, doi1023071521798, doi1023072653993, doi1031020013189x032004003, doi1031020013189x032005019, openalexw1590609196, openalexw605475727, openalexw639149875"
}

Even though the arctic zone of continuous permafrost has relatively cold mean annual air temperatures, we found an abrupt, large increase in the extent of permafrost degradation in northern Alaska since 1982, associated with record warm temperatures during 1989–1998. Our field studies revealed that the recent degradation has mainly occurred to massive wedges of ice that previously had been stable for 1000s of years. Analysis of airphotos from 1945, 1982, and 2001 revealed large increases in the area (0.5%, 0.6%, and 4.4% of area, respectively) and density (88, 128, and 1336 pits/km 2) of degrading ice wedges in two study areas on the arctic coastal plain. Spectral analysis across a broader landscape found that newly degraded, water‐filled pits covered 3.8% of the land area. These results indicate that thermokarst potentially can affect 10–30% of arctic lowland landscapes and severely alter tundra ecosystems even under scenarios of modest climate warming.

@article{doi1010292005gl024960,
    author = "Jorgenson, M. Torre and Shur, Y. and Pullman, Erik R.",
    title = "Abrupt increase in permafrost degradation in Arctic Alaska",
    year = "2006",
    journal = "Geophysical Research Letters",
    abstract = "Even though the arctic zone of continuous permafrost has relatively cold mean annual air temperatures, we found an abrupt, large increase in the extent of permafrost degradation in northern Alaska since 1982, associated with record warm temperatures during 1989–1998. Our field studies revealed that the recent degradation has mainly occurred to massive wedges of ice that previously had been stable for 1000s of years. Analysis of airphotos from 1945, 1982, and 2001 revealed large increases in the area (0.5\%, 0.6\%, and 4.4\% of area, respectively) and density (88, 128, and 1336 pits/km 2) of degrading ice wedges in two study areas on the arctic coastal plain. Spectral analysis across a broader landscape found that newly degraded, water‐filled pits covered 3.8\% of the land area. These results indicate that thermokarst potentially can affect 10–30\% of arctic lowland landscapes and severely alter tundra ecosystems even under scenarios of modest climate warming.",
    url = "https://doi.org/10.1029/2005gl024960",
    doi = "10.1029/2005gl024960",
    openalex = "W2042994920",
    references = "doi101002ppp3430010104, doi101007bf01093225, doi101023a1005667424292, doi10103835073746, doi101111j160005871982tb01034x, doi101126science2344777689, doi101130spe70, doi101130spe70p1, doi101139e04031, doi10230720033020, doi103133pp109"
}

Abstract One expected response to climate warming in the Arctic is an increase in the abundance and extent of shrubs in tundra areas. Repeat photography shows that there has been an increase in shrub cover over the past 50 years in northern Alaska. Using 202 pairs of old and new oblique aerial photographs, we have found that across this region spanning 620 km east to west and 350 km north to south, alder, willow, and dwarf birch have been increasing, with the change most easily detected on hill slopes and valley bottoms. Plot and remote sensing studies from the same region using the normalized difference vegetation index are consistent with the photographic results and indicate that the smaller shrubs between valleys are also increasing. In Canada, Scandinavia, and parts of Russia, there is both plot and remote sensing evidence for shrub expansion. Combined with the Alaskan results, the evidence suggests that a pan‐Arctic vegetation transition is underway. If continued, this transition will alter the fundamental architecture and function of this ecosystem with important ramifications for the climate, the biota, and humans.

@article{doi101111j13652486200601128x,
    author = "Tape, Ken D. and Sturm, Matthew and Racine, Charles H.",
    title = "The evidence for shrub expansion in Northern Alaska and the Pan‐Arctic",
    year = "2006",
    journal = "Global Change Biology",
    abstract = "Abstract One expected response to climate warming in the Arctic is an increase in the abundance and extent of shrubs in tundra areas. Repeat photography shows that there has been an increase in shrub cover over the past 50 years in northern Alaska. Using 202 pairs of old and new oblique aerial photographs, we have found that across this region spanning 620 km east to west and 350 km north to south, alder, willow, and dwarf birch have been increasing, with the change most easily detected on hill slopes and valley bottoms. Plot and remote sensing studies from the same region using the normalized difference vegetation index are consistent with the photographic results and indicate that the smaller shrubs between valleys are also increasing. In Canada, Scandinavia, and parts of Russia, there is both plot and remote sensing evidence for shrub expansion. Combined with the Alaskan results, the evidence suggests that a pan‐Arctic vegetation transition is underway. If continued, this transition will alter the fundamental architecture and function of this ecosystem with important ramifications for the climate, the biota, and humans.",
    url = "https://doi.org/10.1111/j.1365-2486.2006.01128.x",
    doi = "10.1111/j.1365-2486.2006.01128.x",
    openalex = "W2127849277",
    references = "doi101007s1058400553522, doi101023a1005504031923, doi1010292000jd000115, doi10103835079180, doi101038386698a0, doi101038nature02887, doi10108001431168608948944, doi101126science1072497, doi101126science27853411251, doi1023071939337, doi1023072259051"
}

Cretaceous polar dinosaur faunas were taxonomically diverse, which suggests varied strategies for coping with the climatic stress of high latitudes. Some polar dinosaurs, particularly larger taxa such as the duckbill Edmontosaurus Lambe, 1917, were biomechanically and energetically capable of migrating over long distances, up to 2600 km. However, current evidence strongly suggests many polar dinosaurs (including sauropods, large and small theropods, and ankylosaurs of New Zealand) overwintered in preference to migration. Certain groups also appear more predisposed to overwintering based on their physical inability (related to biomechanics, natural history, or absolute size) to migrate, such as ankylosaurs and many small taxa, including hypsilophodontids and troodontids. Lownutrient subsistence is found to be the best overwintering method overall, although the likelihood that other taxa employed alternative means remains plausible. Despite wide distribution of some genera, species-level identification is required to assess the applicability of such distributions to migration distances. Presently, such resolution is not available or contradicts the migration hypothesis.

@article{doi10108003115510802096101,
    author = "Bell, Phil R. and Snively, Eric",
    title = "Polar dinosaurs on parade: a review of dinosaur migration",
    year = "2008",
    journal = "Alcheringa An Australasian Journal of Palaeontology",
    abstract = "Cretaceous polar dinosaur faunas were taxonomically diverse, which suggests varied strategies for coping with the climatic stress of high latitudes. Some polar dinosaurs, particularly larger taxa such as the duckbill Edmontosaurus Lambe, 1917, were biomechanically and energetically capable of migrating over long distances, up to 2600 km. However, current evidence strongly suggests many polar dinosaurs (including sauropods, large and small theropods, and ankylosaurs of New Zealand) overwintered in preference to migration. Certain groups also appear more predisposed to overwintering based on their physical inability (related to biomechanics, natural history, or absolute size) to migrate, such as ankylosaurs and many small taxa, including hypsilophodontids and troodontids. Lownutrient subsistence is found to be the best overwintering method overall, although the likelihood that other taxa employed alternative means remains plausible. Despite wide distribution of some genera, species-level identification is required to assess the applicability of such distributions to migration distances. Presently, such resolution is not available or contradicts the migration hypothesis.",
    url = "https://doi.org/10.1080/03115510802096101",
    doi = "10.1080/03115510802096101",
    openalex = "W2075814369",
    references = "fiorillo2004the"
}

Fossils within accreted terranes are typically used to describe the age or origin of the exotic geologic blocks. However, accretion may also provide new pathways for faunal exchange between previously disconnected landmasses. One such landmass, the result of accretion, is Beringia, that entity encompassing northeastern Asia and northwestern North America and the surmised land connection between the two regions.

@incollection{doi101130200844215,
    author = "Fiorillo, Anthony R.",
    title = "Dinosaurs of Alaska: Implications for the Cretaceous origin of Beringia",
    year = "2008",
    booktitle = "Geological Society of America eBooks",
    abstract = "Fossils within accreted terranes are typically used to describe the age or origin of the exotic geologic blocks. However, accretion may also provide new pathways for faunal exchange between previously disconnected landmasses. One such landmass, the result of accretion, is Beringia, that entity encompassing northeastern Asia and northwestern North America and the surmised land connection between the two regions.",
    url = "https://doi.org/10.1130/2008.442(15)",
    doi = "10.1130/2008.442(15)",
    openalex = "W2345484674",
    references = "fiorillo2004the, openalexw2204429280"
}

Stable carbon and oxygen isotope ratios were measured for carbonate in samples of hadrosaurid tooth enamel and dentine, and gar scale ganoine and dentine from five geologically “contemporaneous“ (two-million-year resolution) and geographically distant late Campanian formations (Two Medicine, Dinosaur Park, Judith River, Kaiparowits, and Fruitland) in the Western Interior Basin. In all cases, isotopic offsets were observed between enamel and dentine from the same teeth, with dentine being characterized by higher and more variable carbon and oxygen isotope ratios. Isotopic offsets were also observed between gar ganoine and hadrosaur enamel in all sites analyzed. Both of these observations indicate that diagenetic overprinting of enamel isotope ratios did not entirely obfuscate primary signals. Decreases in carbon and oxygen isotope ratios were observed in hadrosaur enamel from east to west, and overlap in isotope ratios occurred only between two of the sampled sites (Dinosaur Park and Judith River Formations). The lack of isotopic overlap for enamel among localities could be due to diagenetic resetting of isotope ratios such that they reflect local groundwater effects rather than primary biogenic inputs. However, the large range in carbon isotope ratios, the consistent taxonomic offsets for enamel/ganoine data, and comparisons of enamel-dentine data from the same teeth all suggest that diagenesis is not the lone driver of the signal. In the absence of major alteration, the mostly likely explanation for the isotopic patterns observed is that hadrosaurids from the targeted formations were eating plants and drinking waters with distinct isotopic ratios. One implication of this reconstruction is that hadrosaurids in the Late Cretaceous of the Western Interior did not migrate to an extent that would obscure local isotopic signatures.

