Porrhomma montanum Jackson, 1913

Růžička, Vlastimil, 2018, A review of the spider genus Porrhomma (Araneae, Linyphiidae), Zootaxa 4481 (1), pp. 1-75 : 43

Porrhomma montanum Jackson, 1913

Figs. 36A–F .

Linyphia hebescens L. Koch, 1879 —L. Koch (1879): p. 35, Pl. 1, Figs. 23, 23a (descr. ♀); examined by Holm (1973: 97) and suppressed for lack of usage.

L. desolata L. Koch, 1879 —L. Koch (1879): p. 38, Pl. 1, Figs. 27, 27a (descr. ♂); examined by Holm (1973: 97) and suppressed for lack of usage.

Erigone formosa L. Koch, 1879 —L. Koch (1879): p. 67, Pl. 2, Figs. 18, 18a (descr. ♀); examined by Holm (1973: 97) and suppressed for lack of usage.

Porrhomma montanum Jackson, 1913 — Jackson (1913): p. 40, Pl. II, Figs. 24 , 34 (descr. ♂ ♀).

P. hakusanensis Oi, 1964 —Oi (1964): p. 29, Pl. I, Figs. 11–12 (descr. ♀); synonymised by Ono et al. (2009).

P. montanum — Holm (1973): p. 97; synonymy.

P. hebescens — Eskov & Marusik (1993): p. 67; resurrected older name, but P. montanum clearly eligible for protection under ICZN Article 23.9 ( World Spider Catalog 2017).

P. hebescens — Ono et al. (2009): p. 332, Pl. 2-2-41, Figs. 1105–1109 (♂ ♀); synonymy.

Material examined. CZECHIA. Chlum u Třeboně , Novořecké Močály Reserve , 3 Sep 1987 –30 May 1988, 1 ♂; Suchdol nad Lužnicí , Dvory nad Lužnicí , 12–28 May 1986, 1 Ƌ, V. Růžička. Nižbor, Vůznice Reserve, 1–17 May 1993, 3 Ƌ, F. Pojer ( IECA). Šumava Mts., Mrtvý Luh Reserve, 1 Jul 1980, 5 Ƌ, leg. A. Kůrka (CAK). Lanžhot, Ranšpurk Reserve , 1994–1997, 9 Ƌ 4 ♀, leg. J. Chytil (WSM). RUSSIA: Kurile Islands , Paramushir Island , Severo-Kurilsk env., 50°40'N, 156°06'E, 10 Aug –5 Oct 1996, 2 ♀, leg. Yu. M. Marusik (CYM).

Diagnosis. Species of middle size (CW> 0.60 mm), lacking dorsal spines of Fe I–II. It can be distinguished from P. altaica by AP of the male palp short and curved upwards ( Fig. 36B ), and thick appendices of the vulva, which turn closely around main sacks and are oriented opposite to one another, towards the median plain ( Figs. 36D–F ).

Description. ♀ (from Lanžhot, Czechia, 19 May 1997). Carapace brown, 0.67 mm wide, eyes normal, PME– PME = 0.8 ( Fig. 36A ). Abdomen grey. Fe without dorsal spines, Fe I with one prolateral spine. Ti I with one prolateral spine, Ti I–II with one retrolateral spine. Tm Mt I = 0.33, Mt I/CW = 0.90.

Main sacks and appendices, which are almost in contact, can be seen on the epigynum ( Fig. 36C ). Very compact vulva. Spermathecae start at the midway of the ascending part of the copulatory ducts. Main sacks are oriented oblique upwards. Thick appendices turn closely around main sacks and are oriented opposite to one another, towards the median plain ( Figs. 36D–F ).

Ƌ (together with female). Embolus short, AP short and curved upwards ( Fig. 36B ).

Variation. Ƌ ♀. Carapace 0.60–0.69 mm wide. Tm Mt I = 0.31–0.36, Mt I/CW = 0.81–0.93 (n = 21).

Ecology. In Czechia, the species has been recorded among leaf litter in floodplain forests and in peat bogs ( Buchar & Růžička 2002). In Great Britain, it is typically an upland species occurring beneath rocks on open mountains ( Harvey et al. 2002).

Global distribution. Eurasia after Helsdingen (2017), Mikhailov (2013), this article, Ono et al. (2009) and Namkung et al. (2009). See Fig. 37 .

Figures

FIGURE 11. A–F, Porrhomma borgesi from Azores. A, ♀ carapace, frontal view. B, embolic section. C, epigynum. D–F, vulva, ventral, caudal and dorsal. Scale bars, 0.1 mm.

FIGURE 12. Global distribution of Porrhomma borgesi.

FIGURE 18. Global distribution of Porrhomma cavernicola.

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.

FIGURE 27. A–F, Porrhomma magnum from West Sayan Mts., Russia. A, ♀ carapace, frontal view. B, embolic section. C, epigynum. D–F, vulva, ventral, caudal and dorsal. Abbreviations: A, appendix; AP, anterior process of the embolic plate; MS, main sack; V, velum. Scale bars, 0.1 mm.

FIGURE 34. A–F, Porrhomma microps from Horka nad Moravou, Czechia. A, ♀ carapace, frontal view. B, embolic section. C, epigynum. D–F, vulva, ventral, caudal and dorsal. Abbreviations: A, appendix; AP, anterior process of the embolic plate; F, fold; MS, main sack; SL, side loop of the copulatory duct; V, velum. Scale bars, 0.1 mm.

FIGURE 36. A–F, Porrhomma montanum from Lanžhot, Czechia. A, ♀ carapace, frontal view. B, embolic section. C, epigynum. D–F, vulva, ventral, caudal and dorsal. Scale bars, 0.1 mm.

FIGURE 37. Global distribution of Porrhomma montanum.