Porrhomma errans ( Blackwall, 1841 )

Růžička, Vlastimil, 2018, A review of the spider genus Porrhomma (Araneae, Linyphiidae), Zootaxa 4481 (1), pp. 1-75 : 29-31

Porrhomma errans ( Blackwall, 1841)

Figs. 23A–F .

Neriene errans Blackwall, 1841 — Blackwall (1841): p. 643 (descr. ♂ ♀); examined by F. O. Pickard-Cambridge (1894); transferred by Simon (1884).

Porrhomma errans — Simon (1884): p. 364, Fig. 138 (♂ ♀).

P. errans — F. O. Pickard-Cambridge (1894): p. 100, Pl. II, Fig. 1 (♂ ♀) . Material examined. CZECHIA: Ivanovice na Hané, Chvalkovice na Hané, 1959–1960, 57 Ƌ 65 ♀ , leg. B. Novák. Libčeves-Mnichov, Oblík Hill, 1995–1997, 10 Ƌ, leg. A. Kůrka ( NMP). Chrast , 49.9040°N, 15.9514°E, 2 Apr –3 May 2001, 1 Ƌ, 3 May –7 Jun 2001, 1 Ƌ 1 ♀ , leg. J. Dolanský (CJD). Vilémovice , 49.3588°N, 16.7296°E, 10 Nov 2003, 1 ♀ , leg. J. Horáková (IECA). Lanžhot, Ranšpurk Reserve, 1994–1997, 11 Ƌ 3 ♀, leg. J. Chytil ( WSM). GERMANY: Weichering , 6 Sep 1982, 1 Ƌ , leg. B. Baehr (CGA).

Diagnosis. Porrhomma errans can be easily recognised from all the other species of the genus by metatarsi provided with dorsal spine.

Description. ♀ (from Chrast, Czechia, 3 May–7 Jun 2001). Carapace orange-brown, 0.72 mm wide, eyes normal, PME–PME = 1.2 ( Fig. 23A ). Abdomen brown-grey. 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. All Mt with one dorsal spine. Tm Mt I = 0.61, Mt I/CW = 0.89. Ascending parts of the ducts are S-shaped. Spermathecae are formed behind the ascending part of the ducts ( Fig. 23C–F ).

Ƌ (together with female). Embolus of middle length with a narrow velum. AP has the form of a bird head ( Fig. 23B ).

Variation. Ƌ ♀. Carapace 0.71–0.77 mm wide. Tm Mt I = 0.55–0.61, Mt I/CW = 0.82–0.90 (n = 10).

Ecology. Species of mainly open habitats. Occurs on grassland, soft-rock cliffs, rabbit-grazed grassland and arable land ( Harvey et al. 2002). Found in a beet field as well as on a typical rock steppe.

Global distribution. Europe after Helsdingen (2017), modified. The record in Belarus mentioned by Ivanov (2013) seems to be doubtful and the material is probably lost (Zhukovets in litt.). The occurrence in Romania is also not recently confirmed ( Weiss & Petrisor 1999). The record in northern Asia seems to be a misidentification ( Eskov & Marusik 1993). See Fig. 24 .

Figures

FIGURE 1. Porrhomma cambridgei from Jenišovice-Zalažany, Mravín, Czechia. Female habitus. Scale bar, 0.1 mm.

FIGURE 23. A–F, Porrhomma errans from Chrast, Czechia. A, ♀ carapace, frontal view. B, embolic section. C, epigynum. D– F, vulva, ventral, caudal and dorsal. Scale bars, 0.1 mm.

FIGURE 24. Global distribution of Porrhomma errans.