Ninetis amoud Huber, 2025

Huber, Bernhard A. & Meng, Guanliang, 2025, Like grains of sand: Ninetis spiders on the Arabian Peninsula (Araneae: Pholcidae), Zootaxa 5563 (1), pp. 290-335 : 308-317

Ninetis amoud Huber sp. nov.

urn:lsid:zoobank.org:act:2551B8E8-4CDD-4C13-827D-73DC247D4F10

Figs 3C, D , 13–20 , 34B

Diagnosis. Males are distinguished from known congeners by strongly curved cheliceral apophyses close together ( Fig. 14G–I ; much wider apart in geographically close and morphologically similar N. subtilissima ); by processes on genital bulb (ventral process longer than in other species, dorsal process with unique flattened sclerite absent in other species; Fig. 14D–F ); and by simple short procursus strongly bent towards prolateral at approximately one third of its length ( Fig. 14A–C ; not strongly bent in N. subtilissima ). Females are distinguished from N. subtilissima by pocket medially on epigynal plate not situated on membranous process ( Figs 15 , 16F ) and by strong internal sclerites laterally directed towards anterior ( Fig. 34B ; rather than straight).

Type material. Holotype. SAUDI ARABIA — Jizan • ♂; NE of Wadi ‘ Amoud ; 17.5870 °N, 43.0264 °E; 920 m a.s.l.; 24 Mar. 2024; B.A. Huber leg.; KSMA . Paratypes. SAUDI ARABIA — Jizan • 4 ♂, 10 ♀ ; same collection data as for holotype; KSMA (1 ♂, 1 ♀); ZFMK Ar 24407 (3 ♂, 9 ♀) .

Other material examined. SAUDI ARABIA — Jizan • 1 ♂, 10 ♀, 1 juv., in pure ethanol; same collection data as for holotype; ZFMK SA123 • 5 ♂, 3 ♀; NE of Sabya ; 17.2084 °N, 42.6667 °E; 55 m a.s.l.; 25 Mar. 2024; B.A. Huber leg.; ZFMK Ar 24408 • 1 ♂, 2 ♀, in pure ethanol; same collection data as for preceding; ZFMK SA124 • 3 ♂, 13 ♀; NW of Al Fatiha ; 17.6007 °N, 42.5681 °E; 180 m a.s.l.; 25 Mar. 2024; B.A. Huber leg.; ZFMK Ar 24409 • 6 ♀, in pure ethanol; same collection data as for preceding; ZFMK SA126 .

‘ Asir • 5 ♂, 5 ♀; S of Habeel ; 17.9690 °N, 42.2608 °E; 250 m a.s.l.; 25 Mar. 2024; B.A. Huber leg.; KSMA (1 ♂, 1 ♀) ; ZFMK Ar 24410 (4 ♂, 4 ♀) • 5 ♀, in pure ethanol; same collection data as for preceding; ZFMK SA128 • 8 ♂, 14 ♀ (1 ♂, 1 ♀ used for SEM); E of Muhayil ; 18.5303 °N, 42.2366 °E; 860 m a.s.l.; 21 Mar. 2024; B.A. Huber leg.; ZFMK Ar 24411 • 1 ♂, 6 ♀, in pure ethanol; same collection data as for preceding; ZFMK SA109 • 4 ♂, 4 ♀; SW of Tanomah ; 18.9013 °N, 42.0887 °E; 570 m a.s.l.; 20 Mar. 2024; B.A. Huber leg.; ZFMK Ar 24412 • 4 ♀, in pure ethanol; same collection data as for preceding; ZFMK SA102 .

Al Bahah • 4 ♂, 4 ♀; N of Al Makhwah ; 19.8706 °N, 41.4517 °E; 600 m a.s.l.; 17 Mar. 2024; B.A. Huber leg.; ZFMK Ar 24413 • 4 ♀, in pure ethanol; same collection data as for preceding; ZFMK SA89 .

