The phylogenetic position of Anomochilidae (Reptilia: Serpentes): first evidence from DNA sequences

Abstract

Previously, anilioids (Aniliidae, Anomochilidae, Cylindrophiidae and Uropeltidae) were considered the only extant, non-macrostomatan alethinophidian snakes. Although their monophyly and intrarelationships remained poorly established, their fossoriality, small gape, and inferred phylogenetic position have been important evidence in orthodox scenarios about early snake evolution. Recent molecular studies including aniliids, cylindrophiids and uropeltids indicate anilioid polyphyly, with the latter two families comprising a clade nested within Macrostomata. We carried out the first molecular phylogenetic analysis to include the very poorly known and seemingly rare Anomochilidae. Only partial sequences of 12S and 16S rRNA mitochondrial genes could be amplified from tissue collected from a single dead specimen of Anomochilus leonardi. Amplification failed for nuclear and other mitochondrial genes, and for all the investigated genes for the holotype and paratype of A. leonardi. Analyses recovered a para-or polyphyletic Anilioidea. Anomochilus is recovered as most closely related to Cylindrophis maculatus (rendering Cylindrophiidae possibly paraphyletic). The relatively small amount of available data produces only moderate levels of support, but the stability of taxa and agreement across different analytical methods and with larger analyses of snake phylogeny support the abandonment of Anilioidea as a natural taxon, and the recognition of a higher category for a clade comprising Asian anilioids (Anomochilidae, Cylindrophiidae and Uropeltidae).

A phylogeny and revised classification of Squamata, including 4161 species of lizards and snakes

“…Together, these six families form a strongly supported clade (SHL = 89; Figures 1, 21) that is weakly supported as the sister group to the strongly supported clade of Boidae + Calabariidae. Within the clade of Anomochilidae, Cylindrophiidae, and Uropeltidae (Figure 21), we weakly place Anomochilus as the sister group to Cylindrophiidae [44], in contrast to previous studies which placed Anomochilus within Cylindrophis [161]. However, support for monophyly of Cylindrophis excluding Anomochilus is weak (Figure 21).…”

Comparative mitochondrial genomics of snakes: extraordinary substitution rate dynamics and functionality of the duplicate control region

“…The Scolecophidia (Typhlopoidea), represented here by L. dulcis , formed the sister group to all remaining snakes. Rather than finding support for the Caenophidia ( Acrochordus plus Colubroidea [7,15]), we find strong support for Acrochordus as the sister lineage to the Henophidia (including Cylindrophis ). Hereafter we will therefore operationally refer to this clade including the Henophidia and Acrochordus as the "Acro-Heno" clade, and we will refer to its sister clade as the Colubroidea [16].…”

Extinction, Ecological Opportunity, and the Origins of Global Snake Diversity

“…2) are highly congruent with previous analyses of various subsets (Vidal and Hedges 2002;Lawson et al 2004;Gower et al 2005;Vidal et al 2007Vidal et al , 2009Vidal et al , 2010Wiens et al 2008), representing the first phylogeny to include all known snake families and subfamilies based on molecular data. In concordance with previous studies, we find a sister relationship between the enigmatic Xenophiidae and Bolyeriidae (Lawson et al 2004), and between the poorly known Anomochilidae and Cylindrophiidae (Gower et al 2005). As with previous studies, monophyly of Booidea is weakly supported (Noonan and Chippindale 2006;Burbrink and Pyron 2008;Wiens et al 2008).…”

“…The matrix was 67% complete in terms of the number of total gene sequences present. However, for some rare taxa (e.g., Anomochilidae, Xenophiidae, and Scaphiodontophiinae), we obtained only one or a few genes (Lawson et al 2004; Gower et al 2005; Pyron et al 2011), as these groups are known from only a few specimens.…”