Figures & data
Figure 1 Photographs of well preserved enantiornithine skulls: A, Rapaxavis pani, DNHM D2522; B, Longipteryx sp., DNHM D2889; C, Pengornis houi, IVPP V15336; D, Shenqiornis mengi, DNHM D2950; E, Longipteryx chaoyangensis, IVPP V12552; F, Cathayornis yandica, IVPP V9769; G, juvenile Euenantiornithes indet, GMV 2158. All scale bars = 1 cm.
Figure 2 Camera lucida drawings of select enantiornithine skulls: A, Rapaxavis pani, DNHM D2522; B, Longirostravis hani, IVPP V11309; C, Longipteryx chaoyangensis, IVPP V12325; D, Eoenantiornis buhleri, IVPP 11537; E, Longipteryx sp., DNHM D2889; F, Longipteryx chaoyangensis, IVPP V12552; G, Shenqiornis mengi, DNHM D2951; H, Pengornis houi, IVPP 15336; I, Alethoalaornis agitornis, LPM 00009; J, Cathayornis yandica, IVPP V9769; K, Dapingfangornis sentisorhinus, LPM 00039; L, M, Gobipteryx minuta, IGM-100/1011, right and left lateral views.
Table 1 A list of known enantiornithine specimens that preserve skull material; grey indicates unpublished material.
Figure 3 Interpretive drawings of select juvenile enantiornithine skulls: A, GMV 2159; B, C, LP 4450 slab and counterslab. Anatomical abbreviations: cmf, caudal mandibular fenestra; den, dentary; frn, frontal; jug, jugal; la, lacrimal; max, maxilla; nas, nasal; oc, occipital condyle; pmx, premaxilla; po, postorbital; qd, quadrate; rmf, rostral mandibular fenestra; sq, squamosal; sur, surangular.
Figure 4 Close-up of the skull of Eoenantiornis buhleri IVPP showing the two alternate interpretations of the specimen: A, the S-shaped bone fragment is inferred to be part of the maxilla as in CitationZhou et al. (2005); B, the S-shaped bone as the lacrimal. See for anatomical abbreviations.
Figure 5 Basicrania: A, the Early Cretaceous Shenqiornis mengi, DNHM D2951; B, the Late Cretaceous Neuquenornis volans, MUCPv 142. Abbreviations: boc, basioccipital; bt, basal tubera; cerebral prominence; eoc, exoccipital; fm, foramen magnum; fov, foramen for the external occipital vein; nh, canals for the hypglossus nerve; oc, occipital condyle; ocoe, ostium canalis ophthalmici externi; pop, paraoccipital process; soc, supraoccipital.
Figure 6 Ternary diagram showing the relative proportions of skull units among Enantiornithes, relative to Neornithes. Abbreviations: B, braincase; O, orbit; R, rostrum.
Figure 7 Enantiornithine teeth, photographs and interpretative drawings: A, B, Eoenantiornis buhleri, IVPP 11537; C, D, Shenqiornis mengi, DNHM D2951; E, F, Pengornis houi, IVPP 15336; G, H, Longirostravis hani, IVPP V11309; I, J, Longipteryx chaoyangensis, IVPP V12552; K, L, Longipteryx sp., DNHM D2889.
Figure 8 Reconstructions of the skulls of enantiornithines: A, Shenqiornis mengi; B, Rapaxavis pani; C, Pengornis houi. All scale bars = 1 cm.
