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    Published: March 16, 2011

    Kenneth D. Angielczyk's Publications

    Ken Angielczyk, MacArthur Curator of Paleomammalogy and Section Head, Negaunee Integrative Research Center

    PDF copies of all publications are available on request.

    Journal Publications

    Olroyd, S. L., Sidor, C. A., and Angielczyk, K. D. 2018. New materials of the enigmatic dicynodont Abajudon kaayai (Therapsida, Anomodontia) from the lower Madumabisa Mudstone Formation, middle Permian of Zambia. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1403442.

    Benoit, J. Angielczyk, K. D., Miyamae, J. A., Manger, P., Fernandez, V., and Rubidge, B. 2018. Evolution of facial innervation in anomodont therapsids (Synapsida): insights from x-ray computerized microtomography. Journal of Morphology. DOI: 10.1002/jmor.20804.

    Bernardi, M., Petti, F. M., Kustatscher, E., Franz, M., Hartkopf-Fröder, C., Labandeira, C. C., Wappler, T., van Konijnenburg-van Cittert, J. H. A., Peecook, B. R., and Angielczyk, K. D. 2017. Late Permian (Lopingian) terrestrial ecosystems: a global comparison with new data from the low-latitude Bletterbach Biota. Earth-Science Reviews 175: 18-43.

    Angielczyk, K. D. and Kammerer, C. F. 2017. The cranial morphology, phylogenetic positoion, and biogeography of the upper Permian dicynodont Compsodon helmoedi van Hoepen (Therapsida, Anomodontia). Papers in Palaeontology 3: 513-545.

    Nesbitt, S. J., Butler, R. J. Ezcurra, M. D., Barrett, P. M., Stokcer, M. R., Angielczyk, K. D., Smith, R. M. H., Sidor, C. A., Niedźwiedzki, G., Sennikov, A. G., and Charig, A. J. 2017. The earliest bird-line archosaurs and the assembly of the dinosaur body plan. Nature 544: 484-487.

    Codron, J., Botha-Brink, J., Codron,D., Huttenlocker, A. K., and Angielczyk, K. D. 2017. Predator-prey interactions amongst Permo-Triassic terrestrial vertebrates as a deterministic factor influencing faunal collapse and turnover. Journal of Evolutionary Biology 30: 40-54.

    Bernardi, M., Angielczyk, K.D., Mitchell, J. S., and Ruta, M. 2016. Phylogenetic stability, tree shape, and character compatibility: a case study using early tetrapods. Systematic Biology 65: 737-758.

    Barbolini, N., Smith R. M. H., Tabor, N. J., Sidor, C. A., and Angielczyk K. D. 2016. Resolving the age of Madumabisa fossil vertebrates: palynological evidence from the mid-Zambezi Basin of Zambia. Palaeogeography, Palaeoclimatology, Palaeoecology 457: 117-128.

    Botha-Brink, J., Codron, D., Huttenlocker, A. K., Angielczyk, K. D., and Ruta M. 2016. Breeding young as a survival strategy during Earth's greatest mass extinction. Scientific Reports 6: 24053. DOI: 10.1038/srep24053.

    Polly, P. D., Stayton, C. T., Dumont, E. R., Pierce S. E., Rayfield, E. J., and Angielczyk, K. D. 2016. Combining geometric morphometrics and finite element analysis with evolutionary modeling: towards a synthesis. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2016.1111225.

    Angielczyk, K. D., Rubidge, B. S., Day, M. O., and Lin, F. 2016. A reevaluation of Brachyprosopus broomi and Chelydontops altidentalis, dicynodonts (Therapsida, Anomodontia) from the middle Permian Tapinocephalus Assemblage Zone of the Karoo Basin, South Africa. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2016.1078342.

    Viglietti, P. A., Smith, R. M. H., Angielczyk, K. D., Kammerer, C. F., Fröbisch, J., and Rubidge, B. S. 2016. The Daptocephalus Assemblage Zone (Lopingian), South Africa: a proposed biostratigraphy based on a new compilation of stratigraphic ranges. Journal of African Earth Sciences 113: 153-164.

    Kammerer, C. F., Angielczyk, K. D., and Fröbisch, J. 2015. Redescription of the geikiid Pelanomodon (Therapsida, Dicynodontia), with a reconsideration of 'Propelanomodon.' Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2015.1030408.

