Patterns of morphological and genetic variation in western Indian Ocean members of the Chaerephon 'pumilus' complex (Chiroptera: Molossidae), with the description of a new species from Madagascar

Abstract

The species delimitations of African, Arabian Peninsula, and western Indian Ocean island members of the Molossidae bat species complex Chaerephon pumilus remain largely unresolved. Based on genetic analyses this group is paraphyletic, with C. leucogaster nested within C. pumilus sensu lato, and the latter is composed of several distinct clades. DNA was isolated from a specimen of C. p. pumilus obtained at the type locality (Massawa, Eritrea). Although incomplete, this sequence allowed us to clearly define which clade is referable to nominate pumilus, a critical step in resolving the systematics of this species complex. Using morphological and molecular genetic (cytochrome b and D-loop sequences) characters, we establish that C. leucogaster and C. 'pumilus' on Madagascar represent two different lineages and that the Malagasy population referred to C. 'pumilus' is specifically distinct from those on Africa, the islands and mainland Africa. The population of C. pusillus from the western Seychelles atoll of Aldabra cluster with that of the Comoros, rather than Madagascar. For numerous other species of volant vertebrates (bats and birds), the origin of the Aldabra fauna is mixed between the Comoros and Madagascar (e.g., Goodman & Ranivo 2008; O'Brien et al. 2009; Pasquet et al. 2007; Warren et al. 2003). Hence, in the case of these 9-17 g Chaerephon bats, these water barriers have been associated with the isolation and subsequent differentiation of populations after successful dispersal and colonization events. In contrast, within the Comoros, there is no apparent genetic structure between with the individual islands, which are separated by 40 and 80 km, indicating that this distance is regularly traversed by these bats and giving rise to intra-archipelago panmixia of populations.