Chelostoma (Gyrodromella) clypeale Müller, 2015

Müller, Andreas, 2015, Palaearctic Chelostoma bees of the subgenus Gyrodromella (Megachilidae, Osmiini): biology, taxonomy and key to species, Zootaxa 3936 (3), pp. 408-420 : 410-411

Chelostoma (Gyrodromella) clypeale Müller , spec. nov.

Holotype. TURKEY, Hatay: 30 km W of Gaziantep, 30.5.1998, ♀ (leg. M. Halada). Deposited in the Entomological Collection of ETH Zurich.

Paratypes. TURKEY, Bolu: Yedi Göller National Park, 14.6.1987, 1♀ (leg. Madl); Hakkari: E of Uludere, 5.6.1977, 1♀, 3♂ (leg. K. Warncke); Tanin-Tanin pass, 1700 m, 12.6.1984, 1♀ (leg. K. Warncke); S of Beytüssebap, 1300 m, 13.6.1984, 4♀ (leg. K. Warncke); 5 km N of Oramar, 1500 m, 16.6.1984, 1♂ (leg. K. Warncke); 10km NE of Oramar, 1700 m, 29.6.1985, 1♀ (leg. M. Schwarz); Hatay: 30 km NW of Gaziantep, 2001, 2♀ (leg. M. Snizek); Sirnak: Cizre, 16.5.1975, 2♂ (leg. K. Warncke); 40 km E of Midyat, 900 m, 25.5.1983, 5♂ (leg. K. Warncke). Deposited in the Entomological Collection of ETH Zurich, the Oberösterreichische Landesmuseum Linz and the private collection of M. Schwarz (Ansfelden).

Diagnosis. The female is easily recognizable by the shape of the clypeus characterized by a narrow apical zone, which is flat and distinctly separated from the moderately bulging main part of the clypeus, and by its straight or at most slightly irregular anterior margin lacking small tooth-like projections ( Fig. 5 ). The male differs from all species of the rapunculi species group except C. tonsum by the uninterrupted comb of long bristles at the apical margin of sternum 5 in combination with the widely spaced and parallel-sided upper lateral teeth of tergum 7 ( Fig. 6 ). In contrast to C. tonsum , the distance between the spots of black bristles at the apical margin of sternum 3 is narrower than the maximal spot width ( Fig. 7 ), sternum 4 lacks small lateroapical tufts of bristles, the pilosity along the lower genal area is of normal length, the projecting apex of the upper lateral teeth of tergum 7 are about as long as wide ( Fig. 6 ), the lower median tooth of tergum 7 is of roughly triangular rather than trapezoidal shape ( Fig. 6 ), and the membraneous appendage of sternum 4 is shorter than the length of tarsal segment 3 of the hind leg.

Description. FEMALE: Body length 6.5–8 mm. Head: Head about 1.1x as long as broad. Labrum about 1.25x as long as broad, flat and unpunctured except for its apical fifth, which is slightly thickened and punctured; its anterior margin broadly emarginate. Mandible short, three-toothed. Second segment of labial palpus about 4.5x as long as first segment. Clypeus with narrow apical zone, which is flat and distinctly separated from the slightly bulging main part of the clypeus ( Fig. 5 ); its anterior margin straight or slightly undulated, without tooth-like projections. Clypeus densely punctured with interspaces not exceeding the diameter of one puncture except for a rather broad median zone, where the punctation is distinctly more scattered with interspaces reaching the diameter of two to three, rarely more punctures. Distance between lateral ocellus and preoccipital ridge about 2x as long as ocellar diameter. Preoccipital ridge raised to a very short carina. Mesosoma: Scutum rather densely punctured with interspaces varying in size between the diameter of less than half a puncture and the diameter of one and a half, rarely two punctures. Scutellum densely punctured with interspaces mostly smaller than the diameter of one puncture except mediobasally where the punctation is occasionally more scattered. Basal zone of propodeum sloping, half to two third as long as metanotum and with longitudinal ridges, which laterally become gradually more distinct and more spaced. Metasoma: Anterior surface of tergum 1 shallowly concave. Discs of terga 1–4 with rather coarse punctation, which is scattered medially with interspaces reaching the diameter of up to two, rarely more punctures. Marginal zones of terga 1–4 slightly impressed, medially one third to nearly half as long as tergal length and with finer and denser punctation than on discs. Terga 5–6 very densely punctured with interspaces rarely exceeding the diameter of half a puncture. Bases of terga 2–4 distinctly constricted. Terga 1–4 with dense apical white hair bands, which are uninterrupted in fresh specimens.

MALE: Body length 6–8 mm. Head: Head about as long as broad. Second segment of labial palpus about 4.5x as long as first segment. Pilosity along lower genal area shaggy and long, hairs just behind mandibular base as long as length of first segment of labial palpus or longer. Distance between lateral ocellus and preoccipital ridge about 1.75x as long as ocellar diameter. Preoccipital ridge raised to a very short carina. Mesosoma: Punctation of scutum and scutellum as well as length and sculpture of basal zone of propodeum as in the female. Metasoma: Anterior surface of tergum 1 shallowly concave. Punctation of tergal discs 1–4 less coarse and more scattered than in the female, interspaces reaching the diameter of up to four punctures. Punctation of marginal zones of terga 1–4 slightly finer and distinctly denser than on discs. Terga 5–6 densely punctured with interspaces rarely exceeding the diameter of one puncture. Bases of terga 2–3 constricted. Terga 1–4(5) with dense apical white hair bands, which appear to be interrupted on terga 1–2 even in fresh specimens. Tergum 7 with large, deep and polished pit surrounded by two widely spaced and parallel-sided upper lateral teeth, whose projecting apex is about as long as wide, and one small lower median tooth, which is of roughly triangular shape ( Fig. 6 ). Median elevation on sternum 2 triangular in profile, its anterior surface angularly delimited from the posterior surface, which is evenly sloping, half-elliptical in shape and almost flat. Sternum 3 medioapically with two oval spots of black bristles, which are separated from each other by a distance only about half to three quarters as long as maximal width of spot ( Fig. 7 ). Membraneous appendage of sternum 4 shorter than length of tarsal segment 3 of hind leg. Apical margin of sternum 5 with uninterrupted comb of long yellowish bristles.

Distribution. Central to easternmost Turkey; westernmost record: Yedi Göller National Park (Bolu province).

Pollen hosts. Probably oligolectic on Campanula (Campanulaceae) and possibly also closely related genera (based on the microscopical analysis of 3 pollen loads from the same locality).

Nesting biology. Unknown.

Etymology. clypealis = referring to the unique form of the female clypeus.

Figures

FIGURE 5 – 10. 5: Chelostoma clypeale, head of female. 6: Chelostoma clypeale: terga 4 – 7 of male. 7: Chelostoma clypeale, sterna 2 – 4 of male. 8: Chelostoma tonsum, head of male. 9: Chelostoma tonsum, terga 4 – 7 of male. 10: Chelostoma tonsum, sterna 2 – 3 of male.