Leptochilus (Lionotulus) nacrocephalus Fateryga 2024, stat. nov.
Creators: name: Fateryga, Alexander V.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Eumenidae
Leptochilus
Leptochilus nacrocephalus

description: Leptochilus (Lionotulus) nacrocephalus (Kostylev, 1940), stat. nov.
(Fig. 4E–H)
Odynerus ibizanus nacrocephalus Kostylev 1940: 35, ♀ (type locality: “ Ordoubad (fleuve Arax; Transcaucasie)” [Azerbaijan]; holotype, ♀, ZISP.
Diagnosis. The species belongs to a group of the subgenus Lionotulus with pronotal carina lamellate, metanotum sharply edged posteriorly, hind trochanter rounded posteriorly, and apical lamella of T2 not largely sclerotized, with rounded basal punctures; the only other species with such combination of characters known in the Caucasus is L. signatus Gusenleitner, 1995 (although the structure of its hind trochanter is not reported), which can be distinguished by a broader apical emargination of the clypeus and a yellow band on the scutellum.
Description. Female. Body length (from head to apical margin of T2) 6 mm; forewing length 4 mm. Head about 1.15× as wide as long in frontal view. Mandible with four teeth. Labial palpus very slightly enlarged. Clypeus about 1.3× as wide as long, its apical emargination very shallow, taking 1/5 of clypeal width, apical teeth triangular, strongly carinate. Distance between lateral ocellus and occipital margin significantly exceeding distance between lateral ocellus and eye. Occipital carina not forming angle at lower part of gena. Anterior pronotal carina strongly developed, weakly lamellate, shoulders roundly rectangular. Tegula with outer margin rounded posteriorly, as long as scutellum. Scutellum rather flat. Metanotum slightly raised above scutellum, sharply edged posteriorly. Hind trochanter rounded posteriorly. Propodeum with indistinct dorsal surface only; propodeal concavity with rounded lateral margins; median carina developed at lower half of propodeal concavity. Projection of submarginal carina of propodeum longer than wide, bluntly rounded apically; valvula nearly rectangular. Apical lamella of T2 semitransparent, with basal row of rounded punctures, interstices sclerotized up to at most 1/3 of lamella. S 2 in lateral view rather roundly elevated at base, in ventral view without longitudinal furrow.
Clypeus densely punctate and longitudinally rugose, interstices reaching one puncture diameter, with microsculpture. Punctures on frons and vertex strongly larger than those on clypeus, interstices usually shorter than one puncture diameter, with distinct microsculpture; gena with somewhat finer punctures than on frons and vertex and similar microsculpture. Dorsal surface of pronotum punctate similarly to vertex; punctures become coarser on scutum and scutellum, interstices shorter than one puncture diameter, with microsculpture; punctures sometimes forming longitudinal rows. Tegula shining, with microsculpture only. Dorsal mesepisternum and mesepimeron punctate as pronotum. Ventral mesepisternum with sparser punctures, interstices reaching one puncture diameter, with microsculpture but shining. Epicnemium shagreened, without punctures. Metanotum with punctures on upper part of posterior side and microsculpture only on lower part. Metapleuron longitudinally rugose. Dorsolateral surface of propodeum dull, with hardly visible shallow punctures and microsculpture. Lateral surface of propodeum longitudinally rugose, with indistinct sparse punctures; sculpture of propodeal concavity similar to that on lateral surface but without visible punctures. T1 and T2 densely punctate with coarse punctures, interstices reaching one puncture diameter, with very distinct microsculpture. S1 coarsely rugose longitudinally. S2 punctate similarly to T2. Following terga and sterna with few distinct punctures only, mostly with dull microsculpture.
Posterior side of mandible with straight pale setae about as long as F1. Labial palpus with several setae as long as diameter of F1 at base or slightly longer but not exceeding diameter of F1 at distal end. Clypeus, frons, scapus, vertex, gena, and dorsal surface of mesosoma with very short straight setae, shorter than diameter of F1 at base. Ventral surface of mesosoma and whole metasoma with short appressed setae only.
Basal color black. Lateral spots on pronotum, tegula (except central brownish spot), and apical bands of T1 and T2 pale yellow. Ventral side of flagellum and legs from femora onwards ferruginous. Wings strongly fuscous, particularly on marginal cell; veins dark brown.
Male. Unknown.
Material examined. HOLOTYPE: ♀, labeled “Ordubad (Arax)/ Reitter / 1892// Microdynerus ♀ / macrocephalus, n. sp / G. Kostylev det. 1931 // Holotypus [red label]” [ZISP]. ADDITIONAL MATERIAL: ARMENIA: Kotaik, Jelidja, 7100ʹ, 24.VII.1928, 1 ♀, leg. A. Schelkownikow [ZMMU].
Distribution. Armenia (new record), Azerbaijan.
Remarks. This species is apparently not closely related to L. ibizanus (von Schulthess, 1934), since the latter species has distinctly longer clypeus, about 1.1× as wide as long (Gusenleitner 1993: 769, fig. 12) and is distributed in Portugal and Spain only. The most closely related species to L. nacrocephalus is probably L. signatus, as was stated above. It is noteworthy that a drawing of the clypeus of L. signatus in the original publication (Gusenleitner 1995: 180, fig. 1) shows much narrower apical emargination than can be found in photographs of the holotype published on the Internet (https://www.zobodat.at/belege.php?id=100415475). Leptochilus nacrocephalus has the clypeus similar to that in the drawing of L. signatus but definitely different from that in the photographs. More material is required to ascertain whether L. signatus is conspecific with L. nacrocephalus or represents a distinct species.
The specimen from Armenia has Kostylev’s identification label but he did not include it in the original description (Kostylev 1940).
description: Published as part of Fateryga, Alexander V., 2024, On some new and little-known Palaearctic species of the genus Leptochilus de Saussure, 1853 (Hymenoptera: Vespidae: Eumeninae), pp. 38-53 in Zootaxa 5432 (1) on pages 48-49, DOI: 10.11646/zootaxa.5432.1.3, http://zenodo.org/record/10898506