An early geikiid dicynodont from the Tropidostoma Assemblage Zone (late Permian) of South Africa
Based on specimens previously identified as Tropidostoma, a new taxon of dicynodont (Bulbasaurus phylloxyron gen. et sp. nov.) from the Karoo Basin of South Africa is described. Bulbasaurus is a medium-sized dicynodont (maximum dorsal skull length 16.0 cm) restricted to the Tropidostoma Assemblage Z...
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PeerJ Inc.
2017-01-01
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| Online Access: | https://peerj.com/articles/2913.pdf |
| _version_ | 1797418006226141184 |
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| author | Christian F. Kammerer Roger M.H. Smith |
| author_facet | Christian F. Kammerer Roger M.H. Smith |
| author_sort | Christian F. Kammerer |
| collection | DOAJ |
| description | Based on specimens previously identified as Tropidostoma, a new taxon of dicynodont (Bulbasaurus phylloxyron gen. et sp. nov.) from the Karoo Basin of South Africa is described. Bulbasaurus is a medium-sized dicynodont (maximum dorsal skull length 16.0 cm) restricted to the Tropidostoma Assemblage Zone (early Lopingian) of the Beaufort Group. Bulbasaurus can be distinguished from Tropidostoma by an array of characters including the presence of a tall, sharp premaxillary ridge, large, rugose, nearly-confluent nasal bosses, a nasofrontal ridge, massive tusks, robust pterygoids, prominently twisted subtemporal bar, and absence of a distinct postfrontal. Inclusion of Bulbasaurus in a phylogenetic analysis of anomodont therapsids recovers it as a member of Geikiidae, a clade of otherwise later Permian dicynodonts such as Aulacephalodon and Pelanomodon. Bulbasaurus exhibits many of the characters typical of adult Aulacephalodon, but at substantially smaller skull size (these characters are absent in comparably-sized Aulacephalodon juveniles), suggesting that the evolution of typical geikiid morphology preceded gigantism in the clade. Bulbasaurus is the earliest known geikiid and the only member of the group known from the Tropidostoma Assemblage Zone; discovery of this taxon shortens a perplexing ghost lineage and indicates that abundant clades from the later Permian of South Africa (e.g., Geikiidae, Dicynodontoidea) may have originated as rare components of earlier Karoo assemblage zones. |
| first_indexed | 2024-03-09T06:26:29Z |
| format | Article |
| id | doaj.art-ff797bec0b2e4ef5b34500d49562c4ca |
| institution | Directory Open Access Journal |
| issn | 2167-8359 |
| language | English |
| last_indexed | 2024-03-09T06:26:29Z |
| publishDate | 2017-01-01 |
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| spelling | doaj.art-ff797bec0b2e4ef5b34500d49562c4ca2023-12-03T11:19:51ZengPeerJ Inc.PeerJ2167-83592017-01-015e291310.7717/peerj.2913An early geikiid dicynodont from the Tropidostoma Assemblage Zone (late Permian) of South AfricaChristian F. Kammerer0Roger M.H. Smith1Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, GermanyEvolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South AfricaBased on specimens previously identified as Tropidostoma, a new taxon of dicynodont (Bulbasaurus phylloxyron gen. et sp. nov.) from the Karoo Basin of South Africa is described. Bulbasaurus is a medium-sized dicynodont (maximum dorsal skull length 16.0 cm) restricted to the Tropidostoma Assemblage Zone (early Lopingian) of the Beaufort Group. Bulbasaurus can be distinguished from Tropidostoma by an array of characters including the presence of a tall, sharp premaxillary ridge, large, rugose, nearly-confluent nasal bosses, a nasofrontal ridge, massive tusks, robust pterygoids, prominently twisted subtemporal bar, and absence of a distinct postfrontal. Inclusion of Bulbasaurus in a phylogenetic analysis of anomodont therapsids recovers it as a member of Geikiidae, a clade of otherwise later Permian dicynodonts such as Aulacephalodon and Pelanomodon. Bulbasaurus exhibits many of the characters typical of adult Aulacephalodon, but at substantially smaller skull size (these characters are absent in comparably-sized Aulacephalodon juveniles), suggesting that the evolution of typical geikiid morphology preceded gigantism in the clade. Bulbasaurus is the earliest known geikiid and the only member of the group known from the Tropidostoma Assemblage Zone; discovery of this taxon shortens a perplexing ghost lineage and indicates that abundant clades from the later Permian of South Africa (e.g., Geikiidae, Dicynodontoidea) may have originated as rare components of earlier Karoo assemblage zones.https://peerj.com/articles/2913.pdfSynapsidaTherapsidaDicynodontiaPermianKaroo BasinSouth Africa |
| spellingShingle | Christian F. Kammerer Roger M.H. Smith An early geikiid dicynodont from the Tropidostoma Assemblage Zone (late Permian) of South Africa PeerJ Synapsida Therapsida Dicynodontia Permian Karoo Basin South Africa |
| title | An early geikiid dicynodont from the Tropidostoma Assemblage Zone (late Permian) of South Africa |
| title_full | An early geikiid dicynodont from the Tropidostoma Assemblage Zone (late Permian) of South Africa |
| title_fullStr | An early geikiid dicynodont from the Tropidostoma Assemblage Zone (late Permian) of South Africa |
| title_full_unstemmed | An early geikiid dicynodont from the Tropidostoma Assemblage Zone (late Permian) of South Africa |
| title_short | An early geikiid dicynodont from the Tropidostoma Assemblage Zone (late Permian) of South Africa |
| title_sort | early geikiid dicynodont from the tropidostoma assemblage zone late permian of south africa |
| topic | Synapsida Therapsida Dicynodontia Permian Karoo Basin South Africa |
| url | https://peerj.com/articles/2913.pdf |
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