Glesoconomorphus ekaterinae, Telnov & Perkovsky & Vasilenko & Yamamoto, 2021

Telnov, Dmitry, Perkovsky, Evgeny E., Vasilenko, Dmitry V. & Yamamoto, Shuhei, 2021, The first fossil Coleoptera record from the Volyn Region, Ukraine, with description of a new Glesoconomorphus (Coleoptera, Mycteridae) in syninclusion with Winterschmidtiidae (Acari) and a key to species, ZooKeys 1068, pp. 189-201 : 189

Glesoconomorphus ekaterinae sp. nov.

Figs 1 , 2 , 3 , 4

Material examined.

Holotype ♂ SIZK Les-10, Lisove, Volyn Region , Rovno amber, late Eocene // Glesoconomorphus ekaterinae sp. nov. det. D. Telnov, E. Perkovsky, D.Vasilenko & S.Yamamoto, 2021 [printed]. Syninclusions are represented by three heteromorphic deuteronymphs of supposedly phoretic Winterschmidtiidae Oudemans, 1923 mites attached to abdominal ventrites III, IV, and V of the beetle.

Type locality.

Lisove, Volyn Region, NW Ukraine.

Derivatio nominis.

Patronymic. The new species is named in honour of Ekaterina A. Sidorchuk (1981-2019), who was a renowned acarologist and our helpful colleague.

Measurements.

Holotype ♂, total body length 2.95 mm; head length 0.29 mm, head width across compound eyes 0.67 mm, pronotal length 0.59 mm, maximum pronotal width 0.66 mm, elytral length 2.17 mm, combined maximum elytral width across postmedian area 1.15 mm.

Description.

♂, body cylindrical, slightly convex in dorsal aspect. Dorsum and venter uniformly dark brown with weak metallic coppery lustre, compound eyes reddish brown. Head flattened dorsally, glossy. Labrum transverse, moderately densely punctate, anterior margin broadly emarginate. Frontoclypeal suture not present. Anterolateral margin of frons slightly prominent laterodorsad, not concealing insertion of antenna. Broad, shallow paired frontal furrow present. Minimum interocular distance 1.6 × the dorsal eye length. Ocular (suborbital) groove present, distinct, traceable from frontal canthus to posterolateral extent of compound eye, narrowly separated from eye in anterior part, becoming more distant from it in posterior part. Compound eye large, entire, hemispherical, strongly prominent laterally in dorsal view. Interfacetal setae not present. Tempora slightly constricted posteriad, 0.34 × dorsal eye length. Head dorsal punctures circular to slightly elliptical, rather large, moderately deep and dense. Intervening spaces glossy, glabrous, on frons generally as wide as to 1.5 × wider than punctures. Punctures generally smaller on head base. Inconspicuous, appressed, anteriad-directed setae rising from centre of each puncture, generally not or slightly surpassing length of adjoining puncture. Antenna moniliform, rather short, in male extending towards base of pronotum. Basal antennomere cylindrical, about 1.1 × longer than antennomere two. Antennomere three of about same length as preceding antennomere. Antennomeres 8-10 subtriangular, widened distally. Antennomeres 9-10 slightly transverse. Terminal antennomere elliptical, about 1.2 × longer than penultimate antennomere. Terminal maxillary palpomere subsecuriform. Pronotum flattened dorsally, widest in anterior half, slightly constricted laterally towards base. Anterior and posterior margins truncate to subtruncate. Anterior bead not observed, posterior bead well-defined, broad. Anterolateral angles obsolete, broadly rounded. Posterolateral angles obtuse angulate. Lateral margin of pronotum modified into an obtuse carina delimiting pronotal disc from pronotal hypomeron (observed in lateral view). Pronotal disc with paired, moderately large, shallow, longitudinal, elliptical postmedian impression. Pronotum densely and roughly punctate dorsally and laterally, punctures nearly circular. Intervening spaces glossy, glabrous, generally narrower than punctures except in median part of pronotal disc, where intervening spaces are from as large as to twice as large as punctures. Dorsal pronotal setae similar to those on head. Scutellar shield small, widened posteriad, subtruncate at posterior margin, roughly punctate. Elytron moderately strongly elongate, slightly widened in apical third, slightly convex dorsally. Humerus broadly rounded. Humeral callosity not present. Postbasal transverse impression not indicated. Apical sutural angle broadly rounded. Epipleura rather broad in basal half of elytra. Sutural stria narrow, present in apical fourth of elytra. Elytral punctures rather large, deep and dense, intervening spaces glossy and glabrous, from as large as to narrower than punctures. Each puncture with an inconspicuous, appressed, moderately long, posteriad-directed seta. Metathoracic wings fully developed (functional), long, visible veins darkly pigmented. Radial cell present, fully closed. Legs moderately long, rather robust, finely and sparsely pubescent. Femora thickened but not clavate, glossy, sparsely punctate, subequal in length to tibiae. Ventral side of tarsomeres densely setose. Male basal metatarsomere 1.5 × shorter than combined length of remaining metatarsomeres. Metasternum slightly convex in ventral aspect, glossy, sparsely punctate. Abdominal ventrites rather densely and roughly punctured laterally. Intercoxal process of abdominal ventrite I with particularly large and dense, shallow punctures. Male abdominal ventrite II modified, with an elliptically grouped median group of dense, elongate, scale-like setae comprising a sex patch. Setae of sex patch reaching neither anterior nor posterior margin of male abdominal ventrite II. Male tergite VII broadly rounded at posterior margin, densely punctate-corrugate dorsally. Male genital organs and remaining terminalia not exposed and not studied.

