Gyroscala watanabei

Description:

Dimensions range from 24.3 mm - 29.5 mm high and 8.2 mm - 9.1 mm wide.
Width to height ratio: 0.34:1 ~ 0.31:1

Shell: narrowly acuminate; thin and fragile; moderately small. Exterior colour yellowish brown, costae white. About 10 whorls, convex; with a very thin peripheral cord forming basal disc; protoconch conical smooth, usually defected in matured specimens. Suture deep. Approximately 20 - 25 costae on the body whorl. Costae are very thin and sharp, white in colour, weakly arcuate, crossed on basal cord. Occasional irregular varix present on each whorl varix appearing randomly on the shell. Intercostal spaces glossy with microscopic axial and spiral striae. Base with a thin peripheral cord forming basal disc. Columella margin thin. Aperture ovate; peristome incomplete; outer lip thin and slightly reflexed.

This species is very close to G. (Fragiliscala) tosaensis (Azuma, 1962), however, it is distinguishable in having slender shell, weak spiral striae and irregular varix on each whorl. [Nakayama, 2000]

Distribution:

off Kii Peninsula, Japan [Nakayama, 2000:279]; Aliguay, Island, Philippines [Brown & Neville, 2015:160]

Habitat:

60 m [Brown & Neville, 2015:160] to 300 m (Nakayama 2000: 281).

Etymology:

This species is named in honor of Mr. Tomio Watanabe, who collected the holotype specimen.

Type Material:

Holotype (NSMT Mo-71411), height 29.5 mm; breadth 9.1 mm (Figs. 9, 10). Paratype (Koyama collection), height 24.3 mm; for Gyroscala watanabei Nakayama, 2000 - Type Locality: Off Kumano-nada. off Kii Peninsula. at about 220m deep.. [Nakayama, T., 2000]
Holotype (NSMT-Mo 71411); Paratype (WMNH-Mo-29), off Kushimoto, Kii Peninsula, Japan) for Gyroscala watanabei Nakayama, 2000 - Type Locality: Kumanonada, off Kii Peninsula, Japan. [Nakayama, T., 2003]