Mordellistena microgemellata Ermisch, 1965

Selnekovič, Dávid, Kodada, Ján & Ruzzier, Enrico, 2025, Redescription, DNA barcoding, and new distributional records of Mordellistena microgemellata Ermisch, 1965 (Coleoptera, Mordellidae), Deutsche Entomologische Zeitschrift 72 (2), pp. 449-457 : 449-457

Mordellistena microgemellata Ermisch, 1965

Figs 1 , 2 , 3

Mordellistena microgemellata Ermisch, 1965: 265–267; Ermisch 1977: 163; Kaszab 1979: 40–41; Horák 2008: 99; Horák 2020: 96.

Material examined.

Holotype (designated in original description) Greece • male; “ Graecia ”; SNSD [genitalia dissected] . Photograph of the holotype available at https://doi.org/10.5281/zenodo.17435622.

Other material.

Tunisia • 19 males, 6 females; Bir Al Huffay ; 34.908249°N, 9.179063°E; alt. 435 m; 11 May 2025; D. Selnekovič leg.; ruderal vegetation, on Anethum ; DSBS, DSBS 1079 to DSBS 1083 , DSBS 1088 .

Differential diagnosis.

Mordellistena microgemellata was included in the M. gemellata morphological species group ( Ermisch 1965) based on the following features: antennomeres 5–10 distinctly longer and broader than the preceding two segments, and a metatibia bearing, in addition to the apical ctenidium, two short lateral ctenidia oriented approximately perpendicular to the dorsal tibial margin.

Within the M. gemellata group, M. microgemellata is further characterised by its entirely black integument, including the metatibial spurs; pale vestiture (yellowish to brownish); uniformly coloured elytral vestiture, with only a narrow, darkened band along the suture; and short antennomeres 5–10, each up to 1.25 × longer than wide (Fig. 2 A ). The relative length of antennomeres separates the species from M. gemellata ( Portugal, Spain), in which antennomeres 5–10 are about 2.0 × longer than wide.

Mordellistena microgemellata differs from M. algeriensis ( Algeria, Italy, Tunisia), M. aureotomentosa ( Morocco), M. peloponnesensis ( Cyprus, Greece, Italy, Turkey), and M. pyrenaea ( Spain) by the penultimate abdominal tergite being concealed by the elytra (Fig. 1 ) (in the former species it is usually exposed). In addition, the male sternite VIII of M. microgemellata has broadly rounded and indistinct postero-lateral angles (Fig. 2 H ), whereas in the former species these angles are prominent ( Selnekovič and Kodada 2022; Selnekovič et al. 2024). Each of these species also differs from M. microgemellata in the shape of the parameres [see Selnekovič and Kodada (2022) for M. algeriensis ; Selnekovič et al. (2024) for M. peloponnesensis ; Ermisch (1966 a) for M. pyrenaea ; Ermisch (1966 b) for M. aureotomentosa ]. Mordellistena maroccana ( Morocco, Tunisia) differs from M. microgemellata in having a wider body, with shorter and wider elytra.

The most similar species is M. psammophila , known only from two female syntypes from Algeria ( Peyerimhoff 1943). Females of M. microgemellata can be reliably separated by the structure of sternite VIII: in M. microgemellata the posterior margin is produced and bears long trichoid sensilla, which are nearly as long as the sternite width (Fig. 2 I ), while in M. psammophila the homologous sensilla are much shorter (Fig. 2 J ). Furthermore, the spiculum ventrale is longer and clavate basally in M. microgemellata (ca. 0.7 × as long as sternite along midline), but shorter and cylindrical in M. psammophila (ca. 0.4 ×).

The sympatric M. pseudohirtipes Ermisch, 1965 may also resemble M. microgemellata , but it can be distinguished by having at least three well-developed lateral metatibial ctenidia and differently shaped parameres ( Selnekovič and Kodada 2019).

Description.

