Belonuchus viridipennis Baudi di Selve, 1848

Márquez, Juan & Asiain, Julieta, 2022, Taxonomy of the Mexican species of Belonuchus Nordmann (Coleoptera: Staphylinidae), Zootaxa 5152 (1), pp. 1-129 : 87-88

Belonuchus viridipennis Baudi di Selve, 1848

Figs. 8h , 9g , 12a, i , 13j , 17c, 20-l, 25d, 33a

Belonuchus viridipennis Baudi di Selve, 1848: 125 .

Belonuchus mexicanus Solsky, 1864: 440 , new synonymy.

Total body length 8.0 mm (one single male measured), in females 8.03 (range 6.6–9.4 mm). Body black, with pronotum dark-brown, elytra glossy and genital segment clearest (pale).

Head: quadrangular, wider than long (ratio in male 0.81, in females 0.87, range 0.87–0.91). Dorsal surface with sulcate longitudinal midline visible in anterior half of head; front plane, not foveate between antennal insertions. Eyes 0.45 times the cephalic lateral length, slightly protruding at sides. Antennomere 4 as long as wide, 5–10 transverse. Mandibles ( Fig. 9g ) in male almost as long as head (ratio 0.95), in females shorter than head (ratio 0.85, range 0.81–0.90); base of mandibles with coarse, mesh-like microsculpture; left mandible with a large middle tooth of characteristic shape ( Fig. 9g ), right mandible with two middle teeth, the large one in ventral position close to the small dorsal tooth; mandibles without basal tooth; mandibular channel well developed, external margin moderately carinate, internal margin like impressed line extending forward beyond level of middle teeth. Apical palpomere of maxillary palpi 1.5 times longer than preapical palpomere; apical palpomere of labial palpi nearly twice the length of preapical palpomere. Ventral surface with some sparse, fine punctures. Head notably wider than pronotum (ratio in male 1.41, in females 1.23, range 1.21–1.25).

Thorax: each dorsal row of pronotum with five punctures; pronotum longer than wide (ratio in male 1.25, in females 1.20, range 1.19–1.21) and wider at anterior corners than at posterior corners (ratio in male 1.23, in females 1.53, range 1.35–1.90); lateral margins slightly sinuous. Scutellum with punctures larger and denser than on elytra; elytra with faint metallic reflections contrasting with scutellum that is without these reflections; with fine, dense punctures. Prosternum near to anterior margin slightly elevated transversally, delimited backwards by an impressed line. Intercoxal process of mesoventrite ( Fig. 12a ) scutellum-shaped; transverse discal ridge well developed, broadly U-shaped, reaching close to margin of intercoxal process laterally, but not meeting it. Profemur of male ( Fig. 12i ) and large females with external row of spines difficult to discern because they are very small and are mixed with dense setae, row initiating at base and ending in apical third; internal margin only with three to four spines larger than apical external spines. Metafemur of male ( Fig. 13j ) with two widely separated rows of spines, external row with spines slightly longer than spines of internal row, internal row of spines in females better developed than external row of spines. Tarsomeres slender, slightly flattened dorsally.

Abdomen: first three visible tergites without posterior basal transverse carina, but anterior third (or slightly more) is clearly depressed and with very dense wide-superficial punctures, which in combination with mesh-like microsculpture, gives a rough appearance; this pattern gradually disappears from the depression toward posterior margin and is transformed into fine punctures with also finer microsculpture like wavy lines; visible tergite 4 without depression, but with a pattern similar to that of tergite 3, although less extensive in anterior half; visible tergites 5–6 almost only with fine punctures and microsculpture. Visible sternites 1–3 with posterior basal transverse carina, sternites 4–6 without posterior basal transverse carina; punctures and microsculpure similar to that on tergites. Male pregenital sternite with moderate, very broadly V-shaped emargination at posterior margin (Fig. 17c). Male genital sternite very elongate (3.62 times longer than wide), almost symmetrical, anterior portion occupying 16% and posterior portion 84% of its length, apical emargination deep ( Fig. 20–l ). Abdominal styli slender.

Aedeagus: length 0.85 mm; elongate shape in anterior 2/3 and oval shape in basal third; apex pointed, below apex sides slightly wider than in middle part, but in basal third wide, widest part is best observed in lateral view; internal sac slightly visible ( Fig. 25d ).

Variability. In addition to the little variation related to measurements and ratios included in the description, it was noted that the iridescent sheen or brightness of elytra is, at best, slightly visible in most specimens and in some it is not apparent. The sulcate longitudinal midline in front was indistinct in a specimen, and extended further back from cephalic half. The size of teeth of mandibles varies in proportion to the size of specimens, as well as the more distinct development of punctures and coarse microsculpture of abdomen, which is more pronounced in larger specimens.

Taxonomic comments. Belonuchus viridipennis could be mainly confused with B. pectinipes , but the main differences have been highlighted in the taxonomic comments of the latter species. It was not possible to review any type of B. viridipennis (type locality: Novae Valenciae, Venezuela) or B. mexicanus (type locality: “ Mexique ”). In the case of the latter species, the material may have been lost (personal communication, A. A. Gusakov, curator of Coleoptera , Zoological Museum of the Moscow Lomonosov State University). However, the comparison of information included in the original descriptions and the redescription of B. mexicanus by Silvestri (1945), as well as the wide distribution from Mexico to Brazil and Argentina, allowed us to propose both species to be synonyms. This facilitates the recognition of B. mexicanus (now a synonym of B. viridipennis ), of which there is still very little is known in Mexico.

