Asterocheres abyssi Hansen 1923

Asterocheres abyssi (Hansen, 1923)

Ascomyzon abyssi Hansen 1923: 8.

Asterocheres abyssi: Stock 1966a: 209; Johnsson 1998: 96; Kim 2004: 181.

Material examined. Holotype ɗ (ZMUC. CRU-5026) collected during the “Danish Ingolf expedition” in Davis Strait, Station 36 (61º50΄N, 56º21΄W), at 1,435 fathoms (ca. 2.62 km).

Hosts. Unknown.

Distribution. Atlantic Ocean (Hansen 1923).

Remarks. This species was described by Hansen (1923) based on a damaged male and has not been subsequently recorded. Re-examination of the material deposited in the ZMUC did not yield any useful taxonomic information due to the poor condition of the type specimen. Therefore, the only morphological information regarding this species is that provided by Hansen (1923), who described A. abyssi as possessing: 1) a 5-segmented urosome, with the anal somite nearly as long as wide and slightly longer than the two preceding somites combined; 2) a genital somite as long as broad; 3) caudal rami shorter than anal somite; 4) a presumably 17-segmented antennule (however, Hansen could only observe 15 segments in the type specimen); 5) the terminal claw of the antenna as long as the first endopodal segment; 6) a siphon that extends beyond the insertion of the maxillipeds; 7) a maxillulary palp (outer lobe) about one-third as long as the praecoxal endite (inner lobe) and armed with two terminal setae; and 8) a 2-segmented mandibular palp (see Hansen 1923: Plate I, fig. 4b).

Descriptions of Asterocheres species are, with the exception of A. abyssi, A. ovalis Sewell, 1949 and A. alter Eiselt, 1965, based on females. Indeed, the male is unknown in more than one-third of these descriptions. Among the known males, A. jeanyeatmanae Yeatman, 1970 and A. major (Thompson & Scott, 1903) share the eight aforementioned characteristics with A. abyssi. As there are no known features to distinguish A. abyssi from these congeners, we consider it as an undetermined taxon.