Hylaeus (Hylaeus) mellon Dathe & Proshchalykin

Dathe, Holger H. & Proshchalykin, Maxim Yu., 2016, The genus Hylaeus Fabricius in Mongolia, an updated species inventory (Hymenoptera: Apoidea, Colletidae), Zootaxa 4121 (4), pp. 351-382 : 366-369

Hylaeus (Hylaeus) mellon Dathe & Proshchalykin sp. n.

Figures 4 j, 9–12

Diagnosis. The new species belongs to a species group which is not very clearly circumscribed. To it may be attributed Hylaeus angustifrons Morawitz , H. tibialis Morawitz , H. altaicus Dathe and perhaps also H. tsingtauensis (Strand) . Particularly striking is the short and wide supraclypeal area of both sexes of H. mellon sp. n., in which the ventral part is clearly wider than the distance to the orbits. The mask is white, the integument shiny, but without conspicuous coarse sculpture. The propodeum is angular, largely without sharp ridges. The lower part of the clypeus is strongly arched. A subtle, but seemingly reliable character of the female is a minute shiny area in the middle of the clypeus directly below the border to the supraclypeal area.

Description. Male. Measurements (n=2): total length 5.2–5.5 (5.33) mm, wing length 4.2–4.4 (4.32) mm.

Head proportions HL:HW 0.99, UHW:LHW 1.64, outline rounded trapezoidal, face significantly converging downwards ( Fig. 11 a). Scapi conically expanded, thereby curved and shield-like, SL: SW 1.65; black, outer with wide white spot, the upper edge with a long row of bristles; flagella long, totally black, 2nd segment short, widened. Mask complete, white, side patches expanded to upper margin of scapi bases, surrounding them partly.

Supraclypeal area relatively wide, distinctly protruding from the frons, with dorsal edges sharp, at the upper end merging with a sharp keel into the frons; surface finely striate, dorsally with a short median groove. Clypeus CL:CW 1.45, ventral part wide, about 1.2 times wider than the distance to the orbits, surface strongly arched, surface finely wrinkled striate, silkily shiny, with flat scattered punctation on lower parts and laterally, anterior margin brown. Frons with scapus-range only longitudinally wrinkled, upwards and outwards increasingly densely wrinkled-streaky punctate; punctation strong, close, intervals shiny; vertex with subcontiguous, strong punctation and moderately dense erect pilosity. Foveae faciales short, indistinct. Genae normal, wrinkle-streaky, silkily shiny; occiput narrowly bordered; malae distinct. Labrum and bifid mandibles black.

Mesosoma ( Fig. 11 b) compact; pilosity long, erect. Coloration black, only tegulae with small white spot. Pronotum narrow, only laterally somewhat expanded, anterior margin in the middle narrow, dorsolateral angles sloping. Mesonotum finely shagreen, silkily shiny; punctation strong, dense to subcontiguous; scutellum with somewhat larger and more scattered punctation, more shiny; metanotum matt, coarsely punctate; mesopleura with strong, subcontiguous punctation, similar to mesonotum, intervals shiny, anterior margin rounded. Legs black, anterior surface of foretibiae, bases of other tibiae and proximal parts of basitarsi white, other tarsi black; wings hyaline, venation brown, stigma dark brown. Propodeum ( Fig. 11 c) edged, only medial area shining, this part with rugose-reticulate wrinkles, delimited by a row of meshes; terminal area without distinct border, propodeal furrow broad, edged around.

Metasoma stocky spindle-shaped, coloration black. T1 ( Fig. 11 c) smooth and shiny, punctation moderate, close to sparse; surface without hairs; without lateral fringes. T2 and following terga very finely shagreen, somewhat more finely and densely punctate, with protruding white bristles; depressions brownish translucent. Terminalia ( Figs 12 a–c): genital capsule expanded, with enlarged gonobasis and gonoforcipes, latter apically truncate, bristles short; penis valves in dorsal view little longer than gonoforcipes; sternum 8 with apical lobus in the middle slightly enlarged, ending in a pair of deeply emarginated lobes; sternum 7 with proximal lobes distinctly expanded, distal lobes apically form a blackened disk, which is covered with numerous fine papillae; comb bristles distinctly widened, flags wide but short.

