Christian F. Kammerer

University of the Witwatersrand

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Jörg Fröbisch

Museum für Naturkunde

Kenneth D. Angielczyk

Field Museum of Natural History

Roger M. H. Smith

California Institute of Technology

Richard J. Butler

University of Birmingham

Jonah N. Choiniere

University of the Witwatersrand

Martha Richter

Natural History Museum

Claudia A. Marsicano

Institute of Astronomy and Space Physics

Juan Carlos Cisneros

Universidade Federal do Piauí

Pia A. Viglietti

University of the Witwatersrand

Roger Benson

American Museum of Natural History

Cooperative Institutions

University of the Witwatersrand

Universidade Federal do Rio Grande do Sul

Museum für Naturkunde

American Museum of Natural History

Field Museum of Natural History

Iziko Museums of South Africa

Instituto de Geociencias

University of the Free State

University of Chicago

Centre National de la Recherche Scientifique

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The first record of a probainognathian (Cynodontia: Chiniquodontidae) from the Triassic of Madagascar

Journal of Vertebrate Paleontology (2010)

Christian F. Kammerer John J. Flynn Lovasoa Ranivoharimanana André R. Wyss

Click to increase image sizeClick to decrease image size ACKNOWLEDGMENTS We are extremely grateful for our collaboration with, and the continuing support and encouragement of, the Département de Paléontologie et d'Anthropologie Biologique, Université d'Antananarivo, Madagascar. We also acknowledge the long-time support of Dr. Gisèle Ravololonarivo Randria (former Head of the Palaeontology Laboratories), who recently passed away at too young an age. We thank the National Geographic Society for their extensive support of the fieldwork associated with this project. Additional financial or logistical support for field and laboratory investigations was provided by our home institutions, The Field Museum, and the WWF (Worldwide Fund for Nature, Madagascar). We remain indebted to the Ministère de L'Enérgie et des Mines for authorizing field efforts and for continuing to facilitate our joint U.S.-Madagascar exploration, research and education program, through our collaboration between the AMNH, Université d'Antananarivo, Ministère de L'Enérgie et des Mines, and MICET (Madagascar). We thank Debbie Wagner for her excellent preparation of this specimen, Bill Simpson and Akiko Shinya for facilitating its transport to the AMNH for further study, and Lorraine Meeker for the photographs in Figure 2. C.F.K. would like to thank Paul Barrett, Juan Cisneros, Jessica Cundiff, Michael Maisch, Maria Malabarba, Ricardo Martinez, Jaime Powell, Ana Maria Ribeiro, Chuck Schaff, Cesar Schultz, and Ray Symonds for their kind help and hospitality during his visits to their respective institutions.

Hospitality

10.1080/02724634.2010.520784

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Citations (23)

Guttigomphus avilionisgen. et sp. nov., a trirachodontid cynodont from the upperCynognathusAssemblage Zone, Burgersdorp Formation of South Africa

PeerJ (2022)

Romy R. Rayner Richard J. Butler Christian F. Kammerer Jonah N. Choiniere

The Burgersdorp Formation of South Africa is a richly fossiliferous rock sequence at the top of the Permian–Triassic Beaufort Group and is known for its abundance of Early–Middle Triassic vertebrate remains, particularly cynodonts. Fossils from the Burgersdorp Formation are referred biostratigraphically to the Cynognathus Assemblage Zone (CAZ), which is further divided into three subzones: Langbergia - Garjainia, Trirachodon - Kannemeyeria , and Cricodon-Ufudocyclops . Each subzone is characterised by the presence of a distinct species of trirachodontid, a group of gomphodont cynodonts found relatively abundantly throughout the CAZ, with the lower two subzones characterised by the medium-sized trirachodontids Langbergia and Trirachodon . The uppermost part of the formation, the Cricodon-Ufudocyclops subzone, yields trirachodontids of larger size. The majority of these trirachodontid specimens have previously been referred to Cricodon metabolus , a taxon also known from the Manda Beds of Tanzania and the Ntawere Formation of Zambia. Here we identify one of the specimens (BP/1/5538) previously referred to Cricodon as a new taxon, Guttigomphus avilionis . Guttigomphus can be distinguished from other gomphodont cynodonts by features of the upper postcanine teeth, such as an asymmetric crown in occlusal view (crown narrower along the lingual margin than the labial). Our phylogenetic analysis recovers Guttigomphus as a basal member of Trirachodontidae, outside of the clade including Cricodon , Langbergia and Trirachodon .