@article{doi101666080251,
    author = "Fricke, Henry and Rogers, Raymond R. and Gates, Terry A.",
    title = "Hadrosaurid migration: inferences based on stable isotope comparisons among Late Cretaceous dinosaur localities",
    year = "2009",
    journal = "Paleobiology",
    abstract = "Stable carbon and oxygen isotope ratios were measured for carbonate in samples of hadrosaurid tooth enamel and dentine, and gar scale ganoine and dentine from five geologically “contemporaneous“ (two-million-year resolution) and geographically distant late Campanian formations (Two Medicine, Dinosaur Park, Judith River, Kaiparowits, and Fruitland) in the Western Interior Basin. In all cases, isotopic offsets were observed between enamel and dentine from the same teeth, with dentine being characterized by higher and more variable carbon and oxygen isotope ratios. Isotopic offsets were also observed between gar ganoine and hadrosaur enamel in all sites analyzed. Both of these observations indicate that diagenetic overprinting of enamel isotope ratios did not entirely obfuscate primary signals. Decreases in carbon and oxygen isotope ratios were observed in hadrosaur enamel from east to west, and overlap in isotope ratios occurred only between two of the sampled sites (Dinosaur Park and Judith River Formations). The lack of isotopic overlap for enamel among localities could be due to diagenetic resetting of isotope ratios such that they reflect local groundwater effects rather than primary biogenic inputs. However, the large range in carbon isotope ratios, the consistent taxonomic offsets for enamel/ganoine data, and comparisons of enamel-dentine data from the same teeth all suggest that diagenesis is not the lone driver of the signal. In the absence of major alteration, the mostly likely explanation for the isotopic patterns observed is that hadrosaurids from the targeted formations were eating plants and drinking waters with distinct isotopic ratios. One implication of this reconstruction is that hadrosaurids in the Late Cretaceous of the Western Interior did not migrate to an extent that would obscure local isotopic signatures.",
    url = "https://doi.org/10.1666/08025.1",
    doi = "10.1666/08025.1",
    openalex = "W1992839242",
    references = "davies1987duckbill, doi1010160016703753900519, doi1010160016703778901990, doi1010160016703781902441, doi101111j215334901964tb00181x, doi101146annurevearth241225, doi101146annurevpp40060189002443, doi1023071310735, doi103402tellusav16i48993, fiorillo2004the, openalexw2912219260"
}

The Upper Cretaceous Cantwell Formation in Denali National Park and Preserve (DENA), Alaska, contains an unparalleled fossil avian biodiversity. The Cantwell Formation, thousands of metres thick, was deposited near its current latitude and is exposed throughout much of DENA and elsewhere in the central Alaska Range. The Formation comprises a lower, dominantly fluvial sedimentary unit and an upper, mostly volcanic unit. Sedimentation of the lower unit was mainly in alluvial fan, braided and meandering stream, and lacustrine environments, with possible marginal-marine influence at times. Pollen data suggest that these sedimentary rocks are late Campanian or early Maastrichtian in age; thus the Cantwell Formation is correlative with other well-known dinosaur localities in Alaska. Bird tracks are preserved in multiple locations along a 40-km transect in DENA in fluvial and lacustrine deposits. Some bird tracks are found in association with dinosaur tracks and others are found on beds interbedded with dinosaur track-bearing layers. The approximate body sizes of the birds based on tracks show a range from sparrow- to heron-sized birds (∼25–30% larger than the modern Sandhill Crane Grus canadensis). The Cantwell Formation contains footprints assigned to several ichnotaxa found in either Asia or North America based on such morphological criteria as the presence or absence of a hallux, print size and shape, and angle of divarication: Aquatilavipes swiboldae, Ignotornis mcconnelli, Magnoavipes denaliensis sp. nov., Gruipeda vegrandiunus sp. nov. and Uhangrichnus chuni. The presence of a mixed Asian and North American ichnofauna suggests that at least some birds used Alaska as a bridge between Asia and North America. This diverse assemblage of avian traces, combined with the known fossil bone record and invertebrate trace fossil record, demonstrates that the northern Late Cretaceous polar region contained significant biodiversity.

@article{doi101080147720192010509356,
    author = "Fiorillo, Anthony R. and Hasiotis, Stephen T. and Kobayashi, Yoshitsugu and Breithaupt, Brent H. and McCarthy, Paul J.",
    title = "Bird tracks from the Upper Cretaceous Cantwell Formation of Denali National Park, Alaska, USA: a new perspective on ancient northern polar vertebrate biodiversity",
    year = "2011",
    journal = "Journal of Systematic Palaeontology",
    abstract = "The Upper Cretaceous Cantwell Formation in Denali National Park and Preserve (DENA), Alaska, contains an unparalleled fossil avian biodiversity. The Cantwell Formation, thousands of metres thick, was deposited near its current latitude and is exposed throughout much of DENA and elsewhere in the central Alaska Range. The Formation comprises a lower, dominantly fluvial sedimentary unit and an upper, mostly volcanic unit. Sedimentation of the lower unit was mainly in alluvial fan, braided and meandering stream, and lacustrine environments, with possible marginal-marine influence at times. Pollen data suggest that these sedimentary rocks are late Campanian or early Maastrichtian in age; thus the Cantwell Formation is correlative with other well-known dinosaur localities in Alaska. Bird tracks are preserved in multiple locations along a 40-km transect in DENA in fluvial and lacustrine deposits. Some bird tracks are found in association with dinosaur tracks and others are found on beds interbedded with dinosaur track-bearing layers. The approximate body sizes of the birds based on tracks show a range from sparrow- to heron-sized birds (∼25–30\% larger than the modern Sandhill Crane Grus canadensis). The Cantwell Formation contains footprints assigned to several ichnotaxa found in either Asia or North America based on such morphological criteria as the presence or absence of a hallux, print size and shape, and angle of divarication: Aquatilavipes swiboldae, Ignotornis mcconnelli, Magnoavipes denaliensis sp. nov., Gruipeda vegrandiunus sp. nov. and Uhangrichnus chuni. The presence of a mixed Asian and North American ichnofauna suggests that at least some birds used Alaska as a bridge between Asia and North America. This diverse assemblage of avian traces, combined with the known fossil bone record and invertebrate trace fossil record, demonstrates that the northern Late Cretaceous polar region contained significant biodiversity.",
    url = "https://doi.org/10.1080/14772019.2010.509356",
    doi = "10.1080/14772019.2010.509356",
    openalex = "W2025225522",
    references = "doi101016b9780123558602500302, doi101016jsedgeo200401006, doi101016s0277379100000998, doi10103820167, doi101038nature03150, doi101046j1365294x200301731x, doi1012060003009020042860001mptaso20co2, doi102110scn0651, doi1023071216157, fiorillo2004the, openalexw1535663436"
}

A diverse and prolific record of polar dinosaurs comes from the Upper Cretaceous (Campanian–Maastrichtian) sediments of the Prince Creek Formation exposed on Alaska’s North Slope. Previous assignment of basal ornithopod material from this formation has been based solely on teeth, which have either been referred to “hypsilophodontid” indet. or Thescelosaurus sp. Here, we re-examine this material and describe several new specimens, including five isolated premaxillary teeth and three cheek teeth. The premaxillary teeth are most similar to those of Thescelosaurus, whereas the cheek teeth are more similar to its sister taxon Parksosaurus, for which premaxillary teeth are unknown. Referral of this new material to Thescelosaurus would represent the oldest occurrence of this taxon and considerably extend its stratigraphic range. A more likely possibility is that the premaxillary teeth are referable to Parksosaurus, an interpretation that is more parsimonious from a stratigraphic perspective. Intriguingly, one cheek tooth previously referred to as “hypsilophodontid” cannot be referred to either Thescelosaurus or Parksosaurus. Previously, faunal comparisons of the Prince Creek Formation have largely been made with non-contemporaneous formations, including the Campanian-aged Judith River and Aguja formations, or to the latest Maastrichtian Hell Creek Formation. On the basis of age and faunal similarities, a more appropriate comparison should be made with coeval rocks of the Horseshoe Canyon. This study expands our knowledge of Cretaceous ornithischian diversity at polar paleolatitudes and underscores the importance of small, rare, or easily misidentified fossils in paleoecological studies.

@article{doi101139e11017,
    author = "Brown, Caleb M. and Druckenmiller, Patrick S.",
    title = "Basal ornithopod (Dinosauria: Ornithischia) teeth from the Prince Creek Formation (early Maastrichtian) of Alaska",
    year = "2011",
    journal = "Canadian Journal of Earth Sciences",
    abstract = "A diverse and prolific record of polar dinosaurs comes from the Upper Cretaceous (Campanian–Maastrichtian) sediments of the Prince Creek Formation exposed on Alaska’s North Slope. Previous assignment of basal ornithopod material from this formation has been based solely on teeth, which have either been referred to “hypsilophodontid” indet. or Thescelosaurus sp. Here, we re-examine this material and describe several new specimens, including five isolated premaxillary teeth and three cheek teeth. The premaxillary teeth are most similar to those of Thescelosaurus, whereas the cheek teeth are more similar to its sister taxon Parksosaurus, for which premaxillary teeth are unknown. Referral of this new material to Thescelosaurus would represent the oldest occurrence of this taxon and considerably extend its stratigraphic range. A more likely possibility is that the premaxillary teeth are referable to Parksosaurus, an interpretation that is more parsimonious from a stratigraphic perspective. Intriguingly, one cheek tooth previously referred to as “hypsilophodontid” cannot be referred to either Thescelosaurus or Parksosaurus. Previously, faunal comparisons of the Prince Creek Formation have largely been made with non-contemporaneous formations, including the Campanian-aged Judith River and Aguja formations, or to the latest Maastrichtian Hell Creek Formation. On the basis of age and faunal similarities, a more appropriate comparison should be made with coeval rocks of the Horseshoe Canyon. This study expands our knowledge of Cretaceous ornithischian diversity at polar paleolatitudes and underscores the importance of small, rare, or easily misidentified fossils in paleoecological studies.",
    url = "https://doi.org/10.1139/e11-017",
    doi = "10.1139/e11-017",
    openalex = "W2069206841",
    references = "doi101017cbo9780511536045, doi101017cbo9780511608377011, doi101017s1477201907002271, doi101098rspl18870117, doi101126science239483510b, doi101127njgpa210199841, doi102475ajss319111253, doi102475ajss321125417, doi105962p313819, fiorillo2004the, openalexw2989049194, openalexw3215057009, paul1989late"
}

A paleontological reconnaissance survey on Cretaceous and Tertiary terrestrial units along the Yukon River drainage through much of east-central Alaska has provided new chronostratigraphic constraints for the units, paleoclimatological data, and the first information on the local biodiversity within an ancient, high latitude ecosystem. The studied unnamed rock unit is most notable for its historic economic gold placer deposits but our survey documents its relevance as a source-rock for Mesozoic terrestrial vertebrates, invertebrates and associated flora. Specifically, new U-Pb ages from detrital zircons combined with ichnological data are indicative of a Late Cretaceous age for at least the lower section of the studied rock unit, previously considered to be representative of nearly exclusively Tertiary deposition. Further, the results of our survey show that this sedimentary rock unit preserves the first record of dinosaurs in the vast east-central Alaska region. Lastly, paleobotanical data when compared to correlative rock units support previous interpretation that the Late Cretaceous continental ecosystem of Alaska was heterogeneous in nature and seasonal.

