Micropholcus dhahran Huber, 2024

Huber, Bernhard A. & Meng, Guanliang, 2024, Old World Micropholcus spiders, with first records of acrocerid parasitoids in Pholcidae (Araneae), ZooKeys 1213, pp. 95-182 : 95-182

Micropholcus dhahran Huber sp. nov.

Figs 3 A , 23 , 24 , 25 , 26

Type material.

Holotype. Saudi Arabia – ‘ Asir • ♂; W of Dhahran Al Janub , ‘ site 2 '; 17.7010 ° N, 43.3891 ° E; 2000 m a. s. l.; 24 Mar. 2024; B. A. Huber leg.; KSMA . Paratypes. Saudi Arabia – ‘ Asir • 2 ♂♂, 1 ♀, and 1 cleared ♀ abdomen; same collection data as for holotype; ZFMK Ar 24657 .

Other material.

Saudi Arabia – ‘ Asir • 1 ♀ (abdomen cleared and transferred to ZFMK Ar 24657 ), in pure ethanol; same collection data as for holotype; ZFMK SA 121 .

Diagnosis.

Distinguished from known congeners by unique shapes of bulbal processes (Fig. 24 D, E ; similar only in M. abha sp. nov. but without strong retrolateral spine; without distinctive pointed prolateral sclerite as in geographically closest species, M. harajah sp. nov. and M. alfara sp. nov.); from most congeners (except M. harajah sp. nov. and M. alfara sp. nov.) by rectangular dorsal hinged process of procursus with obtuse tip and ventral terminal pointed process and small proximal spine (in other Saudi Arabian species procursus wider and more curved dorsally, without proximal spine; in M. fauroti relatively longer and without spine); most congeners (except for three species above and M. jacominae and M. darbat sp. nov.) also by long trochanter apophysis (Fig. 23 C ; longer than palpal femur). Female with pair of distinct internal crescent-shaped structures (arrows in Fig. 25 C ), similar only in M. harajah sp. nov. and M. alfara sp. nov., but without external pockets as in M. harajah sp. nov., crescent-shaped structures farther apart than in M. alfara sp. nov., and anterior arc wider and with different curvature than in M. harajah sp. nov. and M. alfara sp. nov.

Description.

Male (holotype). Measurements. Total body length 2.5, carapace width 0.8. Distance PME - PME 180 µm; diameter PME 85 µm; distance PME - ALE 20 µm; distance AME - AME 20 µm; diameter AME 55 µm. Leg 1: 27.1 (6.9 + 0.4 + 6.7 + 12.0 + 1.1), tibia 2: 4.0, tibia 3: 2.1, tibia 4: 3.1; tibia 1 L / d: 84; diameters of leg femora (at half length) 0.09–0.10; of leg tibiae 0.08.

Colour (in ethanol). Carapace pale ochre-yellow with distinct brown mark, ocular area and clypeus without darker pattern; sternum monochromous whitish; legs ochre-yellow, patellae brown, tibia-metatarsus joints with indistinct brown ring, femur 1 proximally barely darkened; abdomen pale ochre-grey, dorsally and laterally with whitish internal marks.

Body. Habitus as in Fig. 3 A . Ocular area slightly raised. Carapace without thoracic groove. Clypeus unmodified. Sternum wider than long (0.62 / 0.50), unmodified. Abdomen oval, approximately twice as long as wide.

Chelicerae. As in Fig. 25 A, B ; with pair of distal apophyses near laminae, each with two cone-shaped hairs; with pair of low proximal frontal humps; with proximal lateral processes in relatively distal position and directed towards distal.

Palps. As in Fig. 23 ; coxa unmodified; trochanter with long ventral apophysis with distinct proximal retrolateral hump and modified hair on distal tip; femur distally widened, with distinct ventral hump; femur-patella joints shifted toward prolateral side; tibia-tarsus joints shifted toward retrolateral side; tarsus with large tarsal organ. Procursus (Fig. 24 A – C ) proximally with sclerotised prolateral hump; at half-length with prolateral sclerotised ridge transforming distally into transparent membrane, and brush of dorsal hairs; distally with small retrolateral ridge and strong ventral apophysis, large bifid membranous ventral-prolateral flap, and distinctive dorsal hinged process. Genital bulb (Fig. 24 D, E ) with strong proximal sclerite; with two sclerotised processes of unclear homology: prolateral process with dorsal row of teeth with short hair-like processes, retrolateral process originating from basis of embolus, S-shaped and distally slightly spiralling; and mostly semi-transparent short embolus with distinct pointed extension.

