Megachile (Pseudomegachile) plumigera Dorchin & Praz, 2018

Dorchin, Achik & Praz, Christophe J., 2018, Taxonomic revision of the Western Palaearctic bees of the subgenus Pseudomegachile (Hymenoptera, Apiformes, Megachilidae, Megachile), Zootaxa 4524 (3), pp. 251-307 : 279-281

Megachile (Pseudomegachile) plumigera Dorchin & Praz , sp. nov.

Distribution: United Arab Emirates, Oman.

Pollen hosts: Some specimens were collected on Crotalaria aegyptiaca (Fabaceae) in the United Arab Emirates.

Nesting biology: unknown.

Diagnosis: This species is very similar in morphology to M. blepharis sp. nov. described above from the Arava desert of Israel, and differs from the third species in the group, M. incana , by essentially the same characteristics listed in the diagnosis for the former species except those mentioned below. The female is easily separable from that of M. blepharis sp. nov. by the lack of facial comb of modified unbranched hairs, instead it has ordinary semi-erect, finely branched, silvery-white hairs on the clypeus, supraclypeal area and frons ( Fig. 125 ). The clypeus is relatively short, about as short as in M. incana (1.7 times broader than long, but the clypeus is normally hidden by dense hairs).

The male is very similar to that of M. blepharis sp. nov. and is difficult or impossible to separate from that species. Possibly, the posterior submedial depressions of S8 are deeper in M. plumigera ( Fig. 169 ) than in M. blepharis ( Fig. 167 ), and the basomedial spine and basolateral angle of the penis valve more angular ( Figs 132 , 168, 170 ).

Description: Female: as described for M. blepharis sp. nov. above, except the following characteristics. Body size slightly smaller, 11-12 mm. Head 1.2 times broader than long; interocellar distance 3.9 lateral ocellus diameters; compound eye about 2.7 times longer than wide in profile; all teeth of mandible comparably sharp ( Fig. 125 ); clypeus relatively short, about 1.7 times broader than long, weakly convex but not distinctly elevated along midline, with small, preapical medial protuberance not obscuring truncate anterior margin in frontal view, and with comparatively long, smooth area along anterior margin, about 3 puncture diameters long, the surface concealed by dense hairs ( Fig. 125 ); scape 2.7 times longer than broad; first flagellomere 1.1 times as long as broad, as broad as pedicle. Omaulus angular (more strongly so than in M. blepharis sp. nov.), obscured by dense hairs; scutellum regularly convex; hind basitarsus oval, weakly convex, about 2.46 times as long as broad (cf. Fig. 133 ).

Integument color black, except reddish-amber on either underside or both sides of antennae, terminal tarsal segment, and sometimes also tarsal segement 3 or 4; tergal and sternal marginal zones reddish amber to ocherous or fulvous; tegulae mostly ocherous. Integument surface sculpture as in M. blepharis sp. nov. (above) except that the clypeus densely punctate with irregular mostly small confluent punctures with no visible interspaces and with smooth apical margin two puncture diameters long; lower gena and hypostomal area with denser punctation.

Vestiture as in M. blepharis sp. nov. (above) ( Fig. 126 ), but unlike that species the face densely covered with light long branched hairs without modified unbranched hairs ( Fig. 125 ).

Male: description as M. blepharis sp. nov. (above) except for the following. Body length 11–13 mm; forewing length 6.75–8 mm; interocellar distance 3.1 lateral ocellus diameters; scape broaden apically, 2.5 times as long as apically broad; first flagellomere about as long as broad, about as broad as pedicle. Preapical carina of T6 broad, irregularly dentate with 7–8 teeth largely varying in size, the longest teeth on both sides of sometimes asymmetrical emargination ( Fig. 129 ); T7 produced into long, robust apicomedian spine, slightly shorter than distance from base of spine to anterior margin of external surface of T7 as seen in ventral view ( Fig. 129 ); structures of S1–8 and genitalia as in M. blepharis sp. nov. (above) except: submedial depressions on posterior of disc of S8 more conspicuous ( Fig. 169 ); and basomedial spine and basolateral angle of penis valve more angular compared to rounded in that species ( Fig. 170 ). These characters are weak and only few specimens were available for study.

Integument and wing color, and vestiture as in female ( Figs 127, 128 ), but antennal flagellum lighter reddishamber on dorsal side, orange on ventral side, and tegulae fulvous. Clypeus uniformly densely punctate with minute punctures covered with dense hairs.

Etymology: The species epithet plumigera refers to the plumose hairs found on the clypeus of the females of the new species, its main distinctive character.

Holotype: ♀, OMAN: 120 km NW Ibri Al Quabil (NW-Oman) [likely Al Qabil, 23°56′51″N 55°49′11″E], 0 2.04.1995, J. Wittmann leg. ( MSCA).

Paratypes: 2♀, OMAN: J. Hawrah Mahdah [likely “Jebel Hawrah”, 24°20’N, 55°53’E according to Baker (2004), a few km SW of the town of Mahdah, approximately 24°24'23"N 55°57'47"E], 17.03.2000, Gillet leg. (coll. B. Tkalců, OLML; CPCN) ; 2♀ 1♂, J. Huwarrah [likely Jebel Wahrah, 23°12'N 56°44'E, according to Baker (2004)], 24.03.2000, Gillet leg. (coll. B. Tkalců, OLML, 1♀ 1♂; SMNH, 1♀) ; 1♂, Muscat, Ruwi , iii.1976, K. Guichard leg. ( BMNH) . UNITED ARAB EMIRATES: 2♂, Al Ain, Snhaiba Dunes , 24.03.2000, Gillet leg. (coll. B. Tkalců, OLML; SMNH) ; 3♀ 3♂, Dubai DDCR, dune area grazing and browsing exclusion plot 24.82096°N 55.61533°E, 2– 16.04.2016, S. Gess leg. ( AMGS, 2♀ 2♂; CPCN 1 ♀ 1♂) .

Figures

FIGURES 125–133. Diagnostic traits of M. plumigera sp. nov.. 125: holotype female (facial view). 126: holotype female (lateral view). 127: habitus of male (facial view). 128: habitus of male (lateral view). 129: underside of metasoma of male. 130: vertex of female. 131: vertex of male. 132: genital capsule of male. 133: segments of hind leg of female M. incana (lateral view). LT: lateral tooth, PAC: preapical carina, AMS: apicomedial spine, PVBMS: basomedial spine of penis valve, PVBLA: basolateral angle of penis valve, GF: gonoforceps

FIGURES 159–170. Sternites 4–8 and genitalia of males of the incana species group. Sternites 4–6 of 159–161: M. incana, 162–164: M. blepharis sp. nov.. Sternite 8 and genitalia of 165, 166: M. incana, 167, 168: M. blepharis sp. nov., 169, 170: M. plumigera sp. nov.. PSMD: posterior submedial depression, GFBDLP: basal dorsolateral projection of gonoforceps, PVBMS: basomedial spine of penis valve, PVBLA: basolateral angle of penis valve, PVLS: lateral spine of penis valve, PVLA: lateral angle of penis valve. Scale bars equal 1 mm, except for 0.5 mm in Figs 165–170.