@article{doi102110palo2013054,
    author = "Fiorillo, Anthony R. and Fanti, Federico and Hults, Chad P. and Hasiotis, Stephen T.",
    title = "NEW ICHNOLOGICAL, PALEOBOTANICAL, AND DETRITAL ZIRCON DATA FROM AN UNNAMED ROCK UNIT IN YUKON-CHARLEY RIVERS NATIONAL PRESERVE (CRETACEOUS: ALASKA): STRATIGRAPHIC IMPLICATIONS FOR THE REGION",
    year = "2014",
    journal = "Palaios",
    abstract = "A paleontological reconnaissance survey on Cretaceous and Tertiary terrestrial units along the Yukon River drainage through much of east-central Alaska has provided new chronostratigraphic constraints for the units, paleoclimatological data, and the first information on the local biodiversity within an ancient, high latitude ecosystem. The studied unnamed rock unit is most notable for its historic economic gold placer deposits but our survey documents its relevance as a source-rock for Mesozoic terrestrial vertebrates, invertebrates and associated flora. Specifically, new U-Pb ages from detrital zircons combined with ichnological data are indicative of a Late Cretaceous age for at least the lower section of the studied rock unit, previously considered to be representative of nearly exclusively Tertiary deposition. Further, the results of our survey show that this sedimentary rock unit preserves the first record of dinosaurs in the vast east-central Alaska region. Lastly, paleobotanical data when compared to correlative rock units support previous interpretation that the Late Cretaceous continental ecosystem of Alaska was heterogeneous in nature and seasonal.",
    url = "https://doi.org/10.2110/palo.2013.054",
    doi = "10.2110/palo.2013.054",
    openalex = "W2153385453",
    references = "fiorillo2004the, openalexw2204429280"
}

@article{fiorillo2014herd,
    author = "Fiorillo, Anthony R. and Hasiotis, Stephen T. and Kobayashi, Yoshitsugu",
    title = "Herd structure in Late Cretaceous polar dinosaurs: A remarkable new dinosaur tracksite, Denali National Park, Alaska, USA",
    year = "2014",
    journal = "Geology",
    url = "https://doi.org/10.1130/g35740.1",
    doi = "10.1130/g35740.1",
    number = "8",
    openalex = "W2133418367",
    pages = "719-722",
    volume = "42",
    references = "doi1010160006320794903379, doi1010160169534789900438, doi101016b9780126906479x50005, doi101016c20090026695, doi101016jpalaeo201002029, doi101017cbo9780511565441, doi10103835086558, doi101080147720192010509356, doi101098rspb20080912, doi1011300813723604333, doi1016710272463420000200115lbhoth20co2, doi102110palo2009p09103r, openalexw1993129830"
}

For the first time a dinosaur track site is identified in Maastrichtian paleopolar coastal plain deposits of the Prince Creek Formation (PCF) along the Colville River, North Slope of Alaska. Tracks were made and preserved by trampling of an ash-covered swamp margin, subsequent filling of tracks with alluvium from nearby rivers, and modification of sediments by pedogensis. Tracks are grouped into three classes based on track width and depth, with the largest tracks (>800 mm wide) recording overstepping by multiple individuals. As no bedding plane views of the tracks are present, the true shapes of the tracks were not available and, thus, a high probability of identification is not achievable. The tracks can be interpreted, however, using hypothetical-deductive reasoning by integrating paleontological and ichnological data from local and regional outcrops. The tracks likely represent the presence of hadrosaurs based on the overwhelming percentage of hadrosaur fossils that comprise nearby bonebeds, dominated by juvenile hadrosaurs (∼ 99%); to date no adult hadrosaur bone has been documented in the PCF. This interpretation is also supported by comparison of PCF hadrosaur track dimensions to exquisitely preserved (three-dimensional tracks with skin impressions) trackways of the coeval Cantwell Formation in Denali National Park (DENA), central Alaska. PCF track size dimensions, in comparison to DENA tracks, also represent a series of growth stages including both juvenile and adult hadrosaurs, and indicate that multiple generations and sizes of individuals lived and traveled together on the Arctic Alaska coastal plain. This is the first evidence for adult hadrosaurs in the PCF. This track site also preserves the highest latitude Maastrichtian footprints known.

@article{doi1010801042094020171337011,
    author = "Flaig, Peter P. and Hasiotis, Stephen T. and Fiorillo, Anthony R.",
    title = "A Paleopolar Dinosaur Track Site in the Cretaceous (Maastrichtian) Prince Creek Formation of Arctic Alaska: Track Characteristics and Probable Trackmakers",
    year = "2017",
    journal = "Ichnos/Ichnos : an international journal for plant and animal traces",
    abstract = "For the first time a dinosaur track site is identified in Maastrichtian paleopolar coastal plain deposits of the Prince Creek Formation (PCF) along the Colville River, North Slope of Alaska. Tracks were made and preserved by trampling of an ash-covered swamp margin, subsequent filling of tracks with alluvium from nearby rivers, and modification of sediments by pedogensis. Tracks are grouped into three classes based on track width and depth, with the largest tracks (>800 mm wide) recording overstepping by multiple individuals. As no bedding plane views of the tracks are present, the true shapes of the tracks were not available and, thus, a high probability of identification is not achievable. The tracks can be interpreted, however, using hypothetical-deductive reasoning by integrating paleontological and ichnological data from local and regional outcrops. The tracks likely represent the presence of hadrosaurs based on the overwhelming percentage of hadrosaur fossils that comprise nearby bonebeds, dominated by juvenile hadrosaurs (∼ 99\%); to date no adult hadrosaur bone has been documented in the PCF. This interpretation is also supported by comparison of PCF hadrosaur track dimensions to exquisitely preserved (three-dimensional tracks with skin impressions) trackways of the coeval Cantwell Formation in Denali National Park (DENA), central Alaska. PCF track size dimensions, in comparison to DENA tracks, also represent a series of growth stages including both juvenile and adult hadrosaurs, and indicate that multiple generations and sizes of individuals lived and traveled together on the Arctic Alaska coastal plain. This is the first evidence for adult hadrosaurs in the PCF. This track site also preserves the highest latitude Maastrichtian footprints known.",
    url = "https://doi.org/10.1080/10420940.2017.1337011",
    doi = "10.1080/10420940.2017.1337011",
    openalex = "W2736106342",
    references = "doi101016jpalaeo201002029, doi101016s0031018202006892, doi101080147720192010509356, doi102110palo2009p09103r, doi104202app001522015, doi104202app20110033, fiorillo2014herd"
}

Abstract The Alaska Range suture zone exposes Cretaceous to Quaternary marine and nonmarine sedimentary and volcanic rocks sandwiched between oceanic rocks of the accreted Wrangellia composite terrane to the south and older continental terranes to the north. New U-Pb zircon ages, 40Ar/39Ar, ZHe, and AFT cooling ages, geochemical compositions, and geological field observations from these rocks provide improved constraints on the timing of Cretaceous to Miocene magmatism, sedimentation, and deformation within the collisional suture zone. Our results bear on the unclear displacement history of the seismically active Denali fault, which bisects the suture zone. Newly identified tuffs north of the Denali fault in sedimentary strata of the Cantwell Formation yield ca. 72 to ca. 68 Ma U-Pb zircon ages. Lavas sampled south of the Denali fault yield ca. 69 Ma 40Ar/39Ar ages and geochemical compositions typical of arc assemblages, ranging from basalt-andesite-trachyte, relatively high-K, and high concentrations of incompatible elements attributed to slab contribution (e.g., high Cs, Ba, and Th). The Late Cretaceous lavas and bentonites, together with regionally extensive coeval calc-alkaline plutons, record arc magmatism during contractional deformation and metamorphism within the suture zone. Latest Cretaceous volcanic and sedimentary strata are locally overlain by Eocene Teklanika Formation volcanic rocks with geochemical compositions transitional between arc and intraplate affinity. New detrital-zircon data from the modern Teklanika River indicate peak Teklanika volcanism at ca. 57 Ma, which is also reflected in zircon Pb loss in Cantwell Formation bentonites. Teklanika Formation volcanism may reflect hypothesized slab break-off and a Paleocene–Eocene period of a transform margin configuration. Mafic dike swarms were emplaced along the Denali fault from ca. 38 to ca. 25 Ma based on new 40Ar/39Ar ages. Diking along the Denali fault may have been localized by strike-slip extension following a change in direction of the subducting oceanic plate beneath southern Alaska from N-NE to NW at ca. 46–40 Ma. Diking represents the last recorded episode of significant magmatism in the central and eastern Alaska Range, including along the Denali fault. Two tectonic models may explain emplacement of more primitive and less extensive Eocene–Oligocene magmas: delamination of the Late Cretaceous–Paleocene arc root and/or thickened suture zone lithosphere, or a slab window created during possible Paleocene slab break-off. Fluvial strata exposed just south of the Denali fault in the central Alaska Range record synorogenic sedimentation coeval with diking and inferred strike-slip displacement. Deposition occurred ca. 29 Ma based on palynomorphs and the youngest detrital zircons. U-Pb detrital-zircon geochronology and clast compositional data indicate the fluvial strata were derived from sedimentary and igneous bedrock presently exposed within the Alaska Range, including Cretaceous sources presently exposed on the opposite (north) side of the fault. The provenance data may indicate ∼150 km or more of dextral offset of the ca. 29 Ma strata from inferred sediment sources, but different amounts of slip are feasible. Together, the dike swarms and fluvial strata are interpreted to record Oligocene strike-slip movement along the Denali fault system, coeval with strike-slip basin development along other segments of the fault. Diking and sedimentation occurred just prior to the onset of rapid and persistent exhumation ca. 25 Ma across the Alaska Range. This phase of reactivation of the suture zone is interpreted to reflect the translation along and convergence of southern Alaska across the Denali fault driven by highly coupled flat-slab subduction of the Yakutat microplate, which continues to accrete to the southern margin of Alaska. Furthermore, a change in Pacific plate direction and velocity at ca. 25 Ma created a more convergent regime along the apex of the Denali fault curve, likely contributing to the shutting off of near-fault extension-facilitated arc magmatism along this section of the fault system and increased exhumation rates.

