Artema dhofar Huber & Carvalho 2019, sp. n.

Artema dhofar Huber sp. n.

Figs 5–6, 11–12, 17–18, 23–24, 27–28, 32, 37–38

Type material. OMAN: ♂ holotype, ZFMK (Ar 20596), Dhofar, Wadi Nahiz, Suhur Cave (17.1420°N, 54.1214°E), 145 m a.s.l., 21.ii.2018 (B.A. Huber).

Other material examined. OMAN: 2♂ 4♀, ZFMK (Ar 20597) and 1♀ in pure ethanol, ZFMK (Om 124), same data as holotype. 1♂ 1♀, ZFMK (Ar 20598) and 1 juv. in pure ethanol, ZFMK (Om 128), Dhofar, Ain Hamran Cave (17.0964°N, 54.2765°E), 85 m a.s.l., in cave, 22.ii.2018 (B.A. Huber). 1♀, ZFMK (Ar 20599), Dhofar, Ain Razad Cave (17.1301°N, 54.2364°E), 115 m a.s.l., in cave, 22.ii.2018 (B.A. Huber). 2♂ 1♀, ZFMK (Ar 20600), Dhofar, Wadi Darbat (17.09°N, 54.45°E), 200 m a.s.l., 23.ii.2018 (B.A. Huber). 1♂ 1♀, ZFMK (Ar 20601), Dhofar, Tayq Cave (17.1822°N, 54.5343°E), 790 m a.s.l., in cave, 23.ii.2018 (B.A. Huber). 1♀, ZFMK (Ar 20602), Dhofar, between Al Marnif and Ajdarawt (16.8356°N, 53.6769°E), 795 m a.s.l., under large rock, 24.ii.2018 (B.A. Huber). 1♂, ZFMK (Ar 20603), Dhofar, near Qairoon Hairitti (17.2600°N, 54.0808°E), 845 m a.s.l., in small cave, 27.ii.2018 (B.A. Huber).

Assigned tentatively. The following record is based on a juvenile only. Since this seems to be the only nonsynanthropic Artema species in the Dhofar Region of Oman, the assignment is likely to be correct.

OMAN: 1 juv. in pure ethanol, ZFMK (Om 136), Dhofar, Shaat sinkhole (16.774°N, 53.587°E), 850 m a.s.l., in wadi leading to sinkhole, 24.ii.2018 (B.A. Huber).

Etymology. The species name is derived from the type locality; noun in apposition.

Diagnosis. Easily distinguished from most congeners (except A. atlanta) by large bulbal process c provided with pointed tines (Figs 12, 17–18) and by trapezoidal anterior epigynal plate posteriorly indented (Fig. 32); from A. atlanta by (1) bulbal process b much smaller, processes d and e absent, and area between processes b and c smooth rather than rugose (compare Fig. 12 with figs 19–20 in Aharon et al. 2017); (2) retrolateral light notch on procursus much smaller than prolateral notch, and prolateral distal projection of procursus smaller (compare Fig. 11 with fig. 20 in Aharon et al. 2017); (3) relatively narrower male chelicerae and anterior cheliceral ridges in lateral view concave rather than convex (compare Figs 23–24 with figs 22–23 in Aharon et al. 2017); (4) anterior epigynal plate longer and posterior margin more evenly curved, with straight median part (compare Fig. 32 with fig. 15 in Aharon et al. 2017).

Description. Male (holotype). MEASUREMENTS. Total length 8.0, carapace width 3.5. Distance PME-PME 210 µm; diameter PME 170 µm; distance PME-ALE 80 µm; distance AME-AME 60 µm, diameter AME 170 µm. Leg 1: 58.6 (15.2 + 1.5 + 16.1 + 22.1 + 3.7), tibia 2: 12.7, tibia 3: 10.0, tibia 4: 12.8; tibia 1 L/d: 51.

COLOR (in ethanol). Carapace pale ochre-yellow with brown pattern medially, light brown ocular area; clypeus with brown median band dividing distally, brown rim; sternum pale ochre-yellow, with narrow brown margins and brown triangular mark posteriorly medially; legs ochre-yellow, with distinct brown rings on femora subdistally, in patella area, and on tibiae subdistally; femora 1 and 2 proximally red-brown. Abdomen pale gray, dorsally with indistinct dark marks; ventrally with brown mark in front of gonopore.

BODY. Habitus as in Fig. 5. Ocular area slightly elevated, deep thoracic pit behind ocular area, shallow thoracic furrow in posterior part of carapace; clypeus unmodified except for slightly thickened brown rim. Sternum wider than long (2.2/1.6), unmodified. Gonopore with five epiandrous spigots.

CHELICERAE. As in Figs 23–24, with several sclerotized cone-shaped hairs in distinctive arrangement, with very indistinct pair of low humps proximally laterally, without stridulatory ridges.

PALPS. In general very similar to known congeners (Fig. 28); coxa unmodified, trochanter ventrally slightly projecting and strongly sclerotized, femur strongly widened, with retrolateral apophysis proximally pointing towards ventral, patella very short, ventrally closed, i.e. not reduced; tibia retrolateral trichobothrium in very proximal position; procursus with distinct dorsal apophysis and ventral pocket in very proximal position, distally widened, with two light notches in dorsal view (Fig. 11); genital bulb with short membranous embolus accompanied by two processes (large process a and very small process b), process c large with many black pointed tines, without processes d and e (Figs 12, 17–18).

LEGS. Without spines and curved hairs, few vertical hairs; regular mechanoreceptive hairs either thick and variably long (~0.15–1.5) or thin and short (~0.08–0.15); retrolateral trichobothrium of tibia 1 at 8%; prolateral trichobothrium present on all tibiae; tarsus 1 with ~15–20 pseudosegments, barely visible.

Male (variation). Lateral humps on chelicerae barely visible in most males. Abdomen pattern variably distinct. Tibia 1 in 5 other males: 12.9–18.0 (mean 15.1). Very small male from Wadi Darbat (tibia 1 missing; tibia 2: 8.0) with process d much smaller than in holotype and with few tines.

Female. In general similar to male but with distinct stridulatory ridges on chelicerae, clypeus rim not brown, and anterior femora proximally not or only slightly red-brown. Tibia 1 in 10 females: 8.1–16.0 (mean 13.6). Epigynum anterior plate trapezoidal (Fig. 32), laterally dark brown, medially light and very slightly bulging, posterior margin evenly curved; pair of light brown plates in front of anterior epigynal plate slightly bulging; posterior plate wide, with pair of low lateral humps. Internal genitalia simple, with pair of elongated pore plates in transversal position (Figs 27, 37–38).

Distribution. Known from several localities in the Dhofar Region of western Oman (Fig. 342).

Natural history. All specimens were collected in caves or cave-like habitats (e.g., in a cavity under a huge boulder or at rock overhangs in Wadi Darbat), but consistently in the entrance areas and twilight zones. At the type locality (Suhur Cave) the spiders were very abundant and occupied mainly the first meter above the ground, with their large domed webs mostly hidden under large rocks on the ground.

Note. This species shares several unique characters with the widespread synanthropic type species A. atlanta (in particular, the unique bulbal process c with black pointed tines), suggesting that the two are sister species. This is the first hint towards the possible geographic origin of A. atlanta. It remains a mystery, however, why A. atlanta is almost entirely absent from the large area where congeneric species occur (Arabian Peninsula, Middle East, Central Asia) (Aharon et al. 2017).