Irregularia

@misc{nichols1959mode1,
    author = "Nichols, D",
    title = "Mode of life and taxonomy in irregular sea-urchins",
    year = "1959",
    howpublished = "Systemists Association, v. 3, p. 61-80",
    note = "talkorigins\_source = {true}; raw\_reference = {Nichols, D., 1959, Mode of life and taxonomy in irregular sea-urchins: Systemists Association, v. 3, p. 61-80.}"
}

@article{hibino2004molecular,
    author = "Hibino, Taku and Harada, Yoshito and Minokawa, Takuya and Nonaka, Masaru and Amemiya, Shonan",
    title = "Molecular heterotopy in the expression of Brachyury orthologs in order Clypeasteroida (irregular sea urchins) and order Echinoida (regular sea urchins)",
    year = "2004",
    journal = "Development Genes and Evolution",
    url = "https://doi.org/10.1007/s00427-004-0437-x",
    doi = "10.1007/s00427-004-0437-x",
    number = "11",
    openalex = "W2028685859",
    pages = "546-558",
    volume = "214",
    references = "doi101002j146020751995tb00158x, doi1010160031018268900989, doi101016016895259090011t, doi101017s0094837300009714, doi10103835051075, doi101038nrg1042, doi101073pnas2235868100, doi101073pnas93168455, doi101242dev127214631, doi1023071483846"
}

@misc{crossref2010life,
    title = "Life in the Shallow Sea: From Shells to Urchins",
    year = "2010",
    booktitle = "Tropical Island Recovery",
    url = "https://doi.org/10.1002/9781444327410.ch13",
    doi = "10.1002/9781444327410.ch13",
    openalex = "W2130145710",
    pages = "80-89"
}

Floating potential fluctuations of a glow discharge plasma are found to exhibit different kinds of mixed mode oscillations. Power spectrum analysis reveals that with change in the nature of the mixed mode oscillation (MMO), there occurs a transfer of power between the different harmonics and subharmonics. The variation in the chaoticity of different types of mmo was observed with the study of Lyapunov exponents. Estimates of correlation dimension and the Hurst exponent suggest that these MMOs are of low dimensional nature with an anti persistent character. Numerical modeling also reflects the experimentally found transitions between the different MMOs.

@article{ghosh2015irregularregularirregular,
    author = "Ghosh, Sabuj and Shaw, Pankaj Kumar and Saha, Debajyoti and Janaki, M. S. and Iyengar, A. N. Sekar",
    title = "Irregular-regular-irregular mixed mode oscillations in a glow discharge plasma",
    year = "2015",
    journal = "Physics of Plasmas",
    abstract = "Floating potential fluctuations of a glow discharge plasma are found to exhibit different kinds of mixed mode oscillations. Power spectrum analysis reveals that with change in the nature of the mixed mode oscillation (MMO), there occurs a transfer of power between the different harmonics and subharmonics. The variation in the chaoticity of different types of mmo was observed with the study of Lyapunov exponents. Estimates of correlation dimension and the Hurst exponent suggest that these MMOs are of low dimensional nature with an anti persistent character. Numerical modeling also reflects the experimentally found transitions between the different MMOs.",
    url = "https://doi.org/10.1063/1.4919962",
    doi = "10.1063/1.4919962",
    number = "5",
    openalex = "W1481989070",
    volume = "22",
    references = "doi10106312779859, doi10106312841032, doi10106313524691, doi10106313544938, doi101088095177152771555, doi101103physrevlett100225005, doi101103physrevlett23760, doi101103physrevlett50346, doi101137100791233, doi101142s0218127498000322"
}

@inproceedings{anuradha2016detecting,
    author = "Anuradha, R. and Rajkumar, N. and Praveenkumar, S.",
    title = "Detecting irregular fuzzy coherent rules in a predefined taxonomy",
    year = "2016",
    booktitle = "2016 IEEE Region 10 Conference (TENCON)",
    url = "https://doi.org/10.1109/tencon.2016.7848363",
    doi = "10.1109/tencon.2016.7848363",
    openalex = "W2586094400",
    pages = "1950-1956",
    references = "doi1010160165011495003053, doi101016s0167739x97000198, doi101023bdami00000052583141883, doi10110969250074, doi10114510106141010616, doi101145170035170072, doi101145233269233311, doi101145312129312274, openalexw1578959085, openalexw3039539181"
}

Experimental evidence of different kinds of oscillations in floating potential fluctuations of glow discharge magnetized plasma is being reported. A spherical gridded cage is inserted into the ambient plasma volume for creating plasma bubbles. Plasma is produced between a spherical mesh grid and chamber. The spherical mesh grid of 80% optical transparency is connected to the positive terminal of power supply and considered as anode. Two Langmuir probes are kept in the ambient plasma to measure the floating potential fluctuations in different positions within the system, viz., inside and outside the spherical mesh grid. At certain conditions of discharge voltage (Vd) and magnetic field, irregular to regular mode appears, and it shows chronological changes with respect to magnetic field. Further various nonlinear analyses such as Recurrence Plot, Hurst exponent, and Lyapunov exponent have been carried out to investigate the dynamics of oscillation at a range of discharge voltages and external magnetic fields. Determinism, entropy, and Lmax are important measures of Recurrence Quantification Analysis which indicate an irregular to regular transition in the dynamics of the fluctuations. Furthermore, behavior of the plasma oscillation is characterized by the technique called multifractal detrended fluctuation analysis to explore the nature of the fluctuations. It reveals that it has a multifractal nature and behaves as a long range correlated process.