The following are several of the same or very similar characters mentioned in the original description of B. viridipennis and B. mexicanus , and the redescription of B. mexicanus by Silvestri (1945), which support the proposal that they are synonyms: small body size; color body black with faint metallic green elytra; both dorsal and ventral teeth of mandibles (mainly on the left); anterior part of pronotum slightly wider than posterior part and convex at sides, dorsal series each composed by five big punctures, and six additional smaller punctures outside each dorsal series; rows of spines on the pro- and metafemora; pregenital sternite emarginate at posterior margin of males, and the small, slender aedeagus.

Material examined (nine males, nine females): Mexico: Chiapas: “ 8 mi N Pueblo Nuevo Solistahuacán, 6000’, 26 a 27-VIII-1973 / under bark, A. Newton” (m 1, FMNH). Hidalgo: “ 3 km N de Tlanchinol, 1450 m, bosque mesófilo de montaña, N21°1.328’, W98°38.77’, sobre vegetación, 1-V-2003, J. Asiain y J. Márquez cols.” (1, MAAS). Morelos: “Mexicapa, bosque de pino, zona 1, NTP-80 calamar, 1 a 25-IV-1993, A. Soria, C. Cabello y E. Córdoba cols.” (1, MAAS). “Tlayacapan, San José de los Laureles, NTP-80, localidad 4, selva baja caducifolia, XII-1995, K. Villavicencio y J. Márquez cols.” (2, MAAS). Veracruz: “Tequila, Kohyomyxtla, 1800 m, coprotrampa, 1 a 30-V-2011, L. Lara et al. cols.” (f 1, IEXA). “Jalapa / viridipennis det. Bernh. / Chicago NHMus, M. Bernhauer Collection” (2, FMNH). “Orizaba / viridipennis det. Bernh. / Chicago NHMus, M. Bernhauer Collection” (1, FMNH). “Jalapa, Höge, Belonuchus dejectus D. S. (in the plaque with the specimen) / Jalapa, Hoege/ B.C.A. Col. I.2. Belonuchus viridipennis Baud. , dejectus Sharp / Chicago Nat. Hist. Mus. (ex D. Sharp Colln. by Exchange with Brit. Mus. Nat. Hist.) (m 1, FMNH). Guatemala: “San Joaquin, Vera Paz. Champion/ B.C.A. Col. I.2. Belonuchus viridipennis Baud. , dejectus Sharp / Chicago Nat. Hist. Mus. (ex D. Sharp Colln. by Exchange with Brit. Mus. Nat. Hist.) (2, FMNH). “Truqui, Mexico / Chicago NHMus, M. Bernhauer Collection” (6, FMNH).

Figures

FIGURE 8. Dorsal view of males of: a) Belonuchus aenigmaticus (paratype), b) B. nigerrimus, c) B. optatus, d) B. platypterus, e) B. juanmorronei, f) B. abnormalis, g) B. pectinipes (paralectotype), h) B. viridipennis. Scale bars = 2.5 mm.

FIGURE 9. Dorsal view of males of: a) Belonuchus sp. Q, b) B. cyanipennis (holotype), c) B. godmani. Head of B. dichrous showing the temporal carina (red arrow): d) lateral view (male), e) dorsal view (male). Dorsal view of the mandibles of males of: f) B. platypterus, g) B. viridipennis. Mandibles of Belonuchus sp. Q (male): h) dorsal view, i) ventral view. Antennae of males of: j) B. godmani, k) B. cyanipennis. Scale bars = 2.5 mm.

FIGURE 12. Mesoventrite of males of: a) Belonuchus viridipennis, b) Belonuchus sp. Q, c) B. cyanipennis. Ventral view of the left femur of male anterior leg of: d) B. apiciventris, e) B. oxyporimimus, f) B. oxyporinus, g) B. tepoztecus, h) B. bidens, i) B. viridipennis. Ventral view of the left posterior leg of males of: j) B. julietitae, k) B. linuzensis (small specimen), l) B. linuzensis (large specimen), m) B. metafemoralis, n) B. oxyporimimus, o) B. oxyporinus. Red arrow: intercoxal process of the mesoventrite, blue arrow: transverse discal ridge.

FIGURE 13. Ventral view of the left posterior leg of males of: a) B. trochanterinus, b) B. tenuistylus, c) B. zunilensis, d) B. rufipennis, e) B. mixtecus, f) B. pollens, g) B. ephippiatus, h) B. aenigmaticus, i) B. iridescens, j) B. viridipennis. Tarsomeres of posterior leg of males of: k) B. colon, l) B. ephippiatus. Yellow ovals: median longitudinal groove.

FIGURE 20. Male genital sternite of: a) Belonuchus cifuentesi, b) B. dichrous, c) B. flavipennis, d) B. aenigmaticus, e) B. iridescens, f) B. nigerrimus, g) B. optatus, h) B. platypterus, i) B. juanmorronei, j) B. abnormalis, k) B. pectinipes, l) B. viridipennis, m) Belonuchus sp. Q, n) B. cyanipennis, o) B. godmani. Scale bars = 0.5 mm.

FIGURE 25. Ventral (left) and lateral (right) view of the aedeagus of: a) Belonuchus juanmorronei, b) B. abnormalis, c) B. pectinipes, d) B. viridipennis, e) Belonuchus sp. Q, f) B. cyanipennis, g) B. godmani. Scale bar = 0.5 mm (all figures).