Spain

@article{glaessner1962precambrian,
    author = "GLAESSNER, M. F.",
    title = "PRE-CAMBRIAN FOSSILS",
    year = "1962",
    journal = "Biological Reviews",
    url = "https://doi.org/10.1111/j.1469-185x.1962.tb01470.x",
    doi = "10.1111/j.1469-185x.1962.tb01470.x",
    number = "4",
    pages = "467-493",
    volume = "37"
}

@incollection{legg1985trace,
    author = "LEGG, IAIN C.",
    title = "TRACE FOSSILS FROM A MIDDLE CAMBRIAN DELTAIC SEQUENCE, NORTH SPAIN",
    year = "1985",
    booktitle = "Biogenic Structures",
    url = "https://doi.org/10.2110/pec.85.35.0151",
    doi = "10.2110/pec.85.35.0151",
    pages = "151-165"
}

@article{mount1985early,
    author = "Mount, Jeffrey F. and Signer, P. W.",
    title = "Early Cambrian innovation in shallow subtidal environments: Paleoenvironments of Early Cambrian shelly fossils",
    year = "1985",
    journal = "Geology",
    url = "https://doi.org/10.1130/0091-7613(1985)13<730:eciiss>2.0.co;2",
    doi = "10.1130/0091-7613(1985)13<730:eciiss>2.0.co;2",
    number = "10",
    pages = "730",
    volume = "13"
}

@book{conwaymorris1986middle1,
    author = "Conway Morris, S. and Robinson, R. A",
    title = "Middle Cambrian priapulids and other soft-bodied fossils from Utah and Spain",
    year = "1986",
    publisher = "University of Kansas Paleontological Contributions; Paper 117",
    note = "talkorigins\_source = {true}; raw\_reference = {Conway Morris, S., and Robinson, R. A., 1986, Middle Cambrian priapulids and other soft-bodied fossils from Utah and Spain: University of Kansas Paleontological Contributions; Paper 117.}"
}

@article{sanz1988unusual,
    author = "Sanz, J.L. and Bonapartet, J.F. and Lacasa, A.",
    title = "Unusual Early Cretaceous birds from Spain",
    year = "1988",
    journal = "Nature",
    url = "https://doi.org/10.1038/331433a0",
    doi = "10.1038/331433a0",
    number = "6155",
    pages = "433-435",
    volume = "331"
}

@misc{sanz1988unusual2,
    author = "Sanz, J. L. and Bonaparte, J. F. and Lacasa, A",
    title = "Unusual Early Cretaceous birds from Spain",
    year = "1988",
    howpublished = "Nature, v. 331, p. 433-435",
    note = "talkorigins\_source = {true}; raw\_reference = {Sanz, J. L., Bonaparte, J. F., and Lacasa, A., 1988, Unusual Early Cretaceous birds from Spain: Nature, v. 331, p. 433-435.}"
}

@article{hagadorn2000early,
    author = "Hagadorn, James W. and Fedo, Christopher M. and Waggoner, Ben M.",
    title = "EARLY CAMBRIAN EDIACARAN-TYPE FOSSILS FROM CALIFORNIA",
    year = "2000",
    journal = "Journal of Paleontology",
    url = "https://doi.org/10.1666/0022-3360(2000)074<0731:ecetff>2.0.co;2",
    doi = "10.1666/0022-3360(2000)074<0731:ecetff>2.0.co;2",
    number = "4",
    pages = "731-740",
    volume = "74"
}

@article{zhang2008microborings,
    author = "Zhang, Xi-guang and Pratt, Brian R.",
    title = "Microborings in Early Cambrian phosphatic and phosphatized fossils",
    year = "2008",
    journal = "Palaeogeography, Palaeoclimatology, Palaeoecology",
    url = "https://doi.org/10.1016/j.palaeo.2008.06.015",
    doi = "10.1016/j.palaeo.2008.06.015",
    number = "3-4",
    pages = "185-195",
    volume = "267"
}

Diverse skeletal assemblage has been discovered in the Ediacaran/Cambrian strata of the Codos locality in NE Spain (Aragón, Cadenas Ibéricas). This assemblage includes at least seven genera, only three of which can be ascribed to known taxa. All the fossils are preserved in phosphate but their original microstructures are traceable by both elementary composition and microstructural features that are indicative for primary aragonite and high-magnesium calcite biomineralogies. Already these early skeletal fossils show sophisticated microstructures represented by heterogeneous multilayered composites to satisfy the requirements for better protection against both chemical dissolution and mechanical predator deterioration. The most common and best-preserved fossil, which is tubicolous Codositubulus grioensis gen. et sp. nov., is described here. The composition of the fossil assemblage and its stratigraphic position are indicative for the lowermost Terreneuvian (lower Cambrian) or even pre-Terreneuvian age of this fauna.

