Molecular phylogenetics reveals extreme morphological homoplasy in Brazilian worm lizards challenging current taxonomy

Abstract

Amphisbaenians are fossorial squamate reptiles distributed mainly in South America and Africa. Brazilian worm lizards belong to the family Amphisbaenidae, which has far more recognized species than any of the other five amphisbaenian families. Morphological datasets recovered Amphisbaenidae as paraphyletic, while previous molecular phylogenetic studies did not include enough taxa to solve the generic-level relationships within this family. We present a molecular phylogenetic hypothesis based on a sample of 58 amphisbaenians, including representatives of six of the seven South American genera. Our molecular data include sequences from two mitochondrial genes (16S, ND2; 1,184 characters) and three nuclear genes (RAG-1, C-MOS, BDNF; 1,898 characters). Our phylogenetic hypothesis is not fully resolved, although it does not support the monophyly of most genera except Leposternon. Morphological characters currently used to diagnose genera of South American amphisbaenians are homoplastic, and the taxonomy based on them is not appropriate. We revise the taxonomy of this group and sink several South American genera of Amphisbaenidae (Cercolophia, Bronia, Aulura, Anops and Leposternon) into Amphisbaena.

Amphisbaena trachura Cope, 1885 (Amphisbaenia: Amphisbaenidae): new record for the northeast of Argentina

“…The family Amphisbaenidae contains about 175 species distributed in 11 genera (Uetz and Josek 2015), this number included the recently synonymized genus by Mott and Vieites (2009) into Amphisbaena (Anops, Aulura, Bronia, Cercolophia and Leposternon).…”

“…The genus Amphisbaena Linnaeus, 1758 includes 107 species (Mott and Vieites 2009;Uetz and Josek 2015), with ten species known from Argentina. Amphisbaena heterozonata Burmeister, 1861, A. hiata Montero and Céspedez, 2002, A. mertensii Strauch, 1881, A. prunicolor (Cope, 1885), A. kingii (Bell, 1833) and A. microcephalum (Wagler, 1824 are known to occur in Corrientes province (Abdala et al 2012).…”

Phylogeny and evolution of head shape in the Amphisbaenia (Reptilia: Squamata)

“…Some studies tried to correlate the cranial variation with geography or phylogeny (Kearney, 2003;Mott & Vieites, 2009;Measey & Tolley, 2013). The present study suggested that these groups defined by cranial variation do not reflect the biogeographical distribution neither the phylogenetic relationship.…”

“…Contrary to Mott and Vieites (2009), Ribeiro et al (2011), described a South American species, and revalidated the genus Leposternon, stating that the taxonomic changes on the Neotropical amphisbaenids were precipitated due to the low bootstrap supports and little morphological evidences. Although plausible, Ribeiro et al (2011) considered that the decision to synonymize the genus Leposternon to Amphisbaena needed more evidence.…”

“…Kearney (2003) using morphological data concluded that the Amphisbaenia with the keel-headed and shovel-headed shape form a monophyletic group, but these groups were considered tentative, given the possibility that this character is functionally correlated (Gans, 1974). However, Kearney & Stuart (2004) and Mott & Vieites (2009), based on their results, stated that the cranial morphotypes are a result of morphological convergence. Furthermore, Kearney & Stuart (2004) emphasized that the different forms of the head would be related to the geographic distribution of these taxa, as suggested by Gans (1978).…”