Assemblage (archaeology)

10.7717/peerj.14355

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Brazilian Permian dvinosaurs (Amphibia, Temnospondyli): revised description and phylogeny

Figshare (2021)

Claudia A. Marsicano Kenneth D. Angielczyk Juan Carlos Cisneros Martha Richter Christian F. Kammerer

Recently collected temnospondyl fossils from the Cisuralian Pedra de Fogo Formation (north-eastern Brazil) indicate a diverse assemblage of aquatic tetrapods, including the dvinosaurs Timonya anneae and Procuhy nazariensis. Here we present revised diagnoses for these species and detailed descriptions of their holotypes. Timonya anneae is distinguished from all other dvinosaurs by several cranial characters including: combined width of both parietals less than interorbital width; presence of a groove-like internal carotid artery foramen; and presence of an ossified opisthotic. In the mandible, T. anneae presents two parasymphyseal fossae on each side of the mandibular symphysis to accommodate palatal fangs and a well-developed postglenoid area. Procuhy nazariensis, mostly preserved as a mold of the skull table and mandible, is diagnosed by the presence of the anteriormost extension of the squamosal posterior to parietal midlength; pineal foramen posterior to the midlength of the parietal; supratemporal exposed on the posterior border of the skull table; and presence of postglenoid process of the surangular separated from the retroarticular process of the articular by the mandibular sulcus. A new inclusive phylogeny of Temnospondyli indicates that Dvinosauria consists of the Trimerorhachidae (including Procuhy as the sister-taxon of Trimerorhachis) and the ‘short-snouted’ dvinosaurs, with Timonya as an early-diverging representative of the latter clade. The Pedra de Fogo dvinosaurs show close relationships with Cisuralian taxa from the North American southwest, reinforcing close paleogeographic connections between these regions in the late Paleozoic, but represent endemic taxa, corroborating the pattern suggested by the plant fossil record.

10.6084/m9.figshare.14545937

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Corrigendum: Taxonomic status of the Least Grebe

Palaeontology (2013)

Daniel T. Ksepka Christian F. Kammerer

In a recent publication (Ksepka et al. in press), the results of a phylogenetic analysis of extant and fossil Podicipediformes (grebes) were reported. Because the Least Grebe 'Tachybaptus' dominicus was recovered outside of the monophyletic group formed by other Tachybaptus species, Poliocephalus, and the fossil taxon Thiornis, it was proposed that the genus Limnodytes be resurrected for this species. However, it has come to our attention that this name is invalid due to being a junior homonym. Ksepka et al. (2013) incorrectly ascribed authorship of the genus name Limnodytes to Linnaeus. Linnaeus (1766) named the species dominicus, but assigned this species to Colymbus Linnaeus, 1758, a 'wastebasket' genus that has since been suppressed under the plenary powers of the ICZN (ICZN 1956, Opinion 401). The name Limnodytes was first applied to grebes by Oberholser (1974), and thus is a junior homonym of Limnodytes Duméril and Bibron, 1841, a ranid frog (currently synonymized with Hylarana Tschudi, 1838; see Frost 2013). Given the history in the ornithological literature of creating tautonymous genera when separating species first named by Linnaeus, we propose Dominicus nom. nov. as a replacement name for Limnodytes Oberholser, 1974. Colymbus dominicus Linnaeus, 1766, is the type and only known species. Dominicus can be distinguished from Tachybaptus by the absence of an accessory hypotarsal canal for the tendon of m. flexor perforatus digiti II, absence of chestnut-coloured patches on the neck and absence of a yellow 'grin patch' at the rima oris. Dominicus can further be distinguished from Tachybaptus and the extinct Thiornis by the presence of a distal notch in the rim of the condylus medialis of the tibiotarsus and from Poliocephalus by its strong, bladelike apophysis furculae and the absence of white, elongate feathers on the side of the head (Ksepka et al. 2013).

