Stygobromus culveri Holsinger 1978

Stygobromus culveri

Stygonectes species.—Holsinger, Baroody, and Culver, 1976:24.

MATERIAL EXAMINED.—WEST VIRGINIA. Randolph Co.: Stillhouse Cave, holotype (USNM 168805). 5 , 1 paratypes (USNM) and 1 paratype on slide mounts (JRH), J. R. Holsinger, D. C. Culver, S. B. Peck, and P. J. Starr, 21 Jun 1968.

DIAGNOSIS.—A small, rather aberrant member of the emarginatus group easily distinguished by the relatively long setae of the antennae and coxal plates of the gnathopods and pereopods 3 and 4, presence of 3 plumose setae on inner plates of maxillae, proportionately rather long posterio margin of 1st gnathopod propod, and long, slender spines on pereopods 5–7, uropods 1–3, and telson. Largest male, 2.3 mm; largest females, 3.2 mm.

FEMALE.—Antenna 1, 50 percent length of body, about 60 percent longer than antenna 2; primary flagellum with 10–13 segments. Antenna 2: flagellum short, with 3 segments. Mandibles subequal; spine row with 4 spines; segment 2 of palp with 2 long setae, segment 3 with 1 long seta on outer margin, several short setae on inner margin, 4 or 5 long setae on apex. Maxilla 1: inner plate with 3 apical, plumose setae; palp with 5 or 6 stiff setae apically. Maxilla 2, inner plate with oblique row of 3 plumose setae on inner margin. Maxilliped: apex of inner plate with 2 bladelike spines, 1 plumose spine and 2 naked setae, inner margin with 1 plumose spine or seta distally; outer plate with naked setae on inner margin and apex and 1 plumose seta apically. Lower lip with small inner lobes.

Propod of gnathopod 1 subequal in size to 2nd propod; palm with 3 spine teeth; defining angle with 3 long spine teeth on outside, 2 shorter ones on inside; medial setae few, singly inserted. Dactyl nail of gnathopod 1 long. Coxal plate of gnathopod 1 longer than broad, with 2 long marginal setae. Gnathopod propod 2: palm equal in length to posterior margin, armed with double row of 2 spine teeth; defining angle with 1 long spine tooth on outside, shorter one on inside; medial setae few, singly inserted. Dactyl nail of gnathopod 2 rather long. Coxal plates of gnathopod 2 and pereopod 3 about as broad as long, margins with 2 long setae each. Coxal plate of pereopod 4 slightly broader than long, about 40 percent length of basis, margin with 4 long setae. Pereopod 7 slightly longer than 6, 50–55 percent length of body, 30–35 percent longer than pereopod 5. Pereopods 5–7: bases with convex posterior margins and broadly rounded distoposterior lobes; segments 4–6 with long, slender spines; dactyls rather long. 40–45 percent length of corresponding propods. Three long, slender median sternal gills on pereonites 2–4; 2 pairs long, simple lateral sternal gills on pereonites 6 and 7; sternal gills absent from pleonite 1. Brood plates sublinear, not expanded distally.

Pleonal plates: posterior margins convex, with 1 seta each; posterior corners small, narrowly rounded; ventral margin of plate 3 with 1 spine. Uronites completely fused. Uropod 1: inner ramus subequal in length to outer ramus, 65–70 percent length of peduncle, armed with 9 long spines; outer ramus with 7 long spines; peduncle with 4 spines. Uropod 2: inner ramus subequal in length to outer ramus and peduncle, armed with 7 mostly long spines; outer ramus with 10 long spines; peduncle with 3 spines. Uropod 3: ramus nearly 50 percent length of peduncle, with 3 long apical spines. Telson longer than broad, slightly tapering distally; apical margin entire, with 11 or 12 long spines.

MALE.—Differing from female as follows: Uropods 1 and 2 with few less spines. Peduncular process of uropod 1 small, apex trilobed. Ramus of uroped 3 with 2 apical spines. Telson with 6 apical spines.

TYPE-LOCALITY.—Stillhouse Cave (sometimes called Hermit Cave), located approximately 9.7 km west of Spruce Knob near Osceola in Randolph Co., West Virginia. This cave is developed in the Greenbrier limestone and lies just north of the drainage divide between the Greenbrier River (upper Kanawha drainage basin) and Gandy Creek (upper Monongahela drainage basin). The cave was originally described by Davies (1958:315) and more recently by Medville and Medville (1971:157–159).

DISTRIBUTION AND ECOLOGY.—This species is known only from its type-locality, where it was collected from a series of mud-bottom seep and drip pools. Four females, measuring 2.4–3.2 mm, had setose brood plates but none were ovigerous.

ETYMOLOGY.—It is a pleasure to name this species in honor of my distinguished colleague, Dr. David C. Culver, who has contributed significantly to our knowledge of the ecology of aquatic cave crustaceans.

The ackerlyi Group

DIAGNOSIS.—Closely allied morphologically with the emarginatus group but distinguished from that group as follows: Adult size range, 4.5(?)–8.0 mm. Posterior margins of pleonal plates with 1 seta each in notch formed just above posterior corner. Uronites free, not fused.