Sexual dimorphism.

Female unknown.

Differential diagnosis.

The new species is generally close to G. nachzehrer but specifically different in the comparatively less slender body, the dorsal outline of the pronotum, which is constricted towards the base (lateral margins of pronotum subparallel in G. nachzehrer ), the transverse pronotum (pronotum subquadrate to slightly wider than broad in G. nachzehrer ), the pronotal disc delimited from the pronotal hypomeron by an obtuse carinate lateral margin in lateral view (lateral margin of pronotum not carinate in lateral view in G. nachzehrer ), the presence of frontal furrows (not observed in G. nachzehrer ), the comparatively less densely punctured frons with some of the intervening spaces twice as wide as the generally circular to slightly elliptical punctures (frons somewhat denser punctured, with punctures generally elongate, in G. nachzehrer ), the labrum broadly emarginate at the anterior margin (labrum broadly rounded in G. nachzehrer ), the comparatively stronger elytral punctures (punctures on elytra comparatively smaller in G. nachzehrer ). The holotype of G. ekaterinae sp. nov. is also significantly smaller than the holotype of G. nachzehrer (total body length 2.95 mm vs 3.6 mm), which should not be considered as an important comparative feature. Indeed, the males of some Eurypinae (for instance, Omineus Lewis, 1895) are known to be smaller than the females ( Alekseev et al. 2020). We consider the holotype of G. nachzehrer a female (this was not stated by the authors of this taxon, see Alekseev et al. (2019)), therefore the difference in body length between the two species should not be considered very significant until the discovery of male G. nachzehrer .

Figures

Figure 1. Glesoconomorphus ekaterinae sp. nov., holotype ♂ A dorsal habitus B ventral habitus.

Figure 2. Glesoconomorphus ekaterinae sp. nov., holotype ♂ A left lateral habitus B right lateral habitus.

Figure 3. Glesoconomorphus ekaterinae sp. nov., holotype ♂ A frontal habitus B head in frontal view.

Figure 4. Glesoconomorphus ekaterinae sp. nov., holotype ♂ A abdomen in ventral view (arrow indicates a setal patch) B pro-, meso-, and metathorax in right lateral view C sexual setal patch on ventrite II, enlarged. Abbreviations: pm = phoretic mite (Acari: Winterschmidtiidae), v 1 - v 5 = ventrites I-V.