    Cisneros, J. C., Marsicano, C., Angielczyk, K. D., Smith, R. M. H, Richter, M., Fröbisch, J.,  Kammerer, C. F., and Sadleir, R. W. 2015. New Permian fauna from tropical Gondwana. Nature Communications 6: 8676. DOI: 10.1038/ncomms9676.

    Angielczyk, K. D. and Cox, C. B. 2015. Distinctive emydopoid dicynodont (Therapsida, Anomodontia) mandibles from the Permian Ruhuhu and Usili formations (Songea Group), Ruhuhu Basin, Tanzania. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2015.1008699.

    Roopnarine, P. D. and Angielczyk, K. D. 2015. Community stability and selective extinction during the Permian-Triassic mass extinction. Science 350: 90-93.

    Huttenlocker, A. K, Sidor, C. A., and Angielczyk, K. D. 2015. A new eutherocephalian (Therapsida, Therocephalia) from the upper Permian Madumabisa Mudstone Formation (Luangwa Basin) of Zambia. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2015.969400.

    Cox, C. B. and Angielczyk, K. D. 2015. A new endothiodont dicynodont (Therapsida, Anomodontia) from the Permian Ruhuhu Formation (Songea Group) of Tanzania and its feeding system. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2014.935388

    Kammerer, C. F., Angielczyk, K. D., and Fröbisch, J. 2015. Redescription of Digalodon rubidgei, an emydopoid dicynodont (Therapsida, Anomodontia) from the Late Permian of South Africa. Fossil Record 18: 43-55.

    Angielczyk, K. D., Burroughs, R. W., and Feldman, C. R. 2015. Do turtles follow the rules? Latitudinal gradients in species richness, body size, and geographic range area of the world's turtles. Journal of Experimental Zoology Part B (Molecular and Developmental Evolution) 324B:270-294.

    Angielczyk, K. D., Huertas, S., Smith, R. M. H., Tabor, N. J., Sidor, C. A., Steyer, J.-S., Tsuji, L. A., and Gostling, N. J. 2014. New dicynodonts (Therapsida, Anomodontia) and updated tetrapod stratigraphy of the Permian Ruhuhu Formation (Songea Group, Ruhuhu Basin) of Southern Tanzania. Journal of Vertebrate Paleontology 34: 1408-1426.

    Nesbitt, S. J., Sidor, C. A., Angielczyk, K. D., Smith, R. M. H., and Tsuji, L. A. 2014. A new archosaur from the Manda beds (Anisian, Middle Triassic) of souther Tanzania and its implications for character state optimizations at Archosauria and Pseudosuchia. Journal of Vertebrate Paleontology 34: 1357-1382.

    Angielczyk, K. D. and Schmitz, L. 2014. Nocturnality in synapsids predates the origin of mammals by over 100 million years. Proceedings of the Royal Society B 281: 20141642. doi:10.1098/rspb.2014.1642.

    Sidor, C. A., Angielczyk, K. D., Smith, R. M. H., Goulding, A. K., Nesbitt, S. J., Peecook, B. R., Steyer, J.-S. and Tolan, S. 2014. Tapinocephalids (Therapsida: Dinocephalia) from the Permian Madumabisa Mudstone Formation (Lower Karoo, Mid-Zambezi Basin) of southern Zambia. Journal of Vertebrate Paleontology 34: 980-986.

    Castanhinha, R., Araújo, R., Júnior, L. C., Angielczyk, K. D., Martins, G. G., Martins, R. M. S., Chaouiya, C., Beckmann, F., and Wilde, F. 2013. Bringing dicynodonts back to life: paleobiology and anatomy of a new emydopoid genus from the Upper Permian of Mozambique. PLoS One 8(12): e80974. doi:10.1371/journal.pone.0080974

    Peecook, B. R., Sidor, C. A., Nesbitt, S. J., Smith, R. M. H., Steyer, J. S., and Angielczyk, K. D. 2013. A new silesaurid from the Upper Ntawere Formation of Zambia (Middle Triassic) demonstrates the rapid diversification of Silesauridae (Avemetatarsalia, Dinosauriformes). Journal of Vertebrate Paleontology 33: 1127-1137.

    Ruta, M. Angielczyk, K. D., Fröbisch, J., and Benton, M. J. 2013. Decoupling of morphological disparity and taxic diversity during the adaptive radiation of anomodont therapsids. Proceedings of the Royal Society Series B 280: 20131071. doi:10.1098/rspb.2013.1071.