Mecca • 3 ♂, 1 ♀; S of Qarn Hudhail ; 19.1328 °N, 41.8309 °E; 340 m a.s.l.; 26 Mar. 2024; B.A. Huber leg.; ZFMK Ar 24414 • 3 ♀, in pure ethanol; same collection data as for preceding; ZFMK SA130 • 3 ♂; NW of Al Awamer ; 19.7047 °N, 41.6862 °E; 660 m a.s.l.; 26 Mar. 2024; B.A. Huber leg.; ZFMK Ar 24415 • 1 ♂, 2 ♀, in pure ethanol; same collection data as for preceding; ZFMK SA133 • 5 ♂, 7 ♀; SW of Mecca; 21.3260 °N, 39.6325 °E; 210 m a.s.l.; 15 Mar. 2024; B.A. Huber leg.; KSMA (1 ♂, 1 ♀) ; ZFMK Ar 24416 (4 ♂, 6 ♀ — 1 ♂, 1 ♀ used for SEM) • 1 ♂, 5 ♀, in pure ethanol; same collection data as for preceding; ZFMK SA82 • 1 ♂, 2 ♀; NW of Ar Rayyan ; 21.6891 °N, 39.8730 °E; 350 m a.s.l.; 30 Mar. 2024; B.A. Huber leg.; ZFMK Ar 24417 • 1 ♀, 2 juvs, in pure ethanol; same collection data as for preceding; ZFMK SA143 • 1 ♂, 5 ♀; NE of Ghran ; 22.0488 °N, 39.4744 °E; 185 m a.s.l.; 31 Mar. 2024; B.A. Huber leg.; ZFMK Ar 24418 • 5 ♀, in pure ethanol; same collection data as for preceding; ZFMK SA144 a • 1 ♀, in pure ethanol; NE of Khulais ; 22.2537 °N, 39.4905 °E; 210 m a.s.l.; 31 Mar. 2024; B.A. Huber leg.; ZFMK SA145 .

Etymology. The species epithet is a noun in apposition, taken from the type locality.

Description Male (holotype) MEASUREMENTS. Total body length 0.95, carapace width 0.41. Distance PME-PME 40 µm; diameter PME 45 µm; distance PME-ALE 15 µm; distance AME-AME 10 µm; diameter AME 25 µm. Leg 1: 2.08 (0.60 + 0.14 + 0.53 + 0.51 + 0.30), tibia 2: 0.42, tibia 3: 0.36, tibia 4: 0.62; tibia 1 L/d: 11; diameters of leg femora 80–90 µm, of leg tibiae 50 µm.

COLOUR (in ethanol). Prosoma and legs ochre-yellow, carapace median third slightly lighter, without distinct pattern; legs without darker rings; abdomen ochre-brown with small darker internal marks dorsally and laterally; ventrally with indistinct light ochre-yellow plate in front of gonopore.

BODY. Habitus as in Fig. 3C . Ocular area barely raised. Carapace without thoracic groove (cf. Fig. 16A ). Clypeus unmodified. Sternum barely wider than long (0.30/0.28), with pair of anterior processes near coxae 1 (~30 µm diameter at basis, 20 µm high). Abdomen oval to globular; gonopore with four epiandrous spigots in two pairs ( Fig. 16E ); spinnerets as in congeners (see genus description above; cf. Fig. 16G, H ).

CHELICERAE. As in Fig. 14G–I ; with pair of strongly curved frontal apophyses close together; stridulatory files ( Fig. 16D ) very fine, not visible in dissecting microscope, consisting of approximately 30 ridges, distances between ridges ~1.3 µm.

PALPS. As in Figs 13 , 17A–D ; coxa unmodified; trochanter with small ventral process; femur proximally with indistinct retrolateral hump, with prolateral stridulatory pick ( Fig. 17E ), on ventral side with tiny tubercles ( Figs 13 , 17A ), distally slightly widened but otherwise unmodified; femur-patella joints shifted toward prolateral side; tibia with two trichobothria in relatively distal position; tibia-tarsus joints slightly shifted toward retrolateral side; tarsus with strong dorsal hairs; procursus short and simple ( Fig. 14A–C ), strongly bent towards prolateral at approximately one third of its length, distally membranous; genital bulb ( Fig. 14D–F ) with long ventral process, dorsal process with distinctive flattened sclerite (wide in dorsal view) provided with sclerotized ventral ridges, and short putative embolus with membranous and sclerotized elements.

LEGS. Without spines, without curved hairs; with short vertical hairs ( Fig. 18G, H ) on tibia 1 only; retrolateral trichobothrium of tibia 1 at 60%; prolateral trichobothrium absent on tibia 1; thin metatarsal hairs present on metatarsi 3 and 4 (one each, in proximal ventral position; cf. Fig. 18E ); tarsus 1 with ~5 pseudosegments, barely visible in dissecting microscope; anterior tarsal organs as in congeners ( Fig. 19A–C ), those of leg 4 apparently non-functional ( Fig. 19D ); chemosensory hairs, rimmed pores, cuticular plates, and tarsal claws as in congeners ( Figs 18–19 ).

Variation (male)

Tibia 1 in 47 males (incl. holotype): 0.46–0.60 (mean 0.53). Dark marks on abdomen variably distinct.

