Porrhomma rakanum Yaginuma & Saito, 1981

Figs. 51A–E.

Porrhomma rakanum Yaginuma & Saito, 1981 — Yaginuma & Saito (1981): p. 33, Figs. 1–4 (descr. ♂ ♀).

Material examined. JAPAN. Porrhomma rakanum, paratypes No. 3–4, Rakan-ana Cave, Koya, Nomura-cho, Ehime Prefecture, 28 Nov 1968, 2 ♂, Masataka Yosida ; paratypes No. 15–19, Rakan-ana Cave, Koya, Nomuracho, Ehime Prefecture, 28 Nov 1968, 5 ♀, Masataka Yosida (ASJ).

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

Description. Male holotype. Carapace pale, 0.65 mm wide, eyes absent or almost absent. Abdomen pale. Fe I with two dorsal spines and one prolateral spine, Fe II with one dorsal spine. Ti I–II with one retrolateral spine. Tm Mt I = 0.29, Mt I/CW = 1.92 (Yaginuma & Saito 1981).

Embolic section characteristic for magnum -group. AP shorter than broad, the space between AP and PA quite open. Velum with pigmented margin (Fig. 51A).

♀ (from Rakan-ana Cave, Japan, 28 Nov 1968). Epigynum with lateral wings (Fig. 51B). Copulatory ducts very long, with ascending and descending parts. Main sacks oriented upwards, appendices narrowed, oriented towards the abdominal wall (Figs. 51C–E).

Ecology. Known exclusively from caves.

Global distribution. Recorded only in the Rakan-ana Cave in Ehime Prefecture, Shikoku Island, Japan. See Fig. 52.