@article{doi101130ges020141,
    author = "Trop, Jeffrey M. and Benowitz, Jeffrey A. and Cole, Ronald B. and O’Sullivan, Paul",
    title = "Cretaceous to Miocene magmatism, sedimentation, and exhumation within the Alaska Range suture zone: A polyphase reactivated terrane boundary",
    year = "2019",
    journal = "Geosphere",
    abstract = "Abstract The Alaska Range suture zone exposes Cretaceous to Quaternary marine and nonmarine sedimentary and volcanic rocks sandwiched between oceanic rocks of the accreted Wrangellia composite terrane to the south and older continental terranes to the north. New U-Pb zircon ages, 40Ar/39Ar, ZHe, and AFT cooling ages, geochemical compositions, and geological field observations from these rocks provide improved constraints on the timing of Cretaceous to Miocene magmatism, sedimentation, and deformation within the collisional suture zone. Our results bear on the unclear displacement history of the seismically active Denali fault, which bisects the suture zone. Newly identified tuffs north of the Denali fault in sedimentary strata of the Cantwell Formation yield ca. 72 to ca. 68 Ma U-Pb zircon ages. Lavas sampled south of the Denali fault yield ca. 69 Ma 40Ar/39Ar ages and geochemical compositions typical of arc assemblages, ranging from basalt-andesite-trachyte, relatively high-K, and high concentrations of incompatible elements attributed to slab contribution (e.g., high Cs, Ba, and Th). The Late Cretaceous lavas and bentonites, together with regionally extensive coeval calc-alkaline plutons, record arc magmatism during contractional deformation and metamorphism within the suture zone. Latest Cretaceous volcanic and sedimentary strata are locally overlain by Eocene Teklanika Formation volcanic rocks with geochemical compositions transitional between arc and intraplate affinity. New detrital-zircon data from the modern Teklanika River indicate peak Teklanika volcanism at ca. 57 Ma, which is also reflected in zircon Pb loss in Cantwell Formation bentonites. Teklanika Formation volcanism may reflect hypothesized slab break-off and a Paleocene–Eocene period of a transform margin configuration. Mafic dike swarms were emplaced along the Denali fault from ca. 38 to ca. 25 Ma based on new 40Ar/39Ar ages. Diking along the Denali fault may have been localized by strike-slip extension following a change in direction of the subducting oceanic plate beneath southern Alaska from N-NE to NW at ca. 46–40 Ma. Diking represents the last recorded episode of significant magmatism in the central and eastern Alaska Range, including along the Denali fault. Two tectonic models may explain emplacement of more primitive and less extensive Eocene–Oligocene magmas: delamination of the Late Cretaceous–Paleocene arc root and/or thickened suture zone lithosphere, or a slab window created during possible Paleocene slab break-off. Fluvial strata exposed just south of the Denali fault in the central Alaska Range record synorogenic sedimentation coeval with diking and inferred strike-slip displacement. Deposition occurred ca. 29 Ma based on palynomorphs and the youngest detrital zircons. U-Pb detrital-zircon geochronology and clast compositional data indicate the fluvial strata were derived from sedimentary and igneous bedrock presently exposed within the Alaska Range, including Cretaceous sources presently exposed on the opposite (north) side of the fault. The provenance data may indicate ∼150 km or more of dextral offset of the ca. 29 Ma strata from inferred sediment sources, but different amounts of slip are feasible. Together, the dike swarms and fluvial strata are interpreted to record Oligocene strike-slip movement along the Denali fault system, coeval with strike-slip basin development along other segments of the fault. Diking and sedimentation occurred just prior to the onset of rapid and persistent exhumation ca. 25 Ma across the Alaska Range. This phase of reactivation of the suture zone is interpreted to reflect the translation along and convergence of southern Alaska across the Denali fault driven by highly coupled flat-slab subduction of the Yakutat microplate, which continues to accrete to the southern margin of Alaska. Furthermore, a change in Pacific plate direction and velocity at ca. 25 Ma created a more convergent regime along the apex of the Denali fault curve, likely contributing to the shutting off of near-fault extension-facilitated arc magmatism along this section of the fault system and increased exhumation rates.",
    url = "https://doi.org/10.1130/ges02014.1",
    doi = "10.1130/ges02014.1",
    openalex = "W2955122008",
    references = "doi101080147720192010509356, fiorillo2014herd"
}

Abstract Hadrosaurid dinosaurs, the dominant large-bodied terrestrial herbivores in most Laurasian Late Cretaceous ecosystems, have an exceptional fossil record consisting of many species known from partial ontogenetic series, making them an ideal clade with which to conduct life-history studies. Previous research considered the Dinosaur Park Formation (DPF) of Alberta as an attritional, or time-averaged, sample and interpreted size–frequency distribution of long bones collected from the DPF with three size classes to suggest that hadrosaurids from the DPF attained near-asymptotic body size in under 3 years. This conflicted with previously published osteohistological estimates of 6+ years for penecontemporaneous hadrosaurids from the Two Medicine Formation (TMF) of Montana, suggesting either extreme variation in hadrosaurid growth rates or that size–frequency distributions and/or osteohistology and growth modeling inaccurately estimate ontogenetic age. We tested the validity of the previously proposed size–age relationship of hadrosaurids from the DPF by significantly increasing sample size and combining data from size–frequency distributions and osteohistology across multiple long-bone elements. The newly constructed size–frequency distributions typically reveal four relatively distinct size–frequency peaks that, when integrated with the osteohistological data, aligned with growth marks. The yearling size class was heavily underrepresented in the size–frequency distribution. If not due to preservation, this suggests that either juvenile (<2 years of age) hadrosaurids from the DPF had increased survivorship following an initially high nestling mortality rate or that yearlings were segregated from adults. A growth-curve analysis revealed asymptotic body size was attained in approximately 7 years, which is consistent with hadrosaurids from the TMF. The data suggest size–frequency distributions of attritional samples underestimate age and overestimate growth rates, but when paired with osteohistology can provide unique life-history insights.

@article{doi101017pab20202,
    author = "Wosik, Mateusz and Chiba, Kentaro and Therrien, François and Evans, David C.",
    title = "Testing size–frequency distributions as a method of ontogenetic aging: a life-history assessment of hadrosaurid dinosaurs from the Dinosaur Park Formation of Alberta, Canada, with implications for hadrosaurid paleoecology",
    year = "2020",
    journal = "Paleobiology",
    abstract = "Abstract Hadrosaurid dinosaurs, the dominant large-bodied terrestrial herbivores in most Laurasian Late Cretaceous ecosystems, have an exceptional fossil record consisting of many species known from partial ontogenetic series, making them an ideal clade with which to conduct life-history studies. Previous research considered the Dinosaur Park Formation (DPF) of Alberta as an attritional, or time-averaged, sample and interpreted size–frequency distribution of long bones collected from the DPF with three size classes to suggest that hadrosaurids from the DPF attained near-asymptotic body size in under 3 years. This conflicted with previously published osteohistological estimates of 6+ years for penecontemporaneous hadrosaurids from the Two Medicine Formation (TMF) of Montana, suggesting either extreme variation in hadrosaurid growth rates or that size–frequency distributions and/or osteohistology and growth modeling inaccurately estimate ontogenetic age. We tested the validity of the previously proposed size–age relationship of hadrosaurids from the DPF by significantly increasing sample size and combining data from size–frequency distributions and osteohistology across multiple long-bone elements. The newly constructed size–frequency distributions typically reveal four relatively distinct size–frequency peaks that, when integrated with the osteohistological data, aligned with growth marks. The yearling size class was heavily underrepresented in the size–frequency distribution. If not due to preservation, this suggests that either juvenile (<2 years of age) hadrosaurids from the DPF had increased survivorship following an initially high nestling mortality rate or that yearlings were segregated from adults. A growth-curve analysis revealed asymptotic body size was attained in approximately 7 years, which is consistent with hadrosaurids from the TMF. The data suggest size–frequency distributions of attritional samples underestimate age and overestimate growth rates, but when paired with osteohistology can provide unique life-history insights.",
    url = "https://doi.org/10.1017/pab.2020.2",
    doi = "10.1017/pab.2020.2",
    openalex = "W3083774641",
    references = "doi1010079781489957405, doi101017cbo9780511608483, doi101017s1464793106007007, doi101029sc005p0175, doi101086284369, doi101086395888, doi101126science327542, doi101163156853974x00345, doi102113gsrocky8specialpaper11, doi1023073802723, doi104202app001522015"
}

Abstract The hadrosauroid Telmatosaurus and the rhabdodontid Zalmoxes were the first and second dinosaur taxa that were described in detail from the famous Upper Cretaceous continental deposits of the Haţeg Basin by Franz Baron Nopcsa at the beginning of the twentieth century. Although they are among the most common and best-known dinosaurs discovered from these deposits, there are still many open questions as to their taxonomy and anatomy. Here, we re-describe two partial braincases from the uppermost Cretaceous of the Haţeg Basin that have been recently referred to the rhabdodontid Zalmoxes and re-assign them to hadrosauroids, possibly to Telmatosaurus. These specimens both exhibit basicranial features that are characteristic of derived hadrosauroids but are absent in more basal iguanodontians. These include an antero-posteriorly short basioccipital lacking a distinct neck, the presence of two well-developed sphenoccipital tubercles on the ventral aspect of the braincase and that are directly positioned anterior to the basioccipital, as well as a deep depression on the ventral aspect of the braincase between the sphenoccipital tubercles. The comparison provided herein demonstrates several important differences between the basicranium of hadrosauroids and that of rhabdodontids, which allows for the confident identification of even isolated and incomplete specimens. Moreover, the removal of the only basicranium that has been referred to Zalmoxes shqiperorum prompts a revised diagnosis of that species.

