Vetusodon elikhulu, 2019

Abdala, Fernando, Gaetano, Leandro C., Smith, Roger M. H. & Rubidge, Bruce S., 2019, A new large cynodont from the Late Permian (Lopingian) of the South African Karoo Basin and its phylogenetic significance, Zoological Journal of the Linnean Society 186, pp. 983-1005 : 987-990

VETUSODON ELIKHULU GEN. ET SP. NOV.

Type and only species, Vetusodon elikhulu

Etymology: From Latin adjective vetus, ‘old, ancient’ and Greek οδοντος [odontos], ‘tooth’, a common Holotype: BP/1/7971, almost complete skull ( Figs 1, 2).

Referred specimens: SAM-PK-K10702, complete skull and articulated lower jaw. CGP GHG141, partial skull. SAM-PK-K10596, pre-orbital region of a skull.

LSID: zoobank.org:act: 055D0DAA-150F-489B-844D- 1C709B894636

Diagnosis: A large Permian cynodont, with a basal skull length of ≥ 18 cm. The skull is almost as wide as long; the snout is short and exceptionally wide. As in several eucynodonts, the dentary extends far posteriorly, with only a short separation from the craniomandibular joint. As is probably the case in Cynosaurus suppostus , the coronoid process of the mandible is very tall, reaching the level of the dorsal portion of the orbit. The dentary is low, with a tall symphysis, producing an anterodorsally directed chin. Autapomorphies of the new cynodont are as follows: a short, incomplete secondary osseous palate, with the posterior portion of the maxilla ventrally overlying the vomer and partly covering it; ventromedial palatal ridge of the premaxilla is slightly projected medially; a robust quadrate; the dorsal posterior projection of the postorbital ends anterior to the parietal foramen and does not form a central sagittal crest; a very short sagittal crest is posterior to the parietal foramen; and the relatively small postcanines bear a single conical cusp that is slightly oriented backwards.

ending for cynodont genera, in reference to the late Permian age of the known specimens. The species name elikhulu , meaning ‘large’ in Zulu, a widespread language in the area where the holotype was found, refers to the relative large size of the specimens.

Provenance: The holotype ( BP/1 /7971) was found during an expedition led by Dr B. Rubidge in 2010. The specimen is from a mudstone bed below a coarse-grained sandstone of the Balfour Formation and is from the Daptocephalus AZ. The specimen was recovered downstream from the causeway bridge crossing the Injisuthi River , close to the Enyezane locality, KwaZulu-Natal Province, South Africa .

CGP GHG141 was collected in the Normandien Formation (= Balfour Formation) at Thaba Nchu, South Africa on 26 March 1985. This specimen was found associated with the specimens CGP GHG140 and CGP GHG142, identified in the CGP catalogue as Dicynodon lacerticeps Owen, 1845 . CGP GHG140 was later assigned to Daptocephalus leoniceps (Owen, 1876) by Kammerer et al. (2011).

SAM-PK-K10702 was recovered from a level ~ 20 m below the Permo-Triassic boundary ( Daptocephalus AZ ), in the Elandsberg Member of the Balfour Formation on Ripplemead Farm, near Nieu Bethesda, South Africa during an expedition led by Dr R. Smith. At the same level, and <1 m away, a Lystrosaurus maccaigi (Seeley, 1898) specimen, including cranial and postcranial remains, was excavated (field number RS 440, SAM-PK-K10690).

SAM-PK-K10596 was found in the Balfour Formation at Groote Valley 133, Grootvlei, Middleburg, South Africa by Dr Crompton on a 1958/1959 expedition. The specimen is currently considered to come from the top of the Daptocephalus AZ , close to the Daptocephalus – Lystrosaurus AZ boundary. A plaster cast of SAM-PK-K10596 is kept at the University Museum of Zoology, Cambridge, UK identified with the number UCMZ T 980 in the figure epigraph ( Kemp, 1972: fig. 19 plate 1) and as UCMZ T 950 in the main text ( Kemp, 1972: 34). Another cast of this specimen is at the Bayerische Staatssammlung für Paläontologie und historische Geologie, Munich (F. Abdala, pers. obs.).

Precise coordinates of the localities are available from curators of the various collections.

DESCRIPTION

The following description is an account of the morphological traits recognized in the different specimens of Vetusodon elikhulu known to date. For clarity, the specimen numbers are provided only when necessary.

SKULL

The broad and relatively low skull is triangular in dorsal view ( Figs 1A, 3A) with the maximal cranial width across the posterior portion of the large, ovoid temporal fenestra. The skull is only slightly longer than wide, with a width-to-length ratio of 88% in BP/1/7971 and 93.5% in SAM-PK-K10702 ( Table 1). The temporal region is relatively long, representing ~60% of the skull length, whereas the snout and the orbital region constitute 40% of the total length of the skull ( Table 1). The snout is noticeably short and wide, its length being 16–21% of the total skull length ( Table 1; Figs 1A, 3A, 4A). The tip of the snout is pointed, projecting anteriorly beyond the incisors, and high in lateral view ( Fig. 2A, B). The orbits and the external nares are anterolaterally oriented.