Thyreus priesneri Lieftinck, 1968

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 priesneri Lieftinck, 1968

Thyreus priesneri Lieftinck, 1968: 124, ♂ [ Egypt, type location unclear].

Material examined.

Saudi Arabia • 1 ♂, 1 ♀; Abu Arish ; 25 Mar. 1980; K. M. Guichard leg.; D. B. Baker det. 1981; NHMUK .

Notes.

Lieftinck (1968) described T. priesneri from a single male specimen collected from southern Egypt (Gebel Elba). This specimen was cited as being in the collection of Hermann Priesner at “ Linz ”, but it could not be located there, and its current deposition is therefore not immediately clear; further study is required to trace it. Fortunately, the description is well illustrated, allowing confident recognition. In the NHMUK collection, two specimens from Saudi Arabia were found; as with T. parthenope , these specimens were identified by Baker but were never published. The male clearly matches the criteria identified by Lieftinck, and due to co-occurrence and close morphology, the female can now be recognised (Fig. 13 ). The female can be diagnosed based on a combination of characters, but care must be taken, as they are quite subtle. The clearest confusion is with Thyreus fallibilis ( Kohl, 1905) , which was described from southern Yemen (Fig. 14 ). Lieftinck (1968) diagnosed this species and described the unknown male; due to the similarity of the females, this species is diagnosed last.

Diagnosis.

As in T. parthenope , T. priesneri has an unbroken line of white hairs running along the entire length of the lateral margins of the scutum (Fig. 13 E ), as in T. ramosus (Lepeletier, 1841) and T. ramosellus Cockerell, 1919 . Thyreus parthenope is diagnosed above, displaying white hair patches on the axillae and scutellum, whereas these areas are black-haired in T. priesneri (Fig. 13 E ), which also shows the lower half of the mesepisternum with large shining interspaces (Fig. 13 D ; with some interspaces reaching 3 puncture diameters), whereas in T. parthenope this area is densely punctate, without large shining interspaces. This shining and sparsely punctate mesepisternum also allows separation from T. ramosus and T. ramosellus , and indeed it is strange that Lieftinck diagnosed T. priesneri against T. ramosus when in the construction of the genital capsule and the shining lower half of the mesepisternum it is much closer to T. hyalinatus (Vachal, 1903) , with which it has an overlapping range in Egypt and the Arabian Peninsula. Thyreus priesneri can be differentiated from the latter species due to the axillae with black hairs (Fig. 13 E ; in T. hyalinatus with white patches of hairs covering the axillae), the L-shaped patches of hairs on the lateral parts of T 1 (Fig. 13 F ), these being uneven, with the apical part projecting further towards the centre of the tergal disc than the basal part (in T. hyalinatus with the C-shaped patches of hairs more even, with both the basal and apical parts uniformly projecting towards the centre of the tergal disc), and the posterior margin of the scutellum, which has posteriorly projecting white hairs emerging from below but not sitting on the dorsal side of the disc (Fig. 13 E ; in T. hyalinatus with hairs emerging both from below the posterior margin of the scutellum and present on the dorsal side of the posterior margin of the disc). This combination of characters (continuous line of white hairs on the lateral margins of the scutum, lower half of the mesepisternum sparsely punctate with large shining interspaces, and axillae and scutellum entirely black-haired) should allow recognition of females of T. priesneri compared to other species in north-eastern Africa and the Arabian Peninsula.

For diagnosis against T. fallibilis , the overall pubescence pattern is highly similar, as well as the punctation and microsculpture of the integument, such as in the lower part of the mesepisternum with large shining interspaces (Fig. 14 D ), the vertex domed in frontal view (Fig. 14 C ), and the scutellum of similar shape and with similar puncture density (Fig. 14 E ). The key difference is in the structure of the individual hairs; in T. fallibilis , the hairs are flattened and strongly plumose, with the branches spreading laterally, becoming almost scale-like (Fig. 14 E, F ). In T. priesneri , the hairs are plumose but are not flattened, and the branches do not spread laterally, meaning that they have a more quill-like appearance (Fig. 13 E, F ). This can be seen most clearly on the disc of T 1. As noted by Lieftinck (1968: 96), the pubescence of T. fallibilis is also slightly tinted with blue, whereas in T. priesneri the pubescence is pure white. We maintain the species concepts presented by Lieftinck, but this putative species pair would benefit from molecular investigation.

