Bainguidae Borsuk-Białynicka, 1984

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 : 97

Bainguidae Borsuk-Białynicka, 1984

(figs. 54B, 55B, 56B)

DEFINITION: All taxa sharing a more recent common ancestor with Bainguis parvus than with Lacerta viridis , Scincus scincus , or Varanus varius .

DIAGNOSIS: Bainguids, as defined here, are united by five unambiguous synapomorphies, including 53(1) presence of a jugal-squamosal contact, 96(2) postorbital extending posteriorly for more than 3/4 the length of the supratemporal fenestra, 121(1) midline contact of the palatines, 193(1) coronoid labial flange present, but not greatly developed posteriorly, and 203(1) presence of a prearticular crest.

COMMENTS: Bainguidae was originally erected as a monospecific ‘‘family’’ described as possessing both scincomorph and anguimorph affinities, but conservatively placed as a member of a ‘‘preanguimorphan grade’’ (Borsuk-Białynicka, 1984). Later, Bainguis parvus was shown to have affinities with Anguidae ( Borsuk-Białynicka, 1991; Gao and Hou, 1996; Gao and Norell, 1998) and Bainguidae was synonymized with Anguidae (Alifanov, 2000) . Gao and Norell (1998) alone have cladistically analyzed the position of Bainguis parvus . They provided evidence of anguine affinities for Bainguis , but cautioned that this poorly known taxon could not be scored for many of the anguid characters ( Gao and Norell, 1998).

The current analysis is the first to include Bainguis parvus in a cladistic analysis with non-anguimorph fossils such as Myrmecodaptria and Eoxanta lacertifrons . Thus, this is the first analysis in which Bainguidae , as it is currently used, had the potential to be discovered. Given the relative completeness of our knowledge of B. parvus , prudence is exercised in the current definition of Bainguidae .

Note that the phylogenetic position of Bainguidae within Autarchoglossa is not strongly supported. A secondary analysis of only osteological characters (see below) suggested that bainguids are lacertoids. Further analysis of the position of Bainguidae is appropriate given this result and the convergences between this clade and the plesiomorphic condition for Scincomorpha and some of its constituent clades.