@article{doi10106314979891,
    author = "Megalingam, Mariammal and Prakash, N. Hari and Solomon, Infant and Sarma, Arun and Sarma, Bornali",
    title = "Irregular-regular mode oscillations inside plasma bubble and its fractal analysis in glow discharge magnetized plasma",
    year = "2017",
    journal = "Physics of Plasmas",
    abstract = "Experimental evidence of different kinds of oscillations in floating potential fluctuations of glow discharge magnetized plasma is being reported. A spherical gridded cage is inserted into the ambient plasma volume for creating plasma bubbles. Plasma is produced between a spherical mesh grid and chamber. The spherical mesh grid of 80\% optical transparency is connected to the positive terminal of power supply and considered as anode. Two Langmuir probes are kept in the ambient plasma to measure the floating potential fluctuations in different positions within the system, viz., inside and outside the spherical mesh grid. At certain conditions of discharge voltage (Vd) and magnetic field, irregular to regular mode appears, and it shows chronological changes with respect to magnetic field. Further various nonlinear analyses such as Recurrence Plot, Hurst exponent, and Lyapunov exponent have been carried out to investigate the dynamics of oscillation at a range of discharge voltages and external magnetic fields. Determinism, entropy, and Lmax are important measures of Recurrence Quantification Analysis which indicate an irregular to regular transition in the dynamics of the fluctuations. Furthermore, behavior of the plasma oscillation is characterized by the technique called multifractal detrended fluctuation analysis to explore the nature of the fluctuations. It reveals that it has a multifractal nature and behaves as a long range correlated process.",
    url = "https://doi.org/10.1063/1.4979891",
    doi = "10.1063/1.4979891",
    openalex = "W2607179173",
    references = "ghosh2015irregularregularirregular"
}

The earliest information on Sri Lankan echinoid species belonging to the Irregularia dates back to Alexander Agassiz (1872). However, the current knowledge of diversity and distribution of irregular echinoids from Sri Lanka (formerly Ceylon) remains sparse. In addition, there are no recent taxonomic studies or biodiversity surveys for irregular echinoids, and no illustrated field-guides or reference collections are available specifically for Sri Lanka. To address these gaps, left open for more than 100 years since the work of Clark (1915), this study was conducted as an island-wide systematic sampling survey. Over 200 echinoid specimens were collected from 24 localities in Sri Lankan coastal waters by snorkelling and SCUBA diving down to 33 m depth. The collected specimens were identified using existing keys and authenticated with specimens available at the Natural History Museum in Vienna, Austria. The present study records 22 irregular echinoid species belonging to 15 genera and nine families in four orders. Among the identified irregular echinoids, six species, Echinocyamus megapetalus H.L. Clark, 1914, Fibularia ovulum Lamarck, 1816, Fibulariella angulipora Mortensen, 1948, Echinodiscus cf. truncatus L. Agassiz, 1841, Peronella oblonga Mortensen, 1948 and Brissus cf. agassizii Döderlein, 1885, are new records for Sri Lanka. Four unidentified, possibly new species belonging to the genera Fibularia, Jacksonaster and Metalia are reported, but kept in open nomenclature until more material becomes available. At present, the diversity of irregular echinoids from Sri Lanka now stands at 37 species representing 11 families in four orders. A dichotomous key is presented for all Sri Lankan irregular echinoids.

@article{arachchige2019taxonomy,
    author = "ARACHCHIGE, GAYASHAN M. and JAYAKODY, SEVVANDI and MOOI, RICH and KROH, ANDREAS",
    title = "Taxonomy and distribution of irregular echinoids (Echinoidea: Irregularia) from Sri Lanka",
    year = "2019",
    journal = "Zootaxa",
    abstract = "The earliest information on Sri Lankan echinoid species belonging to the Irregularia dates back to Alexander Agassiz (1872). However, the current knowledge of diversity and distribution of irregular echinoids from Sri Lanka (formerly Ceylon) remains sparse. In addition, there are no recent taxonomic studies or biodiversity surveys for irregular echinoids, and no illustrated field-guides or reference collections are available specifically for Sri Lanka. To address these gaps, left open for more than 100 years since the work of Clark (1915), this study was conducted as an island-wide systematic sampling survey. Over 200 echinoid specimens were collected from 24 localities in Sri Lankan coastal waters by snorkelling and SCUBA diving down to 33 m depth. The collected specimens were identified using existing keys and authenticated with specimens available at the Natural History Museum in Vienna, Austria. The present study records 22 irregular echinoid species belonging to 15 genera and nine families in four orders. Among the identified irregular echinoids, six species, Echinocyamus megapetalus H.L. Clark, 1914, Fibularia ovulum Lamarck, 1816, Fibulariella angulipora Mortensen, 1948, Echinodiscus cf. truncatus L. Agassiz, 1841, Peronella oblonga Mortensen, 1948 and Brissus cf. agassizii Döderlein, 1885, are new records for Sri Lanka. Four unidentified, possibly new species belonging to the genera Fibularia, Jacksonaster and Metalia are reported, but kept in open nomenclature until more material becomes available. At present, the diversity of irregular echinoids from Sri Lanka now stands at 37 species representing 11 families in four orders. A dichotomous key is presented for all Sri Lankan irregular echinoids.",
    url = "https://doi.org/10.11646/zootaxa.4541.1.1",
    doi = "10.11646/zootaxa.4541.1.1",
    number = "1",
    openalex = "W2907271592",
    volume = "4541",
    references = "doi105962bhltitle126954"
}

