Micropholcus jacominae Deeleman-Reinhold & van Harten, 2001

Figs 19, 20, 21, 22

Micropholcus jacominae Deeleman-Reinhold & van Harten, 2001: 199, figs 17, 18, 21–26 (♂ ♀).

Material examined.

Yemen – Al Mahwit • 1 ♂, 1 ♀, paratypes; Khamis Bani Sa’d; 15.185 ° N, 43.510 ° E (see Note below); 490 m a. s. l.; 11 Oct. 1999; A. van Harten leg.; RMNH ARA 15019 .

Note.

The coordinates in Deeleman-Reinhold and van Harten (2001) (15 ° 11 ' N, 43 ° 25 ' E) mark a spot 10 km W of Khamis Bani Sa’d, at ~ 440 m a. s. l. (rather than 550 m as reported in the original description). We suspect that our coordinates above are closer to the actual collecting site that could only be reconstructed as being “ close to Khamis Bani Sa’d, but not in the village ” (A. van Harten, pers. comm. 22 Apr. 2021, 13 Mar. 2024).

Diagnosis.

Easily distinguished from known congeners by numerous details of male palp: long ventral apophysis on trochanter (Fig. 19 C; similar in some Saudi Arabian species, cf. Figs 27 C, 31 C); distinct dorsal process on femur (arrowed in Fig. 19 C; similar only in M. abha sp. nov., cf. Fig. 35 C); dorsal-distal hinged process on procursus short and directed towards prolateral (Fig. 20 A – C); unique processes of genital bulb (Fig. 20 E, F), and by female epigynum and internal genitalia (Figs 21 C, 22): extensible knob in posterior position; pair of strongly curved lateral internal sclerites; long pore plates widening and only slightly converging anteriorly.

Redescription.

Male. Measurements. Total body length 2.3, carapace width 0.85. Distance PME - PME 200 µm; diameter PME 65 µm; distance PME - ALE 20 µm; distance AME - AME 25 µm; diameter AME 45 µm. Leg 1: 23.3 (5.9 + 0.4 + 5.7 + 10.2 + 1.1), tibia 2: 3.5, tibia 3: 2.1, tibia 4: 2.9; tibia 1 L / d: 76; diameters of leg femora (at half length) 0.08–0.09; of leg tibiae 0.07–0.08.

Colour (in ethanol). Prosoma and legs pale ochre-whitish, carapace with complex brown median mark similar to Saudi Arabian species (cf. Fig. 3); legs with darkened patellae and tibia-metatarsus joints; abdomen pale grey to whitish.

Body. Habitus similar to Saudi Arabian species (cf. Fig. 3). Ocular area raised (distinct in frontal view). Carapace without thoracic groove. Clypeus unmodified. Sternum wider than long (0.50 / 0.40), unmodified. Abdomen oval, almost twice as long as wide.

Chelicerae. As in Fig. 21 A, B; with pair of relatively long distal apophyses near laminae, each with two modified (cone-shaped) hairs; pair of proximal lateral processes weakly sclerotised and directed towards proximal; and pair of small but distinct proximal frontal processes.

Palps. As in Fig. 19; coxa unmodified; trochanter with long ventral apophysis with very indistinct retrolateral hump proximally and modified hair at tip (Fig. 20 D); femur with weakly sclerotised but distinct processes retrolateral-dorsally and prolateral-ventrally; femur-patella joints shifted toward prolateral side; tibia-tarsus joints shifted toward retrolateral side; tarsus with large tarsal organ. Procursus (Fig. 20 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 retrolateral ridge, membranous ventral-prolateral flap, pointed prolateral process, and distinctive dorsal hinged process. Genital bulb (Fig. 20 E, F) with strong proximal sclerite; two sclerites of unclear homology, with two pointed processes each; and mostly semi-transparent short embolus, proximally sclerotised, distally membranous with pointed transparent extension.

Legs. Without spines, without curved hairs, without sexually dimorphic short vertical hairs (many hairs missing); retrolateral trichobothrium of tibia 1 at 8 %; prolateral trichobothrium absent on tibia 1; tarsus 1 with> 20 pseudosegments, distally distinct.

Female. In general very similar to male but ocular area slightly less raised and triads closer together (PME - PME 170 µm), carapace pattern more fragmented than in male. Tibia 1: 4.4. Epigynum (Fig. 22 A) anterior plate oval, protruding, with membranous, possibly expandable knob in posterior position, tip directed towards posterior; lateral internal sclerites clearly visible in untreated specimens; posterior epigynal plate very short and indistinct. Internal genitalia (Figs 21 C, 22 B, C) with pair of long pore plates converging and widening anteriorly, pair of lateral sclerites, and transversal ventral sclerotised band; with sclerotised anterior arc continued to posterior margin.

Distribution.

Known from type locality only, in western Yemen (Fig. 13 C).

Natural history.

Deeleman-Reinhold and van Harten (2001) report that the spiders were shaken from dry plant debris in an irrigated banana plantation. This microhabitat is unusual for Micropholcus on the Arabian Peninsula and needs confirmation.