@article{doi101007s1254202200621x,
    author = "Augustin, Felix J. and Dumbravă, Mihai D. and Bastiaans, Dylan and Csiki‐Sava, Zoltán",
    title = "Reappraisal of the braincase anatomy of the ornithopod dinosaurs Telmatosaurus and Zalmoxes from the Upper Cretaceous of the Haţeg Basin (Romania) and the taxonomic reassessment of some previously referred specimens",
    year = "2022",
    journal = "Paläontologische Zeitschrift",
    abstract = "Abstract The hadrosauroid Telmatosaurus and the rhabdodontid Zalmoxes were the first and second dinosaur taxa that were described in detail from the famous Upper Cretaceous continental deposits of the Haţeg Basin by Franz Baron Nopcsa at the beginning of the twentieth century. Although they are among the most common and best-known dinosaurs discovered from these deposits, there are still many open questions as to their taxonomy and anatomy. Here, we re-describe two partial braincases from the uppermost Cretaceous of the Haţeg Basin that have been recently referred to the rhabdodontid Zalmoxes and re-assign them to hadrosauroids, possibly to Telmatosaurus. These specimens both exhibit basicranial features that are characteristic of derived hadrosauroids but are absent in more basal iguanodontians. These include an antero-posteriorly short basioccipital lacking a distinct neck, the presence of two well-developed sphenoccipital tubercles on the ventral aspect of the braincase and that are directly positioned anterior to the basioccipital, as well as a deep depression on the ventral aspect of the braincase between the sphenoccipital tubercles. The comparison provided herein demonstrates several important differences between the basicranium of hadrosauroids and that of rhabdodontids, which allows for the confident identification of even isolated and incomplete specimens. Moreover, the removal of the only basicranium that has been referred to Zalmoxes shqiperorum prompts a revised diagnosis of that species.",
    url = "https://doi.org/10.1007/s12542-022-00621-x",
    doi = "10.1007/s12542-022-00621-x",
    openalex = "W4281787298",
    references = "doi104202app006982019"
}

A metatarsal IV from a hitherto unknown endemic small-bodied styracosternan is described from uppermost Maastrichtian strata of NE Spain, part of the Ibero-Armorican island of the Late Cretaceous European Archipelago. This element is unique among the fourth metatarsals of all other ornithopods in combining the greatly elongated proportions of basally branching members of the clade with the prominent medial flange seen in other styracosternans. This specimen becomes the holotype of a new genus and species. Histological data indicate that this individual was a late subadult at the time of death, but not far from reaching somatic maturity. By analogy with the elongate metatarsals of lightly built, small-bodied cursorial ornithopods, it is likely that this animal was also capable of rapid locomotion. This is consistent with the differential distribution of intense bone remodeling in metatarsal IV, likely resulting from biomechanical stress produced during rapid hindlimb propelling. Notably, this styracosternan represents an exception to the mediportality and large body size that characterize all other members of the clade. The elongation of metatarsal IV, inferred cursoriality, and small body size constitute a case of evolutionary convergence with the distantly related non-iguanodontian ornithopods and dryosaurid and elasmarian iguanodontians. Unlike other regions of the world where, during the latest stages of the Cretaceous, the small-bodied cursorial herbivore ecological niche was represented by non-iguanodontians and non-hadrosauriforms, in the Ibero-Armorican island this niche was likely occupied by a styracosternan.

@article{doi1010800272463420232210632,
    author = "Prieto‐Márquez, Albert and Sellés, Albert G.",
    title = "Evolutionary convergence in a small cursorial styracosternan ornithopod dinosaur from western Europe",
    year = "2022",
    journal = "Journal of Vertebrate Paleontology",
    abstract = "A metatarsal IV from a hitherto unknown endemic small-bodied styracosternan is described from uppermost Maastrichtian strata of NE Spain, part of the Ibero-Armorican island of the Late Cretaceous European Archipelago. This element is unique among the fourth metatarsals of all other ornithopods in combining the greatly elongated proportions of basally branching members of the clade with the prominent medial flange seen in other styracosternans. This specimen becomes the holotype of a new genus and species. Histological data indicate that this individual was a late subadult at the time of death, but not far from reaching somatic maturity. By analogy with the elongate metatarsals of lightly built, small-bodied cursorial ornithopods, it is likely that this animal was also capable of rapid locomotion. This is consistent with the differential distribution of intense bone remodeling in metatarsal IV, likely resulting from biomechanical stress produced during rapid hindlimb propelling. Notably, this styracosternan represents an exception to the mediportality and large body size that characterize all other members of the clade. The elongation of metatarsal IV, inferred cursoriality, and small body size constitute a case of evolutionary convergence with the distantly related non-iguanodontian ornithopods and dryosaurid and elasmarian iguanodontians. Unlike other regions of the world where, during the latest stages of the Cretaceous, the small-bodied cursorial herbivore ecological niche was represented by non-iguanodontians and non-hadrosauriforms, in the Ibero-Armorican island this niche was likely occupied by a styracosternan.",
    url = "https://doi.org/10.1080/02724634.2023.2210632",
    doi = "10.1080/02724634.2023.2210632",
    openalex = "W4381249017",
    references = "doi101038202234a0, doi101098rspl18870117, doi101111cla12160, doi101111j17550998201002924x, doi101146annurevanthro34081804120613, doi101371journalpbio1001853, doi1023072408678, doi1023072408870, doi102475ajss321125417, openalexw2894525608"
}

The Late Cretaceous (Maastrichtian) Ruth Mason Dinosaur Quarry (RMDQ) represents a monodominant Edmontosaurus annectens bonebed from the Hell Creek Formation of South Dakota and has been determined as a catastrophic death assemblage likely belonging to a single population, providing an ideal sample to investigate hadrosaurid growth and population dynamics. For this study, size-frequency distributions were constructed from linear measurements of long bones (humeri, femora, tibiae) from RMDQ that revealed five relatively distinct size classes along a generally right-skewed distribution, which is consistent with a catastrophic assemblage. To test the relationship between morphological size ranges and ontogenetic age classes, subsets from each size-frequency peak were transversely thin-sectioned at mid-diaphysis to conduct an ontogenetic age assessment based on growth marks and observations of the bone microstructure. When combining these independent datasets, growth marks aligned with size-frequency peaks, with the exclusion of the overlapping subadult-adult size range, indicating a strong size-age relationship in early ontogeny. A growth curve analysis of tibiae indicated that E. annectens exhibited a similar growth trajectory to the Campanian hadrosaurid Maiasaura, although attaining a much larger asymptotic body size by about 9 years of age, further suggesting that the clade as a whole may have inherited a similar growth strategy. This rich new dataset for E. annectens provides new perspectives on other hypotheses of hadrosaurid life history. When the RMDQ population was compared with size distributions from other hadrosaurid bonebed assemblages, juveniles (categorized as ages one and two) were either completely absent from or heavily underrepresented in the samples, providing support for the hypothesized segregation between juvenile and adult hadrosaurids. Osteohistological comparison with material from polar and temperate populations of Edmontosaurus revealed that previous conclusions correlating osteohistological growth patterns with the strength of environmental stressors were a result of sampling non-overlapping ontogenetic growth stages.

@article{doi101111joa13679,
    author = "Wosik, Mateusz and Evans, David C.",
    title = "Osteohistological and taphonomic life‐history assessment of Edmontosaurus annectens (Ornithischia: Hadrosauridae) from the Late Cretaceous (Maastrichtian) Ruth Mason dinosaur quarry, South Dakota, United States, with implication for ontogenetic segregation between juvenile and adult hadrosaurids",
    year = "2022",
    journal = "Journal of Anatomy",
    abstract = "The Late Cretaceous (Maastrichtian) Ruth Mason Dinosaur Quarry (RMDQ) represents a monodominant Edmontosaurus annectens bonebed from the Hell Creek Formation of South Dakota and has been determined as a catastrophic death assemblage likely belonging to a single population, providing an ideal sample to investigate hadrosaurid growth and population dynamics. For this study, size-frequency distributions were constructed from linear measurements of long bones (humeri, femora, tibiae) from RMDQ that revealed five relatively distinct size classes along a generally right-skewed distribution, which is consistent with a catastrophic assemblage. To test the relationship between morphological size ranges and ontogenetic age classes, subsets from each size-frequency peak were transversely thin-sectioned at mid-diaphysis to conduct an ontogenetic age assessment based on growth marks and observations of the bone microstructure. When combining these independent datasets, growth marks aligned with size-frequency peaks, with the exclusion of the overlapping subadult-adult size range, indicating a strong size-age relationship in early ontogeny. A growth curve analysis of tibiae indicated that E. annectens exhibited a similar growth trajectory to the Campanian hadrosaurid Maiasaura, although attaining a much larger asymptotic body size by about 9 years of age, further suggesting that the clade as a whole may have inherited a similar growth strategy. This rich new dataset for E. annectens provides new perspectives on other hypotheses of hadrosaurid life history. When the RMDQ population was compared with size distributions from other hadrosaurid bonebed assemblages, juveniles (categorized as ages one and two) were either completely absent from or heavily underrepresented in the samples, providing support for the hypothesized segregation between juvenile and adult hadrosaurids. Osteohistological comparison with material from polar and temperate populations of Edmontosaurus revealed that previous conclusions correlating osteohistological growth patterns with the strength of environmental stressors were a result of sampling non-overlapping ontogenetic growth stages.",
    url = "https://doi.org/10.1111/joa.13679",
    doi = "10.1111/joa.13679",
    openalex = "W4284889573",
    references = "doi101007s1082700901804, doi101017pab20202, doi101017s0094837300005820, doi101017s0094837300021308, doi10103835086558, doi101111joa13679, doi101162neco20071961503, doi101186174170071060, doi1016710272463420000200115lbhoth20co2, doi102113gsrocky8specialpaper11, doi1023073802723, doi10560219780801881206, doi107717peerj11290"
}

The Wapiti Formation of northwest Alberta and northeast British Columbia, Canada, preserves an Upper Cretaceous terrestrial vertebrate fauna that is latitudinally situated between those documented further north in Alaska and those from southern Alberta and the contiguous U.S.A. Therefore, the Wapiti Formation is important for identifying broad patterns in vertebrate ecology, diversity, and distribution across Laramidia during the latest Cretaceous. Tracksites are especially useful as they provide a range of palaeoecological, palaeoenvironmental, and behavioural data that are complementary to the skeletal record. Here, we describe the Tyrants Aisle locality, the largest in-situ tracksite known from the Wapiti Formation. The site occurs in the lower part of Unit 4 of the formation (~72.5 Ma, upper Campanian), exposed along the southern bank of the Redwillow River. More than 100 tracks are documented across at least three distinct track-bearing layers, which were deposited on an alluvial floodplain. Hadrosaurid tracks are most abundant, and are referable to Hadrosauropodus based on track width exceeding track length, broad digits, and rounded or bilobed heel margins. We suggest the hadrosaurid trackmaker was Edmontosaurus regalis based on stratigraphic context. Tyrannosaurids, probable troodontids, possible ornithomimids, and possible azhdarchid pterosaurs represent minor but notable elements of the ichnofauna, as the latter is unknown from skeletal remains within the Wapiti Formation, and all others are poorly represented. Possible social behaviour is inferred for some of the hadrosaurid and small theropod-like trackmakers based on trackway alignment, suitable spacing and consistent preservation. On a broad taxonomic level (i.e., family or above), ichnofaunal compositions indicate that hadrosaurids were palaeoecologically dominant across Laramidia during the late Campanian within both high-and low-latitude deposits, although the role of depositional environment requires further testing.

