Amigdoscalpellum costellatum (Withers, 1935) Figure 20

Scalpellum elongatum Hoek, 1883: 93, pl. IV, figs 8, 9. - Nilsson-Cantell 1928: 8, fig. 4. - 1931: 3, text-fig.1. - 1938: 7.

non Scalpellum ( Arcoscalpellum) elongatum . - Steenstrup, 1837: 409.

Scalpellum (Scalpellum) elongatum . - Stubbings, 1936: 25, text-fig. 10.

Scalpellum (Arcoscalpellum) costellatum Withers, 1935: 279.

Arcoscalpellum buccinum Newman & Ross, 1971: 55, pl. VIII, figs 22, 23.

Arcoscalpellum costellatum . - Foster, 1978: 56, pl. 7B, C, fig. 33.

Amigdoscalpellum costellatum . - Foster, 1980: 527-529, fig. 3J. - Zevina 1981: 270-271, fig. 204. - Jones et al. 1990: 5 - Jones 2012: 371, 376 - Poltarukha 2013: 52-53, fig. 1. - Shalaeva and Boxshall 2014: 16, fig. 9.

Material examined.

- Tanimbar Island: 2 specimens, MNHN-IU-2019-4922, Stn. CC 21, 05°14'S, 133°00'E, 688-694 m depth, 25 October 1991, attached to glass rope sponge.

Diagnosis.

Capitulum triangular; plates ornamented with radial ridges, covered by sparsely hirsute integument; carina with roof deeply grooved; scutum with apex overlapping tergum; inframedian latus triangular, very small.

Desciption. Capitulum yellowish, with 13 fully calcified plates. Peduncles short with scales slightly overlapping in the middle part. Scutum with pit for complemental males, above shallow pit for adductor muscle. Carina wide in lower part, ribbed in upper part. Upper latus with straight sides; rostrum appearing externally as inverted triangle. Cirrus I unequal, anterior ramus oval, posterior ramus slender, long; cirrus VI with very short caudal appendages. Maxillule with notch between two or three stout setae at upper angle, group of more slender setae on cutting edge; mandible with three teeth excluding inferior angle; labrum cutting edge slightly concave, numerous pointed teeth on cutting edge. Measurements of two specimens: height of capitulum 12.44-13.88 mm, width 6.97-7.52 mm, thickness 2.77-3.47 mm; length of peduncle 2.99-3.15 mm, width 2.94-3.24 mm.

Distribution.

Indian Ocean, Eastern and Western; Pacific, Southwest and Western Central; Atlantic, Southeast and Eastern central; 110-2,397 m depth (Shalaeva and Boxshall 2014). In this study, Amigdoscalpellum costellatum was found at Tanimbar Island, Indonesia.

Type locality.

1. Station 135: Island of Tristan da Cunha; depth: 110 m, 137 m, 183 m, 274 m, 1,006 m, 1,829 m, 2,012 m; bottom: rocky, shells. 2. Station 164a: off Sydney, 34°13'S, 151°38'E; depth: 750 m; bottom: grey ooze. 3. Station 169: off East Cape, Auckland, 37°34'S, 179°22'E; depth: 1,280 m; bottom temperature: 4.2 °C; bottom: grey ooze (Hoek 1883).