    Kammerer, C. F., Fröbisch, J., and Angielczyk, K. D. 2013. On the validity and phylogenetic position of Eubrachiosaurus browni, a kannemeyeriiform dicynodont (Anomodontia) form Triassic North America. PLoS One 8(5): e64203. doi:10.1371/journal.pone.0064203

    Sidor, C. A., Vilhena, D. A., Angielczyk, K. D., Huttenlocker, A. K., Nesbitt, S. J., Peecook, B. R., Steyer, J.-S., Smith, R. M. H., and Tsuji, L. A. 2013. Provincialization of terrestrial faunas following the end-Permian mass extinction. Proceedings of the National Academy of Sciences 110: 8129-8133.

    Hancox, P. J., Angielczyk, K. D., and Rubidge, B. S. 2013. Angonisaurus and Shansiodon, dicynodonts (Therapsida, Anomodontia) from subzone C of the Cynognathus Assemblage Zone (Middle Triassic) of South Africa. Journal of Vertebrate Paleontology 33: 655-676.

    Angielczyk, K. D. and Feldman, C. R. 2013. Are diminutive turtles miniaturized? The ontogeny of plastron shape in emydine turtles. Biological Journal of the Linnean Society108: 727-755.

    Angielczyk, K. D. and Rubidge, B. S. 2013. Skeletal morphology, phylogenetic relationships, and stratigraphic range of Eosimops newtoni Broom, 1921, a pylaecephalid dicynodont (Therapsida, Anomodontia) from the Middle Permian of South Africa. Journal of Systematic Palaeontology 11: 191-231.

    Mitchell, J. S., Roopnarine, P. D., and Angielczyk, K. D. 2012. Late Cretaceous restructuring of terrestrial communities facilitated the end-Cretaceous mass extinction in North America. Proceedings of the National Academy of Sciences 109:18857-18861.

    Angielczyk, K. D. and Ruta, M. 2012. The roots of amphibian morphospace: a geometric morphometric analysis of Paleozoic temnospondyls. Fieldiana: Life and Earth Sciences 5: 40-58.

    Parham, J. F., Donoghue, P. C. J., Bell, C. J., Calway, T. D., Head, J. J., Holroyd, P. A., Inoue, J. G., Irmis, R. B., Joyce, W. G., Ksepka, D. T., Patané, J. S. L., Smith, N. D., Tarver, J. E., van Tuinen, M., Yang, Z., Angielczyk, K. D., Greenwood, J. M., Hipsley, C. A., Jacobs, L., Makovicky, P. J., Müller, J., Smith, K. T., Theodor, J. M., Warnock, R. C. M., and Benton, M. J. 2012. Best practices for justifying fossil calibrations. Systematic Biology 61: 346-359.

    Roopnarine, P. D. and Angielczyk, K. D. 2012. The evolutionary palaeoecology of species and the tragedy of the commons. Biology Letters 8: 147-150.

    Kammerer, C. F., Angielczyk, K. D., and J. Fröbisch. 2011. A comprehensive taxonomic revision of Dicynodon (Therapsida, Anomodontia), and its implications for dicynodont phylogeny, biogeography, and biostratigraphy. Society of Vertebrate Paleontology Memoir 11: 1-158.

    Angielczyk, K. D., Feldman, C. R., and Miller, G. R. 2011. Adaptive evolution of plastron shape in emydine turtles. Evolution 65: 377-394.

    Botha-Brink, J. and Angielczyk, K. D. 2010. Do extraordinarily high growth rates in Permo-Triassic dicynodonts (Therapsida, Anomodontia) explain their success before and after the end-Permian extinction? Zoological Journal of the Linnean Society 160: 341-365.

    Angielczyk, K. D. and Rubidge, B. S. 2010. A new pylaecephalid dicynodont from the Tapinocephalus Assemblage Zone, Karoo Basin, Middle Permian of South Africa. Journal of Vertebrate Paleontology 30: 1396-1409.

    Simon, R. V., Sidor, C. A., Angielczyk, K. D., and Smith, R. M. H. 2010. First record of a tapinocephalid (Therapsida: Dinocephalia) from the Ruhuhu Formation (Songea Group) of southern Tanzania. Journal of Vertebrate Paleontology 30: 1289-1293.