@article{doi101371journalpone0262824,
    author = "Enriquez, Nathan J. and Campione, Nicolás E. and White, Matt A. and Fanti, Federico and Sissons, Robin L. and Sullivan, Corwin and Vavrek, Matthew J. and Bell, Phil R.",
    title = "The dinosaur tracks of Tyrants Aisle: An Upper Cretaceous ichnofauna from Unit 4 of the Wapiti Formation (upper Campanian), Alberta, Canada",
    year = "2022",
    journal = "PLoS ONE",
    abstract = "The Wapiti Formation of northwest Alberta and northeast British Columbia, Canada, preserves an Upper Cretaceous terrestrial vertebrate fauna that is latitudinally situated between those documented further north in Alaska and those from southern Alberta and the contiguous U.S.A. Therefore, the Wapiti Formation is important for identifying broad patterns in vertebrate ecology, diversity, and distribution across Laramidia during the latest Cretaceous. Tracksites are especially useful as they provide a range of palaeoecological, palaeoenvironmental, and behavioural data that are complementary to the skeletal record. Here, we describe the Tyrants Aisle locality, the largest in-situ tracksite known from the Wapiti Formation. The site occurs in the lower part of Unit 4 of the formation (\textasciitilde 72.5 Ma, upper Campanian), exposed along the southern bank of the Redwillow River. More than 100 tracks are documented across at least three distinct track-bearing layers, which were deposited on an alluvial floodplain. Hadrosaurid tracks are most abundant, and are referable to Hadrosauropodus based on track width exceeding track length, broad digits, and rounded or bilobed heel margins. We suggest the hadrosaurid trackmaker was Edmontosaurus regalis based on stratigraphic context. Tyrannosaurids, probable troodontids, possible ornithomimids, and possible azhdarchid pterosaurs represent minor but notable elements of the ichnofauna, as the latter is unknown from skeletal remains within the Wapiti Formation, and all others are poorly represented. Possible social behaviour is inferred for some of the hadrosaurid and small theropod-like trackmakers based on trackway alignment, suitable spacing and consistent preservation. On a broad taxonomic level (i.e., family or above), ichnofaunal compositions indicate that hadrosaurids were palaeoecologically dominant across Laramidia during the late Campanian within both high-and low-latitude deposits, although the role of depositional environment requires further testing.",
    url = "https://doi.org/10.1371/journal.pone.0262824",
    doi = "10.1371/journal.pone.0262824",
    openalex = "W4210394626",
    references = "doi107717peerj11290, therrien2015dinosaur"
}

Abstract The near‐global distribution of hadrosaurid dinosaurs during the Cretaceous has been attributed to mastication, a behaviour commonly recognized as a mammalian adaptation. Its occurrence in a non‐mammalian lineage should be accompanied by the evolution of several morphological modifications associated with food acquisition and processing. This study investigated morphological variation in the dentary, a major element of the hadrosauroid lower jaw. Eighty‐four hadrosauroid dentaries were subjected to geometric morphometric and statistical analyses to investigate their taxonomic, ontogenetic, and individual variation. Results suggest increased food acquisition and processing efficiency in saurolophids through a complex pattern of evolutionary and growth‐related changes. The edentulous region grew longer relative to dentary length, allowing for food acquisition specialization anteriorly and processing posteriorly, and became ventrally directed, possibly associated with foraging low‐growing vegetation, especially in younger individuals. The saurolophid coronoid process became anteriorly directed and relatively more elongate, with an expanded apex, increasing moment arm length, with muscles pulling the jaw more posteriorly, increasing mechanical advantage. During growth, all hadrosauroids underwent anteroposterior dental battery elongation by the addition of teeth, and edentulous region ventralization decreased. The dental battery became deeper in saurolophids by increasing the number of teeth per tooth family. The increased coronoid process anterior inclination and relative edentulous region elongation in saurolophids are hypothesized to have evolved through hypermorphosis and/or acceleration, peramorphic heterochronic processes; the development of an anteroposteriorly shorter but dorsoventrally taller saurolophid dentary, is probably due to post‐displacement in dental battery elongation and edentulous region decreased ventral orientation, a paedomorphic heterochronic process.

@article{doi101111pala12674,
    author = "Söderblom, D. Fredrik K. and Blanco, Alejandro and Prieto‐Márquez, Albert and Campione, Nicolás E.",
    title = "The dentary of hadrosauroid dinosaurs: evolution through heterochrony",
    year = "2023",
    journal = "Palaeontology",
    abstract = "Abstract The near‐global distribution of hadrosaurid dinosaurs during the Cretaceous has been attributed to mastication, a behaviour commonly recognized as a mammalian adaptation. Its occurrence in a non‐mammalian lineage should be accompanied by the evolution of several morphological modifications associated with food acquisition and processing. This study investigated morphological variation in the dentary, a major element of the hadrosauroid lower jaw. Eighty‐four hadrosauroid dentaries were subjected to geometric morphometric and statistical analyses to investigate their taxonomic, ontogenetic, and individual variation. Results suggest increased food acquisition and processing efficiency in saurolophids through a complex pattern of evolutionary and growth‐related changes. The edentulous region grew longer relative to dentary length, allowing for food acquisition specialization anteriorly and processing posteriorly, and became ventrally directed, possibly associated with foraging low‐growing vegetation, especially in younger individuals. The saurolophid coronoid process became anteriorly directed and relatively more elongate, with an expanded apex, increasing moment arm length, with muscles pulling the jaw more posteriorly, increasing mechanical advantage. During growth, all hadrosauroids underwent anteroposterior dental battery elongation by the addition of teeth, and edentulous region ventralization decreased. The dental battery became deeper in saurolophids by increasing the number of teeth per tooth family. The increased coronoid process anterior inclination and relative edentulous region elongation in saurolophids are hypothesized to have evolved through hypermorphosis and/or acceleration, peramorphic heterochronic processes; the development of an anteroposteriorly shorter but dorsoventrally taller saurolophid dentary, is probably due to post‐displacement in dental battery elongation and edentulous region decreased ventral orientation, a paedomorphic heterochronic process.",
    url = "https://doi.org/10.1111/pala.12674",
    doi = "10.1111/pala.12674",
    openalex = "W4388200771",
    references = "doi101006nimg20010977, doi101017s0094837300006588, doi10108002724634199510011271, doi1011112041210x12035, doi1011112041210x13029, doi101111j1469185x1988tb00630x, doi101111j2041210x201100153x, doi101127njgpa210199841, doi101371journalpbio1001853, doi1023071378712"
}

In the dusk of the Mesozoic, advanced duck-billed dinosaurs (Hadrosauridae) were so successful that they likely outcompeted other herbivores, contributing to declines in dinosaur diversity. From Laurasia, hadrosaurids dispersed widely, colonizing Africa, South America, and, allegedly, Antarctica. Here, we present the first species of a duck-billed dinosaur from a subantarctic region, Gonkoken nanoi, of early Maastrichtian age in Magallanes, Chile. Unlike duckbills further north in Patagonia, Gonkoken descends from North American forms diverging shortly before the origin of Hadrosauridae. However, at the time, non-hadrosaurids in North America had become replaced by hadrosaurids. We propose that the ancestors of Gonkoken arrived earlier in South America and reached further south, into regions where hadrosaurids never arrived: All alleged subantarctic and Antarctic remains of hadrosaurids could belong to non-hadrosaurid duckbills like Gonkoken. Dinosaur faunas of the world underwent qualitatively different changes before the Cretaceous-Paleogene asteroid impact, which should be considered when discussing their possible vulnerability.

@article{doi101126sciadvadg2456,
    author = "Alarcón-Muñoz, Jhonatan and Vargas, Alexander O. and Püschel, Hans P. and Soto‐Acuña, Sergio and Manríquez, Leslie M.E. and Leppe, Marcelo and Kaluza, Jonatan and Milla, Verónica and Gutstein, Carolina S. and Palma-Liberona, José and Stinnesbeck, Wolfgang and Frey, Eberhard and Pino, Juan Pablo and Bajor, Dániel and Núñez, Elaine and Ortíz, Héctor and Rubilar-Rogers, David and Cruzado‐Caballero, Penélope",
    title = "Relict duck-billed dinosaurs survived into the last age of the dinosaurs in subantarctic Chile",
    year = "2023",
    journal = "Science Advances",
    abstract = "In the dusk of the Mesozoic, advanced duck-billed dinosaurs (Hadrosauridae) were so successful that they likely outcompeted other herbivores, contributing to declines in dinosaur diversity. From Laurasia, hadrosaurids dispersed widely, colonizing Africa, South America, and, allegedly, Antarctica. Here, we present the first species of a duck-billed dinosaur from a subantarctic region, Gonkoken nanoi, of early Maastrichtian age in Magallanes, Chile. Unlike duckbills further north in Patagonia, Gonkoken descends from North American forms diverging shortly before the origin of Hadrosauridae. However, at the time, non-hadrosaurids in North America had become replaced by hadrosaurids. We propose that the ancestors of Gonkoken arrived earlier in South America and reached further south, into regions where hadrosaurids never arrived: All alleged subantarctic and Antarctic remains of hadrosaurids could belong to non-hadrosaurid duckbills like Gonkoken. Dinosaur faunas of the world underwent qualitatively different changes before the Cretaceous-Paleogene asteroid impact, which should be considered when discussing their possible vulnerability.",
    url = "https://doi.org/10.1126/sciadv.adg2456",
    doi = "10.1126/sciadv.adg2456",
    openalex = "W4380989179",
    references = "doi101016jjsames2021103369, doi101038s41559021016515, doi101111cla12524, doi101371journalpone0045712, doi1016711110, doi104202app20110051, doi107717peerj11290, doi107717peerj12362, longrich2016a, tsogtbaatar2019a"
}

Dinosaurs have attracted varying degrees of scientific and public interest since their initial description in 1824. Interest has steadily increased, however, since the late 1960s when the Dinosaur Renaissance began, and when the Canadian Journal of Earth Sciences started to publish. Since then, there has been a feedback system (international in scope) promoting increased scientific activity and ever-increasing public attention. This has led to ever more dinosaur discoveries internationally; increased numbers of museums and parks displaying dinosaurs; more publications, blogs, and other media on dinosaurs; and (most importantly) increased numbers of people and institutions doing research on dinosaurs. About 30 new species of dinosaurs are now being described every year, adding to the more than 1000 species already known. Furthermore, it is now acknowledged by most biologists and palaeontologists that modern birds are the direct descendants of dinosaurs, and that they are classified as part of the Dinosauria. Recognizing that there are more than 11 000 species of living dinosaurs has given us a better understanding of many aspects of the biology of nonavian dinosaurs. Along with technological improvements, this has revealed new—and often surprising—facts about their anatomy (bones, soft tissues, and even colours), interrelationships, biomechanics, growth and variation, ecology, physiology, behaviour, and extinction. In spite of the intensity of research over the last six decades, there is no indication that the discovery of new species and new facts about their biology is slowing down. It is quite clear that there is still a lot to be learned!

