Porrhomma pygmaeum

• Main Author: Růžička, Vlastimil
• Format: Other/Unknown Material
• Language: unknown
• Published: 2018
• Subjects: Biodiversity; Taxonomy; Animalia; Arthropoda; Arachnida; Araneae; Linyphiidae; Porrhomma; Porrhomma pygmaeum; Kamchatka Peninsula; Petropavlovsk; Petropavlovsk-Kamchatsky; Blackwall; Kamchatka
• Online Access: https://zenodo.org/record/5964008; https://doi.org/10.5281/zenodo.5964008

Porrhomma pygmaeum (Blackwall, 1834) Figs. 49A–F. Neriene pygmaea Blackwall, 1834 — Blackwall (1834): p. 52 (descr. ♂ ♀); transferred by Simon (1884). Erigone barbata Thorell, 1875 — Thorell (1875): p. 89 (descr. ♂); synonymised by Holm (1944). Porrhomma pygmaeum — Simon (1884): p. 366, Figs. 139–140 (♂ ♀). Bathyphantes arcticus — Strand (1901): p. 23, Figs. 8a–b (descr. ♂ ♀); preoccupied, replaced by Charitonov (1928); examined and synonymised by Holm (1944). B. strandi Charitonov, 1928 — Charitonov (1928): p. 56; replacement name for B. arcticus. P. pygmaeum — Holm (1944): p. 130; synonymy. Material examined. CZECHIA: Třeboň, 12 May –1 Jul 1977, 1 ♂ 1 ♀; Suchdol nad Lužnicí, Dvory nad Lužnicí, 22 May 1989, 39 ♂ 29 ♀; Sedlec (distr. Břeclav), Lednické Rybníky Ponds Reserve, 5 May 1974, 1 ♂ 1 ♀; Míšov, Padrťský Rybník Pond, 6 Jul 1998, 9 ♀, leg. V. Růžička. Tisá, 14 Jul 1999, 1 Ƌ 1 ♀, leg. J. Hajer (IECA). FINLAND: Esbo, 13 May 1951, 1 Ƌ 1 ♀, leg. W. Hackman (AMNH). SWEDEN: Uppsala, 29 May 1939, 1 Ƌ 3 ♀, leg. Å. Holm (AMNH). GREAT BRITAIN: Cairngorm Summit, 30 Jun 1966, 1 Ƌ 1 ♀, leg. J.R. Parker (AMNH). RUSSIA: Kamchatka Peninsula, Petropavlovsk-Kamchatsky, 17 Sep 1996, 1 ♂ 3 ♀; Kurile Islands, Shumshu Island, NW shore, 50°46'N, 156°15'E, 9–13 Sep 1996, 13 Ƌ 17 ♀, leg. Yu. M. Marusik (CYM). Diagnosis. P. pygmaeum differs from other species by dark brown carapace. Description. ♀ (from Dvory nad Lužnicí, Czechia, 22 May 1989). Carapace dark brown, 0.62 mm wide, eyes normal, PME–PME = 0.7 (Fig. 49A). Abdomen dark gray. Fe I–II with one dorsal spine, Fe I with one prolateral spine. Ti I with one prolateral spine, Ti I–II with one retrolateral spine. Tm Mt I = 0.40, Mt I/CW = 0.85. Ascending parts of the ducts are S-shaped. Spermathecae are formed behind the ascending part of the ducts (Figs. 49C–F). Because of a dark colouration, the epigynum is usually hardly visible. Ƌ (together with female). Embolus of middle length with a narrow velum. AP has the form of a bird head (Fig. 49B). Variation. Ƌ ♀. Carapace 0.60–0.71 ...