Chelostoma ( Chelostoma ) scabiosae Müller, 2025

Chelostoma ( Chelostoma) scabiosae Müller , sp. nov.

Holotype. TURKEY: Şırnak: 19 km S Beytisebap , 1200 m, 26.6.1985, 1♀ (leg. M. Schwarz). Deposited in the Entomological Collection of ETH Zurich.

Paratypes. IRAN: Ilam: Abda Man, Dinar Gaouh , 32.915°N / 47.301°E, 1830 m, 12.5.2016, 3♂ (leg. M. Kafka) GoogleMaps . TURKEY: Hakkari: 25 km SW Hakkari, 1200 m, 31.5.1980, 13.6.1981, 2♂ (leg. M. Schwarz, K. Warncke). Deposited in the Entomological Collection of ETH Zurich .

Diagnosis. C. scabiosae has very long mouthparts ( Fig. 10 View FIGURES 10–18 ) with the second segment of the labial palpus being distinctly longer than the compound eye and the proboscis distinctly surpassing the coxa of the fore leg when folded. It shares this trait with the three representatives of the C. meronense species group and the three other representatives of the C. grande species group. The females of C. scabiosae can be separated from those of the C. meronense species group by i) the longer body length of about 10 mm, ii) the long and slender labrum, which is about 3.5× as long as apically wide ( Fig. 13 View FIGURES 10–18 ), and iii) the basally distinctly constricted terga 2–3. They differ from the other species of the C. grande group by the following combination of characters: i) declivous apical part of clypeus bent a right angles to flat basal part ( Fig. 12 View FIGURES 10–18 ), only about one fourth as long and as densely punctate as basal part, ii) mandible long and slender with two apical teeth, iii) labrum about 3.5× as long as apically wide, its mediobasal part slightly concave and laterally bordered by two narrow longitudinal swellings and its apical part flat to weakly projecting upwards ( Fig. 12, 13 View FIGURES 10–18 ), iv) antennal segment 3 about 1.75× as long as wide, and v) basal area of propodeum medially almost as long as metanotum ( Fig. 14 View FIGURES 10–18 ). The males of C. scabiosae can be separated from those of the C. meronense species group by i) the apical margin of sternum 1, which is only shallowly emarginate, ii) the median projection of sternum 2, whose apex is not projecting over the sternal base, and i) the absence of a row of stiff yellowish bristles along the apical margin of sternum 3. They differ from the other species of the C. grande group by the following combination of characters: i) median projection of sternum 2 roof-shaped, its anterior margin straight to very slightly curved ( Fig. 17 View FIGURES 10–18 ), ii) sternum 3 without lateral processes ( Fig. 17 View FIGURES 10–18 ), iii) hairs forming loose band at apical margin of sternum 4 slightly less than half as long as membraneous appendage at apical margin of sternum 4 ( Fig. 17 View FIGURES 10–18 ), and iv) stepped apical part of gonoforceps on inner side without long and inwardly directed hairs ( Fig. 18 View FIGURES 10–18 ).

Description. FEMALE ( Fig. 10 View FIGURES 10–18 ): Body length 10 mm. Head: Head about 1.1× long as wide. Distance between posterior margin of lateral ocellus and occipital margin about 3 as long as ocellar diameter. Clypeus with medially flat basal and strongly declivous apical part; declivous apical part bent a right angles to basal part ( Fig. 12 View FIGURES 10–18 ), only about one fourth as long as basal part and as densely punctate as basal part with interspaces rarely exceeding the diameter of half a puncture. Labrum about 3.5× as long as apically wide, mediobasally slightly concave, densely punctate and laterally bordered by two narrow longitudinal swellings, its apicalmost part flat to weakly curved upwards ( Fig. 12, 13 View FIGURES 10–18 ). Mandible long and slender with two apical teeth. Proboscis very long ( Fig. 10 View FIGURES 10–18 ), distinctly surpassing coxa of fore leg and almost reaching coxa of middle leg; second segment of labial palpus almost 5.5× as long as first segment and about 1.5 as long as compound eye. Antennal segment 3 about 1.75× as long as wide. Mesosoma : Posterior and lateral surface of propodeum largely polished. Basal area of propodeum medially almost as long as metanotum, declivous and without raised carina along its posterior margin ( Fig. 14 View FIGURES 10–18 ). Metasoma: Terga 2–3 basally distinctly constricted. Marginal zone of terga 1–4 with dense and short white hair bands ( Fig. 10 View FIGURES 10–18 ), which are not interrupted in fresh specimens. Scopa white, its hairs not plumose ( Fig. 10 View FIGURES 10–18 ).

MALE ( Fig. 11 View FIGURES 10–18 ): Body length 10–12 mm. Head: Head about as long as wide. Distance between posterior margin of lateral ocellus and occipital margin 2.6-2.9× as long as ocellar diameter. Hypostomal area with two sharp, acute and roughly triangular tooth-like projections formed by hypostomal carina in its basal half ( Fig. 16 View FIGURES 10–18 ). Proboscis very long, distinctly surpassing coxa of fore leg and almost reaching coxa of middle leg. Antennal segments 3-13 about 2× as long as wide, their anterior sides varying in colour from almost uniformly brownish to predominantly yellowish-red. Mesosoma : Posterior and lateral surface of propodeum largely polished. Basal area of propodeum medially slightly to significantly shorter than metanotum, declivous, crossed by numerous weak longitudinal carinae of varying thickness and without raised carina along its posterior margin. Tibia of fore leg ventroapically with long spine at base of tibial spur. Tibial spur of fore leg apically prolonged into rounded tip resulting in a concave outer margin of the spur. Metasoma: Marginal zones of terga 1–5(6) with loose white hair bands ( Fig. 11 View FIGURES 10–18 ), which are widely interrupted on terga 1–3. Tergum 2 basally distinctly constricted. Tergum 7 basally with roundish pit and apically with two teeth, which are roughly parallel-sided, shorter than basally wide, apically weakly rounded to truncate and separated from each other by semicircular incision of about the same width as tooth width ( Fig. 15 View FIGURES 10–18 ). Sternum 1 basally with weakly bilobed tubercle, its apical margin medially shallowly emarginate. Median projection of sternum 2 roof-shaped, its anterior margin straight to very slightly curved ( Fig. 17 View FIGURES 10–18 ). Sternum 3 basally densely covered with whitish pilosity and lateroapically with small patches of short black thorns, which are separated by a polished, almost impunctate and slightly impressed zone ( Fig. 17 View FIGURES 10–18 ); apical margin of sternum 3 slightly emarginate and with short membraneous appendage ( Fig. 17 View FIGURES 10–18 ). Apical margin of sternum 4 with large membraneous appendage that is medially divided into two flat lobes and with loose band of yellowish-white hairs, which are slightly less than half as long as membraneous appendage ( Fig. 17 View FIGURES 10–18 ). Apical margin of sternum 5 with single row of long, yellowish and moniliform bristles ( Fig. 17 View FIGURES 10–18 ). Sternum 6 roughly quadrangular in shape, its apical half polished, very sparsely haired and almost impunctate. Stepped apical part of gonoforceps on inner side almost hairless ( Fig. 18 View FIGURES 10–18 ).

Distribution. Southeastern Turkey, northwestern Iran ( Fig. 74 View FIGURE 74 ).

Pollen hosts. The only available pollen load consisted of pollen of Scabiosa , suggesting that C.scabiosae is oligolectic on Dipsacoideae as are the other species of the C. grande species group.

Nesting biology. Unknown.

Etymology. The species epithet refers to the most probable pollen specialization on Dipsacoideae including Scabiosa .