Qianshanosuchus, YOUNGI S P.

Boerman, Sophie A., Perrichon, Gwendal, Yang, Jian, Li, Cheng-Sen, Martin, Jeremy E., Speijer, Robert P. & Smith, Thierry, 2023, A juvenile skull from the early Palaeocene of China extends the appearance of crocodyloids in Asia back by 15 - 20 million years, Zoological Journal of the Linnean Society 197, pp. 787-811 : 791

QIANSHANOSUCHUS YOUNGI S P. NOV.

Z o o b a n k r e g i s t r a t i o n: u r n: l s i d: z o o b a n k. org:act: 018A0422-637B-413C-81CF-D86213843B7D

Etymology: ‘ youngi ’ in honour of Dr Chung-Chien Young (official name Zhongjian Yang) for his contribution to the knowledge of Chinese fossil crocodylians.

Holotype: IBCAS QS15 , incompletely preserved skull and left posterior part of lower jaw ( Figs 2–6 ).

Type-locality and horizon: Xialou, Qianshan County, Anhui Province: lower part of the Upper Member of the Wanghudun Formation, Shanghuan Asian Land Mammal Age ( Wang et al., 2016a), late Danian, early Palaeocene ( Wang et al., 2019).

Diagnosis: Basal crocodyloid differing from other crocodyloids by the following unique combination of characters: large size of the maxillary foramen for cranial nerve V; parietal–squamosal suture on skull table elevated on a ridge; acute indentation on the sagittal axis of the supraoccipital and parietal; dorsal margins of orbits upturned; supraoccipital largely exposed on skull table; anteroposterior prominent ridge on the lateral surface of the surangular.

DESCRIPTION

Figures

Figure 2. Skull of Qianshanosuchus youngi gen. & sp. nov. (IBCAS QS15), photograph (A) and interpretative drawing (B) in dorsal view. Abbreviations: ec, ectopterygoid; en, external naris; ex, exoccipital; fr, frontal; fV, foramen for cranial nerve V; itf, infratemporal fenestra; j, jugal; lac, lacrimal; mx, maxilla; n, nasal; or, orbit; par, parietal; par ridge, parietal ridge forming the medial margin of the supratemporal fenestrae; pmx, premaxilla; po, postorbital; q, quadrate; qj, quadratojugal; soc, supraoccipital; soc-par groove, medial groove on the supraoccipital and parietal; sq, squamosal; sq ridge, ridge on the lateral edge of the squamosal; stf, supratemporal fenestra. Scale bar: 1 cm.

Figure 3. Skull of Qianshanosuchus youngi gen. & sp. nov. (IBCAS QS15), photograph (A) and interpretative drawing (B) in ventral view. Abbreviations: ec, ectopterygoid; ex, exoccipital; fi, foramen incisivum; fr, frontal; fV, foramen for cranial nerve V; itf, infratemporal fenestra; j, jugal; mx, maxilla; mxt, maxillary tooth; pal, palatine; pmx, premaxilla; pmxt, premaxillary tooth; po, postorbital; q, quadrate; qj, quadratojugal; sof, suborbital fenestra; sofn, notch at the posterolateral margin of the suborbital fenestra. Scale bar: 1 cm.

Figure 4. Skull of Qianshanosuchus youngi gen. & sp. nov. (IBCAS QS15), photographs (A, C) and interpretative drawings (B, D) in left lateral view (A, B) and right lateral view (C, D).Abbreviations: ec, ectopterygoid; fr, frontal; j, jugal; lac, lacrimal; mx, maxilla; mxt, maxillary tooth; n, nasal; pmx, premaxilla; pmxt, premaxillary tooth; po, postorbital; q, quadrate; qj, quadratojugal; sq, squamosal; sq groove, squamosal groove. Scale bar: 1 cm.

Figure 5. Skull of Qianshanosuchus youngi gen. & sp. nov. (IBCAS QS15), photograph (A) and interpretative drawing (B) in occipital view. Abbreviations: ex, exoccipital; fm, foramen magnum; fr, frontal; j, jugal; par, parietal; po, postorbital; q, quadrate; qj, quadratojugal; soc, supraoccipital; soc-par groove, medial groove on the supraoccipital and parietal; sq, squamosal; sq ridge, ridge on the lateral edge of the squamosal. Scale bar: 1 cm.

Figure 6. Mandible of Qianshanosuchus youngi gen. & sp. nov. (IBCAS QS15), photographs (A, C, E, G) and interpretative drawings (B, D, F, H) in dorsal view (A, B), ventral view (C, D), labial view (E, F) and lingual view (G, H). Abbreviations: an, angular; ar, articular; emf, external mandibular fenestra; fic, foramen intermandibularis caudalis; glf, glenoid fossa; sur, surangular; sur ridge, ridge on the lateral surface of the surangular. Scale bar: 1 cm.