Anguidae

Villa, Andrea & Delfino, Massimo, 2019, A comparative atlas of the skull osteology of European lizards (Reptilia: Squamata), Zoological Journal of the Linnean Society 187 (3), pp. 828-928 : 863

Anguidae ( Fig. 22V –AA)

The quadrate of European anguids is a straight and subrectangular bone in anterior view. Only a low to moderately developed lamina is present along the lateral margin of the pillar. The degree of development of this lamina is higher in Pseudopus apodus ( Fig. 22Y, Z ) than in Anguis gr. An. fragilis ( Fig. 22V, W ). Because of this, Anguis gr. An. fragilis lacks a real conch ( Fig. 22W ), whereas the conch of Pseudopus apodus is narrow and very shallow ( Fig. 22Z ). A similar-sized or slightly more developed lamina is present on the medial side of the bone, developing a small pterygoid flange near its ventral end (less recognizable in Pseudopus apodus and in juveniles of Anguis gr. An. fragilis ). The cephalic condyle is very strongly expanded both posteriorly and anteriorly and so the bone appears very wide in its dorsal portion in lateral view. In Anguis gr. An. fragilis , the anterior expansion tends to bend ventrally, creating an anterodorsally directed articulation surface with a rounded outline in lateral view ( Fig. 22X ). In Pseudopus apodus , the same expansion does not bend ventrally and the anterior outline of the bone appears angular in lateral view ( Fig. 22 AA). The posterior expansion is straighter in lateral view and slightly wider in dorsal view. A ridge runs ventrally from the expansion along the posterior surface of the pillar body of the bone. The mandibular condyle is moderately wide in posterior view and its portions are poorly ventrally developed and similar in size. Even if the lateral lamina is not much developed, a small ( Anguis gr. An. fragilis ) or deep ( Pseudopus apodus ) notch on the lateral side of the cephalic condyle is still recognizable in dorsal view: this could be a remnant of the foramen for the chorda tympani nerve. The maximum length varies from 1.9 mm to 2.7 mm in Anguis gr. An. fragilis and from 6.5 mm to 7.8 mm in Pseudopus apodus .

EPIPTERYGOID

The epipterygoid ( Fig. 23 ) is a rod-like paired bone.

Figures

Figure 22. Quadrates (continued). A–C, Ac. erythrurus (UAM.R.ACVII), right quadrate in anterior (A), posterior (B) and medial (C) views. D–F, Po. bocagei (UAM.R.PB48), right quadrate in anterior (D), posterior (E) and medial (F) views. G–I, Ti. lepidus (MDHC 216), right quadrate in anterior (G), posterior (H) and medial (I) views. J–L, Chalcides chalcides (MDHC 398), right quadrate in anterior (J), posterior (K) and medial (L) views. M–O, Chalcides ocellatus (MDHC 250), right quadrate in anterior (M), posterior (N) and medial (O) views. P–R, Ophiomorus punctatissimus (MDHC 427), left quadrate in anterior (P), posterior (Q) and medial (R) views. S–U, Tr. aurata (MDHC 280), right quadrate in anterior (S), posterior (T) and medial (U) views. V–X, Anguis gr.An. fragilis (MDHC 102), right quadrate in anterior (V), posterior (W) and medial (X) views. Y– AA, Pseudopus apodus (MDHC 214), left quadrate in anterior (Y), posterior (Z) and medial (AA) views. Abbreviations: ap, anterior platform; c, conch; cc, cephalic condyle; ll, lateral lamina; mc, mandibular condyle; ml, medial lamina; p, pillar; pf, pterygoid flange; qf, quadrate foramen; tc, tympanic crest. Scale bars = 1 mm.

Figure 23. Epipterygoids.A, Laudakia stellio (NHMW 570; not to scale). B, Lacerta bilineata (MDHC 381). C, Chalcides chalcides (MDHC 94). D, Ophiomorus punctatissimus (MDHC 427; reversed for comparison). E, Anguis gr. An. fragilis (MDHC 102). Abbreviations: e, epipterygoid; p, prootic. Scale bars = 1 mm.