Chelostoma ( Chelostoma ) meronense Müller, 2025

Müller, Andreas, Pisanty, Gideon & Dorchin, Achik, 2025, Western Palaearctic Chelostoma bees of the subgenus Chelostoma (Megachilidae, Osmiini): biology, taxonomy and key to species, Zootaxa 5717 (3), pp. 329-369 : 347-349

Chelostoma ( Chelostoma) meronense Müller , sp. nov.

Holotype. ISRAEL: Northern District: Mount Meron, Station , 4.5.2000, ♂ (leg. M. Török). Deposited in the Entomological Collection of ETH Zurich.

Paratypes. ISRAEL: Northern District: Yir’on , 14.5.1974, 1♂ (leg. A. Freidberg) ; 40 km NE Haifa, 1 km E Hurfeish , 33°01′N / 35°21′E, 15.5.1996, 7♀ (leg. C. Schmid-Egger) ; Har Meron , 33°0′N / 35°25′E, 1120 m, 26.5.2009, 1♂ (leg. A. Freidberg) ; 1 km SW Ziv ›on, 33.019°N 35.407°E, 15.5.2015, 1♀, 1♂ (leg. G. Pisanty); 1 km SW Ziv ›on, 33.02°N 35.41°E, 22.4.2016, 3♀ (leg. G. Pisanty) ; 1 km SW Ziv’on , 33.0195°N / 35.408°E, 21.4.2017, 1♂ (leg. G. Pisanty) . Deposited in the Entomological Collection of ETH Zurich and the Steinhardt Museum of Natural History Tel Aviv.

Diagnosis. The females of C. meronense can be separated from those of the two other species of the C. meronense group by the following combination of characters: i) head 1.1–1.2× as long as wide ( Fig. 32 ), ii) third segment of labial palpus shorter than fourth segment, iii) basal area of propodeum medially about as long as metanotum ( Fig. 33 ), and iv) anterior surface of coxa of fore leg densely punctate with interspaces rarely exceeding the diameter of one puncture ( Fig. 34 ). The males differ from the two related species by the following combination of characters: i) hypostomal area with tooth-like projection of roughly rectangular shape ( Fig. 36 ), ii) third segment of labial palpus shorter than fourth segment, iii) antennal segments 5-12 symmetrical and longer than wide ( Fig. 35 ), iv) last antennal segment elongated oval and not distinctly button-like ( Fig. 35 ), v) anterior side of antennal flagellum predominantly yellowish-red ( Fig. 25 ), vi) basal area of propodeum medially about as long as metanotum, vii) anterior margin of median projection of sternum 2 evenly rounded ( Fig. 39 ), and viii) patches of short black thorns of sternum 3 narrow and curved, covering entire sides of sternal impression ( Fig. 39 ).

Description. FEMALE ( Fig. 30 ): Body length 6.5–7.5 mm. Head: Head 1.1–1.2× as long as wide ( Fig. 32 ). Distance between posterior margin of lateral ocellus and occipital margin 1.4-1.6× as long as ocellar diameter. Clypeus rather strongly convex, its anteriormost point slightly projecting over supraclypeal area in lateral view. Punctation of clypeus laterally and apically very dense with interspaces rarely exceeding diameter of half a puncture and on narrow median zone more scattered with interspaces reaching diameter of one to two punctures. Supraclypeal area basally and laterally densely and medioapically more sparsely punctate. Labrum 1.8–1.9× as long as apically wide; its apical margin shallowly emarginate over entire width. Mandible three-toothed. Proboscis very long ( Fig. 30 ), slightly surpassing coxa of fore leg when folded; second segment of labial palpus about 4.75× as long as first segment and 1.3–1.4× as long as compound eye. Third segment of labial palpus shorter than fourth segment. Anterior side of antennal segments (8,9)10–11 reddish-brown. Mesosoma : Posterior and lateral surface of propodeum largely polished. Basal area of propodeum medially about as long as metanotum, flat, crossed by numerous rather fine longitudinal and occasionally branched carinae and bordered by narrow impunctate polished zone around its posterior margin ( Fig. 33 ). Anterior surface of coxa of fore leg densely punctate with interspaces rarely exceeding the diameter of one puncture ( Fig. 34 ). Apical margin of tibial spur of fore leg prolonged into very short tip. Tibial spurs of hind leg yellowish-brown. Metasoma: Marginal zones of terga 1–4 with dense and short white hair bands ( Fig. 30 ), which are usually not interrupted in fresh specimens. Terga 2–3 basally not or only weakly constricted. Scopa white, its hairs not plumose ( Fig. 30 ).

