Ninetis subtilissima Simon 1890
Creators: name: Huber, Bernhard A.
name: Meng, Guanliang
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Pholcidae
Ninetis
Ninetis subtilissima

description: Ninetis subtilissima Simon, 1890
Figs 3A, B, 6–12, 34A
Ninetis subtilissima Simon, 1890: 96 (♂ ♀).
Ninetis subtilissima — Simon 1893: 486, figs 487–489. Fage 1912: 155, fig. 3a (copied from Simon 1893), fig. 134. Bristowe 1938: 310, fig. 2 (copied from Simon 1893), fig. 7 (copied from Fage 1912). Huber 2000: 82, figs 310–314. Huber & van Harten 2001: 2, figs 1–28.
Remarks. Simon (1890, 1893) described and illustrated both sexes of this species, but his male specimen(s) from Aden seem to be lost (Huber 2000). The redescription in Huber and van Harten (2001) was based on specimens collected ~ 60 km NE of the type locality, in Jaʽar. This new material was identified as N. subtilissima with some hesitation because of a discrepancy with Simon’s (1983) figure 488: a different curvature of the ventral bulbal apophysis. There is still no topotypical material available of this species, but our new material below shows that N. subtilissima is in fact widespread along the southern Arabian Peninsula. This supports the idea that the specimens in Huber and van Harten (2001) (and those listed below) are correctly identified.
Diagnosis. Males differ from all known congeners (and the Omani Magana velox) by combination of: pointed procursus (Fig. 7A–C; Huber & van Harten 2001, fig. 4; similar only in N. faro Huber and N. toliara Huber & El Hennawy; in other species not pointed); long cheliceral apophyses wide apart (Fig. 7G–I; Huber and van Harten 2001, figs 5–6; similar only in N. minuta (Berland); in other species shorter and/or closer together); and genital bulb with pointed dorsal process (Fig. 7D–F; Huber & van Harten 2001, fig. 4; in other species not pointed). From geographically close and morphologically similar N. amoud sp. nov. also by absence of flattened sclerite on dorsal bulbal process (present in N. amoud sp. nov., cf. Fig. 14D–F). Females distinguished by combination of: trapezoidal epigynum with central pocket on membranous process (pocket in other species either absent or not on membranous process) and with pair of lateral indentations (Figs 8, 9, 10F) (otherwise present only in N. russellsmithi); internal genital sclerites almost in straight line (Fig. 34A) (similar only in N. samail sp. nov.; more curved in other species).
Type material. YEMEN — Aden • Eight syntypes (4– 5 adult females, others juvenile); Aden; 12.78 °N, 45.04 °E; 10 m a.s.l., 1889; E. Simon leg.; MNHN Ar 10788 (examined by BAH in 1999).
New material examined. OMAN — Dhofar • 3 ♀; Wadi Shalyon; 17.1844 °N, 54.9538 °E; 350 m a.s.l.; under rocks in wadi; 1 Mar. 2018; B.A. Huber leg.; ZFMK Ar 24402 • 1 ♀, in pure ethanol; same collection data as for preceding, ZFMK Om150.
Ad Dakhiliyah • 2 ♂, 1 ♀; Wadi Ghul, ‘site 3’; 23.2359 °N, 57.1496 °E; 1445 m a.s.l.; 15 Feb. 2018; B.A. Huber leg.; ZFMK Ar 24403 • 2 ♀, in pure ethanol; same collection data as for preceding, ZFMK Om107.
Ash Sharqiyah South • 3 ♂, 6 ♀; Wadi Shab; 22.8332 °N, 59.2380 °E; 90 m a.s.l.; 19 Feb. 2018; B.A. Huber leg.; ZFMK Ar 24404 • 4 ♀, in pure ethanol; same collection data as for preceding, ZFMK Om 121 • 11 ♂, 8 ♀ (1 ♂, 1 ♀ used for SEM); Wadi Tiwi; 22.8130 °N, 59.2536 °E; 35 m a.s.l.; 19 Feb. 2018; B.A. Huber leg.; ZFMK Ar 24405 • 1 ♂, 7 ♀, 11 juvs, in pure ethanol (3 female prosomata used for molecular work; 1 ♀ used for SEM); same collection data as for preceding, ZFMK Om 120 • 2 ♀; Wadi Tiwi; 22.8169 °N, 59.2538 °E; 40 m a.s.l.; 22 Mar. 2017; B.A. Huber leg.; ZFMK Ar 24406 • 1 juv., in pure ethanol; same collection data as for preceding, ZFMK Om 28.
Description (amendments, see Huber & van Harten 2001)
Tibia 1 in 16 males from Oman: 0.52–0.60 (mean 0.57); in 20 females from Oman: 0.50–0.64 (mean 0.60). Male chelicerae with stridulatory files consisting of ~35 ridges each, distances between ridges 1.4 µm (Fig. 10C). Female chelicerae without stridulatory files (Fig. 10D). Male gonopore with four epiandrous spigots in two pairs (Fig. 10E). Sexually dimorphic short vertical hairs (Fig. 12D) on male tibia 1 only, apparently in four rows, with ~4–14 hairs in each row. Thin metatarsal hairs present in female (one each on metatarsi 3 and 4; Fig. 12A, B), not seen in male. Tarsal organ of leg 4 apparently non-functional. Other SEM characters as in congeners (leg cuticular plates and pores; other tarsal organs; trichobothria; chemosensory hairs; tarsal claws; spinnerets; Figs 10–12).
Intraspecific distances. The genetic (K2P) distance between two sequenced specimens (from Wadi Tiwi and Wadi Ghul; geographic distance: 220 km) was 11%; no morphological differences were seen between specimens of these localities.
Distribution. Known from several localities in Yemen and Oman (Fig. 4B).
Natural history. Simon (1890) collected this species under stones and in the cracks of rocks (“sous les pierres et dans les fissures des rochers”). The specimens reported in Huber and van Harten (2001) were shaken from Sorghum (Sudan grass) in a garden in town. The newly collected specimens from Oman were collected under rocks and in leaf litter. At Wadi Shalyon, N. subtilissima was found together with N. marnif sp. nov., but in slightly different microhabitats: while N. marnif sp. nov. was found under rocks lying on sandy soil, N. subtilissima was found in a rocky area without sand. In Wadi Ghul, the spiders were found under small stones at the base of a large rock used by goats as a shelter (Fig. 5A). In Wadi Shab and Wadi Tiwi, the species was extremely abundant in the shaded leaf litter of mango trees at the trailside/roadside (Fig. 5B). Simon (1890) noted that egg sacs usually contained only 2– 3 eggs. Four newly collected egg sacs contained 5– 8 eggs, with an egg diameter of 0.39–0.44.
description: Published as part of Huber, Bernhard A. & Meng, Guanliang, 2025, Like grains of sand: Ninetis spiders on the Arabian Peninsula (Araneae: Pholcidae), pp. 290-335 in Zootaxa 5563 (1) on pages 307-308, DOI: 10.11646/zootaxa.5563.1.19, http://zenodo.org/record/14596047