Two copepod species largely confused: Asterocheres echinicola (Norman, 1868) and A. violaceus (Claus, 1889). Taxonomical implications

Abstract

Due to its extremely brief description, Asterocheres echinicola (Norman, 1868) has been confused with some Asterocheres species such as Asterocheres suberitis Giesbrecht, 1897, Asterocheres parvus Giesbrecht, 1897 and Asterocheres latus (Brady, 1872). Furthermore, this species has been considered conspecific with Cyclopicera lata (Brady, 1872) and Asterocheres kervillei Canu, 1898. The objective of this paper is to study the syntypes of Asterocheres echinicola deposited in the Museum of Natural History of London together with abundant material from this and other institutions. Re-examination of these syntypes revealed that Asterocheres echinicola was conspecific with the currently known Asterocheres species, A. violaceus. Therefore, this latter species should be considered as a junior synonym of the former. The specimens described by Brady as Cyclopicera lata represent distinctively Asterocheres echinicola (=Asterocheres violaceus) and are identical to Sars's Ascomyzom parvum and to Giesbrecht's Asterocheres echinicola. We propose to rename Cyclopicera lata as Asterocheres latus (Brady, 1872), and raise Sars' Ascomyzon latus, a species which is different from Asterocheres echinicola (=Asterocheres violaceus) and from Asterocheres latus (=Cyclopicera lata), as a new species. In this paper, we not only redescribe both species A. echinicola and A. latus, but also compare them with their previous descriptions, with the new material available and with their congeners. The redescription of Asterocheres latus revealed new specific differences between this species and Asterocheres kervillei, a species considered as synonymous of Asterocheres latus for almost 40 years. We strongly recommend that these differences are sufficient to consider these two species different. Finally, we analyzed the implications of all these taxonomical changes with respect to the diversity of the hosts utilized by these copepods and their geographical distribution. © Springer-Verlag and AWI 2009.