Stygobromus gracilipes (Holsinger 1967)

Stygobromus gracilipes (Holsinger)

Stygonectes gracilipes Holsinger, 1967:36–40, fig. 7 [type-locality: Skyline Caverns, Warren Co., Virginia]; 1969a:32–33; 1972:60.—Holsinger, Baroody, and Culver, 1976:23–24.—Holsinger, 1976:76.

Stygobromus gracilipes (Holsinger).—Karaman, 1974:111–112.—Holsinger, 1977:261.

MATERIAL EXAMINED.—MARYLAND. Washington Co.: Jug town Cave, 1 , L. R. Franz, Nov 1967 and 1 , 4 Jan 1969. VIRGINIA. Frederick Co.: Ogdens Cave, 1 , J. R. Holsinger, 25 Jan 1969; Rockingham Co.: Deer Hole Cave, 1 , J. R. Holsinger and R. W. Burnette, 9 Mar 1963; Endless Caverns, 1 , 1 juv., J. R. Holsinger, G. W. Dickson, and S. W. Hetrick, 17 Jan 1976; Massanutten Caverns, 1 (USNM). L. Hubricht, 13 Aug 1939; 3-D Maze Cave, 1 , J. R. Holsinger, 27 Jun 1974. WEST VIRGINIA. Berkeley Co.: Nestle Quarry Cave, 1 , 1 , J. R. Holsinger, 31 Mar 1973.

DIAGNOSIS.—A large cavernicolous species distinguished by proportionately long 6th and 7th pereopods, small, 1-spined ramus of uropod 3, dorsolaterally spinose telson, and by the description of Holsinger (1967). Largest males, 10.5 mm; largest females, 18.0 mm.

DISTRIBUTION AND ECOLOGY.—The range of this species extends from Rockingham Co., Virginia, north-northeast to Franklin Co., Pennsylvania, covering a linear distance of approximately 177 km. To date the specimens have been collected from 11 caves, all of which are situated in the Potomac River drainage and are developed in Cambrian and Ordovician limestones and dolomites.

Despite its comparatively long range, S. gracilipes is quite rare in most of the caves in which it occurs. Only in Skyline Caverns, Virginia, where seven collections over a 20-year period yielded 49 specimens, has this species been found in any abundance. Stygobromus gracilipes inhabits small streams and pools but has been found more frequently in the latter habitat. Females (10.0–18.0 mm in length) with setose brood plates have been collected during fall, winter, and spring but so far not in summer. One female (11.7 mm) from a January collection in Jugtown Cave, Maryland, was ovigerous and contained nine embryos in the brood pouch.