    Sidor, C. A., Angielczyk, K. D., Weide, D. M., Smith, R. M. H., and Tsuji, L. A. 2010. Tetrapod fauna of the lowermost Usili Formation (Songea Group, Ruhuhu Basin) of southern Tanzania, with a new burnetiid record. Journal of Vertebrate Paleontology 30: 696-703.

    Nesbitt, S. J., Sidor, C. A., Irmis, R. B., Angielczyk, K. D., Smith, R. M. H., and Tsuji, L. A. 2010. Ecologically distinct dinosaurian sister-group indicates early diversification of Ornithodira. Nature 464: 95-98.

    Fröbisch, J., Angielczyk, K. D., and Sidor, C. A. 2010. The Triassic dicynodont Kombuisia (Synapsida, Anomodontia) from Antarctica, a refuge for terrestrial tetrapods during and after the end-Permian extinction. Naturwissenschaften 97: 187-196.

    Weide, D. M., Sidor, C. A., Angielczyk, K. D., and Smith, R. M. H. 2009. A new record of Procynosuchus delaharpeae (Therapsida: Cynodontia) from the Upper Permian Usili Formation, Tanzania. Palaeontologia africana 44: 21-26.

    Angielczyk, K. D., Sidor, C. A., Nesbitt, S. J., Smith, R. M. H., and Tsuji, L. A. 2009. Taxonomic revision and new observations on the postcranial skeleton, biogeography, and biostratigraphy of the dicynodont genus Dicynodontoides, the senior subjective synonym of Kingoria (Therapsida, Anomodontia). Journal of Vertebrate Paleontology 29: 1174-1187.

    Angielczyk, K. D. and Rubidge, B. S. 2009. The Permian dicynodont Colobodectes cluveri (Therapsida, Anomodontia), with notes on its ontogeny and stratigraphic range in the Karoo Basin, South Africa. Journal of Vertebrate Paleontology 29: 1162-1173.

    Pierce, S. E., Angielczyk, K. D., and Rayfield, E. J. 2009. Morphospace occupation in thalattosuchian crocodylomorphs: skull shape variation, species delineation, and temporal patterns. Palaeontology 52: 1057-1097.

    Pierce, S. E., Angielczyk, K. D., and Rayfield, E. J. 2009. Shape and mechanics in thalattosuchian (Crocodylomorpha) skulls: implications for feeding behavior and niche partitioning. Journal of Anatomy 215: 555-576.

    Kammerer, C. F. and Angielczyk, K. D. 2009. A proposed higher taxonomy of anomodont therapsids. Zootaxa 2018: 1-24.

    Angielczyk, K. D. 2009. Dimetrodon is not a dinosaur: using tree thinking to understand the ancient relatives of mammals and their evolution. Evolution: Education and Outreach 2: 257-271. DOI: 10.1007/s12052-009-0117-4.

    Angielczyk, K. D. and Sullivan, C. 2008. Diictodon feliceps (Owen, 1876), a dicynodont (Therapsida, Anomodontia) species with a Pangaean distribution. Journal of Vertebrate Paleontology 28: 788-802.

    Pierce, S. E., Angielczyk, K. D., and Rayfield, E. J. 2008. Patterns of morphospace occupation and mechanical performance in extant crocodilian skulls: a geometric morphometric and finite element modeling approach. Journal of Morphology 269: 840-864.

    Angielczyk, K. D. and Walsh M. L. 2008. Patterns in the evolution of nares size and secondary palate length in anomodont therapsids (Synapsida): implications for hypoxia as a cause for end-Permian terrestrial vertebrate extinctions. Journal of Paleontology 82: 528-542.

    Botha, J. and Angielczyk, K. D. 2007. An integrative approach to distinguishing the Late Permian dicynodont species Oudenodon bainii and Tropidostoma microtrema (Therapsida: Anomodontia). Palaeontology 50: 1175-1209.

    Roopnarine, P. D., Angielczyk, K. D., Wang, S. C., and Hertog, R. 2007. Food web models explain instability of Early Triassic terrestrial communities. Proceedings of the Royal Society Series B 274: 2077-2086.

    Angielczyk, K. D. 2007. New specimens of the Tanzanian dicynodont “Cryptocynodonparringtoni Von Huene, 1942 (Therapsida, Anomodontia), with an expanded analysis of Permian dicynodont phylogeny. Journal of Vertebrate Paleontology 27: 116-131.