MALE: Body length 7.5–8.5 mm. Head: Head 1.05–1.1× long as wide. Distance between posterior margin of lateral ocellus and occipital margin 1.4–1.5× as long as ocellar diameter. Hypostomal carina prolonged into large tooth-like projection of roughly rectangular shape in lateral view ( Fig. 36 ). Genal area along lower margin of compound eye not distinctly impressed and densely punctate. Proboscis very long ( Fig. 31 ), slightly surpassing coxa of fore leg when folded; second segment of labial palpus about 4.5× as long as first segment and 1.3-1.4 as long as compound eye; third segment of labial palpus shorter than fourth segment. Antennal segments 5–12 almost symmetrical and longer than wide ( Fig. 35 ). Last antennal segment elongated oval and not distinctly button-like ( Fig. 35 ). Anterior side and to different degree also posterior side of antennal segments 4–12 yellowish-red ( Fig. 35 ); antennal segments 1–3 and 13 (almost) completely black ( Fig. 35 ). Mesosoma : Posterior and lateral surface of propodeum largely polished. Basal area of propodeum about as long as metanotum, flat, crossed by numerous rather fine longitudinal and occasionally branched carinae and bordered by narrow impunctate polished zone around its posterior margin. Mesosternum medioapically with widely triangular and densely sculptured impression, the margins of which are only basally slightly raised. Anterior surface of coxa of fore leg rather densely punctate with interspaces reaching the diameter of one, rarely one and a half to two punctures. Apical margin of tibial spur of fore leg slightly emarginate. Metasoma: Marginal zones of terga 1–5(6) with loose white hair bands ( Fig. 31 ), which are widely interrupted on terga 1–3(4). Terga 2–3 basally not or only weakly constricted. Tergum 7 basally with oval pit, laterally triangularly toothed and apically with two teeth, which are roughly parallel-sided, about as long as to slightly longer than basally wide, apically (obliquely) truncate and separated from each other by semicircular incision about twice as wide as tooth width ( Fig. 37 ). Apical margin of sternum 1 medially distinctly emarginate. Median projection of sternum 2 half-elliptical and concave in ventral view, its anterior half evenly rounded in ventral view and overhanging concave anterior surface of median projection in lateral view ( Fig. 38, 39 ). Sterna 2–3 lateroapically with tuft of long white hairs. Sternum 3 with two narrow and curved spots of short black thorns, which cover entire sides of sternal impression ( Fig. 39 ). Sternum 3 with row of stiff yellowish bristles along its apical margin ( Fig. 39 ). Sternum 4 densely covered with whitish pilosity, its apical margin with membraneous appendage that is medially divided into two flat lobes. Apical margin of sternum 5 with single row of long, yellowish and moniliform bristles ( Fig. 39 ) Sternum 6 roughly quadrangular in shape, its apical half polished, very sparsely haired, impunctate and medially impressed.

Distribution. Northern Israel ( Fig. 74 ).

Pollen hosts. Seven pollen loads from three different localities in northern Israel exclusively consisted of hexacolpate pollen of the Nepetoideae ( Lamiaceae ), strongly suggesting that C. meronense is oligolectic on Lamiaceae . This assumption is supported by the observation of a male visiting the flowers of Salvia (label record).

Nesting biology. Unknown.

Etymology. The species epithet refers to the Har Meron, a mountain in northern Israel, where the new species was found.

Figures

FIGURE 74. Distribution of the eight Chelostoma species newly described in the present publication: C. dolichocephalum (violet), C. kurdistanicum (orange), C. levantense (white), C. meronense (dark blue), C. miripalpum (light blue), C. negevense (red), C. ornithogali (yellow) and C. scabiosae (green). Made with Natural Earth (ww w.naturalearthdata.com).

FIGURES 30–39. Chelostoma meronense: 30: Female, 31: Male, 32: Head of female, 33: Basal area of propodeum of female, 34: Coxa of fore leg of female, 35: Antenna of male, 36: Head of male, 37: Terga 5–7 of male, 38: Sternum 2 of male in lateral view, 39: Sterna 2–4 of male.

FIGURES 19–29. Chelostoma dolichocephalum: 19: Female, 20: Male, 21: Head of female, 22: Basal area of propodeum of female, 23: Coxa of fore leg of female, 24: Head of male, 25: Antenna of male, 26: Terga 5–7 of male, 27: Sternum 2 of male in lateral view, 28: Median projection of sternum 2 of male in ventral view, 29: Sterna 3–5 of male.