Thyreus impressus Wood, 2025

Wood, Thomas, Leclercq, Vincent, Schmid-Egger, Christian & Praz, Christophe, 2025, A contribution to the knowledge of the genus Thyreus Panzer in the West and Central Palaearctic (Hymenoptera, Apidae), with two new species, taxonomic updates, host relationships, and a key to European species, Deutsche Entomologische Zeitschrift 72 (2), pp. 259-302 : 259-302

Thyreus impressus Wood sp. nov.

Type materials.

Holotype: Kyrgyzstan • 1 ♂; 45 km W of Naryn ; 41.4160°N, 75.3969°E; 20 Jul. 2019; K. Janssen leg.; RMNH; RMNH.INS.1714347 (BOLD accession number WPATW 950-22) .

Paratype: Kyrgyzstan • 1 ♂; 45 km W of Naryn ; 20 Jul. 2019; 41.4160°N, 75.3969°E; K. Janssen leg.; TJWC (BOLD accession number WPATW 951-22) .

Diagnosis.

Thyreus impressus can be placed into the scutellaris - group due to the genital capsule, which is simple, with the gonostylus greatly reduced in size and pointed-triangular without an additional dorsal projection (Fig. 5 E ), and the gonostylus with only a few inconspicuous hairs. It can be separated from all other members of the group except T. scutellaris by the structure of the scutellum, which is medially impressed and sulcate, with the axillae slightly diverging from the outer margins of the scutellum and produced into slight but distinct points (Fig. 4 C ), and due to the white hair patches at the base and on the marginal area of T 1, both widely separated medially and laterally by abundant black hairs, thus forming 4 distinct patches in dorsal view (Fig. 4 D ).

The two species are similar, but T. impressus can be recognised due to the gonostylus which is small and acutely pointed, with the inner margin straight (Fig. 5 E ; in T. scutellaris with the gonostylus more elongate and apically blunt to rounded, and the inner margin with a distinct subapical kink, Fig. 5 F ; see also illustration in Lieftinck 1968: 46), in frontal view with A 3 only slightly exceeding A 4 in length (Fig. 5 A ; in T. scutellaris with A 3 clearly exceeding A 4 in length, approaching A 4 + 5, Fig. 5 B ), and the posterior faces of the antennal segments with strongly produced individual rhinaria (not paired), clearly visible on the posterior face of A 13 (Fig. 5 C ; in T. scutellaris with the posterior faces of the antennal segments with weakly produced individual rhinaria, that on A 13 so small and weak as to not be immediately visible, Fig. 5 D ).

Description.

Female. Unknown.

Male. Body length: 9.5–10 mm (Fig. 4 A ). Head: Dark, 1.25 times wider than long (Fig. 4 B ). Clypeus flattened, densely punctate, punctures confluent, surface dull with exception of narrow shining margin. Labrum rounded rectangular, 1.5 times longer than wide, apex with elevated subapical transverse carina forming obtusely pointed tooth; labrum basally weakly produced into two tubercles laterally. Gena narrower than width of compound eye; ocelloccipital distance 1.5 times diameter of lateral ocellus. Hind margin of vertex with narrow obscure slightly raised carina-like rim. Face between antennal insertions with weak raised longitudinal carina, rapidly reducing in height and becoming medial impression on frons anterior to median ocellus. Frons punctate, punctures separated by ≤ 0.5 puncture diameters, punctation becoming slightly weaker on vertex, here separated by up to 1 puncture diameter. Face with abundant white pubescence, decumbent on lower half of face below antennal insertions. Gena ventrally with dark hairs, dorsally and laterally with scattered white hairs. Antenna dark, with very fine granular microreticulation, A 3 slightly exceeding A 4, shorter than A 4 + 5 (Fig. 5 A ). Posterior faces of A 3–13 with strongly impressed individual rhinaria (Fig. 5 C ).

Mesosoma: Scutum and scutellum densely punctate, punctures separated by ≤ 0.5 puncture diameters, interspaces slightly shining. Scutellum 1.6 times wider than long, posterior margin widely emarginate, medially distinctly impressed and sulcate (Fig. 4 C ) with dorsal and ventral tufts of white hairs; axillae with outer margins slightly but distinctly diverging from outer margins of scutellum and produced into slight but distinct points. Remaining surface of scutellum and axilla covered with dark hairs which do not obscure surface. Mesepisternum densely punctate, punctures separated by 0.5–1 puncture diameter. Legs dark, with white pubescence on outer face of tibiae, covering entire length on all tibiae. Forewing weakly infuscate.

Metasoma: Terga dark, tergal discs densely punctate with hair-bearing punctures, punctures presenting short, posteriorly projecting black plumose hairs; punctures separated by ≤ 0.5 puncture diameters. T 1 with 4 patches of white hairs laterally, 2 basally and 2 apically, patches widely separated by black hairs on lateral margins of terga (Fig. 4 D ). T 2 with almost rectangular patches of white hairs laterally, with clear but narrow extension towards base of disc laterally. T 3–5 with rectangular patches of white adpressed hairs, not forming complete bands. T 7 with apical margin shallowly and evenly emarginate. Genital capsule compact, rounded, gonostylus greatly reduced in size and pointed-triangular without additional dorsal projection (Fig. 5 E ). Gonostylus with only scattered inconspicuous hairs.

Etymology.

Masculine nominative singular form of the Latin adjective impressus meaning impressed, in reference to the more strongly produced antennal rhinaria compared to T. scutellaris .

Distribution.

Kyrgyzstan.

Figures

Figure 4. Thyreus impressus Wood, sp. nov. male holotype (RMNH). A. Habitus, lateral view; B. Face, frontal view; C. Scutellum, dorsal view; D. Metasoma, dorsal view.

Figure 5. Thyreus impressus Wood, sp. nov. male holotype (RMNH). A. A 3–5, frontal view; C. A 9–13, posterior view; E. Genital capsule, detail of gonostylus, dorsolateral view; Thyreus scutellaris (Fabricius, 1781) male (TJWC); B. A 3–5, frontal view; D. A 9–13, posterior view; F. Genital capsule, detail of gonostylus, dorsal view.