Examination of the Calumma nasutum group shows cryptic diversity
A comprehensive molecular phylogeny for the whole group of short-nosed chameleons (comprising the seven nominal species: Calumma boettgeri, C. fallax, C. gallus, C. guibei, C. linotum, C. nasutum, C. vohibola) was conducted to examine the genetic and species diversity in this widespread Malagasy chameleon group. Molecular and morphological differentiation was compared in detail for one particularly diverse clade (the Calumma boettgeri complex) from northern Madagascar. To assess the species boundaries within this group an integrative taxonomic approach was used, combining evidence from two independent molecular markers (ND2 and CMOS), together with distribution patterns (i.e., degree of syntopy) and genital and other external morphological characters (pholidosis). In conclusion, some of the newly discovered operational taxonomical units (OTU) are indeed separate species (confirmed candidate species, CCS), while others should best be considered as deep conspecific lineages (DCL). The analysis supported a total of 33 OTUs of which seven correspond to described species, two are CCS and three are DCL, suggesting that the taxonomy of the C. nasutum group is in need of revision. Practically this means that previous distribution data and conservation assessments for the nominal species of the C. nasutum group are in need of revision, given the presence of these comprise newly recognized cryptic species or lineages.
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