Asterocheres intermedius ( Hansen, 1923 )

Bandera, Eugenia & Conradi, Mercedes, 2009, Redescription of Asterocheres suberitis Giesbrecht, 1897 and A. tenerus (Hansen, 1923) (Copepoda: Siphonostomatoida), including notes on A. abyssi (Hansen, 1923) and A. intermedius (Hansen, 1923), Zootaxa 1980, pp. 41-52 : 43

Asterocheres intermedius ( Hansen, 1923)

Ascomyzon intermedium Hansen 1923: 6 .

Asterocheres intermedius: Stock 1966b: 152 ; Johnsson 1998: 91.

Material examined. Holotype Ψ ( ZMUC. CRU-6873/8357) collected during the “Danish Ingolf Expedition” in Davis Strait, Station 25 (63º30΄N, 54º25΄W), at 582 fathoms (ca. 1.06 km).

Hosts. Unknown.

Distribution. Atlantic Ocean ( Hansen 1923).

Remarks. Hansen (1923) omitted some taxonomically important appendages, such as the mandible and fifth legs (the latter lost in the type specimen), in his description of A. intermedius . Unfortunately, this species has not been recorded again, and only the antennule and antenna could be observed in the damaged, dissected holotype. Our observations of the pre-oral appendages differed from the original description as follows: 1) the antennule, despite being cleanly broken in half in the holotype, consists of 21 rather than 20 free segments; and 2) the endopod of the antenna is comprised of 3 instead of 2 segments. Despite these amendations, a detailed redescription of this species is still badly needed.

Contrary to the above species, A. intermedius can be easily differentiated from its congeners. For instance, A. intermedius , along with the following 19 congeners, possess a 21-segmented antennule in females: A. astroidicola Conradi, Bandera & López-González, 2006 ; A. bacescui ( Marcus, 1965) ; A. echinicola (Norman, 1868) ; A. ellisi Hamond, 1968 ; A. flustrae Ivanenko & Smurov, 1997 ; A. hirsutus Bandera, Conradi & López- González, 2005; A. jeanyeatmanae Yeatman, 1970 ; A. lilljeborgi (Boeck, 1859) ; A. lunatus Johnsson, 1998 ; A. madeirensis Bandera, Conradi & López-González, 2007 ; A. minutus (Claus, 1889) ; A. reginae Boxshall & Huys, 1994 ; A. simulans ( T. Scott, 1898) ; A. suberitis Giesbrecht, 1897 ; A. tenerus ( Hansen, 1923) (redescribed below as possessing a 21-segmented antennule in female); A. tenuicornis Brady, 1910 ; A. uncinatus (Kritchagin, 1873) ; A. urabensis Kim, 2004 ; and A. violaceus (Claus, 1889) . Among these species, only A. ellisi , A. urabensis , A. hirsutus , A. tenerus and A. astroidicola have a siphon extending beyond the insertion of leg 1 as in A. intermedius . However, these four species do not have a genital double-somite that is longer than wide as in A. intermedius .