Taxonomic investigation of the zooplanktivorous Lake Malawi cichlids Copadichromis mloto (Iles) and C. virginalis (Iles).

Abstract

The taxonomic status of the zooplanktivorous cichlids Copadichromis mloto and C. virginalis has been confused since their original descriptions by lles in 1960. While two forms of C. virginalis, Kaduna and Kajose, were distinguished in the type material, C. mloto has not been positively identified since its original description. Here we re-examined the types as well as 54 recently collected specimens from multiple sampling locations. Genome sequencing of 51 recent specimens revealed two closely related but reciprocally monophyletic clades. Geometric morphological analysis indicated that one clade morphologically encompasses the type specimens of C. virginalis identified by Iles as the Kaduna form, including the holotype, while the other clade encompasses not only the paratypes identified as the Kajose form, but also the type series of C. mloto. Given that all three forms have the same type locality, that there are no meristic or character states to differentiate them and that there are no records of adult male C. mloto in breeding colours, we conclude that the Kajose form previously identified as C. virginalis represents relatively deeper bodied sexually active or maturing individuals of C. mloto.