A taxonomic revision helps to clarify differences between the Atlantic invasive Ptilohyale littoralis and the Mediterranean endemic Parhyale plumicornis (Crustacea, Amphipoda)

Abstract

Ptilohyaleexplorator (formerly Parhyaleexplorator), described by Arresti (1989), can be considered to be a synonym of west-Atlantic Ptilohyalelittoralis (Stimpson, 1853), based on morphological observations of paratypes and specimens recently collected in the type locality of Ptilohyaleexplorator. The first collections of Ptilohyalelittoralis, from the eastern Atlantic were from the port of Rotterdam (The Netherlands) in 2009 and later in Wimereux, Opal Coast (France) in 2014; however, the synonymy of Ptilohyaleexplorator with Ptilohyalelittoralis backdates to the first European record of Ptilohyalelittoralis in 1985 at La Vigne, Bay of Arcachon (France). This indicates that Ptilohyalelittoralis has been established along European Atlantic coast for many years. An assessment of the nominal valid species belonging to the genus Ptilohyale was carried out and a comparison between the Atlantic Ptilohyalelittoralis and the very similar Mediterranean hyalid species, Parhyaleplumicornis, is presented based on morphological features and distribution. Due to the invasive ability of Ptilohyalelittoralis, a comparison between the two species is necessary.