Stygobromus barryi Holsinger 1978

Stygobromus barryi

MATERIAL EXAMINED.—TENNESSEE. Unicoi Co.: Rlankenship Cave, holotype partly on slide mounts (USNM 168794) and 2 paratypes (JRH), L. M. and B. L. Ferguson, 8 Jul 1972.

DIAGNOSIS.—A medium-sized cavernicolous species distinguished from S. sparsus, with which it is apparently closed allied, by the presence of a distinct peduncular process on uropod 1 of the male and a tiny ramus on uropod 3 (of mature male). Largest male, 5.5 mm; largest females (immature), 3.0 mm.

MALE.—Antenna 1, 45–50 percent length of body, 40–45 percent longer than antenna 2; primary flagellum with 15 segments. Antenna 2, flagellum with 6 segments. Mandibles subequal; spine row with 5 spines; segment 2 of palp with row of long setae on inner margin, segment 3 with 1 long seta on outer margin, 1 long seta and row of short setae on inner margin, and 4 or 5 long setae apically. Maxilla 1: inner plate with 9 apical, plumose setae; palp with 2 slender spines and 4 stiff setae apically. Maxilla 2, inner plate with oblique row of 10 plumose setae on inner margin. Maxilliped: inner plate with 2 bladelike spines, 2 plumose spines and 1 naked seta apically, and 1 or 2 plumose spines (or coarse setae?) and 1 naked seta subapically; outer plate with naked setae on inner margin and apex and sometimes 1 very lightly plumose seta on apex. Inner lobes of lower lip small.

Propod of gnathopod 1 a little smaller than 2nd propod; palm with double row of 9 spine teeth; defining angle with 3 long spine teeth on outside, 2 shorter ones on inside; posterior margin with 3 setae; medial setae singly inserted. Dactyl nail of gnathopod 1 rather short. Coxal plate of gnathopod 1 longer than broad, margin with 3 setae. Gnathopod propod 2: palm slightly convex, armed with double row of 12 spine teeth; defining angle with 1 long spine tooth on outside, 2 shorter ones on inside; posterior margin with 2 sets setae; medial setae singly inserted. Dactyl nail of gnathopod 2 rather short. Coxal plates of gnathopod 2 and pereopod 3 longer than broad, margins with 4 setae each. Coxal plate of pereopod 4 as broad as long, reaching about 45 percent length of basis, margin with 6 setae. Pereopod 6 a little longer than pereopod 7, 50–55 percent length of body, about 30 percent longer than pereopod 5. Bases of pereopods 6 and 7 narrowing somewhat distally, distoposterior lobes distinct, bluntly rounded. Dactyls of pereopods 5–7, 30–35 percent length of corresponding propods. Coxal gill absent from pereopod 7. Median and pleonite sternal gills absent; 2 pairs rather long, simple lateral sternal gills on pereonites 6 and 7.

Pleonal plates: posterior margins convex, with 1 seta each; posterior corners of plates 1 and 3 indistinct, bluntly rounded, that of plate 2 small and distinct; ventral margins of plates 2 and 3 with 3 spines each. Uronites partly fused. Uropod 1: inner ramus longer than outer ramus, about 65 percent length of peduncle, armed with 10 spines; outer ramus with 10 spines; peduncle with 13 spines; peduncular process about 30 percent length of outer ramus, tapering distally, apex weakly serrate. Uropod 2: inner ramus longer than outer ramus, slightly shorter than peduncle, armed with 11 spines; outer ramus with 9 spines; peduncle with 6 or 7 spines. Uropod 3: ramus tiny, only about 1/12 length of peduncle, armed with 1 apical spine. Telson about as broad as long; apical margin incised about 25 percent the distance to base, armed with 16–18 spines.

FEMALE.—Two specimens in collection immature but differing from male as follows: Antennae, gnathopods, pereopods, and telson having fewer setae and spines overall. Three long, median sternal gills on pereonites 2–4. Ramus absent from uropod 3. Brood plates small and narrow, not setose.

TYPE-LOCALITY.—Blankenship Cave, located 3.2 km northeast of Erwin in Unicoi Co., Tennessee, is a small cave developed in Lower Cambrian dolomite of the Shady or Rome formation. The cave is essentially dry except for a stream trickle in the rear (Barr, 1961:445).

DISTRIBUTION AND ECOLOGY.—This species is known only from its type-locality, where it was collected from under rocks in a stream trickle with a clay substrate. Blankenship Cave lies approximately 145 km northeast of Gregorys Cave (type-locality of 5. sparsus) and is in the Nolichucky River drainage (upper Tennessee River basin).