Female

In general very similar to male but usually lighter than male (orange rather than ochre), sternum unmodified, chelicerae without stridulatory files ( Fig. 16B ), tibia 1 without short vertical hairs. Tibia 1 in 70 females: 0.47–0.64 (mean 0.54). Palp ends distally in simple sclerotized tip ( Fig. 18A ). Spinnerets as in male. Epigynum ( Figs 15 , 16F ) anterior plate trapezoidal, with median pocket opening medially on anterior epigynal plate and directed towards anterior; with variably distinct anterior ridge; with pair of strong transversal internal sclerites visible through posterior epigynal plate; posterior plate wide and short. Internal genitalia ( Fig. 15 ) with pair of transversal sclerites and complex median structures, apparently without pore plates.

Intraspecific distances. The genetic (K2P) distances between four sequenced specimens ranged from 3–17% ( Table 2). There was no apparent pattern between geographic and genetic distances: specimens from SW of Mecca and from E of Muhayil (distance 410 km) had a K2P distance of only 3%; SW of Mecca versus NE of Ghran: 80 km, 12%; E of Muhayil versus NE of Wadi ‘Amoud: 130 km, 17%. No morphological differences were seen among specimens of these localities.

Distribution. Widely distributed along the Red Sea coast of Saudi Arabia ( Fig. 4B ). The species seems to be restricted to low elevation areas. In the 2024 expedition, the species was found at 13 of 16 localities sampled below 1000 m, but at none of 23 localities sampled above 1000 m.

Natural history. At several localities, the spiders were found among small stones in the shade of large boulders ( Fig. 5C ; NE of Wadi ‘Amoud, NW of Al Awamer, E of Muhayil, SW of Mecca, NW of Ar Rayyan, NE of Ghran). Near Habeel, they were collected from the undersides of large rocks on a bare rock plate. SW of Tanomah, the spiders were beaten from dry branches and pieces of bark on the ground in an area shaded by bushes. NE of Sabya, they were found under blocks of construction material in a sandy habitat. The spiders ran rapidly when disturbed and dropped to the ground. Males appeared to run faster and to hide better than females, with all legs tucked up, making them almost invisible. In the collecting vials, the spiders built tiny webs ( Fig. 20A ). Egg sacs were flat, i.e. with only one layer of eggs ( Fig. 20 ). Of 21 egg-sacs, 19 contained five (N=5), six (N=9) or seven (N=5) eggs. The two other egg sacs contained eight and nine eggs, respectively. There was a tendency for the number of eggs per egg-sac to increase with latitude and decrease with altitude. Egg diameter was 0.40–0.42 mm.

Figures

FIGURE 3. Ninetis Simon, live specimens. A, B. Ninetis subtilissima Simon, male from Oman, Wadi Ghul and female with embryos from Oman, Wadi Shab. C, D. Ninetis amoud Huber sp. nov., male from Saudi Arabia, NW of Al Fatiha, female from Saudi Arabia, S of Habeel. E, F. Ninetis samail Huber sp. nov., male and female from Oman, near Samail. G, H. Ninetis marnif Huber sp. nov., male and female with eggs from Oman, near Marnif. Scale line: 1 mm (all at same scale). Photos BAH.

FIGURE 4. Known distribution of Ninetis Simon. A. Distribution of the entire genus. B. Distribution of Ninetis on the Arabian Peninsula.

FIGURE 5. Typical habitats of Ninetis Simon on the Arabian Peninsula. A, B. Oman, Wadi Ghul and Wadi Tiwi (N. subtilissima Simon). C, D. Saudi Arabia, SW of Mecca and NW of Al Fatiha (N. amoud Huber sp. nov.). E, F. Oman, near Samail and near Al Hoota cave (N. samail Huber sp. nov.). G, H. Oman, near Marnif and Wadi Shalyon (N. marnif Huber sp. nov.).

FIGURE 13. Ninetis amoud Huber sp. nov.; male paratype from Saudi Arabia, NE of Wadi ‘Amoud; ZFMK Ar 24407. Left male palp in prolateral (A), dorsal (B), and retrolateral (C) views. Scale line: 0.1 mm.

FIGURE 14. Ninetis amoud Huber sp. nov.; male paratype from Saudi Arabia, NE of Wadi ‘Amoud; ZFMK Ar 24407. A– C. Left palpal tarsus and procursus, prolateral, dorsal, and retrolateral views. D–F. Left genital bulb, prolateral, dorsal, and retrolateral views; thick arrows point at distinctive flattened dorsal sclerite. G–I. Chelicerae, frontal, lateral, and distal views. Abbreviations: dp, dorsal process; vp, ventral process. Scale lines: 0.1 mm.