Dimensions (mm; males n = 10, females n = 4): TL: ♂♂ 3.14–3.62 (3.40 ± 0.16), ♀♀ 3.14–3.41 (3.32 ± 0.12); HL: ♂♂ 0.61–0.69 (0.65 ± 0.02), ♀♀ 0.60–0.66 (0.63 ± 0.03); HW: ♂♂ 0.65–0.76 (0.70 ± 0.03), ♀♀ 0.61–0.67 (0.65 ± 0.03); PL: ♂♂ 0.78–0.91 (0.85 ± 0.04), ♀♀ 0.76–0.83 (0.81 ± 0.03); PW: ♂♂ 0.77–0.92 (0.86 ± 0.05); ♀♀ 0.78–0.86 (0.84 ± 0.04); EL: ♂♂ 1.76–2.05 (1.90 ± 0.11), ♀♀ 1.79–1.94 (1.89 ± 0.07); EW ♂♂ 0.85–0.95 (0.91 ± 0.03), 0.82–0.95 (0.91 ± 0.06); PygL: ♂♂ 1.01–1.14 (1.09 ± 0.04), ♀♀ 0.88–0.97 (0.94 ± 0.04); RPrL: 0.25–0.30 (0.27 ± 0.01); LPrL: 0.31–0.36 (0.34 ± 0.02).

Body elongate, wedge-shaped (Fig. 1 ); widest at middle of pronotum in males and before midlength of elytra in females. Integument entirely black. Vestiture yellowish with a weak reddish to purplish lustre, slightly darkened in a narrow band along the elytral suture, and dark brownish to black on the posterior portions of ventrites 3 and 4, the whole of ventrite 5, and the pygidium.

Head moderately convex, highest point situated behind the middle in lateral view; HW / HL ratio: ♂♂ 1.03–1.14 (1.07 ± 0.03), ♀♀ 1.02–1.06 (1.04 ± 0.02). Anterior clypeal margin straight. Occipital carina evenly convex. Surface finely microreticulate, with round setiferous punctures. Labrum transverse, setose, shallowly emarginate at anterior margin. Eyes oval, about 1.6 × longer than wide, finely faceted, setose; interfacetal setae longer than facet diameter; ocular index: ♂♂ 1.44–1.60 (1.52 ± 0.05), ♀♀ 1.46–1.55 (1.49 ± 0.04). Postocular gena explanate, slightly narrower than facet diameter, not angulate. Antenna weakly serrate (Fig. 2 A ); scapus and pedicel cylindrical, subequal in width, pedicel slightly longer; antennomere 3 smallest, conical, slightly shorter and narrower than following; antennomere 4 conical, about 0.7 × as long as following and slightly narrower; antennomeres 5–10 subtrapezoidal, 1.20–1.25 × longer than wide in both sexes; antennomere 11 oval, about 2.0 × longer than wide. Galea moderately long, not produced (Fig. 2 B, C ). Maxillary palpomere 2 strongly expanded with long trichoid sensilla on ventral surface in males (Fig. 2 B ), not expanded and without markedly long setae in females (Fig. 2 C ); terminal palpomere triangular, about 2.2 × longer than wide, with inner angle at midlength in males, slenderer and with inner angle behind midlength in females. Labial terminal palpomere cylindrical. (Fig. 2 D )

Pronotum moderately convex, widest at middle; PW / PL ratio: ♂♂ 0.99–1.07 (1.02 ± 0.03), ♀♀ 1.01–1.06 (1.04 ± 0.02); anterior margin weakly produced at middle; lateral carina concave in lateral view; postero-lateral angles rectangular, narrowly rounded in lateral view. Surface microreticulate, with rasp-like setiferous punctures. Scutellum triangular. Metanepisternum subtrapezoidal, dorsal margin concave, ventral margin straight, posteriorly about as wide as mesotibia.

Elytra moderately convex; EL / EW ratio: ♂♂ 1.97–2.22 (2.10 ± 0.08), ♀♀ 2.03–2.18 (2.07 ± 0.07); lateral margins rounded, evenly converging (Fig. 1 ); surface strongly microreticulate, with very dense rasp-like setiferous punctures.