@incollection{current2019taxonomy,
    author = "Current, W. L. and Upton, Steve J. and Long, Peter L.",
    title = "Taxonomy and Life Cycles",
    year = "2019",
    booktitle = "Coccidiosis of Man and Domestic Animals",
    url = "https://doi.org/10.1201/9781351070744-1",
    doi = "10.1201/9781351070744-1",
    openalex = "W1454838053",
    pages = "1-16"
}

Introduction: Sea urchins in the order Spatangoida are the most diverse group of extant echinoids. Objective: Describe a new genus and species of Spatangoida from abyssal depths, and add new records for known species. Methods: Specimens were collected during several cruises at different areas of the southwestern Atlantic Ocean (SWAO), among 37-55° S latitude at depths ranging from 55 to 3 000 m. We present morphological and ultrastructure analyses. Results: Corparva lyrida gen. et sp. nov. (Palaeotropidae) is described from the Mar del Plata Canyon on the Argentine continental slope (2 950 m depth), the first record of this family from Argentina. Corparva gen. nov. differs in having an apical system semi-ethmolytic, and labrum reaching to rear part of second adjacent ambulacral plate. We also report the northernmost distribution and deepest record for Brisaster moseleyi (38° S latitude, 2 212 m depth), the northward extension of the distribution range of Tripylus excavatus (39° S latitude, 74 m depth), and the first record of Abatus philippii and Abatus agassizii at the Burdwood Bank/MPA Namuncurá. Conclusions: The present work brings novel and updated data about the diversity and distribution of spatangoids from the SWAO, including the description of C. lyrida gen. et sp. nov., and new records of species. This shows how much remains to be known about the diversity and distribution of heart urchins in the SWAO, especially from the deep-sea.

@article{doi1015517rbtv69isuppl146320,
    author = "Flores, Jonathan-N. and Penchaszadeh, Pablo-E. and Brogger, Martín",
    title = "Heart urchins from the depths: Corparva lyrida gen. et sp. nov. (Palaeotropidae), and new records for the southwestern Atlantic Ocean",
    year = "2021",
    journal = "Revista de Biología Tropical",
    abstract = "Introduction: Sea urchins in the order Spatangoida are the most diverse group of extant echinoids. Objective: Describe a new genus and species of Spatangoida from abyssal depths, and add new records for known species. Methods: Specimens were collected during several cruises at different areas of the southwestern Atlantic Ocean (SWAO), among 37-55° S latitude at depths ranging from 55 to 3 000 m. We present morphological and ultrastructure analyses. Results: Corparva lyrida gen. et sp. nov. (Palaeotropidae) is described from the Mar del Plata Canyon on the Argentine continental slope (2 950 m depth), the first record of this family from Argentina. Corparva gen. nov. differs in having an apical system semi-ethmolytic, and labrum reaching to rear part of second adjacent ambulacral plate. We also report the northernmost distribution and deepest record for Brisaster moseleyi (38° S latitude, 2 212 m depth), the northward extension of the distribution range of Tripylus excavatus (39° S latitude, 74 m depth), and the first record of Abatus philippii and Abatus agassizii at the Burdwood Bank/MPA Namuncurá. Conclusions: The present work brings novel and updated data about the diversity and distribution of spatangoids from the SWAO, including the description of C. lyrida gen. et sp. nov., and new records of species. This shows how much remains to be known about the diversity and distribution of heart urchins in the SWAO, especially from the deep-sea.",
    url = "https://doi.org/10.15517/rbt.v69isuppl.1.46320",
    doi = "10.15517/rbt.v69isuppl.1.46320",
    openalex = "W3149229231",
    references = "doi101006rwos20010358, doi101007978364220051911, doi101016jjembe200502002, doi101016jmargeo201305002, doi10108014772011003603556, doi101111j14636409200500201x, doi101111j155856461996tb03891x, doi1023072410854, doi105194os69832010, doi105479si097884601x13"
}