Scincidae

Scincidae View in CoL ( Fig. 12C–L, S–U View Figure 12 )

Scincids have a very deep, U-shaped concavity on the anterior margin of the anterior premaxillary process, due to the presence of well-developed and pointed anterolateral and anteromedial processes ( Fig. 12S– U View Figure 12 ). The two processes are roughly similar in size. The posterior process is long and usually pointed

(MDHC 427), left maxilla in dorsal view. V, Anguis gr. An. fragilis (MDHC 102), left maxilla in dorsal view. Abbreviations: alp, anterolateral process; amp, anteromedial process; app, anterior premaxillary process; ar, arched ridge; l, lappet; ps, palatal shelf; sdf, superior dental foramen; vnf, vomeronasal foramen. Scale bars = 1 mm.

and does not present steps. Except for Ophiomorus punctatissimus ( Fig. 12I, J View Figure 12 ), its posterior tip is slightly shifted in the dorsal direction ( Fig. 12C–H, K, L View Figure 12 ). The location of the small vomeronasal foramen is similar to the condition seen in lacertids, but in scincids the concavity is shallower because of the absence of a clearly developed lateral ridge. The medial ridge, on the other hand, is present but low in Chalcides ocellatus ( Fig. 12G, H View Figure 12 ) and Tr. aurata ( Fig. 12K, L View Figure 12 ), and well developed in Ab. kitaibelii ( Fig. 12C, D View Figure 12 ), Chalcides chalcides ( Fig. 12E, F View Figure 12 ), Chalcides striatus and Ophiomorus punctatissimus ( Fig. 12I, J View Figure 12 ). In the latter four species, the ridge continues on the dorsal surface of the anteromedial process in a distinct lappet. In Ophiomorus punctatissimus , the lappet bends strongly in the medial direction, giving a forked aspect to the anterior end of the anteromedial process in dorsal view ( Fig. 12U View Figure 12 ). The opening of the superior dental foramen is medially oriented. A moderately deep groove is present on the dorsal surface of the posterior process, posteriorly to the latter foramen, although it seems not to be in continuity with it (as it is, for example, in lacertids). As in the premaxillae, teeth are similar to those of gekkotans ( Villa et al., 2018a), but they have a slightly posterolingually curved crown provided with light striae on the lingual surface. Teeth are absent only on the tip of the posterior process. The ones of Chalcides ocellatus are robust and have a blunt and very enlarged crown ( Fig. 12G, H View Figure 12 ). Even if not as much as in Chalcides ocellatus , more robust teeth are present in Ophiomorus punctatissimus too ( Fig. 12I, J View Figure 12 ). In the latter species, the increase in robustness is less marked in the anteriormost teeth, but becomes more evident towards the posterior end of the tooth row. Anyway, the last tooth is slightly smaller than the preceding one. The facial process is roughly pentagonal in lateral view. The anterior and posterior margins are concave, whereas the anterodorsal and posterodorsal ones are roughly straight, although slightly irregular. Trachylepis aurata differs from the other species in having a strongly concave posterodorsal margin ( Fig. 12K, L View Figure 12 ). Ophiomorus punctatissimus does not display a clear distinction between an anterodorsal and a posterodorsal segment of the dorsal margin, which is rather convex in this species ( Fig. 12I, J View Figure 12 ). In Chalcides chalcides , Chalcides striatus and Tr. aurata , the dorsal margins are similar in length ( Fig. 12E, F, K, L View Figure 12 ), whereas in Ab. kitaibelii and Chalcides ocellatus the anterodorsal one is longer than the posterodorsal one ( Fig. 12C, D, G, H View Figure 12 ). In Ab. kitaibelii , this difference in length is very strongly marked, because the posterodorsal margin is less than one-third of the anterodorsal one ( Fig. 12C, D View Figure 12 ). The anterior, dorsal and posterior corners of the process are pointed in Chalcides ( Fig. 12E–H View Figure 12 ), but they do not develop projections. Trachylepis aurata shares a similar morphology, but the dorsal corner is rounded ( Fig. 12K, L View Figure 12 ), whereas all corners are rounded in Ab. kitaibelii and Ophiomorus punctatissimus ( Fig. 12C, D, I, J View Figure 12 ). The lateral surface is smooth, whereas a very low arched ridge is visible on the medial one. This latter ridge is similar to the one present in some lacertids, but much lower (almost not recognizable in Ab. kitaibelii , Chalcides ocellatus , Ophiomorus punctatissimus and Tr. aurata ). The Supporting Information 4 includes measurements, number of tooth positions and number of ventrolateral foramina.