Anguidae

Anguidae View in CoL View at ENA ( Fig. 42D View Figure 42 )

In anguids, the stapes has a short shaft with no stapedial foramen, and a large and elliptical footplate.

DENTARY

The dentary ( Fig. 43 View Figure 43 ) is a long, paired bone. It is straight in both dorsal and medial views, but the anterior end bends moderately in the medial direction. The mandibular symphysis covers the medial surface of the anterior end. The Meckelian fossa stands out on the medial surface of the bone, housing the anterior portion of the Meckel’s cartilage. Dorsally to the fossa, there is an alveolar shelf [parapet in Rage & Augé (2010)] supporting the teeth. The bony structures separating the Meckelian fossa from the alveolar shelf were differently named by different authors in the past [including the authors of the present paper; see, for example: Villa et al. (2018a, b)], generating a certain degree of ambiguity on how to correctly define some terms. We herein follow the terminology proposed by Rage & Augé (2010), updating it with a single addition (the subdental ridge; see below). We choose this terminology because it gives clear definitions of the terms used. Teeth are supported ventrally by a subdental table. This table more or less extends medially to form a subdental shelf that is not covered dorsally by the tooth bases. Dorsally, the subdental shelf can have a subdental ridge, which marks the medial margin of the sulcus dentalis. The alveolar canal is present between the Meckelian fossa and the subdental table, housing the inferior alveolar nerve. This canal is visible only as a foramen opening in the posterior direction, since the intramandibular septum closes it medioventrally. The inferior posterior process and the superior posterior process develop at the posterior end of the dentary. They are laminar and posteriorly directed. The lateral surface of the dentary is smooth in extant European lizards, except for a variable number of anteroposteriorly aligned mental foramina.

Before describing the dentaries of the different lizard groups herein considered, we briefly revise the descriptions of the groups treated by Villa et al. (2018a, b), using a terminology different to those of Rage & Augé (2010). In gekkotans, the subdental table strongly develops medially to form a subdental shelf that is extensively expanded ventrally and contributes to the enclosure of the Meckelian fossa. Dorsally, a distinct subdental ridge and the related sulcus dentalis are visible. In Blanus , the subdental shelf is rather high in medial view, but not strongly extended in the medial direction. Posteriorly, the subdental shelf displays a wide V-shaped notch in medial view. A low subdental ridge and a shallow sulcus dentalis are present dorsally. The reader is still referred to the original papers for the rest of the description of the dentary in these two groups.