The taxonomy of the Tarentola mauritanica species complex (Gekkota: Phyllodactylidae): Bayesian species delimitation supports six candidate species

Abstract

The lack of morphological diagnosable characters typical of cryptic species, poses a particular problem to taxonomists. This is especially true when taxa are closely related, sharing considerable amounts of ancestral polymorphism. Phylogenetic studies on the Moorish gecko species-complex, Tarentola mauritanica, uncovered extremely high levels of mtDNA diversity with six identified clades, including one from the Canary Islands identified as T. angustimentalis. Because of the conserved morphology of this species and its paraphyletic status with respect to T. angustimentalis, it was suggested that T. mauritanica is a cryptic species complex. Nevertheless, none of the nuclear loci used were reciprocally monophyletic regarding the mitochondrial lineages due to retention of ancestral polymorphism. In this study, we added three new intron markers to the already available dataset and used additional tools, namely phylogenetic gene trees, species tree and species limits within a Bayesian coalescent framework to confirm the support of the main lineages. Bayesian clustering analysis supports all six mtDNA lineages as independent groups, despite showing signs of ancestral polymorphism or possibly gene flow between the Maghreb/South Iberia and Central Morocco clades. The species tree recovered two major groups; one clustering taxa from Europe and Northern Maghreb and another one encompassing the lineages from Central/Southern Morocco, Central Morocco and Canary Islands, indicating that the ancestor of T. angustimentalis came from the Central/Southern Morocco region. Finally, Bayesian coalescent species delimitation analysis supports all six mitochondrial clades as “unconfirmed candidate species”, pending morphological data to define them.