Family Trogonophidae (Shorthead Worm Lizards)

Order Squamata
Suborder Amphisbaenia

---

Family Trogonophidae (Shorthead Worm Lizards)

Trogonophis wiegmanni;
© Axel Kwet

Content: 4 genera with 6 species

Appearance: Trogonophids can be distinguished from other amphisbaenians by their triangular cross section. In addition they have acrodont teeth as opposed to pleurodont teeth in other amphisbaenians (in acrodont vertebrates teeth are attached to the apex = acron of the dentaries, maxillae, or premaxillae, whereas pleurodont species have their teeth attached to the medial surface of the bone). They lack caudal autonomy which is present in most other amphisbaenians. Snout strongly flattened snout with slightly upturned edges.

Diagnosis: Acrodonty, an enlarged sternal plate, an elongated nasal process of the premaxilla, scapulocoracoids bent posteriorly, short tail, absence of caudal autotomy, and a strong craniofacial angle (also present in rhineuroids). [After Kearney 2003].

Size: 8-24 cm snout-vent length.

Distribution: Turkey, Northern Africa, Somalia and the Middle East.

Habitat: Dry, loose sand

Behavior: Burrowing; unlike the other amphisbaenians, trogonophids use their tail as a brace to support the backward thrust of their digging. Their burrows match the shape of their noncircular bodies. They create their burrow by an alternating rotational movement of the head, which simultaneously shaves off the sides of the tunnel and compacts the wall.

Reproduction: oviparous, except the live-bearing Trogonophis

Relationships and sytematic notes: Trogonophids are the most divergent amphisbaenians. Vanzolini (1951) diagnosed this group (his subfamily Trogonophinae) based on acrodont dentition. Gans (1960) elevated the subfamily to family status. He also listed many characters in support of the monophyly of Trogonophidae: acrodonty, ossification of the extracolumella, a relatively short and stout body, and lack of caudalautotomy, among others. The monophyly of the trogonopids has been confirmed by Kearney (2003) who also included the fossil genus Listromycter, which was previously assigned to the Amphisbaenidae. See the Amphisbaenidae page for a phylogenetic tree that includes the Trogonophidae.