@article{gámezvintaned2018the,
    author = "GÁMEZ VINTANED, JOSÉ ANTONIO and LIÑÁN, ELADIO and NAVARRO, DAVID and ZHURAVLEV, ANDREY YU.",
    title = "The oldest Cambrian skeletal fossils of Spain (Cadenas Ibéricas, Aragón)",
    year = "2018",
    journal = "Geological Magazine",
    abstract = "Diverse skeletal assemblage has been discovered in the Ediacaran/Cambrian strata of the Codos locality in NE Spain (Aragón, Cadenas Ibéricas). This assemblage includes at least seven genera, only three of which can be ascribed to known taxa. All the fossils are preserved in phosphate but their original microstructures are traceable by both elementary composition and microstructural features that are indicative for primary aragonite and high-magnesium calcite biomineralogies. Already these early skeletal fossils show sophisticated microstructures represented by heterogeneous multilayered composites to satisfy the requirements for better protection against both chemical dissolution and mechanical predator deterioration. The most common and best-preserved fossil, which is tubicolous Codositubulus grioensis gen. et sp. nov., is described here. The composition of the fossil assemblage and its stratigraphic position are indicative for the lowermost Terreneuvian (lower Cambrian) or even pre-Terreneuvian age of this fauna.",
    url = "https://doi.org/10.1017/s0016756817000358",
    doi = "10.1017/s0016756817000358",
    number = "7",
    pages = "1465-1474",
    volume = "155"
}

—Preservation of soft-bodied organisms as casts is common in the Ediacaran fossil record and extremely rare in Cambrian rocks. Among the factors, limiting fossilization of soft tissues, there is bioturbation–sediment disturbance by burrowing organisms. It is the emergence of burrowing metazoans and associated sediment bioturbation that is thought to be one of the major causes for the disappearance of Ediacaran soft-bodied organisms from the fossil record around ~540 Ma. Here, we study an assemblage of fossils preserved as casts in the Fortunian carbonates of the Olenek Uplift (northeastern Siberian Platform) in association with a typical Fortunian ichnoassemblage. The overall morphology and preservation of the fossils reveal that they comprise microbially induced sedimentary structures and soft-bodied holdfasts. The latter are vaguely reminiscent of some Ediacaran holdfasts, though it is unlikely that they include their phylogenetic descendants. Three-dimensional preservation of the studied fossils was caused by authigenic crystallization of calcite and its further early-diagenetic dolomitization. Our study confirms the critical importance of specific environmental conditions ensuring preservation of soft-bodied organisms as three-dimensional molds and casts. This unique interplay of environmental factors became rare in the Cambrian Period, which was caused by intensification and expansion of bioturbation in marine basins.

@article{marusin2023preservation,
    author = "Marusin, V.V. and Bykova, N.V.",
    title = "Preservation of Soft-Bodied Organisms in Early Cambrian Carbonates",
    year = "2023",
    journal = "Russian Geology and Geophysics",
    abstract = "—Preservation of soft-bodied organisms as casts is common in the Ediacaran fossil record and extremely rare in Cambrian rocks. Among the factors, limiting fossilization of soft tissues, there is bioturbation–sediment disturbance by burrowing organisms. It is the emergence of burrowing metazoans and associated sediment bioturbation that is thought to be one of the major causes for the disappearance of Ediacaran soft-bodied organisms from the fossil record around \textasciitilde 540 Ma. Here, we study an assemblage of fossils preserved as casts in the Fortunian carbonates of the Olenek Uplift (northeastern Siberian Platform) in association with a typical Fortunian ichnoassemblage. The overall morphology and preservation of the fossils reveal that they comprise microbially induced sedimentary structures and soft-bodied holdfasts. The latter are vaguely reminiscent of some Ediacaran holdfasts, though it is unlikely that they include their phylogenetic descendants. Three-dimensional preservation of the studied fossils was caused by authigenic crystallization of calcite and its further early-diagenetic dolomitization. Our study confirms the critical importance of specific environmental conditions ensuring preservation of soft-bodied organisms as three-dimensional molds and casts. This unique interplay of environmental factors became rare in the Cambrian Period, which was caused by intensification and expansion of bioturbation in marine basins.",
    url = "https://doi.org/10.2113/rgg20234595",
    doi = "10.2113/rgg20234595",
    number = "10",
    pages = "1179-1195",
    volume = "64"
}

