Opening a box of cryptic taxa - the first review of the North African desert lizards in the Trapelus mutabilis Merrem, 1820 complex (Squamata: Agamidae) with descriptions of new taxa

Abstract

We present a review of the morphology and current taxonomy of North African Trapelus species. The Saharo-Sindian agamid genus contains 15 species, of which five occur in northern Africa. The taxonomy of this complex group continues to provide difficulties for taxonomists because of a lack of consistent morphologically diagnostic characters and relatively high intraspecific morphological variation. In particular, the widespread species Trapelus mutabilis, which occurs from Egypt in the east to Mauritania in the west, has been identified as a species complex and probably represents an artificial grouping of unrelated taxa. This taxonomic uncertainty is exacerbated because a type specimen for T. mutabilis was never designated. In our taxonomic review, we designate a neotype for T. mutabilis, allowing a review of the northern African species, the description of two new taxa, and the compilation of a comprehensive identification key. We present a multivariate analysis of morphology within T. mutabilis and, in addition, we present a molecular phylogenetic analysis incorporating a ∼500-bp region of the mitochondrial 16S ribosomal RNA gene, and a relaxed molecular clock analysis to estimate the ages of clades within Trapelus. Our results demonstrate that these lineages have a deep and complex biogeographical history.