@article{doi101139cjes20220131,
    author = "Currie, Philip J.",
    title = "Celebrating dinosaurs: their behaviour, evolution, growth, and physiology",
    year = "2023",
    journal = "Canadian Journal of Earth Sciences",
    abstract = "Dinosaurs have attracted varying degrees of scientific and public interest since their initial description in 1824. Interest has steadily increased, however, since the late 1960s when the Dinosaur Renaissance began, and when the Canadian Journal of Earth Sciences started to publish. Since then, there has been a feedback system (international in scope) promoting increased scientific activity and ever-increasing public attention. This has led to ever more dinosaur discoveries internationally; increased numbers of museums and parks displaying dinosaurs; more publications, blogs, and other media on dinosaurs; and (most importantly) increased numbers of people and institutions doing research on dinosaurs. About 30 new species of dinosaurs are now being described every year, adding to the more than 1000 species already known. Furthermore, it is now acknowledged by most biologists and palaeontologists that modern birds are the direct descendants of dinosaurs, and that they are classified as part of the Dinosauria. Recognizing that there are more than 11 000 species of living dinosaurs has given us a better understanding of many aspects of the biology of nonavian dinosaurs. Along with technological improvements, this has revealed new—and often surprising—facts about their anatomy (bones, soft tissues, and even colours), interrelationships, biomechanics, growth and variation, ecology, physiology, behaviour, and extinction. In spite of the intensity of research over the last six decades, there is no indication that the discovery of new species and new facts about their biology is slowing down. It is quite clear that there is still a lot to be learned!",
    url = "https://doi.org/10.1139/cjes-2022-0131",
    doi = "10.1139/cjes-2022-0131",
    openalex = "W4321453118",
    references = "crossref1998encyclopedia, doi101017s247526300000091x, doi101038001189d0, doi101038137179b0, doi10103831635, doi10103834356, doi105860choice326223, doi105860choice435902, openalexw1535663436, openalexw2527820321"
}

@article{doi101016jcretres2023105819,
    author = "Nikolov, Vladimir and Dochev, Docho and Brusatte, Stephen L.",
    title = "The ontogenetic status of a small hadrosauroid dinosaur from the uppermost Cretaceous of Bulgaria, and implications for the paleobiogeography and assembly of European island faunas",
    year = "2024",
    journal = "Cretaceous Research",
    url = "https://doi.org/10.1016/j.cretres.2023.105819",
    doi = "10.1016/j.cretres.2023.105819",
    openalex = "W4390480585",
    references = "doi101002ar25021"
}

@article{doi101016jcretres2024105983,
    author = "Alarcón-Muñoz, Jhonatan and Cruzado‐Caballero, Penélope and Vicencio-Campos, Omar and Bravo-Ortiz, Claudio and Bugueño, Erick Vargas and Bajor, Dániel and Suárez, Mario E. and Guevara, Juan Pablo and Vargas, Alexander O. and Rubilar-Rogers, David",
    title = "Lower Cretaceous iguanodontian dinosaurs from the southwestern margin of Gondwana",
    year = "2024",
    journal = "Cretaceous Research",
    url = "https://doi.org/10.1016/j.cretres.2024.105983",
    doi = "10.1016/j.cretres.2024.105983",
    openalex = "W4401662305",
    references = "doi101016jjsames2021103369, doi1010800891296320242318406, doi1022215etd202114769"
}

@article{doi101016jcretres2024105995,
    author = "Dai, Hui and Ma, Qingyu and Xiong, Can and Lin, Yu and Zeng, Hui and Tan, Chao and Wang, Jun and Zhang, Yuguang and Hai, Xing",
    title = "A new late-diverging non-hadrosaurid hadrosauroid (Dinosauria: Ornithopoda) from southwest China: Support for interchange of dinosaur faunas across East Asia during the Late Cretaceous",
    year = "2024",
    journal = "Cretaceous Research",
    url = "https://doi.org/10.1016/j.cretres.2024.105995",
    doi = "10.1016/j.cretres.2024.105995",
    openalex = "W4401931617",
    references = "doi101017s1477201903001032, doi1010800272463420212085111, doi101098rsos210127, doi101111j10960031200800217x, doi101111j10963642200900617x, doi101111pala12674, doi101127njgpa210199841, doi101130spe40p1, doi101146annurevearth251435, doi101371journalpone0045712, doi101371journalpone0175253, doi1023071005355, doi1023075209, openalexw3215057009, openalexw51761775, tsogtbaatar2019a"
}

@article{doi101016jcretres2024106075,
    author = "Navarro, Bruno A. and Giaretta, Ariovaldo A. and Fernandes, Marcelo Adorna and Carvalho, Alberto B. and Zaher, Hussam",
    title = "First dinosaur ichnofauna from the Bauru Group indicates Cenomanian–Turonian events led to an ‘Ornithischian Hiatus’ in the Upper Cretaceous of Southeast Brazil",
    year = "2024",
    journal = "Cretaceous Research",
    url = "https://doi.org/10.1016/j.cretres.2024.106075",
    doi = "10.1016/j.cretres.2024.106075",
    openalex = "W4405854590",
    references = "doi101016jjsames2021103369, doi101038s41598022155356, doi1010800891296320181516766, doi1010800891296320242318406"
}

In the Late Cretaceous, northern and southern hemispheres evolved distinct dinosaurian faunas. Titanosaurians and abelisaurids dominated the Gondwanan continents; hadrosaurids, ceratopsians and tyrannosaurs dominated North America and Asia. Recently, a lambeosaurine hadrosaurid, Ajnabia odysseus, was reported from the late Maastrichtian phosphates of the Oulad Abdoun Basin Morocco, suggesting dispersal between Laurasia and Gondwana. Here we report new fossils from the phosphates of Morocco showing lambeosaurines achieved high diversity in the late Maastrichtian of North Africa. A skull represents a new dwarf lambeosaurine, Minqaria bata. Minqaria resembles Ajnabia odysseus in size, but differs in the ventrally positioned jugal facet and sinusoidal toothrow. The animal is small, ~ 3.5 m long, but the fused braincase shows it was mature. A humerus and a femur belong to larger hadrosaurids, ~ 6 m long, implying at least three species coexisted. The diversity of hadrosaurids in Europe and Africa suggests a dispersal-driven radiation, with lambeosaurines diversifying to take advantage of low ornithischian diversity. African lambeosaurines are small compared to North American and Asia hadrosaurids however, perhaps due to competition with titanosaurians. Hadrosaurids are unknown from eastern Africa, suggesting Moroccan hadrosaurids may be part of a distinct insular fauna, and represent an island radiation.

@article{doi101038s41598024534479,
    author = "Longrich, Nicholas R. and Suberbiola, Xabier Pereda and Bardet, Nathalie and Jalil, Nour‐Eddine",
    title = "A new small duckbilled dinosaur (Hadrosauridae: Lambeosaurinae) from Morocco and dinosaur diversity in the late Maastrichtian of North Africa",
    year = "2024",
    journal = "Scientific Reports",
    abstract = "In the Late Cretaceous, northern and southern hemispheres evolved distinct dinosaurian faunas. Titanosaurians and abelisaurids dominated the Gondwanan continents; hadrosaurids, ceratopsians and tyrannosaurs dominated North America and Asia. Recently, a lambeosaurine hadrosaurid, Ajnabia odysseus, was reported from the late Maastrichtian phosphates of the Oulad Abdoun Basin Morocco, suggesting dispersal between Laurasia and Gondwana. Here we report new fossils from the phosphates of Morocco showing lambeosaurines achieved high diversity in the late Maastrichtian of North Africa. A skull represents a new dwarf lambeosaurine, Minqaria bata. Minqaria resembles Ajnabia odysseus in size, but differs in the ventrally positioned jugal facet and sinusoidal toothrow. The animal is small, \textasciitilde\ 3.5 m long, but the fused braincase shows it was mature. A humerus and a femur belong to larger hadrosaurids, \textasciitilde\ 6 m long, implying at least three species coexisted. The diversity of hadrosaurids in Europe and Africa suggests a dispersal-driven radiation, with lambeosaurines diversifying to take advantage of low ornithischian diversity. African lambeosaurines are small compared to North American and Asia hadrosaurids however, perhaps due to competition with titanosaurians. Hadrosaurids are unknown from eastern Africa, suggesting Moroccan hadrosaurids may be part of a distinct insular fauna, and represent an island radiation.",
    url = "https://doi.org/10.1038/s41598-024-53447-9",
    doi = "10.1038/s41598-024-53447-9",
    openalex = "W4391770790",
    references = "doi101016jgr201010005, doi101016jjsames2021103369, doi101371journalpone0175253, doi103390fossils2010001, doi104202app20110051, tsogtbaatar2019a"
}

Supposed dinosaur remains were collected between 1859 and 1906 in the Lower Cretaceous Recôncavo Basin (Northeast Brazil). Since these materials remained undescribed, and most were considered lost. Recently, some of these historical specimens were rediscovered in the Natural History Museum of London, providing an opportunity to revisit them after 160 years. The specimens come from five different sites, corresponding to the Massacará (Berriasian-Barremian) and Ilhas (Valanginian-Barremian) groups. Identified bones comprise mainly isolated vertebral centra from ornithopods, sauropods, and theropods. Appendicular remains include a theropod pedal phalanx, humerus, and distal half of a left femur with elasmarian affinities. Despite their fragmentary nature, these specimens represent the earliest dinosaur bones discovered in South America, enhancing our understanding of the Cretaceous dinosaur faunas in Northeast Brazil. The dinosaur assemblage in the Recôncavo Basin resembles coeval units in Northeast Brazil, such as the Rio do Peixe Basin, where ornithopods coexist with sauropods and theropods. This study confirms the presence of ornithischian dinosaurs in Brazil based on osteological evidence, expanding their biogeographic and temporal range before the continental rifting between South America and Africa. Additionally, these findings reinforce the fossiliferous potential of Cretaceous deposits in Bahia State, which have been underexplored since their initial discoveries.

