* Family Amphisbaenidae (Worm Lizards)
* Family Bipedidae (Two-legged Worm Lizards)
* Family Blanidae (see Amphisbaenidae)
* Family Cadeidae (see Amphisbaenidae)
* Family Rhineuridae (see Amphisbaenidae)
* Family Trogonophidae (Shorthead Worm Lizards)
Phylogenetic relationships according to Vidal et al. (2007)
Phylogenetic relationships according to Macey et al. (2004)
Single most parsimonious tree based on the analysis of 11,946 aligned nucleotide positions containing 5797 phylogenetically informative sites from 13 protein coding and 22 tRNA genes. Note that Gondwanan taxa, Trogonophidae (Diplometapon), and Amphisbaenidae (Amphisbaena and Geocalamus), are monophyletic. The two Laurasian families Rhineuridae (Rhineura) and Bipedidae (Bipes) represent successive, paraphyletic basal lineages indicating that amphisbaenian reptiles predate the breakup of Pangaea 200 million years ago. Modified from Figure 4 in Macey et al. (2004).
Order Squamata
Suborder Amphisbaenia
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.
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.
