Morphology of the Mandible and Gill of the Asian Freshwater Crayfish Cambaroides (Decapoda: Cambaridae) with Implications for Their Phylogeny

Abstract

Morphology of the masticatory surface of the mandibles, branchiae on pereiopods, and gill formulae have phylogenetic implications in freshwater crayfishes of the Northern Hemisphere (Astacidae, Cambaridae in Asia and North America). Here the mandibles and branchiae are described and illustrated for all four species of Cambaroides (Decapoda: Cambaridae). The mandible, gill, and gill formulae are similar in morphology in all four species of Cambaroides (Asian Cambaridae). However, the masticatory surfaces on the mandible of the members of Asian Cambaridae differ from those of the Astacidae and Cambaridae occurring in North America (American Cambaridae). The morphology and formula of the branchiae of Cambaroides show similarity to those observed in the members of Astacidae and American Cambaridae. However, the all species of Cambaroides differ from both Astacidae and American Cambaridae in lacking pleurocoxal lappet (= pendant) on the fourth pereiopod. These findings support phylogenetic results from molecular analyses.