Stygobromus parvus (Holsinger 1969)

Stygobromus parvus (Holsinger)

Apocrangonyx species A.—Holsinger, 1969a:28.

Apocrangonyx parvus Holsinger, 1969b:22–25, fig. 9 [type-locality: Crawford Cave No. 2, Randolph Co., West Virginia]; 1972:54.—Holsinger, Baroody, and Culver, 1976:21.

Stygobromus parvus (Holsinger).—Karaman, 1974:116.—Holsinger, 1977:262.

MATERIAL EXAMINED.—WEST VIRGINIA. Pocahontas Co.: Piddling Pit Cave, 2 , 2 , J. R. Holsinger and D. C. Culver, 12 Aug 1972.

DIAGNOSIS.—A small cavernicolous species, closely allied morphologically with S. ephemerus, but distinguished from that species by the diagnosis of Holsinger (1969b:22) and in the above key. Largest males, 2.6 mm; largest female, 3.0 mm.

DESCRIPTION.—Corresponding to the description by Holsinger (1969b:22–25) with the following additions and modifications: Antenna 1, 50–60 percent length of body. Propod of gnathopod 1 a little larger than 2nd propod. Pereopods 6 and 7 sometimes about equal in length, 50–60 percent length of body, 30–35 percent longer than pereopod 5. Uronites fused.

DISTRIBUTION AND ECOLOGY.—This species is recorded from three caves in eastern West Virginia: Piddling Pit and Cassell caves, which are developed along the eastern flanks of Cloverlick and Back Allegheny mountains, respectively, in the upper Greenbrier River drainage; and Crawford Cave No. 2, which is west of Cheat Mountain in the upper Tygart River drainage (upper Monongahela basin). Stygobromus parvus has been collected from mud-bottom, drip, and seep pools in all three caves. Several females (2.5–3.0 mm) from August collections in Piddling Pit and Crawford No. 2 caves had setose brood plates. In Piddling Pit, this species occurs sympatrically with both S. emarginatus and S. nanus, new species, but these species have not been found together in the same place within the cave.

Stygobromus parvus, commonly called the minute cave amphipod, is a troglomorphic species of amphipod in family Crangonyctidae. It is endemic to West Virginia in the United States.