Fig. 3
Scalpellum japonicum Hoek, 1883: 67, pl. III, figs 9–10; Annandale, 1906a: 141, fig. 3; Pilsbry, 1911: 66, pl. II, figs 1–3; Weltner, 1922: 69, Taf. II, fig. 4; Hiro, 1937a: 392; Tarasov & Zevina, 1957: 144, figs 46–47; Zevina, 1969: 68; 1970: 257–259, figs 5–6.
Scalpellum chitinosum Hoek, 1907: 73. Scalpellum curiosum Hoek, 1907: 49. Scalpellum japonicum biramosum Pilsbry, 1911: 68, fig. 4; Weltner, 1922: 69, Taf. II, fig. 5; Nilsson-Cantell, 1938: 7. Scalpellum japonicum metapleurum Pilsbry, 1907b: 360. Annandaleum japonicum Newman & Ross, 1971: 122; Zevina, 1981a: 166–167; Jones et al., 2000: 251; Young, 2001b: 465, fig. 8; 2007: 23, fig. 22.
Annandaleum japonicum biramosum Chan et al.: 2009: 98–99, fig. 80; Chan et al., 2010: 17–18, figs 2A, 14, 15.
Material examined. Holotype NHM UK 2013.1066, Stn 235: Pacific, Northwest (Off Nagoya, South of Japan); 1017 m. Found attached to an opisthobranch gastropod shell.
Supplementary descriptions. Zevina (1981a) and Chan et al. (2009).
Distribution. Pacific, Northwest and Western Central; Indian Ocean, Eastern. Known depth range 794 to 6810 m.
Habitat. Attached to rocks, gastropod shells, and gorgonian corals.
Remarks. The taxonomic status and morphological variability of A. japonicum and A. j. biramosum are in need of re-evaluation because of significant intraspecific variation in plate morphology, which seems to be dependent on body size. Changes during ontogenetic development include: the loss of the hairs on the external cuticle; the tergum becomes clearly bifurcate; the scutum develops two or three distinct branches; the shape of the carinal latus changes from quadrilateral to triangular or v-shaped, the rostral margin may show incipient branching; the shape of the upper latus changes from pentagonal to triangular, the carinal margin becomes branched; and the rostral latus carinal margin may be branched.