Belonuchus abnormalis ( Sharp, 1885 )

Márquez, Juan & Asiain, Julieta, 2022, Taxonomy of the Mexican species of Belonuchus Nordmann (Coleoptera: Staphylinidae), Zootaxa 5152 (1), pp. 1-129 : 85-86

Belonuchus abnormalis ( Sharp, 1885)

Figs. 8f , 17a, 20j, 25b, 30a

Philonthus abnormalis Sharp, 1885: 397 . Belonuchus abnormalis comb. nov. ex Philonthus ( Chani-Posse et al. 2018b) .

Total body length in males 10.1 mm (range 10.0– 10.2 mm), in females 10.4 mm (range 9.9–10.7 mm). Body black, except last two visible abdominal segments and genital segment that are reddish. Fifth visible abdominal segment almost black or very dark from its anterior margin and gradually becoming lighter, already in anterior third and even posterior margin reddish; sixth visible segment entirely reddish and genital segment yellowish, abdominal styli reddish at base and black on remaining portion.

Head: oval, slightly narrowed posteriad, dorsally flattened; ratio length/width in males 0.91 (range 0.89–0.92), in females 0.95 (range 0.92–0.96). Dorsal surface with faintly visible microsculpture like wavy lines; punctures sparser than in majority of species; sulcate longitudinal midline visible only at front; front moderately foveate between antennal insertions and slightly posteriorly. Eyes nearly 0.5 times the cephalic lateral length, slightly protruding at sides. First antennomere as long as antennomeres 2–3 combined, antennomere 3 slightly longer than 2, 4–5 elongate, 6–10 transverse. Mandibles shorter than head (ratio in males 0.82, range 0.80–0.84, in females 0.76, range 0.72–0.78); right mandible with a middle, acute tooth of moderate size, and a very small tooth (difficult to see) in ventral position below previous tooth; left mandible with two middle teeth very close to each other, the longer in ventral position and the smaller in dorsal position; in both mandibles basal tooth is slightly discernible; mandibular channel well developed, narrow, external margin not carinate and internal margin slightly carinate from base to near level of the most apical middle tooth, where it becomes an impressed line that extends slightly higher. Apical palpomere of maxillary and labial palpi almost twice as long as preapical palpomere, aplical palpomere with faint microsculpture of longitudinal lines and microgranules. Head 1.13 times wider than pronotum in males (range 1.11–1.14) and 1.07 times in females (range 1.04–1.09). Neck in ventral view with mesh-like microsculpture.

Thorax: pronotum with microsculpture as on head, but more conspicuous; each dorsal row with three punctures, with anterior puncture separated from anterior margin more than usual and third puncture more distinctly separated from two previous; pronotum 1.24 times longer than wide (males without variation, in females range 1.17–1.29); at anterior corners almost as wide as at posterior corners (ratio in males 1.09, range 1.08–1.09, in females 1.06, range 1.04–1.09). Scutellum and elytra with punctures moderately dense, punctures on elytra finer than on scutellum. Prosternum slighly impressed in a narrow strip close to anterior margin. Intercoxal process of mesoventrite triangularly scutellum-shaped, apex only weakly acute; transverse discal ridge well developed, broadly V-shaped, reaching very close to margin of intercoxal process laterally. Profemur of males with external margin completely visible, but internal margin visible only at apex; row of spines at external margin initiating in basal third, where spines are very small, and ending near apical third with last three to four spines notably larger than previous spines; internal apex with three to four small spines. Remainder of legs without modifications. Tarsomeres very slender, moderately flattened dorsally.

Abdomen: first three visible tergites with posterior basal transverse carina well developed; adjacent area weakly depressed on tergites 1–2, and even less so on tergite 3; with wide-superficial punctures combined with fine punctures that cover anterior 2/3 of tergites 1–2, anterior half of tergites 3–4, and anterior 1/4 of tergite 5; tergite 6 only with fine punctures. Visible sternites 1–4 with posterior basal transverse carina well developed and with punctures as on tergites, but slightly denser. Male pregenital sternite with a narrow, moderately deep emargination at posterior margin, V-shaped (Fig. 17a). Male genital sternite very elongate (3.16 times longer than wide), almost symmetrical, anterior portion occupying 17% and posterior portion 83% of its length, apical emargination moderately deep ( Fig. 20j ). Abdominal styli slender.

Aedeagus: length 1.1 mm; elongate shape; apex pointed; narrowest part of apical portion occupying more than 1/2 of apical portion and wider basal portion occupying near 1/3 of aedeagus length; basal part moderately wider than apical part; internal sac not visible ( Fig. 25b ).

Variability. In addition to the variation in measurements and ratios included in the description, it was only found that in females the head has more oval sides and is slightly narrowing posteriad.

Taxonomic comments. Belonuchus abnormalis is easily distinguished from B. pectinipes and B. viridipennis by having the last two visible abdominal segments reddish (except anterior third of fifth segment) and only three punctures in each dorsal row of pronotum. It could also be confused with Belonuchus sp. Q for its similar abdominal coloration, but B. abnormalis has an oval head, three punctures in each dorsal row of pronotum, male pregenital sternite with a narrow, moderately deep V-shaped emargination at posterior margin (Fig. 17a), male genital sternite almost symmetrical, with apical emargination moderately deep ( Fig. 20j ), and aedeagus with elongate shape ( Fig. 25b ). While Belonuchus sp. Q has a subquadrangular head, five punctures in each dorsal row of pronotum, male pregenital sternite with distinctly deep, V-shaped emargination at posterior margin (Fig. 17e), male genital sternite very asymmetrical, with apical emargination deep ( Fig. 20m ), and aedeagus acute in apical portion and oval in basal portion ( Fig. 25e ).

Although the type material of this species was studied, the redescription was based on non-type specimens because the types were returned to the collection of origin prior to this activity.

Type material examined (one male, one female): Lectotype (male, NHM): “ Philonthus abnormalis Type D.S. Oaxaca. Mexico. Höge (on the card with the specimen) / Type/ Oaxaca, Mexico. Hoege / B. C. A. Col. I. 2. Philonthus abnormalis, Sharp / Sharp Coll. 1905.-313/ Lectotype Philonthus abnormalis des. Chani Posse et al. 2018” . Paralectotype: same data as lectotype, except: “Sp. figured / Paralectotype Philonthus abnormalis des. Chani Posse et al. 2018” (f 1, NHM) . Additional material examined (three males, four females): Mexico: Estado de México: “ Ixtapan de la Sal , 2 km S de Zacango, N18°58’05”, W99°51’31”, 2000 m, en bromelia, 18-III- 2004, L. Cervantes col.” (2, IEXA). Oaxaca: “Santiago Yosondua, camino a El Vergel, bosque de encino, 1893 m, N16°50’10”, W97°34’33”, en bromelias, 7-VIII-2001, J. Asiain, S. Bautista y J. Márquez cols.” (2, MAAS). “Santiago Yosondua, camino a El Vergel, La Cascada, bosque de encino, 1905 m, N16°50’49.6”, W97°34’470.5”, sobre bromelias, 12-VII-2002, J. Asiain y J. Márquez cols.” (2, MAAS). “Santiago Yosondua, La Cascada, 1905 m, N16°50’50”, W97°34’47”, bosque de pino-encino, en bromelias, 9-VIII-2001, S. Bautista, J. Asiain y J. Márquez cols.” (1, CC-UAEH) .

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 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).