Diversification in the Comoros: Review of the Laccophilus alluaudi Species Group with the Description of Four New Species (Coleoptera: Dytiscidae)

Abstract

The <i>Laccophilus alluaudi</i> species group is an interesting case of an endemic species radiation of Madagascar and the Comoros. To date, a single species, <i>Laccophilus tigrinus</i> Guignot, 1959 (Anjouan), is known from the Comoro Islands, with eight other species known from Madagascar. Here we review the <i>Laccophilus alluaudi</i> species group from the Comoro Islands based on partly new material. We recognize five species, out of which four are here described as new: <i>L. mohelicus</i> n. sp. (Moh&eacute;li), <i>L. denticulatus</i> n. sp. (Grande Comore), <i>L. michaelbalkei</i> n. sp. (Mayotte) and <i>L. mayottei</i> n. sp. (Mayotte). Based on morphology of male genitalia, we hypothesize that the five species form a monophyletic group and originated from a single colonization event from Madagascar. If confirmed, this would constitute one of the few examples of intra-archipelago diversification in the Comoros. The knowledge of species limits in relation to their distribution in the Comoros archipelago is also urgently needed in the face of rapid habitat degradation.