Porrhomma cavernicola (Keyserling, 1886)

Figs. 17A–F.

Linyphia incerta Emerton, 1875 — Emerton (1875): p. 280, Plate I, Figs. 13–21 (descr. ♂ ♀); preoccupied, replaced by Roewer (1942); examined by Miller (2005).

Willibaldia cavernicola Keyserling, 1886 — Keyserling (1886): p. 123, Tab. XV, Fig. 204 (descr. ♀); transferred by Roewer (1942); examined by Miller (2005).

Troglohyphantes cavernicolus — Crosby (1905): p. 368, Figs. 20–22 (descr. ♂); examined by Miller (2005).

Porrhomma incertum — Berland (1931): p. 384.

P. cavernicola — Roewer (1942): p. 603.

P. emertoni Roewer, 1942 — Roewer (1942): p. 603; replacement name for Linyphia incerta; synonymised by Miller (2005).

P. cavernicola — Miller (2005): p. 428, Figs. 1–26 (redescr. ♂ ♀); synonymy.

Material examined. USA: Alabama, Limestone County, Spence Cave, 19 Aug 1965, 1 Ƌ 1 ♀, leg. S. Peck . Arkansas, Washington County, Devil’s Den State Park, Devil’s Den Cave, 28–31 May 1979, 4 Ƌ 7 ♀, leg. S. & J. Peck . Georgia, Bartow County, Kingston Saltpeter Cave, 13 Jul 1967, 1 Ƌ 3 ♀, leg. J.R. Holsinger, S. Peck, A. Fiske & R. Baroody . Illinois, Jo Daviess County, Angoma Farm Cave, 14 Nov 1965, 5 ♀, leg. S. Peck . Indiana, Lawrence County, Spring Mill State Park, Donaldson Cave, 10 Nov 1934, 2 ♀, leg. D.C. Lowrie. Orange County, Elrod Cave, 8 Aug 1964, 1 Ƌ, leg. T.C. Barr & S. Peck . Iowa, Jaskson County, Maquoketa Caves State Park, Barrea Cave, 1 Nov 1965, leg. S. Peck . Maryland, Washington County, Snively Cave, 4 Apr 1971, 2 Ƌ 1 ♀, leg. A. Norden. Misssouri, Stone County, Marvel Cave, 2 Apr 1959, 1 Ƌ 1 ♀, leg. T.C. Barr . Tennessee, Hawkins County, Sensabaugh Saltpeter Cave, 15 Apr 1967, 2 Ƌ 1 ♀, leg. J.R . Holsinger. Virginia, Augusta County, Madison Cave, 23 Aug 1958, 1 ♀, leg. T.C. Barr ; Gilea County, Clover Hollow Cave, 27 Jan 1962, 2 ♀, leg. J.R. Holsinger ; Tazewell County, Gully Cave (4 mi. SE Pounding Hill), 24 Jul 1974, 4 ♀, leg. J.R. Holsinger & D.C . Culver. West Virginia, Greenbrier County, Branford Cave, 10 Aug 1958, 1 ♀, leg. T.C. Barr (AMNH) .

Diagnosis. The troglomorphic features—depigmentation, reduced eyes (Fig. 17A), and elongated legs (Mt I/ CW = 1.46)—separate this species from the other species occurring in North America ( P. convexum, P. terrestre, and P. nekolai). Males of P. cavernicola (Fig. 17B) and P. microcavense are easily identified by the sickle-shaped and extremely thick AP. P. cavernicola is native in North America, P. microcavense in Europe.

Description. ♀ (from Devil’s Den Cave, Arkansas, U.S.A., 28–31 May 1979). Carapace yellow-brown, 0.79 mm wide, PME–PME = 6 (Fig. 17A). Abdomen greyish-yellow. Fe I–II with one or two dorsal spines, Fe I with one or two prolateral spines. Ti I with one prolateral spine, Ti I–II with one retrolateral spine. Tm Mt I = 0.48, Mt I/CW = 1.46.

Epigynum with translucent ducts and spermathecae (Fig. 17C). Ascending parts of the ducts are curved twice. Ducts reach deep into the abdomen (Figs. 17D–F).

Ƌ (together with female). Embolus of middle length with a narrow velum. The sickle-shaped AP is extremely thick (Fig. 17B).

Ecology. Exclusively in caves.

Global distribution. North America after Miller (2005) and this article. See Fig. 18.