    Angielczyk, K. D. and Sheets, H. D. 2007. Investigation of simulated tectonic deformation in fossils using geometric morphometrics. Paleobiology 33: 125-148.

    Angielczyk, K. D. and Fox, D. L. 2006. New uses for measures of the fit of phylogenetic hypotheses to the fossil record. Paleobiology 32: 147-165.

    Angielczyk, K. D., Fröbisch, J., and Smith, R. M. H. 2005. On the stratigraphic range of the dicynodont taxon Emydops (Therapsida, Anomodontia) in the Karoo Basin, South Africa. Palaeontologia africana 41: 23-33.

    Dayrat, B., Schander, C., and Angielczyk, K. D. 2004. Suggestions for a new species nomenclature. Taxon 53: 485-491.

    Angielczyk, K. D. 2004. Phylogenetic evidence for and implications of a dual origin of propaliny in anomodont therapsids (Synapsida). Paleobiology 30: 268-296.

    Angielczyk, K. D. and Kurkin, A. A. 2003. Phylogenetic analysis of Russian Permian dicynodonts (Therapsida: Anomodontia): implications for Permian biostratigraphy and Pangaean biogeography. Zoological Journal of the Linnean Society 139: 157-212.

    Angielczyk, K. D. and Kurkin, A. A. 2003. Has the utility of Dicynodon for Upper Permian terrestrial biostratigraphy been overstated? Geology 31: 363-366.

    Angielczyk, K. D. 2002. Character state transformations and the fit of phylogenies to the fossil record. Palaeontologia africana 38: 27-32.

    Angielczyk, K. D. 2002. Redescription, phylogenetic position, and stratigraphic significance of the dicynodont genus Odontocyclops (Synapsida; Therapsida). Journal of Paleontology 76: 1047-1059.

    Nesbitt, S. J. and Angielczyk, K. D. 2002. New evidence of large dicynodonts in the Upper Moenkopi Formation (Middle Triassic) of northern Arizona. PaleoBios 22: 10-17.

    Angielczyk, K. D. 2002. A character-based method for measuring the fit of a cladogram to the fossil record. Systematic Biology 51: 176-191.

    Angielczyk, K. D. 2001. Preliminary phylogenetic analysis and stratigraphic congruence of the dicynodont anomodonts (Synapsida: Therapsida). Palaeontologia Africana 37: 53-79.

    Angielczyk, K. D. and Gingerich, P. D. 1998. New specimen of cf. Asiatosuchus (Crocodyloidea) from the Middle Eocene Drazinda Formation of the Sulaiman Range, Punjab (Pakistan). Contributions from the Museum of Paleontology, University of Michigan 30 (5): 163-189.

    Edited Volumes

    Kammerer, C. F., Angielczyk, K. D., and Fröbisch, J. 2014. Early Evolutionary History of the Synapsida. Springer, Dordrecht. 337pp.

    Contributions to Edited Volumes

    Angielczyk, K. D. and Kammerer, C. F. 2017. Non-mammalian synapsids: the deep roots of the mammalian family tree. In Zachos, F. E. and Asher, R. J. (eds.), Handbook of Zoology: Mammalia: Mammalian Evolution, Diversity, and Systematics. De Gruyter, Berlin.

    Roopnarine, P. D. and Angielczyk, K. D. 2016. The stability of ecological communities as an agent of evolutionary selection. Pp. 307-333 in Eldredge, N., Pievani T., Serrelli, E., and Temkin I. (eds.), Evolutionary Theory: A Hierarchical Perspective. University of Chicago Press, Chicago.

    Angielczyk, K. D. 2014. Therapsid diversity patterns and the end-Permian extinction: Introduction. Pp. 283-287 in: Kammerer, C. F., Angielczyk, K. D., and Fröbisch, J. (eds.), Early Evolutionary History of the Synapsida. Springer, Dordrecht.

    Angielczyk, K. D., Steyer, J. S., Sidor, C. A., Smith, R. M. H., Whatley, R. L., and Tolan, S. 2014. Permian and Triassic dicynodont (Therapsida: Anomodontia) faunas of the Luangwa Basin, Zambia: taxonomic update and implications for dicynodont biogeography and biostratigraphy. Pp. 93-138 in: Kammerer, C. F., Angielczyk, K. D., and Fröbisch, J. (eds.), Early Evolutionary History of the Synapsida. Springer, Dordrecht.