Protrochantin with extended sensillum only slightly longer and thicker than surrounding setae, which are distinctly longer in males than females (Fig. 2 E, F ). Profemur uniformly setose, without conspicuous extended sensilla; setae distinctly longer in males than in females (Fig. 2 E, F ). Protibia about as long as protarsus; in males weakly expanded behind base and bearing a distinct fringe of extended setae (Fig. 2 E ), in females straight, without extended setae (Fig. 2 F ). Protarsomeres cylindrical; in males with several thick extended setae ventro-laterally. Protarsomere 1 slightly longer than next two combined; protarsomere 3 not expanded, apical margin weakly concave. Mesotrochantin with distinct extended sensillum. Mesotibia about 0.8 × as long as mesotarsus. Metatibia with two short lateral ctenidia reaching to mid-width of tibia, sometimes with trace of a third ctenidium (Fig. 2 G ); apical spurs dark brown to black, inner spur about 1.6 × as long as outer one. Metatarsomere 1 with three ctenidia; metatarsomere 2 with two (Fig. 2 G ).

Pygidium acuminate, not constricted (Fig. 1 ); EL / PygL ratio: ♂♂ 1.65–1.87 (1.75 ± 0.07), ♀♀ 1.96–2.07 (2.02 ± 0.05). Ventrite 5 with apical margin convex. Sternite VIII in males about 1.5 × longer than wide, with posterior margin produced and bearing long trichoid sensilla (Fig. 2 H ); in females posterior margin produced, with markedly long trichoid sensilla along lateral and posterior margins, being nearly as long as sternite width (Fig. 2 I ); spiculum ventrale clavate, about 0.7 × as long as sternite midline.

Phallobase long (Fig. 2 K ), 0.5 × as long as EL; epimere sclerotised, lateral margins weakly concave. Left paramere long (Fig. 3 ); dorsal process strongly expanded, obliquely truncate apically; median process short and rounded; ventral process short and weakly curved dorsad; five to seven campaniform sensilla in longitudinal row situated near base of dorsal process. Right paramere long (Fig. 3 ); dorsal process moderately expanded, rounded apically; ventral process slightly shorter than dorsal one, shallowly bifurcate apically. Penis long, weakly expanded before apex.

Ovipositor with paraprocts short (Fig. 2 L ); coxite about 1.3 × as long as paraproct, with three strongly extended lateral sensilla; stylus with two apical trichoid sensilla; proctiger wide, apex truncate.

Secondary sexual dimorphism.

Males are slightly more slender than females (Fig. 1 ). The second maxillary palpomere is expanded and bears strongly extended setae in males (Fig. 2 B ) but is unexpanded and lacks extended setae in females (Fig. 2 C ); in addition, the male fourth (apical) maxillary palpomere is substantially wider than that of the female. The protrochantin and profemur carry distinctly longer setae in males (Fig. 2 E ) than in females (Fig. 2 F ). The protibia is expanded behind the base and bears a distinct fringe of extended setae in males (Fig. 2 E ), while it is straight and without extended setae in females (Fig. 2 F ). The pygidium is shorter in females.

DNA sequences.

Six partial sequences of the COI gene are available on BOLD and GenBank. For accession numbers refer to Suppl. material 1.

Distribution.

Bulgaria, Cyprus, Greece, Hungary, Tunisia (new record).

Figures

Figure 1. Mordellistena microgemellata Ermisch, 1965 habitus. A. Male, DSBS 1080; B. Female.

Figure 2. Mordellistena microgemellata Ermisch, 1965. A. Antenna, male DSBS 1079 (left), female (right); B. Maxilla, male DSBS 1079; C. Maxilla, female; D. Labium, male DSBS 1079; E. Foreleg, male DSBS 1079; F. Foreleg, female; G. Hindleg, male DSBS 1079; H. Sternite VIII, male DSBS 1079; I. Sternite VIII, female; K. Phallobase, DSBS 1079; L. Ovipositor. Mordellistena psammophila Peyerimhoff, 1943; J. Sternite VIII, female, syntype EC 33082.

Figure 3. Mordellistena microgemellata Ermisch, 1965 parameres. A. Holotype; B. DSBS 1081; C. DSBS 1080; D. DSBS 1079. Scale bar: 0.1 mm.