Metacrangon variabilis Rathbun, 1902 sensu lato (Crustacea: Decapoda: Crangonidae) in the North-West Pacific, and applicability of subspecies rank to marine invertebrate taxa

Abstract

Metacrangon variabilis Rathbun, 1902 sensu lato was earlier considered to consist of two subspecies: the nominotypical one from the North-East Pacific, and M. variabilis asiaticus (Kobjakova, 1955), occurring in the waters of Kuril and Komandor Islands. Although recently both have been given a species rank, and this status is accepted in World Register of Marine Species (WoRMS). In the present study we report a new record of M. varaiabilis variabilis from the western Bering Sea. The type series of M. variabilis asiaticus (female holotype from off Shikotan I. and 42 paratypes) along with non-type material was located in the collection of Zoological Institute of Russian Academy of Sciences. They were examined with regard to variation of characters used to distinguish between the two subspecies (or species in the alternative view). Most of characters strongly vary, and only relative size of the middorsal carapace teeth may be used for diagnosing M. variabilis variabilis and M. variabilis asiaticus. Assuming a likely existence of the contact zone in the distribution of these subspecies in the western Bering Sea, it appears premature to elevate their subspecies rank to species. From cognitive standpoint, such nomenclature act would create a false impression of understanding a complex structure of M. variabilis sensu lato. For taxonomic revisions, we recommend to consider marine invertebrate subspecies described by earlier authors on case by case basis, but avoiding to rise their rank to species in the absence of extensive analysis of distribution-related morphological variation, and gene markers data. How to cite this article: Spiridonov V.A., Petryashov V.V. 2019. Metacrangon variabilis Rathbun, 1902 sensu lato (Crustacea: Decapoda: Crangonidae) in the North-West Pacific, and applicability of subspecies rank to marine invertebrate taxa // Invert. Zool. Vol.16. No.3. P.239–253. doi: 10.15298/invertzool.16.3.05