Сохранность мягкотелых организмов в виде слепков широко распространена в эдиакарской ископаемой летописи и встречается чрезвычайно редко в кембрии. Одним из факторов, негативно влияющих на сохранность мягких тканей, является биотурбация - перемешивание осадка роющими организмами. Именно появление зарывающихся билатерий и связанное с этим развитие биотурбации осадка рассматриваются в качестве одной из главных причин, приведших к исчезновению эдиакарских мягкотелых организмов около 540 млн лет. В рамках настоящего исследования нами изучены ископаемые остатки, сохранившиеся в виде слепков и отпечатков в карбонатных отложениях фортунского яруса кембрия Оленекского поднятия (северо-восток Сибирской платформы) в ассоциации с типичными для этого стратиграфического уровня ископаемыми следами жизнедеятельности. Общая морфология и сохранность этих остатков схожа с эдиакарскими органами прикрепления и микробиально-индуцированными осадочными текстурами. Объемная сохранность изученных остатков обусловлена аутигенной кристаллизацией кальцита и его дальнейшей раннедиагенетической доломитизацией. Хотя верхние интервалы слоев и были умеренно- и интенсивно биотурбированы, нижние интервалы, к которым и приурочены остатки, практически не перемешивались роющими организмами. Наше исследование подтверждает критическую важность специфических условий для сохранности мягкотелых организмов в виде слепков, которые все реже и реже появлялись в кембрии по мере интенсификации и пространственного распространения биотурбации в морских бассейнах. Preservation of soft-bodied organisms as casts is common in the Ediacaran fossil record and extremely rare in Cambrian rocks. Among the factors, limiting fossilization of soft tissues, there is bioturbation-sediment disturbance by burrowing organisms. It is the emergence of burrowing metazoans and associated sediment bioturbation that is thought to be one of the major causes for the disappearance of Ediacaran soft-bodied organisms from the fossil record around ~540 Ma. Here, we study an assemblage of fossils preserved as casts in the Fortunian carbonates of the Olenek Uplift (northeastern Siberian Platform) in association with a typical Fortunian ichnoassemblage. The overall morphology and preservation of the fossils reveal that they comprise microbially induced sedimentary structures and soft-bodied holdfasts. The latter are vaguely reminiscent of some Ediacaran holdfasts, though it is unlikely that they include their phylogenetic descendants. Three-dimensional preservation of the studied fossils was caused by authigenic crystallization of calcite and its further early-diagenetic dolomitization. Our study confirms the critical importance of specific environmental conditions ensuring preservation of soft-bodied organisms as three-dimensional molds and casts. This unique interplay of environmental factors became rare in the Cambrian Period, which was caused by intensification and expansion of bioturbation in marine basins.