Description.

Female. Body length: 9 mm (Fig. 13 A ). Head: Dark, 1.2 times wider than long (Fig. 13 B ). Clypeus slightly elevated, more or less flattened across disc, densely punctate, punctures separated by ≤ 0.5 puncture diameters, interspaces shining. Labrum broadly rounded rectangular, lateral margins converging, apex thus narrower than base, labrum only slightly longer than basal width. Labrum basally with two slightly raised tubercules, medially with impressed furrow, this terminating subapically at strong transverse carinae, medially produced into pointed tooth (Fig. 13 C ). Gena much narrower than width of compound eye, posteriorly with strongly raised winged carinae, narrowing to be almost imperceptible along posterior margin of vertex; ocelloccipital distance 1.5 times diameter of lateral ocellus. Face between antennal insertions with weakly raised longitudinal carina, not strongly extending dorsally. Frons densely punctate, punctures separated by 0.5–1 puncture diameters, with slight impunctate space adjacent to lateral ocelli, space subequal to diameter of lateral ocellus. Head almost entirely white-haired, with brownish hairs restricted to mandibles. Antenna dark, measured along ventral surface A 3, slightly but distinctly shorter than A 4.

Mesosoma: Scutum and scutellum densely punctate, punctures somewhat irregular, separated by <0.5–1 puncture diameters, punctures most consistently dense on scutellum, surface shiny. Scutum with contrasting black and white pubescence, abundant white pubescence along anterior margin, lateral margins, medially with longitudinal line covering anterior ½ of segment, anterio-laterally with two white spots, postero-laterally with two thick patches along posterior margin (Fig. 13 E ). Axillae and scutellum entirely black haired on dorsal surface. Scutellum produced into two posteriorly projecting points, between these with shallow emargination, scutellum itself relatively long, maximum width 1.5 times longer than maximum length (measured from base to midpoint between posterior points); emargination between posterior points with thick broad tuft of white hairs emerging from ventral surface.

Mesepisternum in dorsal ½ covered with dense patch of adpressed white hairs, entirely obscuring surface; in ventral ½ with surface lacking hairs, with split punctation; in anterior portion with surface abundantly punctate, punctures separated by <0.5–1, in posterior portion with punctures becoming very sparse, punctures separated by 1–4 puncture diameters, interspaces smooth and polished (Fig. 13 D ). Legs dark, outer surface of tibiae covered with dense felt-like white hairs, mid and hind tibiae with short dark spines projecting through pubescence. Forewing with varied colouration, predominantly hyaline with infuscation adjacent to vein, within submarginal and marginal cells, and on apical papillate region.

Metasoma: Terga dark, tergal discs densely punctate with hair-bearing punctures, punctures presenting short, posteriorly projecting black plumose hairs, punctures separated by 0.5–2 puncture diameters, extending onto majority of marginal areas, with marginal areas narrowly impunctate along apical rim (Fig. 13 F ). T 1 laterally with large patch of white hairs, these not typically C-shaped, more L-shaped with apical part projecting further towards centre of disc than basal part. T 2 with broad L-shaped patch of white hairs, T 3–5 with rectangular white hair patches, hair patches on all terga broadly separated medially, never complete. Pygidial plate long, triangular, narrowly rounded, lateral margins slightly raised, surface flat, irregularly punctate with punctures of variable sizes, surface very obscurely shining.

Distribution.

Southern Egypt and Saudi Arabia * ( Lieftinck 1968).

Other material examined.

( Thyreus fallibilis ( Kohl, 1905)) Yemen • 1 ♀; Makalla [Al Mukalla]; 1–30 Apr. 1899; O. Simony leg.; NHMW ( holotype) .

New distributional data and range clarifications

Figures

Figure 13. Thyreus priesneri Lieftinck, 1968, female. A. Habitus, lateral view; B. Head, frontal view; C. Labrum, ventral view; D. Mesepisternum, ventrolateral view; E. Scutum, dorsal view; F. Metasoma, dorsal view.

Figure 14. Thyreus fallibilis (Kohl, 1905) holotype female. A. Label details; B. Habitus, lateral view; C. Face, frontal view; D. Mesepisternum, lateral view; E. Scutum, dorsolateral view; F. Metasoma, dorsal view.