Anguidae

Anguidae View in CoL View at ENA ( Fig. 43Q–T View Figure 43 )

Dentaries of anguids have a narrow and horizontal mandibular symphysis, like lacertids and scincids. In dorsal view,a small, medially developed expansion of the posterior end of the symphysis is recognizable ( Fig. 44 View Figure 44 ). The subdental shelf is distinctly developed in the ventral direction and covers the narrow Meckelian fossa almost entirely. Thefore, the fossa opens ventrally and only its wider posterior end is visible in medial view. The subdental ridge is not present and the dorsomedial surface of the shelf is, therefore, smooth. The sulcus dentalis is also absent. Roughly at the beginning of the posterior fourth ( Anguis gr. An. fragilis ; Fig. 43Q View Figure 43 ) or third ( Pseudopus apodus ; Fig. 43S View Figure 43 ) of the tooth row, the subdental shelf presents a posteriorly developed and pointed splenial spine that is moderately long in Anguis gr. An. fragilis and short in Pseudopus apodus . The intramandibular septum develops posteriorly with a pointed portion, which reaches the notch between the posterior processes. This portion is free (i.e. unfused to the wall of the fossa) in Anguis gr. An. fragilis ( Fig. 43Q View Figure 43 ), but fused with the wall of the bone in Pseudopus apodus ( Fig. 43S View Figure 43 ). The opening of the alveolar canal is located at the end of the ninth tooth position in Anguis gr. An. fragilis [near the last tooth position, as stated by Klembara et al. (2014); Fig. 43Q View Figure 43 ] and between the ninth and the 11 th tooth position in Pseudopus apodus ( Fig. 43S View Figure 43 ). Like in the maxilla, teeth are large and subpleurodont, with the maximum size that is reached in the middle of the tooth row in Anguis gr. An. fragilis and in its third-quarter in Pseudopus apodus . In the former species, teeth are monocuspid, trenchant, well-spaced, unstriated and distinctly posterolingually bent at their tip ( Fig. 43Q, R View Figure 43 ), whereas the latter species has monocuspid, cylindrical and slightly robust teeth, provided with a pointed and not curved tip, anteriorly and large, cylindrical and stout teeth, provided with a blunt and rounded crown posteriorly ( Fig. 43S, T View Figure 43 ). Moreover, teeth of Pseudopus apodus are closely spaced and their change in size is gradual. Weak striae are visible both labially and lingually on the crowns of the teeth of Pseudopus apodus , but not in those of Anguis gr. An. fragilis . The inferior posterior process [angular process in Klembara et al. (2014)] is short and pointed, whereas the superior one is long and large (more than twice the former in length). The two posterior projections of the superior process [named, from the dorsal one to the ventral one, coronoid and surangular processes in Klembara et al. (2014)] are separated by a moderately wide and deep U-shaped notch [coronoid incisure in Klembara et al. (2014)]. They are similar in size in Anguis gr. An. fragilis ( Fig. 43Q, R View Figure 43 ), but the dorsal one is distinctly shorter than the ventral one in Pseudopus apodus ( Fig. 43S, T View Figure 43 ). The surangular process of Pseudopus apodus bears an opening for the anterior surangular foramen ( Fig. 43T View Figure 43 ), since this process covers the surangular opening of this foramen in this species. In medial view, the bone has a rather convex ventral margin, whose posterior end bends distinctly in dorsal direction. The flexure of the posterior end appears to be stronger in Anguis gr. An. fragilis than in Pseudopus apodus . The maximum length of the alveolar shelf goes from 3.8 mm to 6.5 mm in Anguis gr. An. fragilis and from 17 mm to 20 mm in Pseudopus apodus . Anguis gr. An. fragilis has ten or 11 tooth positions [eight or nine in the specimens studied by Edmund (1969)] and three or four mental foramina, whereas in Pseudopus apodus they range from 12 to 18 and from four to seven, respectively.

SPLENIAL

The paired splenial ( Fig. 45 View Figure 45 ) is a blade-like bone, pierced by two foramina: the anterior inferior foramen anterodorsally and the anterior mylohyoid foramen posteroventrally.