The fairy shrimp genus Branchinella Sayce (Crustacea: Anostraca: Thamnocephalidae) in Western Australia,including a description of four new species

The genus Branchinella is diverse in Western Australia, with 18 species, including four new species described here. B. complexidigitata n. sp. is characterized by an intricate frontal appendage, unlike any within the genus. The other three are less remarkable; B. halsei n. sp. is like B. lyrifera, B. kadjikadji n. sp. belongs to the B. affinis group and B. nana n. sp. is similar to B. simplex; similarities are based on frontal appendage and to a lesser extent on the second antennae and penis. Only two species, B. affinis and B. longirostris, are common and widespread; many of the remainder being localized endemics. The high diversity in Western Australia is explained by broad latitudinal range, habitat diversity, and great age and isolation of the landscape.