Chevroderma Scheltema 1985

Chevroderma Scheltema, 1985

Scheltema, 1985: 512.

Type species: Chevroderma turnerae Scheltema, 1985 (OD).

Diagnosis (emended): Sclerites with a usually distinct, but sometimes faint, medial groove extending part way or entire length of sclerite. Growth lines and base of sclerites chevron-shaped. Plane of sclerite blade bent outwards from plane of base; or blade reduced to a sharp, raised nipple. Longitudinal axis straight or bent at waist. Waist usually distinct, blade narrower than base at waist, edges of blade nearly straight and tapered. Isochromes on each side of groove asymmetrical, thickest beside groove. Two rows of oral shield sclerites.

Distribution: Species have been found in most of the world’s oceans: eastern and western north and south Atlantic including the Gulf of Mexico, eastern and western Indian Ocean, eastern and western north and south Pacific, and central north Pacific; the genus has not been found in the Mediterranean Sea. The shallowest depth recorded is 357 m (herein for Ch. cuspidatum n. sp.); the deepest, for Ch. hadalis Ivanov, is 8,390 m in the Kurile-Kamchatka Trench. Only new species described here occur at continental slope depths; all other Chevroderma species have been found at continental rise, abyssal, and hadal depths (Scheltema, 1985; Ivanov, 1996; Ivanov & Scheltema, 2001a, 2002; including unpublished data).

Composition: Ch. cuspidatum n. sp., Ch. gauson Scheltema, 1985, Ch. hadalis Ivanov, 1996, Ch. javanicum Ivanov & Scheltema, 2002, Ch. lusae Ivanov & Scheltema, 2002, Ch. paradoxum Ivanov & Scheltema, 2001, Ch. scalpellum Scheltema, 1985, Ch. turnerae Scheltema, 1985, Ch. vityazi Ivanov & Scheltema, 2002, and Ch. whitlachi Scheltema, 1985 (Panama Basin only).