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 SaharoSindian 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.

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

“…We therefore retain Laudakia and Uromastyx as previously defined, to preserve taxonomic stability in these groups [113]. We note that recent studies have also begun to revise species limits in other groups such as Trapelus [145], and taxa such as T. pallidus (Figure 16) may represent populations within other species.…”

Small, rare and trendy: traits and biogeography of lizards described in the 21st century

“…V aranus palawanensis , Koch, Gaulke & Bohme, and Varanus bitatawa , Welton et al ., ; see Feldman et al ., ) were only recently described. Newly described lizards, however, never have very large ranges: the largest‐ranged species described in the 21st century, Trapelus boehmei (Wagner et al ., ), has only the 218th largest range of all lizards.…”

Unravelling biodiversity, evolution and threats to conservation in the Sahara‐Sahel

“…), where there is scarce or non‐existent sampling effort. Compilation and analysis of available species distribution data for Sahara‐Sahel fauna (Dumont, ; Le Berre, , ; Lévêque, ; Kingdon, ; Rödel, ; Denys, Granjon & Poulet, ; Crochet, Geniez & Ineich, ; Carranza et al ., , ; Geniez et al ., ; Wilson & Reeder, ; Baha El Din, ; Geniez & Arnold, ; Johnson et al ., ; Trape & Mané, ; Brito et al ., 2008, 2010, 2011 c ; Sindaco & Jeremčenko, ; Arnold, Robinson & Carranza, ; Granjon & Duplantier, ; Hoath, ; Nicolas et al ., ; Trape, ; Brahmi et al ., ; African Chiroptera Report, ; Ferreira et al ., ; Geniez, Padial & Crochet, ; Hekkala et al ., ; Wagner et al ., ; Trape, Chirio & Trape, ) indicates the presence of a total of 305 species of dragonflies, fishes, amphibians, reptiles and mammals, distributed mainly along a series of potential corridors and refugia (Table ). The role of mountains in deserts and arid regions as refugia now is being emphasised, and supported by studies in several taxa, such as ferns (Anthelme, Mato & Maley, ; Anthelme, Abdoulkader & Viane, ), fishes (Trape, ), amphibians and reptiles (Geniez & Arnold, ; Tellería et al ., ; Brito et al ., 2011 b , c ; Vale et al ., 2012 b ), birds (Tellería, ), and mammals (Busby et al ., ; Brito et al ., ; Vale, Álvares & Brito, 2012 a ).…”

“…Phylogeographic studies are revealing that diversification and speciation events that occurred in the Sahara‐Sahel are most likely related to temporal and spatial variation of desert extent. The onset of the Sahara presumably acted mainly as a North‐South vicariant feature, being associated with diversification processes for several species (Carranza et al ., , ; Carranza, Arnold & Pleguezuelos, ; Geniez & Arnold, ; Wagner et al ., ; Metallinou et al ., ) and to allopatric effects (Douady et al ., ; Muwanika et al ., ; Pook et al ., ; Gonçalves et al ., ). The palaeoclimatic oscillations following Sahara formation are estimated to have occurred at cycles of approximately 100000–20000 years during the last million years (Le Houérou, ), which greatly shaped the range of desert and savannah environments and constrained species distribution (Dumont, ; Le Houérou, , ; Drake et al ., ) and genetic structure (Fig.…”

“…Molecular studies will likely continue to reveal biodiversity and genetic analysis of museum specimens will provide essential material from regions where sampling is currently nearly impossible due to political instability. Geological and palaeoclimatic events are thought to be major drivers of biodiversity (e.g. Carranza et al ., , ; Geniez & Arnold, ; Wagner et al ., ; Metallinou et al ., ). Although the climate‐driven speciation hypothesis has been suggested to explain the evolutionary patterns at interspecific and intraspecific levels in the Sahara‐Sahel (e.g.…”