    Felice, R. N. and Angielczyk, K. D. 2014. Was Ophiacodon (Synapsida, Eupelycosauria) a swimmer? A test using vertebral dimensions. Pp. 25-51 in: Kammerer, C. F., Angielczyk, K. D., and Fröbisch, J. (eds.), Early Evolutionary History of the Synapsida. Springer, Dordrecht.

    Aronowsky, A., Sanzenbacher, B., Childs, M., Peachey, A., Villanosa, K., Thompson, J., and Angielczyk, K. D. 2013. Promoting embodied learning through virtual and real world gaming experiences. Pp. 68-74 in: Williams, C. C., Ochsner, A., Dietmeier, J., and Steinkuehler, K. (eds.),  Proceedings, GLS 9.0, Games + Learning + Society Conference. ETC Press, Pittsburgh.

    Angielczyk, K., Aronowsky, A., Sanzenbacher, B., and Villanosa, K. 2012. Game of Bones: decisions and early feedback from a vertical slice. Pp. 63-68 in: Martin, C., Ochsner, A., and Squire, K. (eds.), Proceedings, GLS 8.0, Games + Learning + Society Conference. ETC Press, Pittsburgh.

    Padian, K. and Angielczyk, K. D. 2007. “Transitional forms” versus transitional features. Pp. 197-230 in: A. J. Petto and L. Godfrey (eds.); Scientists Confront Intelligent Design and Creationism. W. W. Norton & Co., New York.

    Angielczyk, K. D., Roopnarine, P. D., and Wang, S. C. 2005. Modeling the role of primary productivity disruption in end-Permian extinctions, Karoo Basin, South Africa. In: S. G. Lucas and K. E. Zeigler (eds.); The Nonmarine Permian. Bulletin of the New Mexico Museum of Natural History and Science 30: 16-23.

    Angielczyk, K. D. 2002. A selective annotation of published Triassic vertebrates from the UCMP collection. In: A. B. Heckert and S. G. Lucas (eds.); Triassic Stratigraphy and Paleontology. Bulletin of the New Mexico Museum of Natural History and Science 21: 297-301.

    Padian, K. and Angielczyk, K. D. 1999. Are there transitional forms in the fossil record? In: P. H. Kelley, J. R. Bryan, and T. A. Hansen (eds.); The Evolution-Creation Controversy II: Perspectives on Science, Religion, and Geological Education. Paleontological Society Papers 5: 47-82.

    Encyclopedia Entries

    Angielczyk, K. D. 2011. Dicynodontia. Pp. 76-79 in: 2011 McGraw-Hill Yearbook of Science & Technology. McGraw-Hill, New York.

    Technical Comments

    Roopnarine, P. D., Angielczyk, K. D., and Hertog, R. 2006. Comment on “Statistical independence of escalatory ecological trends in Phanerozoic marine invertebrates.” Science 314: 925d.

    Book Reviews

    Angielczyk, K. D. 2008. Non-Marine Permian Biostratigraphy and Biochronology, Edited by Spencer G. Lucas, Giuseppe Cassinis, and Joerg W. Schneider. Palaios. DOI: 10.2110/palo.2008.BR28.

    Angielczyk, K. D. 2005. Review of Robert A. Martin, Missing Links: Evolutionary Concepts & Transitions Through Time. Reports of the National Center for Science Education 25: 42-43.


    Ken Angielczyk
    MacArthur Curator of Paleomammalogy and Section Head

    I am a paleobiologist interested in three main topics: 1) understanding the broad implications of the paleobiology and paleoecology of extinct terrestrial vertebrates, particularly in relation to large scale problems such as the evolution of herbivory and the nature of the end-Permian mass extinction; 2) using quantitative methods to document and interpret morphological evolution in fossil and extant vertebrates; and 3) tropic network-based approaches to paleoecology. To address these problems, I integrate data from a variety of biological and geological disciplines including biostratigraphy, anatomy, phylogenetic systematics and comparative methods, functional morphology, geometric morphometrics, and paleoecology.

    A list of my publications can be found here.

    More information on some of my research projects and other topics can be found on the fossil non-mammalian synapsid page.