Female. Measurements (n=7): total length 5.4–6.1 (5.90) mm, wing length 4.5–5.0 (4.78) mm.

Head proportions HL:HW 1.04, UHW:LHW 1.49, outline long trapezoidal, clypeus somewhat expanded ( Fig. 11 d). Scapi black, flagella short, black. Face with white lateral spots close to scapus bases, their shape long oval to rectangular. Supraclypeal area longitudinally striate, silkily shiny, above less steeply merging with the frons; separated from clypeus by a fine seam, that is almost obscured by sculpture, in the middle below this line a little shiny area can be seen, which is apparently characteristic for this species. Clypeus CL:CW 1.45, strongly arched below, upper part longitudinally striate, matt, anteriorly with scattered shallow punctation; Frons and vertex with subcontiguous strong punctation similar to the male. Foveae faciales long, reaching upper eye border. Genae distinct, in outline sloping below; occiput rounded; malae narrow. Labrum and bifid mandibles black.

Mesosoma ( Fig. 11 e) oval, rounded; pilosity inconspicuous, thorax and propodeum with dense white pilosity, dorsally somewhat sparser. Coloration black, only tegulae and calli each with a white spot. Pronotum slightly expanded forward as a narrow flange. Mesonotum and scutellum only weakly shining, with strong, dense to close punctation; metanotum matt, finer punctate; mesopleurae with similar punctation as mesonotum, anterior margin rounded. Legs completely black, except white bases of tibiae; wings hyaline, venation brown, stigma dark brown. Propodeum edged, surface grid wrinkled, slightly shiny as in male; medial area shiny, with rugose-reticulate wrinkles, delimited by a row of meshes; terminal area with very fine ridge, propodeal furrow broad, edged around. Metasoma compact spindle-shaped, coloration black. T1 ( Fig. 11 f) smooth and shiny, punctation fine, close, distally denser; T2 and following terga finely shagreen, with denser and finer punctation; terga with adpressed hairs, but without lateral fringes; depression margins brownish translucent; fringe of last sternum yellowish.

Type material: 2 ♂, 7 ♀

Holotype: ♂ Mongolia. Khovd Aimag: 31 km NNE Bulgan, Ulyastain-Gol, 18.VI.2012, AT ( IBSS)

Paratypes: Mongolia. Khovd Aimag: 1 ♀, 31 km NNE Bulgan, Ulyastain-Gol, 18.VI.2012, AT ( IBSS); 1 ♂, 20 km N Bulgan, Ulyastain-Gol, 30.VI–1.VII.1980, VT ( ZISP); 6 ♀ 25 km N Uench, Uench River, 1700 m, 15.VI.2012, AT ( IBSS).

Etymology. mellon (High Elvish [Sindarin]): friend; a noun in apposition.

In reverence for J.R.R. Tolkien.

Figures

FIGURE 4. Distribution of Hylaeus species in Mongolia: a — H. sibiricus, H. pirus; b — H. pfankuchi, H. gracilicornis; c — H. przewalskyi, H. paulus; d — H. tsingtauensis, H. nimbatus; e — H. stubbei, H. valinis; f — H. confusus, H. ulanus; g — H. dorni, H. montivagus; h — H. kozlovi sp. n.; i — H. mongolicus, H. potanini; j — H. mellon sp. n.

FIGURE 11. Hylaeus (Hylaeus) mellon sp. n. Holotypus male: a — face, b — mesonotum, c — propodeum and basal terga. — Paratypus female: d — face, e — mesonotum, f — propodeum and basal terga. — Scale bar 1 mm.

FIGURE 12. Hylaeus (Hylaeus) mellon sp. n., holotypus male a — sternum 7, b — sternum 8, c — genital capsule. Scale bar 0.2 mm.