An updated classification of the freshwater crayfishes (Decapoda: Astacidea) of the world, with a complete species list

Abstract

The freshwater crayfishes are a group of decapod crustaceans that have played a critical role in a diversity of biological studies, from physiology, to ecology, neurobiology, conservation, and evolution. Central to many of these fields of study is the dependence on a robust taxonomic framework for accurate communication relating to species diversity and associated attributes. Despite a huge body of taxonomic work since Linnaeus, there has never been a single, comprehensive taxonomic summary of all the species of crayfish of the world. There has also been an abundance of recent taxonomic work in terms of new species descriptions and taxonomic insights gained from a variety of phylogenetic studies. Here we gather diverse taxonomic and phylogenetic information into a single resource. We develop an updated classification system that includes all the crayfishes worldwide and taxonomic changes to better reflect the current phylogenetic knowledge of the group. We also include all the fossil crayfish taxa for a complete classification of extant and extinct crayfishes. Our classification results in two superfamilies (Astacoidea and Parastacoidea), five families, 38 genera, and 669 species (692 including distinct subspecies). We provide a checklist of all species and include validated taxonomic authorities, type localities, figure references, and synonyms. We also provide arguments for our revised classification. The updated and complete classification aims to provide a robust framework for future studies of the freshwater crayfishes of the world.

Phenotypic variability of rusty crayfish (Faxonius rusticus) at the leading edge of its riverine invasion

“…In this study, we investigated changes in rusty crayfish (Faxonius rusticus, Girard 1852, previously Orconectes rusticus, Crandall & De Grave, 2017) traits across their invasion gradient in the John Day River (JDR), the only known occurrence of this species west of the North American continental divide (Olden, Adams, & Larson, 2009) and where secondary spread is ongoing (Messager & Olden, 2018).…”

The marbled crayfish (Decapoda: Cambaridae) represents an independent new species

“…However, the International Code of Zoological Nomenclature (ICZN, 1999) excludes "forma" for names published after 1960 (Article 15.2). Consequently, the provisional name for marbled crayfish was also considered "unavailable" in a recent taxonomic summary of freshwater crayfish (Crandall & De Grave, 2017).…”

Comparative morphology of crayfish mandibles, with insight into their evolution

“…The generalized phylogenetic tree (after Crandall & De Grave, ) showing the evolutionary position of the main crayfish taxa, by comparing the main types of mandibles of their representatives, is presented in Figure . The tree indicates the basal divisions of the examined crayfish taxa, thereby separating (a) the Northern and Southern Hemisphere crayfish, while the further subdivisions of the “northern” crayfish branch reveal, (b) the East Asiatic genus Cambaroides as basally separated (Cambaroididae), and (c) the European ( Astacus , Austropotamobius , Pontastacus ) with American ( Pacifastacus ) Astacidae and the American Cambaridae as sister‐positioned clades.…”