Redescription of Asterocheres suberitis Giesbrecht, 1897 and A. tenerus (Hansen, 1923) (Copepoda: Siphonostomatoida), including notes on A. abyssi (Hansen, 1923) and A. intermedium (Hansen, 1923)

摘要

The present paper reviews the type material of four poorly described species of Asterocheres Boeck, 1859 deposited in the Zoologisk Museum of the University of Copenhagen. For A. abyssi (Hansen, 1923) and A. intermedius (Hansen, 1923), each taxon wasrepresented by only the poorly preserved, dissected holotype. Consequently, neither species could be redescribed in detail. As the original description of A. abyssi is not sufficient to differentiate it from its congeners, we propose to regard this species as undetermined. Although only the antennule and antenna of A. intermedius were amended, this species is still considered valid based on a combination of characters that include a 21-segmented antennule, oral siphon extending beyond leg 1 insertion, and genital double-somite being longer than wide. The other two species, A. suberitis Giesbrecht, 1897 and A. tenerus (Hansen, 1923), were redescribed which revealed inaccuracies in the original descriptions. Asterocheres suberitis is characterized by having a 21-segmented antennule, oral siphon extending to the maxilliped insertion, 2-segmented mandibular palp, and genital double-somite being wider than long. Asterocheres tenerus is distinguished by a combination of characters that include a 21-segmented antennule, oral siphon extending to the intercoxal plate of leg 2, 2-segmented mandibular palp, relatively slimmer and longer claws on the antenna, maxilla and maxilliped, and genital double-somite being about as long as wide.