Homonym (biology)

Monophyly

10.1111/pala.12068

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Early–middle Permian Mediterranean gorgonopsian suggests an equatorial origin of therapsids

Nature Communications (2024)

Rafel Matamales‐Andreu Christian F. Kammerer Kenneth D. Angielczyk Tiago R. Simões Eudald Mujal

Abstract Therapsids were a dominant component of middle–late Permian terrestrial ecosystems worldwide, eventually giving rise to mammals during the early Mesozoic. However, little is currently known about the time and place of origin of Therapsida. Here we describe a definitive therapsid from the lower–?middle Permian palaeotropics, a partial skeleton of a gorgonopsian from the island of Mallorca, western Mediterranean. This specimen represents, to our knowledge, the oldest gorgonopsian record worldwide, and possibly the oldest known therapsid. Using emerging relaxed clock models, we provide a quantitative timeline for the origin and early diversification of therapsids, indicating a long ghost lineage leading to the evolutionary radiation of all major therapsid clades within less than 10 Myr, in the aftermath of Olson’s Extinction. Our findings place this unambiguous early therapsid in an ancient summer wet biome of equatorial Pangaea, thus suggesting that the group originated in tropical rather than temperate regions.

Pangaea

Biome

Extinction (optical mineralogy)

Lineage (genetic)

Molecular clock

10.1038/s41467-024-54425-5

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The many faces of synapsid cranial allometry

Paleobiology (2019)

Isaac W. Krone Christian F. Kammerer Kenneth D. Angielczyk

Abstract Previous studies of cranial shape have established a consistent interspecific allometric pattern relating the relative lengths of the face and braincase regions of the skull within multiple families of mammals. In this interspecific allometry, the facial region of the skull is proportionally longer than the braincase in larger species. The regularity and broad taxonomic occurrence of this allometric pattern suggests that it may have an origin near the base of crown Mammalia, or even deeper in the synapsid or amniote forerunners of mammals. To investigate the possible origins of this allometric pattern, we used geometric morphometric techniques to analyze cranial shape in 194 species of nonmammalian synapsids, which constitute a set of successive outgroups to Mammalia. We recovered a much greater diversity of allometric patterns within nonmammalian synapsids than has been observed in mammals, including several instances similar to the mammalian pattern. However, we found no evidence of the mammalian pattern within Therocephalia and nonmammalian Cynodontia, the synapsids most closely related to mammals. This suggests that the mammalian allometric pattern arose somewhere within Mammaliaformes, rather than within nonmammalian synapsids. Further investigation using an ontogenetic series of the anomodont Diictodon feliceps shows that the pattern of interspecific allometry within anomodonts parallels the ontogenetic trajectory of Diictodon. This indicates that in at least some synapsids, allometric patterns associated with ontogeny may provide a “path of least resistance” for interspecific variation, a mechanism that we suggest produces the interspecific allometric pattern observed in mammals.

Allometry

Morphometrics

Neurocranium

10.1017/pab.2019.26

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Citations (28)

A new kannemeyeriiform dicynodont (Ufudocyclops mukanelai, gen. et sp. nov.) from Subzone C of the Cynognathus Assemblage Zone, Triassic of South Africa, with implications for biostratigraphic correlation with other African Triassic faunas (project)

MorphoBank datasets (2020)

Christian F. Kammerer Pia A. Viglietti P. John Hancox Richard J. Butler Jonah N. Choiniere

Assemblage (archaeology)

10.7934/p3602

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A new large gomphodont from the Triassic of South Africa and its implications for Gondwanan biostratigraphy

Journal of Vertebrate Paleontology (2021)

Frederick Tolchard Christian F. Kammerer Richard J. Butler Christophe Hendrickx Julien Benoît

A partial skull (BP/1/7976) of a very large cynodont from the Middle Triassic Cynognathus Assemblage Zone (Cricodon-Ufudocyclops subzone) of South Africa is described. The specimen represents a new gomphodont taxon, Impidens hancoxi, gen. et sp. nov., diagnosed by five sectorial teeth constituting just over half of the length of the upper postcanine tooth row, and enlarged canine and incisor teeth. BP/1/8123, a skull fragment also from the Cricodon-Ufudocyclops subzone, and AMNH FARB 24421, a partial skull from the upper Fremouw Formation of Antarctica, are also referred to the new species. The presence of this taxon in both the upper Fremouw Formation and Cricodon-Ufudocyclops subzone strengthens evidence of biostratigraphic correlation between these units. Impidens hancoxi, with an inferred skull length of up to 460 mm, was a large-bodied and likely omnivorous gomphodont, and may have played the role of apex predator within the tetrapod fauna of the Cricodon-Ufudocyclops subzone.

