Porrhomma ohkawai Saito, 1977

Růžička, Vlastimil, 2018, A review of the spider genus Porrhomma (Araneae, Linyphiidae), Zootaxa 4481 (1), pp. 1-75 : 48-50

Porrhomma ohkawai Saito, 1977

Figs. 43A–E .

Porrhomma ohkawai Saito, 1977 — Saito (1977a): p. 29, Figs. 15–17 (descr. ♂).

P. ohkawai — Saito (1977b): p. 48, Figs. 1–7 (♂, descr. ♀).

Material. Type material is not available; no other material is available.

Diagnosis. Among four species of the magnum -group, P. ohkawai and P. rakanum are characterised by absent eyes. P. ohkawai differs from P. rakanum by the presence of four dorsal spines on Fe I. It was recorded exclusively in caves in Japan.

Description. Male holotype. Carapace pale, 0.75 mm wide, eyes only perceptible by pale marks beneath the integument, or absent. Abdomen pale. Fe I with four dorsal spines ( Fig. 43A ) and one retrolateral spine, Fe II with one dorsal spine. Ti I with one prolateral and one retrolateral spine. Tm Mt I = 0.26, Mt I/CW = 1.91. Embolic section characteristic for magnum -group. AP as long as wide, the space between AP and PA very broad in comparison with other species of this group. Velum with pigmented margin ( Fig. 43B ).

Allotype female. Similar to the holotype in color and shape. Carapace 0.75 mm wide. Mt I/CW = 1.63. Epigynum with lateral wings, vulva with long copulatory ducts ( Figs. 43C–E ) ( Saito 1977b).

Comments. The type series should be “preserved in the collection of the Arachnological Society of East Asia ” ( Saito 1977b). This society has been continuing as Arachnological Society of Japan since 1988. However, the material of P. ohkawai is not deposited neither in collections of this society (Kamura in litt.) nor in collections of the National Museum of Nature and Science, Tokyo (Ono in litt.).

Ecology. Collected exclusively in caves.

Global distribution. Known only from caves in Tochigi Prefecture, Honshu Island , Japan. See Fig. 44 .

Figures

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

FIGURE 2. A–B, Porrhomma pygmaeum, male palp. A, retrolateral view. B, prolateral view. Abbreviations: AP, anterior process of the embolic plate; DSA, distal suprategular apophysis; E, embolus; EM, embolic membrane; EP, embolic plate; PA, posterior apex of the embolic plate; PT-OP, protegulum, outer process; PT-IM, protegulum, inner membrane; ST, subtegulum; T, tegulum. Scale bar, 50 µm.

FIGURE 3. A–B, Porrhomma microphthalmum, male palp. A, retrolateral view. B, prolateral view. Abbreviations as in Fig. 2. V, velum. Scale bar, 50 µm.

FIGURE 4. Porrhomma microps. Female vulva coloured by chlorazol black, dorsal view. Abbreviations: A, appendix; MS, main sack; SL, side loop of the copulatory duct. Scale bar, 0.1 mm.

FIGURE 5. A–C, female vulva, lateral view. A, Porrhomma pygmaeum. B, Porrhomma microcavense. C, Porrhomma microps. Scale bars, 0.1 mm.

FIGURE 6. A–F, Porrhomma altaica new species from Altai Mts., Azutau Ridge. 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; E, embolus; MS, main sack; PA, posterior apex of the embolic plate; V, velum. Scale bars, 0.1 mm.

FIGURE 7. Porrhomma altaica new species from Altai Mts., Gor’ky Belok Mt. Ridge, male palp. Scale bar, 0.1 mm.

FIGURE 15. A–F, Porrhomma campbelli from Stožec-Dobrá, Czechia; except B, Harrachov, Czechia. A, ♀ carapace, frontal view. B, embolic section. C, epigynum. D–F, vulva, ventral, caudal and dorsal. Scale bars, 0.1 mm.

FIGURE 16. Global distribution of Porrhomma campbelli.

FIGURE 17. A–F, Porrhomma cavernicola from Devil’s Den Cave, Arkansas. A, ♀ carapace, frontal view. B, embolic section. C, epigynum. D–F, vulva, ventral, caudal and dorsal. Scale bars, 0.1 mm.

FIGURE 43. A–E. Porrhomma okhawai from Tochigi Prefecture, Honshu Island, Japan. A, femur I. B, embolic section. C, epigynum. D–E, vulva, ventral and dorsal. Redrawn after Saito (1977b).

FIGURE 44. Records of Porrhomma ohkawai. Tochigi Prefecture, Honshu Island, Japan.