Anguidae Gray, 1825

Conrad, J. L., 2008, Phylogeny And Systematics Of Squamata (Reptilia) Based On Morphology, Bulletin of the American Museum of Natural History 2008 (310), pp. 1-182 : 114

Anguidae Gray, 1825

(figs. 54D, 55D, 56C)

DEFINITION: Anguis fragilis , Gerrhonotus liocephalus , Diploglossus fasciatus , and all descendants of their last common ancestor.

DIAGNOSIS: Anguids form a clade diagnosed by 9(0) absence of dermal sculpturing on the prefrontal, 10(0) absence of dermal sculpturing from the frontal and parietal, 31(1) neochoanate condition, 58(0) linear interorbital margins of the frontal, 67(1) presence of a frontal-palatine contact, 171(2) free posteroventral margin of the intramandibular septum, 183(2) dentary contributing to dorsal and anterior margin of the anterior inferior alveolar foramen, 207(1) retroarticular process that is posteriorly expanded (broadened), 210(2) strongly twist- ed retroarticular process, 254(2) chevrons fused to the vertebrae, and 304(1) presence of a lateral body fold.

COMMENTS: The definition of Anguidae used here follows that of Estes et al. (1988), but uses more specific anchor taxa. Note that if glyptosaurines are found to be outside of crown-anguids, then they must be considered distinct from Anguidae following this definition. However, the current analysis supports the general hypothesis of Gauthier (1982) that glyptosaurines are nested within extant anguids (figs. 54–56).

Gerrhonotinae McDowell and Bogert, 1954 (figs. 54D, 55D, 56C)

DEFINITION: All taxa sharing a more recent common ancestor with Gerrhonotus liocephalus than with Anguis fragilis , Anniella pulchra , or Diploglossus fasciatus .

DIAGNOSIS: The current analysis recovers five unambiguous gerrhonotine synapomorphies based on the included taxa, these are 88(1) supratemporal elongate, 173(1) coronoid contribution to the external border of the anterior surangular foramen, 186(1) angular process of dentary terminates anterior to the level of the coronoid process, 251(2) double, converging, caudal transverse processes, and 312(1) presence of keeled body osteoderms.

COMMENTS: The position of Parophisaurus pawneensis (5? Xestops pawneensis Gilmore, 1928 ; 5 Pancelosaurus pawneensis Meszoely, 1970 ; 5 Odaxosaurus pawneensis Meszoely et al., 1978 ) as a basal gerrhonotine in this analysis is unexpected. Sullivan (1987) regarded P. pawneensis as a proximal outgroup to the North American anguine Ophisaurus , but did not offer a cladistic analysis. Sullivan (1987) further cautioned, however, that P. pawneensis is a difficult taxon to interpret because it is relatively plesiomorphic in much of its known morphology. A preliminary phylogenetic study of squamates suggested that P. pawneensis is the sister-taxon to a clade containing Anguinae and Diploglossinae ( Conrad, 2005a) . Comparisons of Parophisaurus pawneensis (AMNH FR8711) with extant taxa reveal that Parophisaurus pawneensis more closely resembles Ophisaurus ventralis than Gerrhonotus liocephalus in muzzle shape, dermal sculpturing, possessing extensive internasal contact, and in the relative contribution of the dentary to the anterior inferior alveolar foramen margin, but this parsimony analysis interprets those similarities as plesiomorphies or convergence.

Gerrhonotines are interpreted by this analysis to be the basalmost lineage of Anguidae . Although P. pawneensis is from the Middle Oligocene, the gerrhonotine lineage must have been distinct by the Late Cretaceous.