Tetrapod (structure)

10.1080/02724634.2021.1929265

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Citations (6)

Novel hind limb morphology in a kannemeyeriiform dicynodont from the Manda Beds (Songea Group, Ruhuhu Basin) of Tanzania

Journal of Vertebrate Paleontology (2017)

Christian F. Kammerer Kenneth D. Angielczyk Sterling J. Nesbitt

A partial hind limb (femur and tibia) from the Triassic Lifua Member of the Manda Beds (Tanzania) is recognized as a new morphotype of kannemeyeriiform dicynodont. The femur of this specimen is the largest known dicynodont postcranial element from the Manda Beds and indicates an animal nearing the size of the Late Triassic Stahleckeria potens from Brazil and Namibia. This specimen also resembles both Stahleckeria and the related Argentine stahleckeriid Ischigualastia in having an unusually elongate, straight femoral shaft and a massive and bulbous femoral head, but it differs in its compact distal end of the femur and the relative gracility of both its femur and tibia. The recognition of this specimen as a novel form of Manda dicynodont indicates that as many as six distinct kannemeyeriiforms are present in the mid-to-upper Lifua Member fauna, equaling or exceeding the species richness of previously known Laurasian faunas and substantially exceeding the richness of coeval Gondwanan faunas.Citation for this article: Kammerer, C. F., K. D. Angielczyk, and S. J. Nesbitt. 2018. Novel hind limb morphology in a kannemeyeriiform dicynodont from the Manda Beds (Songea Group, Ruhuhu Basin) of Tanzania; pp. 178–188 in C. A. Sidor and S. J. Nesbitt (eds.), Vertebrate and Climatic Evolution in the Triassic Rift Basins of Tanzania and Zambia. Society of Vertebrate Paleontology Memoir 17. Journal of Vertebrate Paleontology 37(6, Supplement).

Vertebrate paleontology

10.1080/02724634.2017.1309422

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Citations (10)

A comprehensive taxonomic revision ofDicynodon(Therapsida, Anomodontia) and its implications for dicynodont phylogeny, biogeography, and biostratigraphy

Journal of Vertebrate Paleontology (2011)

Christian F. Kammerer Kenneth D. Angielczyk Jörg Fröbisch

ABSTRACT The dicynodont wastebasket genus Dicynodon is revised following a comprehensive review of nominal species. Most nominal species of Dicynodon pertain to other well-known dicynodont genera, especially Oudenodon and Diictodon. Of the Karoo Permian species that are referable to "Dicynodon" sensu lato, we recognize four common, valid morphospecies: Dicynodon lacerticeps, D. leoniceps, D. woodwardi, and Dinanomodon gilli, comb. nov. Eleven additional species of "Dicynodon" are recognized worldwide: D. alticeps, D. amalitzkii, D. bathyrhynchus, D. benjamini, D. bogdaensis, D. huenei, D. limbus, D. sinkianensis, D. traquairi, D. trautscholdi, and D. vanhoepeni. Morphometric analysis of D. lacerticeps and D. leoniceps specimens recovers statistically significant separation between these species in snout profile and squamosal shape, supporting their distinction. A new phylogenetic analysis of Anomodontia reveals that "Dicynodon" is polyphyletic, necessitating taxonomic revision at the generic level. D. benjamini and D. limbus are basal cryptodonts, whereas the other valid "Dicynodon" species are basal dicynodontoids. The genus Dicynodon is restricted to D. lacerticeps and D. huenei. We reinstate use of Daptocephalus, Sintocephalus, Turfanodon, Daqingshanodon, Jimusaria, and Gordonia for other species. We synonymize Vivaxosaurus permirus and Dicynodon trautscholdi (as V. trautscholdi, comb. nov.) We establish new generic names for several species formerly included in Dicynodon: Peramodon amalitzkii, comb. nov., Keyseria benjamini, comb. nov., Euptychognathus bathyrhynchus, comb. nov., Syops vanhoepeni, comb. nov., and Basilodon woodwardi, comb. nov. Of the main Karoo Permian taxa, Dicynodon, Basilodon, and Dinanomodon range throughout the Cistecephalus and Dicynodon assemblage zones, but Daptocephalus is restricted to the Dicynodon Assemblage Zone. An online version of this Memoir containing color versions of Figures 4 to 152 is available online on the publishers' website. Subscribers accessing the Memoir online may also download a high-resolution version of the pages, but due to its size please note that it is available in 4 parts in the "supplemental files" area. Supplemental data matrices and specimen lists are also available in the "supplemental files" area.

Sensu

Polyphyly

10.1080/02724634.2011.627074

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Citations (126)