    Most of my research in vertebrate paleobiology focuses on anomodont therapsids, an extinct clade of non-mammalian synapsids ("mammal-like reptiles") that was one of the most diverse and successful groups of Permian and Triassic herbivores. Much of my dissertation research concentrated on reconstructing a detailed morphology-based phylogeny for Permian members of the clade, as well as using this as a framework for studying anomodont biogeography, the evolution of the group's distinctive feeding system, and anomodont-based biostratigraphic schemes. My more recent research on the group includes: species-level taxonomy of taxa such as Dicynodon, Dicynodontoides, Diictodon, Oudenodon, and Tropidostoma; development of a higher-level taxonomy for anomodonts; testing whether anomodonts show morphological changes consistent with the hypothesis that end-Permian terrestrial vertebrate extinctions were caused by a rapid decline in atmospheric oxygen levels; descriptions of new or poorly-known anomodonts from Antarctica, Tanzania, and South Africa; and examination of the implications of high growth rates in anomodonts. Fieldwork is an important part of my paleontological research, and recent field areas include the Parnaíba Basin of Brazil, the Karoo Basin of South Africa, the Ruhuhu Basin of Tanzania, and the Luangwa Basin of Zambia. My collaborators and I have made important discoveries in the course of these field projects, including the first remains of dinocephalian synapsids from Tanzania and a dinosaur relative that implies that the two main lineages of archosaurs (one including crocodiles and their relatives and the other including birds and dinosaurs) were diversifying in the early Middle Triassic, only a few million years after the end-Permian extinction. Finally, the experience I have gained while studying Permian and Triassic terrestrial vertebrates forms the foundation for work I am now involved in using models of food webs to investigate how different kinds of biotic and abiotic perturbations could have caused extinctions in ancient communities.

    Geometric morphometrics is the basis of most of my quantitative research on evolutionary morphology, and I have been using this technique to address several biological and paleontological questions. For example, I conducted a simulation-based study of how tectonic deformation influences our ability to extract biologically-relevant shape information from fossil specimens, and the effectiveness of different retrodeformation techniques. I also used the method to address taxonomic questions in biostratigraphically-important anomodont taxa, and I served as a co-advisor for a Ph.D. student at the University of Bristol who used geometric morphometrics and finite element analysis to examine the functional significance of skull shape variation in fossil and extant crocodiles. Focusing on more biological questions, I am currently working on a large geometric morphometric study of plastron shape in extant emydine turtles. To date, I have compiled a data set of over 1600 specimens belonging to nine species, and I am using these data to address causes of variation at both the intra- and interspecific level. Some of the main goals of the work are to examine whether plastron morphology reflects a phylogeographic signal identified using molecular data in Emys marmorata, whether the "miniaturized" turtles Glyptemys muhlenbergiiand Clemmys guttata have ontogenies that differ from those of their larger relatives, and how habitat preference, phylogeny, and shell kinesis affect shell morphology.

    A collaborative project that began during my time as a postdoctoral researcher at the California Academy of Sciences involves using using models of trophic networks to examine how disturbances can spread through communities and cause extinctions. Our model is based on ecological principles, and some of the main data that we are using are a series of Permian and Triassic communities from the Karoo Basin of South Africa. Our research has already shown that the latest Permian Karoo community was susceptible to collapse brought on by primary producer disruption, and that the earliest Triassic Karoo community was very unstable. Presently we are investigating the mechanics that underlie this instability, and we're planning to investigate how the perturbation resistance of communities as changed over time. We've also experimented with ways to use the model to estimate the magnitude and type of disruptions needed to cause observed extinction levels during the end-Permian extinction event in the Karoo. Then there's the research project I've been working on almost my whole life.

    Morphology and the stratigraphic occurrences of fossil organisms provide distinct, but complementary information about evolutionary history. Therefore, it is important to consider both sources of information when reconstructing the phylogenetic relationships of organisms with a fossil record, and I am interested how these data sources can be used together in this process. In my empirical work on anomodont phylogeny, I have consistently examined the fit of my morphology-based phylogenetic hypotheses to the fossil record because simulation studies suggest that phylogenies which fit the record well are more likely to be correct. More theoretically, I developed a character-based approach to measuring the fit of phylogenies to the fossil record. I also have shown that measurements of the fit of phylogenetic hypotheses to the fossil record can provide insight into when the direct inclusion of stratigraphic data in the tree reconstruction process results in more accurate hypotheses. Most recently, I co-advised two masters students at the University of Bristol who are examined how our ability to accurately reconstruct a clade's phylogeny changes over the course of the clade's history.