@article{марусин2023preservation,
    author = "МАРУСИН, В.В. and БЫКОВА, Н.В.",
    title = "PRESERVATION OF SOFT-BODIED ORGANISMS IN EARLY CAMBRIAN CARBONATES",
    year = "2023",
    journal = "Геология и геофизика",
    abstract = "Сохранность мягкотелых организмов в виде слепков широко распространена в эдиакарской ископаемой летописи и встречается чрезвычайно редко в кембрии. Одним из факторов, негативно влияющих на сохранность мягких тканей, является биотурбация - перемешивание осадка роющими организмами. Именно появление зарывающихся билатерий и связанное с этим развитие биотурбации осадка рассматриваются в качестве одной из главных причин, приведших к исчезновению эдиакарских мягкотелых организмов около 540 млн лет. В рамках настоящего исследования нами изучены ископаемые остатки, сохранившиеся в виде слепков и отпечатков в карбонатных отложениях фортунского яруса кембрия Оленекского поднятия (северо-восток Сибирской платформы) в ассоциации с типичными для этого стратиграфического уровня ископаемыми следами жизнедеятельности. Общая морфология и сохранность этих остатков схожа с эдиакарскими органами прикрепления и микробиально-индуцированными осадочными текстурами. Объемная сохранность изученных остатков обусловлена аутигенной кристаллизацией кальцита и его дальнейшей раннедиагенетической доломитизацией. Хотя верхние интервалы слоев и были умеренно- и интенсивно биотурбированы, нижние интервалы, к которым и приурочены остатки, практически не перемешивались роющими организмами. Наше исследование подтверждает критическую важность специфических условий для сохранности мягкотелых организмов в виде слепков, которые все реже и реже появлялись в кембрии по мере интенсификации и пространственного распространения биотурбации в морских бассейнах. Preservation of soft-bodied organisms as casts is common in the Ediacaran fossil record and extremely rare in Cambrian rocks. Among the factors, limiting fossilization of soft tissues, there is bioturbation-sediment disturbance by burrowing organisms. It is the emergence of burrowing metazoans and associated sediment bioturbation that is thought to be one of the major causes for the disappearance of Ediacaran soft-bodied organisms from the fossil record around \textasciitilde 540 Ma. Here, we study an assemblage of fossils preserved as casts in the Fortunian carbonates of the Olenek Uplift (northeastern Siberian Platform) in association with a typical Fortunian ichnoassemblage. The overall morphology and preservation of the fossils reveal that they comprise microbially induced sedimentary structures and soft-bodied holdfasts. The latter are vaguely reminiscent of some Ediacaran holdfasts, though it is unlikely that they include their phylogenetic descendants. Three-dimensional preservation of the studied fossils was caused by authigenic crystallization of calcite and its further early-diagenetic dolomitization. Our study confirms the critical importance of specific environmental conditions ensuring preservation of soft-bodied organisms as three-dimensional molds and casts. This unique interplay of environmental factors became rare in the Cambrian Period, which was caused by intensification and expansion of bioturbation in marine basins.",
    url = "https://doi.org/10.15372/gig2023133",
    doi = "10.15372/gig2023133",
    number = "10",
    pages = "1413-1433",
    volume = "64"
}

The soft parts of animals are fossilized only in exceptional circumstances. The deposits at Chengjiang (about 520 million years ago) have preserved the soft parts of a wide range of different kinds of animal, and show the extent of the early Cambrian radiation. They include not only sponges and polyps but also many kinds of bilaterians, especially arthropods, and illustrate the growing separation of visceral (internal organs) from somatic features such as limbs, fins, brain and eyes. The Chengjiang animals are not unique, but rather represent a Cambrian community that has been found at many sites throughout the world. The earlier deposits at Kuanpuanchu show that this radiation was well under way 15 million years earlier. Even earlier there was a diverse fauna of animals with hard parts, mostly shells, that is especially preserved in Siberia. Some of these fragments can be identified as the armour of animals where intact individuals have been preserved. At the base of the Cambrian, shells and teeth show that the distinction between predators and prey had already evolved.

@incollection{bell2026the,
    author = "Bell, Graham",
    title = "The Early Cambrian Fossils",
    year = "2026",
    booktitle = "The Sea-Change",
    abstract = "The soft parts of animals are fossilized only in exceptional circumstances. The deposits at Chengjiang (about 520 million years ago) have preserved the soft parts of a wide range of different kinds of animal, and show the extent of the early Cambrian radiation. They include not only sponges and polyps but also many kinds of bilaterians, especially arthropods, and illustrate the growing separation of visceral (internal organs) from somatic features such as limbs, fins, brain and eyes. The Chengjiang animals are not unique, but rather represent a Cambrian community that has been found at many sites throughout the world. The earlier deposits at Kuanpuanchu show that this radiation was well under way 15 million years earlier. Even earlier there was a diverse fauna of animals with hard parts, mostly shells, that is especially preserved in Siberia. Some of these fragments can be identified as the armour of animals where intact individuals have been preserved. At the base of the Cambrian, shells and teeth show that the distinction between predators and prey had already evolved.",
    url = "https://doi.org/10.1093/9780197797464.003.0009",
    doi = "10.1093/9780197797464.003.0009",
    pages = "96-148"
}