Phylogenetic relationships in the Sceloporus variabilis (Squamata: Phrynosomatidae) complex based on three molecular markers, continuous characters, and geometric morphometric data. ZOOLOGICA SCRIPTA 48:419–439. DOI: 10.1111/zsc.12349
Abstract
The monophyly of the Sceloporus variabilis group is well established with five species
and two species complexes, but phylogenetic relationships within species complexes
are still uncertain. We studied 278 specimens in 20 terminals to sample all
taxa in the “variabilis group,” including three subspecies in the “variabilis complex,”
and two outgroups (Sceloporus grammicus and Sceloporus megalepidurus).
We assembled an extensive morphological data set with discrete and continuous
characters (distances and scale counts), including geometric morphometric data
(landmark coordinates of three shapes), and a three‐marker molecular data set as well
(ND4, 12S and RAG1). We conducted parsimony and Bayesian phylogenetic inferences
on these data, including several partitioning and weighting schemes. We suggest
elevating three subspecies to full species status. Therefore, we recommend
recognition of nine species in the “variabilis group.” First, S. variabilis is sister to
Sceloporus teapensis. In turn, Sceloporus cozumelae is sister to Sceloporus olloporus.
These four species are a monophyletic group, which is sister to Sceloporus
smithi. Finally, Sceloporus marmoratus is sister of the clade of five species. The
other species in the “variabilis group” (Sceloporus chrysostictus, Sceloporus couchii
and Sceloporus parvus) are a paraphyletic grade at the base of the tree. Our analyses
reject the existence of the “variabilis complex.” We conducted a parsimony‐based
ancestral reconstruction on body size (snout–vent length), femoral pores and dorsal
scales and related morphological changes to geographic distribution of the species.
Our phylogenetic hypothesis will allow best designs of comparative studies with species
in the “variabilis group,” one of the earliest divergent lineages in the genus.
KEYWORDS
geometric morphometrics, homology, phylogenetic morphometrics, Sceloporus, species complex
