Scincidae

Scincidae View in CoL ( Fig. 26I–P View Figure 26 )

The most distinctive feature of the palatine of scincids is a strongly gutter-like shape in ventral view, due to the fact that both medial and lateral margins can develop laminar expansions that envelop the choanal duct [incipient secondary palate sensu Caputo (1991)]. The duct, therefore, appears very deep. The expansion of the medial margin is absent in Ab. kitaibelii and Tr. aurata ( Fig.26I, J, O, P View Figure 26 ) and poorly developed and ventrolaterally directed in Chalcides and Ophiomorus punctatissimus ( Fig. 26K–N View Figure 26 ). Its medial surface is the articulation surface with the opposite palatine. This expansion continues anteriorly in the dorsally concave (less concave in Ophiomorus punctatissimus ) vomerine process, which is short and small in Chalcides chalcides , Chalcides striatus and Ophiomorus punctatissimus ( Fig. 26K–N View Figure 26 ), long and narrow in Ab. kitaibelii and Chalcides ocellatus ( Fig. 26I, J View Figure 26 ), and long and wider in Tr. aurata ( Fig. 26O, P View Figure 26 ). The anterior projection is not well individualized in Chalcides ( Fig. 26K, L View Figure 26 ), slightly more recognizable in Ab. kitaibelii and Tr. aurata ( Fig. 26I, J, O, P View Figure 26 ), and distinctly recognizable in Ophiomorus punctatissimus ( Fig. 26M, N View Figure 26 ). The expansion of the lateral margin is directed ventromedially and very well developed, approaching the opposite one. Ablepharus kitaibelii and Tr. aurata have the maximum development of this lamina, which almost touches the medial margin of the bone in these two species ( Fig. 26I, J, O, P View Figure 26 ). The ventral surface of the expansion is smooth and its anterior end projects beyond the anterior margin of the bone and the anterior end of the vomerine process, being, therefore, visible in dorsal view too as a triangular projection. The anterolateral margin of this projection bears an articulation surface with the maxilla. The very short maxillary process is not clearly distinguishable from the rest of the bone. Its lateral margin has a notch that represent the medial margin of the infraorbital foramen. The notch is deeper in Ab. kitaibelii and Tr. aurata than it is in Chalcides , being also almost closed laterally in the former species. Only Ophiomorus punctatissimus displays a complete and moderately wide infraorbital foramen ( Fig. 26M, N View Figure 26 ). The pterygoid process is wide and subtrapezoidal, except for Ab. kitaibelii , in which it is very narrow and anteroposteriorly elongated. Because of the narrowing of the pterygoid process, a large portion of the posterior part of the expansion of the lateral margin of Ab. kitaibelii is visible in dorsal view ( Fig. 26I View Figure 26 ). A long and pointed process, slender in Chalcides chalcides and Chalcides striatus ( Fig. 26K, L View Figure 26 ), and wider in Ab. kitaibelii , Chalcides ocellatus , Ophiomorus punctatissimus and Tr. aurata ( Fig. 26I, J, M–P View Figure 26 ), develops posteriorly from its posterior margin, splitting the latter into two portions: the medial portion is oblique and regular, whereas the lateral one is straight and slightly irregular. The latter represents the contact with the pterygoid, whose palatine process is housed in an articulation surface recognizable on the ventral surface (marked anteromedially by a low and arched ridge in Chalcides chalcides ; Fig. 26L View Figure 26 ). The palatine ridge is moderately developed. The dorsal surface of the bone is smooth and no palatine teeth are present on the ventral one.