Bambiraptor feinbergi

Brownstein, Chase Doran, 2021, Dromaeosaurid crania demonstrate the progressive loss of facial pneumaticity in coelurosaurian dinosaurs, Zoological Journal of the Linnean Society 191 (1), pp. 87-112 : 95-96

“ Bambiraptor feinbergi ”

The jugal of “ Bambiraptor ” bears a row of small foramina that are placed at the ventral edge of the bone (e.g. Burnham et al., 2000; Burnham, 2007) that recalls the foramina row just described in the holotype of Velociraptor mongoliensis . One of these was identified by Burnham (2007) as the jugal foramen.

POSTORBITAL, FRONTAL, SQUAMOSAL AND QUADRATOJUGAL

Although the bones constituting the posterior portion of the exterior crania of coelurosaurs have been found to house pneumatic sinuses in their interiors for some genera [e.g. Tyrannosaurus ( Brochu, 2003; Witmer & Ridgely, 2008); Ornithomimus ( Tahara & Larsson, 2011) ; Alioramus ( Gold et al., 2013) ], I could find no indication of major exterior pneumatic features on these bones in the dromaeosaurids studied in this paper (see also Ostrom, 1969; Burnham et al., 2000; Turner et al., 2012). Notably, the postorbital of other theropods is limited in its pneumaticity (e.g. Gold et al., 2013). An interesting aspect of the holotype of Velociraptor is the apparent 414 pneumatization of the ventral surface of the frontal, a feature that is also present in Tsaagan ( Norell et al., 2006) . Potentially pneumatic features of the frontal in Velociraptor includes a large, ovoid foramen centered on the ventral surface of the bone ( Fig. 2B ).

GENERAL MORPHOLOGY OF THE CRANIAL SINUSES

Figures

Figure 2. Craniofacial pneumaticity of Velociraptor. Skull AMNH FARB 6515 in (A, C) lateral and (B, D) medial views, with the rostrum in (E) lateral and (F) medial views. Abbreviations: aofen, antorbital fenestra; aof, antorbital fossa; mf, maxillary fenestra; mx, maxilla; pmf, promaxillary fenestra; mi, maxilla interior;?pipf, premaxillary pneumatic foramina; pmx, premaxilla; pf, pneumatic foramina of the frontal; front, frontal; nf, neurovascular foramina; rugose, rugose bone surface; smooth, smooth bone surface. In (C) and (D), light blue are neurovascular foramina, light green is the maxillary fenestra, light red is the promaxillary fenestra, tan is an additional maxillary fenestra.