Legs. Without spines, without curved hairs, without sexually dimorphic short vertical hairs; retrolateral trichobothrium of tibia 1 at 7 %; prolateral trichobothrium absent on tibia 1; tarsus 1 with> 20 pseudosegments, only distally distinct.

Variation (male). Tibia 1 in two other males: 6.5, 6.7.

Female. In general very similar to male. Tibia 1 in one female: 4.3 (missing in second female). Epigynum (Fig. 26 A, B ) barely protruding, anterior plate oval, with indistinct knob-shaped process posteriorly; with pair of lateral and median internal dark structures visible through cuticle; posterior epigynal plate very short and indistinct. Internal genitalia (Figs 25 C , 26 C, D ) with pair of elongated pore plates in transversal position; with pair of lateral sclerites, median crescent-shaped structures, and large membranous anterior arc.

Etymology.

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

Distribution.

Known from type locality only, in Saudi Arabia, ‘ Asir Province (Fig. 13 C ).

Natural history.

The spiders were found sitting on the undersides of large boulders, in small cave-like spaces between ground and boulder.

Figures

Figure 3. Micropholcus Deeleman-Reinhold & Prinsen; live specimens from Saudi Arabia A M. dhahran Huber, sp. nov., male from ‘ Asir, W of Dhahran Al Janub B M. harajah Huber, sp. nov., female with egg-sac from ‘ Asir, SE of Harajah C, D M. alfara Huber, sp. nov., male and female with egg-sac from ‘ Asir, S of Al Fara E M. abha Huber, sp. nov., male from ‘ Asir, N of Abha F M. tanomah Huber, sp. nov., male from ‘ Asir, NW of Tanomah G M. bashayer Huber, sp. nov., female with egg-sac from ‘ Asir, NW of Al Bashayer H M. maysaan Huber, sp. nov., male from Mecca, NW of Maysaan. Photographs BAH.

Figure 13. Known distribution of Micropholcus fauroti (Simon) (A) and of Old World Micropholcus in Mindanao (B), on the Arabian Peninsula (C) and in Morocco (D).

Figure 23. Micropholcus dhahran Huber, sp. nov.; male from Saudi Arabia, ‘ Asir, W of Dhahran Al Janub (ZFMK Ar 24657). Left palp in prolateral (A), dorsal (B), and retrolateral (C) views. Scale bar: 0.3 mm.

Figure 24. Micropholcus dhahran Huber, sp. nov.; male from Saudi Arabia, ‘ Asir, W of Dhahran Al Janub (ZFMK Ar 24657) A – C left procursus in prolateral, dorsal, and retrolateral views; bold arrow in C points at proximal spine on hinged process D, E left genital bulb in prolateral and retrolateral views; bold arrows in D point at distinctive processes of unclear homology. Abbreviations: e, embolus; hp, dorsal hinged process; mf, membranous prolateral flap; ps, proximal bulbal sclerite; rr, retrolateral ridge; tm, transparent membrane; Scale bars: 0.3 mm.

Figure 25. Micropholcus dhahran Huber, sp. nov.; from Saudi Arabia, ‘ Asir, W of Dhahran Al Janub (ZFMK Ar 24657) A, B male chelicerae, frontal and lateral views C cleared female genitalia, dorsal view; bold arrows point at crescent-shaped structures. Abbreviation: pp, pore plate. Scale bars: 0.3 mm.

Figure 26. Micropholcus dhahran Huber, sp. nov.; female from Saudi Arabia, ‘ Asir, W of Dhahran Al Janub (ZFMK Ar 24657) A, B abdomen, ventral and lateral views C, D cleared genitalia, ventral and dorsal views. Scale bars: 0.3 mm.