Belonuchus sp.

Márquez, Juan & Asiain, Julieta, 2022, Taxonomy of the Mexican species of Belonuchus Nordmann (Coleoptera: Staphylinidae), Zootaxa 5152 (1), pp. 1-129 : 89-90

Belonuchus sp. Q

Figs. 9a, h, i , 12b , 17e, 20m, 25e, 29a

Total body length 11.9 mm. Body almost completely black, except mandibles reddish-brown, 5–6 visible abdominal segments reddish (except anterior border of fifth segments that is black), genital segment yellow, abdominal styli reddish in basal half and black in apical half.

Head: subquadrate, somewhat flat in lateral view, slightly wider than long (ratio 0.87), posterior corners round- ed. Dorsal surface slightly foveate at front; sulcate longitudinal midline slightly visible only at front. Eyes less than 0.5 times the cephalic lateral length, a little protruding laterally. Antennomere 4 elongate, 5 almost as long as wide, 6–10 transverse. Mandibles ( Fig. 9a ) as long as head; left mandible with a basal tooth and two middle teeth, the longest in dorsal position and the smallest in ventral position; right mandible with a basal tooth and three middle teeth, the longest in dorsal position and higher than two small dorsal teeth; base of mandibles with conspicuous meshed microsculpture; mandibular channel moderately developed, external margin not carinate and internal margin carinate at base, extending forwards like impressed line. Apical palpomere of maxillary palpi 1.35 times longer than preapical palpomere and with faint microsculpture of longitudinal lines and microgranules. Apical palpomere of labial palpi nearly 1.5 times longer than preapical palpomere and with microsculpture as on apical maxillary palpomere. Head 1.22 times wider than pronotum. Ventral surface with sparse, fine punctures and setae near posterior corners.

Thorax: each dorsal row of pronotum with five punctures; pronotum 1.13 times longer than wide, anterior corners 1.15 times wider than posterior corners. Scutellum with punctures as dense as on elytra, but deeper. Elytra wider than pronotum and almost as wide as head; with microsculpture making them look more dull than pronotum and abdomen. Prosternum with elevated transverse zone close to anterior margin delimited posteriad by a faint contriction. Intercoxal process of mesoventrite ( Fig. 12b ) scutellum-shaped; transverse discal ridge well developed, broadly U-shaped, not meeting margin of intercoxal process laterally. Profemur with external row of spines initiating near base of femur, where spines are very short, and reaching until slightly before apex, where spines are notably larger; internal margin only developed in apical third of femur, where it has three to four more or less large spines. Middle and posterior legs without modifications. Tarsomeres moderately flattened dorsally.

Abdomen: first three visible tergites with posterior basal transverse carina well developed, adjacent area slightly depressed, with microsculpture coarser than on remaining segments; first visible tergite with sparse wide-superficial punctures near anterior margin and depression, visible tergites 2–3 with wide-superficial punctures denser than on respective area of first tergite; visible tergite 4 with wide-superficial punctures in anterior 1/4, remaining surface of tergites 1–4 and entire surface of tergites 5–6 with dense, fine punctures. Visible sternites 1–4 with sinuate posterior basal transverse carina, space between anterior margin and posterior basal transverse carina of sternites 1–3 wider than on sternite 4 and covered with coarse mesh-like microsculpture; visible sternites 1–3 with dense wide-superficial punctures covering almost entire surface, combined with fine punctures; visible sternite 4 with wide-superficial punctures only in anterior half; visible sternite 5 with same type of punctures only in anterior 1/4; visible sternite 6 with fine punctures only. Male pregenital sternite with distinct V-shaped emargination at posterior margin (Fig. 17e). Male genital sternite very elongate (3.1 times longer than wide), very asymmetrical, anterior portion occupying 19% and posterior portion 81% of its length, apical emargination deep ( Fig. 20m ). Abdominal styli slender.

Aedeagus: length 1.25 mm; slender in apical part and oval in basal part; apex pointed; apical portion occupying nearly 2/3 and basal portion 1/3 of aedeagus length, apical portion with a moderate contriction at its transition with basal portion, distad increasingly acute; basal portion notably wider than apical portion; internal sac visible, with characteristic shape like apex appearing basad of apex of median lobe ( Fig. 25e ).

Variability: Unknown, single specimen.

Taxonomic comments. This species could be confused with B. abnormalis , and their differences have been pointed out under the taxonomic comments of the latter species. It is necessary to have more specimens to be able to decide if it is a new species or one already known from other places outside of Mexico.

Material examined (one male): Mexico: Oaxaca: “ Ixtepeji, Peña Prieta , N17°36´, W96°11´, 2850 m, bosque de pino-encino, en bromelia Tilandsia carlos-hanlai (¿), III-2006, A. D. Franco Méndez col.” (m 1, IEXA) .

Group 8: godmani

Included species: B. cyanipennis sp. nov., and B. godmani ( Sharp, 1885) .

Diagnosis of the godmani group: head without temporal carina; male mandibles not expanded at base, in both sexes slender and shorter than head (ratio mandibular length/cephalic length 0.78 to 0.82; Figs. 10h, i ); head oval (ratio length/width 0.94 to 1.03; Figs. 10h, i ); body color black, shining, with elytra, or elytra and pronotum, metallic blue, green or violaceous ( Figs. 9b, c ); tarsomeres slender, dorsally slightly flattened; sparse setae and punctures on elytra and abdomen; aedeagus with reduced paramere ( Figs. 25f, g ).

Key to Mexican species of Belonuchus of the godmani group

1 Pronotum black, with same tonality as head, but different from that of elytra, which are metallic blue ( Fig. 9b ); male pregenital sternite not emarginate at posterior margin ( Fig. 15g ); male genital sternite moderately asymmetrical, apical emargination very deep ( Fig. 20n ); aedeagus oval in basal half and elongate in apical half ( Fig. 25f )........................ B. cyanipennis

- Pronotum metallic, with same tonality or very similar tonality as on elytra, but different from that of head, which is black ( Fig. 9c ); male pregenital sternite very slightly emarginate at posterior margin ( Fig. 16g ); male genital sternite very asymmetrical, apical emargination not deep ( Fig. 20–o ); aedeagus oval-elongate, with apical part slender but with convex apex ( Fig. 25g )............................................................................................. B. godmani

Figures

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 10. Dorsal view of the head of males of: a) Belonuchus julietitae, b) B. singularis, c) B. connexus, d) B. platypterus, e) B. bidens, f) B. nigerrimus, g) B. optatus, h) B. cyanipennis, i) B. godmani. Dorsal view of the head and pronotum of the holotype female of: j) B. optatus.

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 15. Male pregenital sternite of: a) Belonuchus alternans, b) B. oxyporinus, c) B. tepoztecus, d) B. jalappensis, e) B. iridescens, f) B. platypterus, g) B. cyanipennis, h) B. apiciventris, i) B. linuzensis, j) B. metafemoralis, k) B. rufisternus, l) B. tenuistylus, m) B. bidens, n) B. pollens, o) B. longitarsus.

FIGURE 16. Male pregenital sternite of: a) Belonuchus moroni, b) B. dichrous, c) B. flavipennis, d) B. aenigmaticus, e) B. nigerrimus, f) B. juanmorronei, g) B. godmani, h) B. magnistylus, i) B. trochanterinus, j) B. rufipennis, k) B. basiventris, l) B. connexus, m) B. xanthomelas, n) B. ephippiatus, o) B. optatus.

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).