FIGURE 15. Ninetis amoud Huber sp. nov.; female paratype from Saudi Arabia, NE of Wadi ‘Amoud (A–C, J; ZFMK Ar 24407), female from Saudi Arabia, N of Al Makhwah (D–F, K; ZFMK Ar 24413), and female from Saudi Arabia, NE of Ghran (G–I; ZFMK Ar 24418). A, D, G. Epigyna, ventral views. B–C, E–F, H–I. Cleared genitalia, ventral and dorsal views; arrow in E points at epigynal pocket. J–K. Internal transversal sclerites at higher magnifications. Scale lines: 0.2 mm.

FIGURE 16. Ninetis amoud Huber sp. nov.; from Saudi Arabia, E of Muhayil (D, G, H; ZFMK Ar 24411) and SW of Mecca (A–C, E, F; ZFMK Ar 24416). A. Female prosoma, frontal view. B. Female chelicerae, oblique frontal view. C. Female left cheliceral fang, distal view. D. Male left chelicera, oblique frontal view. E. Male gonopore and epiandrous spigots. F. Epigynum, ventral view; arrow points at epigynal pocket. G. Left female ALS and PMS. H. Right female ALS. Scale lines: 100 µm (A), 10 µm (B–E, G, H), 30 µm (F).

FIGURE 17. Ninetis amoud Huber sp. nov.; from Saudi Arabia, E of Muhayil (E, F; ZFMK Ar 24411) and SW of Mecca (A–D; ZFMK Ar 24416). A, B. Left male palp, retrolateral and retrolateral-dorsal views; thick arrow points at distinctive flattened dorsal sclerite. C, D. Right male palp, prolateral and prolateral-dorsal views. E. Stridulatory pick on left male palpal femur. F. Male palpal tarsal organ (arrow) and neighboring slit sensillum and mechanoreceptive hairs. Abbreviations: dp, dorsal process; pr, procursus; vp, ventral process. Scale lines: 100 µm (A–D), 2 µm (E), 10 µm (F).

FIGURE 18. Ninetis amoud Huber sp. nov.; from Saudi Arabia, E of Muhayil (A–D, F; ZFMK Ar 24411) and SW of Mecca (E, G, H; ZFMK Ar 24416). A. Tip of right female palp, dorsal view; arrow points at tarsal organ. B. Trichobothrium base on left male metatarsus 1. C. Rimmed pore (arrow) on left male metatarsus 1. D. Putative chemoreceptor on right male tarsus 1. E. Thin metatarsal hair (arrow) on female right metatarsus 3, prolateral-ventral view. F. Basis of thin metatarsal hair (arrow) on left male metatarsus 4, retrolateral-ventral view. G, H. Sexually dimorphic short vertical hairs and neighboring regular mechanoreceptive hairs and trichobothrium on left male tibia 1, retrolateral views; arrows points at cuticular plates. Scale lines: 10 µm (A, B, E, G, H), 2 µm (C, D, F).

FIGURE 19. Ninetis amoud Huber sp. nov.; from Saudi Arabia, E of Muhayil (A; ZFMK Ar 24411) and SW of Mecca (B–H; ZFMK Ar 24416). A, B. Tarsal organs and neighboring slit sensilla on left female tarsi 1 and 2. C. Tarsal organ and neighboring slit sensillum on left male tarsus 3. D. Vestigial tarsal organ (arrow) on left male tarsus 4. E. Tip of right female tarsus 1, prolateral view. F. Tip of right male tarsus 2, prolateral view. G. Tip of right female tarsus 3, prolateral view. H. Tip of right male tarsus 4, prolateral view; arrow points at comb-hair. Scale lines: 2 µm (A–D), 10 µm (E–H).

FIGURE 20. Ninetis amoud Huber sp. nov. A. Female in small web in collecting vial. B–H. Females with egg-sacs, ventral views, photographed through glass of collecting vial; from Saudi Arabia, E of Muhayil (B, D), NE of Wadi ‘Amoud (C, E), NE of Ghran (F, G), and SW of Mecca (H).

FIGURE 34. Female internal genitalia, transversal sclerites at same magnification. A. Ninetis subtilissima Simon, 1890; from Oman, Wadi Shalyon; ZFMK Ar 24402. B. N. amoud Huber sp. nov.; paratype from Saudi Arabia, NE of Wadi ‘Amoud; ZFMK Ar 24407. C. N. samail Huber sp. nov.; from Oman, near Samail; ZFMK Ar 24420. D. N. marnif Huber sp. nov.; from Oman, W of Al Marnif; ZFMK Ar 24424. Scale line: 0.1 mm.