A review of Dendrocephalus (Dendrocephalinus) (Crustacea: Anostraca) with the first records of male-male anostracan aggressive competition

We present a review of Dendrocephalus (Dendrocephalinus) with an updated diagnosis for the subgenus and a key to all known species. We provide new records of Dendrocephalus alachua, which was previously supposed to be extinct, and we describe a new species, Dendrocephalus proeliator sp. nov., which is separated from all other species based on the form of the male frontal appendage. Dendrocephalus proeliator sp. nov. appears to be morphologically intermediate between D. alachua and D. lithaca. In addition, we provide conservation assessments for all four species in the subgenus, according to IUCN Red List standards. We also report for two species the first known examples of direct male-male agonistic behaviour and competition for access to areas frequented by receptive females.