Porrhomma montanum Jackson 1913
Creators: name: Růžička, Vlastimil
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Linyphiidae
Porrhomma
Porrhomma montanum

description: 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.
description: Published as part of Růžička, Vlastimil, 2018, A review of the spider genus Porrhomma (Araneae, Linyphiidae), pp. 1-75 in Zootaxa 4481 (1) on page 43, DOI: 10.11646/zootaxa.4481.1.1, http://zenodo.org/record/1454736