@article{doi1010800891296320242318406,
    author = "Bandeira, Kamila L. N. and Navarro, Bruno A. and Pêgas, Rodrigo V. and Brilhante, Natan Santos and Brum, Arthur Souza and de Souza, Rafael Gomes and da Silva, Rafael Costa and Gallo, Valéria",
    title = "A reassessment of the historical fossil findings from Bahia State (Northeast Brazil) reveals a diversified dinosaur fauna in the Lower Cretaceous of South America",
    year = "2024",
    journal = "Historical Biology",
    abstract = "Supposed dinosaur remains were collected between 1859 and 1906 in the Lower Cretaceous Recôncavo Basin (Northeast Brazil). Since these materials remained undescribed, and most were considered lost. Recently, some of these historical specimens were rediscovered in the Natural History Museum of London, providing an opportunity to revisit them after 160 years. The specimens come from five different sites, corresponding to the Massacará (Berriasian-Barremian) and Ilhas (Valanginian-Barremian) groups. Identified bones comprise mainly isolated vertebral centra from ornithopods, sauropods, and theropods. Appendicular remains include a theropod pedal phalanx, humerus, and distal half of a left femur with elasmarian affinities. Despite their fragmentary nature, these specimens represent the earliest dinosaur bones discovered in South America, enhancing our understanding of the Cretaceous dinosaur faunas in Northeast Brazil. The dinosaur assemblage in the Recôncavo Basin resembles coeval units in Northeast Brazil, such as the Rio do Peixe Basin, where ornithopods coexist with sauropods and theropods. This study confirms the presence of ornithischian dinosaurs in Brazil based on osteological evidence, expanding their biogeographic and temporal range before the continental rifting between South America and Africa. Additionally, these findings reinforce the fossiliferous potential of Cretaceous deposits in Bahia State, which have been underexplored since their initial discoveries.",
    url = "https://doi.org/10.1080/08912963.2024.2318406",
    doi = "10.1080/08912963.2024.2318406",
    openalex = "W4394757978",
    references = "breeden2021the, doi101016jcretres201512004, doi101016jjsames2021103369, doi101038s41598022155356, doi101046j10963642200200029x, doi10108002724634199810011115, doi101098rspl18870117, doi101111cla12160, doi101111j109600311994tb00179x, doi101111pala12496, doi1023072802289, doi10230730135049, doi102475ajss31695411, doi104202app005402018, doi105281zenodo16171435, doi105852crpalevol2020v19a6, doi107717peerj12727, openalexw193970361"
}

Dinosaurs potentially originated in the mid-palaeolatitudes of Gondwana 245-235 million years ago (Ma) and may have been restricted to cooler, humid areas by low-latitude arid zones until climatic amelioration made northern dispersals feasible ca 215 Ma. However, this scenario is challenged by new Carnian Laurasian fossils and evidence that even the earliest dinosaurs had adaptations for arid conditions. After becoming globally distributed in the Early-Middle Jurassic (200-160 Ma), dinosaurs experienced vicariance driven by Pangaean fragmentation. Regional extinctions and trans-oceanic dispersals also played a role, and the formation of ephemeral land connections meant that older vicariance patterns were repeatedly overprinted by younger ones, creating a reticulate biogeographic history. Palaeoclimates shaped dispersal barriers and corridors, including filters that had differential effects on different types of dinosaurs. Dinosaurian biogeographic research faces many challenges, not the least of which is the patchiness of the fossil record. However, new fossils, extensive databasing and improved analytical methods help distinguish signal from noise and generate fresh perspectives. In the future, developing techniques for quantifying and ameliorating sampling biases and modelling the dispersal capacities of dinosaurs are likely to be two of the key components in our modern research programme.

@article{doi101098rsbl20240429,
    author = "Upchurch, Paul and Chiarenza, Alfio Alessandro",
    title = "A brief review of non-avian dinosaur biogeography: state-of-the-art and prospectus",
    year = "2024",
    journal = "Biology Letters",
    abstract = "Dinosaurs potentially originated in the mid-palaeolatitudes of Gondwana 245-235 million years ago (Ma) and may have been restricted to cooler, humid areas by low-latitude arid zones until climatic amelioration made northern dispersals feasible ca 215 Ma. However, this scenario is challenged by new Carnian Laurasian fossils and evidence that even the earliest dinosaurs had adaptations for arid conditions. After becoming globally distributed in the Early-Middle Jurassic (200-160 Ma), dinosaurs experienced vicariance driven by Pangaean fragmentation. Regional extinctions and trans-oceanic dispersals also played a role, and the formation of ephemeral land connections meant that older vicariance patterns were repeatedly overprinted by younger ones, creating a reticulate biogeographic history. Palaeoclimates shaped dispersal barriers and corridors, including filters that had differential effects on different types of dinosaurs. Dinosaurian biogeographic research faces many challenges, not the least of which is the patchiness of the fossil record. However, new fossils, extensive databasing and improved analytical methods help distinguish signal from noise and generate fresh perspectives. In the future, developing techniques for quantifying and ameliorating sampling biases and modelling the dispersal capacities of dinosaurs are likely to be two of the key components in our modern research programme.",
    url = "https://doi.org/10.1098/rsbl.2024.0429",
    doi = "10.1098/rsbl.2024.0429",
    openalex = "W4403856200",
    references = "chiarenza2024early, crossref1998encyclopedia, doi101016jcretres201603008, doi101016jcub202105041, doi101016jcub202111061, doi101016jearscirev201203002, doi101016jearscirev2023104537, doi101016jjsames2021103341, doi101016jpalaeo201602033, doi101017s1755691013000431, doi101038s41467018051281, doi101038s41559021016515, doi101038s4158602205133x, doi101038s41598020576677, doi101038s41598021837455, doi101073pnas2020778118, doi101080027246342010520779, doi1010800272463420232199810, doi1010800891296320201793979, doi1010800891296320242336992, doi10108010635150701883881, doi1010801477201920242345333, doi101086648217, doi101093sysbiosyu056, doi101098rsbl20180431, doi101111pala12496, doi101111pala12514, doi101126science1161833, doi101146annurevearth081320064052, doi101371journalpone0012553, doi101371journalpone0112055, doi101371journalpone0235078, doi1021425f55419694, doi1023072413039, doi1023073243019, doi1029920070860302, doi105860choice353642"
}

This study investigates the occurrence of osteomyelitis in non-avian dinosaurs, focusing on the Ibirá locality, a site with a high incidence of this pathological condition. We analyzed six new osteopathic sauropod specimens from the Upper Cretaceous of Brazil. The results revealed a relationship between infection and bone remodeling, denoted by various manifestations of reactive bone neoformation, including periosteal reaction. Healing tissues were not identified, which implies that the individuals died when the infection was still active. We described distinct manifestations of osteomyelitis with periosteal bone neoformation: (1) periosteal reaction within small circular protrusions; (2) ellipsoid protrusions in a fingerprint pattern; (3) enlarged protrusions both in height and area. This study underscores the importance of examining pathological conditions in extinct species to enhance our understanding of their physiology and interactions with their ancient environments.

@article{doi101002ar70003,
    author = "Aureliano, Tito and de Oliveira Almeida, Waltécio and Fernandes, Marcelo Adorna and Ghilardi, Aline M.",
    title = "Several occurrences of osteomyelitis in dinosaurs from a site in the Bauru Group, Cretaceous of Southeast Brazil",
    year = "2025",
    journal = "The Anatomical Record",
    abstract = "This study investigates the occurrence of osteomyelitis in non-avian dinosaurs, focusing on the Ibirá locality, a site with a high incidence of this pathological condition. We analyzed six new osteopathic sauropod specimens from the Upper Cretaceous of Brazil. The results revealed a relationship between infection and bone remodeling, denoted by various manifestations of reactive bone neoformation, including periosteal reaction. Healing tissues were not identified, which implies that the individuals died when the infection was still active. We described distinct manifestations of osteomyelitis with periosteal bone neoformation: (1) periosteal reaction within small circular protrusions; (2) ellipsoid protrusions in a fingerprint pattern; (3) enlarged protrusions both in height and area. This study underscores the importance of examining pathological conditions in extinct species to enhance our understanding of their physiology and interactions with their ancient environments.",
    url = "https://doi.org/10.1002/ar.70003",
    doi = "10.1002/ar.70003",
    openalex = "W4410923160",
    references = "doi101038s41598022057613, doi101098rsbl20230245, doi101111joa14053"
}

Recent fossil discoveries have cast considerable light on the palaeobiology of Megaraptora, a group of large-clawed carnivorous theropod dinosaurs known from Cretaceous deposits in Asia, Australia, and especially South America. Nevertheless, many important aspects of megaraptoran morphology and evolution remain poorly understood, due in large part to the fragmentary nature of most fossils of these theropods and the scarcity of anatomically overlapping skeletal elements among the known taxa. Here we report a previously unknown megaraptoran genus and species represented by a partially articulated partial skeleton recovered from an uppermost Cretaceous stratum of the Lago Colhué Huapi Formation of south-central Chubut Province in central Patagonia, Argentina. Pertaining to the derived megaraptoran subclade Megaraptoridae, the taxon is among the most completely represented and latest-surviving megaraptorans. Its stratigraphic occurrence indicates that these dinosaurs likely persisted to the Cretaceous/Palaeogene boundary; moreover, the preservation of a crocodyliform humerus between the dentaries of the new theropod may provide information on megaraptoran dietary preferences and feeding strategies. Megaraptorids appear to have been the apex predators in central and southern Patagonian palaeoecosystems approaching the end of the Cretaceous, in contrast to more northerly areas of South America where these niches were occupied by other non-avian theropod groups.

@article{doi101038s41467025637935,
    author = "Ibiricu, Lucio M. and Lamanna, Matthew C. and Álvarez, Bruno N. and Cerda, Ignacio A. and Caglianone, Julieta L. and Cardozo, Noelia V. and Luna, Marcelo and Martínez, Rubén D.",
    title = "Latest Cretaceous megaraptorid theropod dinosaur sheds light on megaraptoran evolution and palaeobiology",
    year = "2025",
    journal = "Nature Communications",
    abstract = "Recent fossil discoveries have cast considerable light on the palaeobiology of Megaraptora, a group of large-clawed carnivorous theropod dinosaurs known from Cretaceous deposits in Asia, Australia, and especially South America. Nevertheless, many important aspects of megaraptoran morphology and evolution remain poorly understood, due in large part to the fragmentary nature of most fossils of these theropods and the scarcity of anatomically overlapping skeletal elements among the known taxa. Here we report a previously unknown megaraptoran genus and species represented by a partially articulated partial skeleton recovered from an uppermost Cretaceous stratum of the Lago Colhué Huapi Formation of south-central Chubut Province in central Patagonia, Argentina. Pertaining to the derived megaraptoran subclade Megaraptoridae, the taxon is among the most completely represented and latest-surviving megaraptorans. Its stratigraphic occurrence indicates that these dinosaurs likely persisted to the Cretaceous/Palaeogene boundary; moreover, the preservation of a crocodyliform humerus between the dentaries of the new theropod may provide information on megaraptoran dietary preferences and feeding strategies. Megaraptorids appear to have been the apex predators in central and southern Patagonian palaeoecosystems approaching the end of the Cretaceous, in contrast to more northerly areas of South America where these niches were occupied by other non-avian theropod groups.",
    url = "https://doi.org/10.1038/s41467-025-63793-5",
    doi = "10.1038/s41467-025-63793-5",
    openalex = "W4414434589",
    references = "doi101016jjsames2021103369, doi1010800272463420242441903"
}