Belonuchus apiciventris ( Sharp, 1885 )

Márquez, Juan & Asiain, Julieta, 2022, Taxonomy of the Mexican species of Belonuchus Nordmann (Coleoptera: Staphylinidae), Zootaxa 5152 (1), pp. 1-129 : 24-25

Belonuchus apiciventris ( Sharp, 1885)

Figs. 2c , 12d , 15h , 18b , 21b , 26a

Philonthus apiciventris Sharp, 1885: 419 . Belonuchus apiciventris comb. nov. ex Philonthus (Jiménez-Sánchez et al. 2000) .

Note: the redescription of this species excludes female specimens from Morelos State, which are indistinguishable from the female specimens of B. tepoztecus , known only from Morelos State.

Total body length 9.2 mm. Black on head, pronotum, scutellum, anterior half of mesoventrite, posterior 2/3 of sixth visible abdominal segment and abdominal styli. Reddish on elytra, legs, posterior half of mesoventrite, metaventrite, 1–5 visible abdominal segments and anterior third of 6 visible segment. Prosternum reddish-brown. Genital segment pale reddish. Antennae black, with last antennomere reddish-brown; mandibles, maxillary and labial palpi brown.

Head: transverse (ratio length/width 0.92), dorsally slightly convex. Dorsal surface with sulcate longitudinal midline visible at anterior 2/3 of head, frontal area slightly foveate. Eyes 0.5 times the cephalic lateral length, not protruding at sides. Antennomere 4 elongate, 5 as long as wide, 6–10 transverse. Mandibles shorter than head (ratio 0.91); each with two well separated small teeth (basal and middle); mandibular channel well developed, external margin widely separated from internal margin at base, internal margin carinate until near level of middle tooth, continuing higher as impressed line. Maxillary and labial palpi with the apical palpomere nearly 1.25 times as long as subapical palpomere. Head almost as wide as pronotum (ratio 1.04).

Thorax: pronotum with five punctures in left dorsal row and six in right dorsal row; 1.17 times as long as wide; as wide at anterior corners as at posterior corners. Elytra with punctures moderately dense, with fine and pale setae; scutellum with punctures denser than elytra. Prosternum with anterior margin slightly depressed in comparison with central area that is slightly bulky, without carina. Intercoxal process of mesoventrite shield-shaped; transverse discal ridge broadly V-shaped, meeting margin of intercoxal process laterally. Row of spines in external margin of anterior femur with a space without spines before apex, as if one or two spines are missing ( Fig. 12d ), basal spines small, initiating slightly before middle part of femur, increasing in size toward space without spines; internal margin with three or four spines of medium size near to apex. Trochanter of posterior legs modified like small hook or like robust spine curved at apex, with length less than 1/4 of length of posterior femur; posterior femur weakly curved, or only slightly flattened, at level of its overlap with hook; posterior tibia slightly curved in apical third. Tarsomeres flattened dorsally.

Abdomen: first three visible tergites with posterior basal transverse carina not completely straight; adjacent depressed area very narrow, slightly visible on tergite 3, with sparse wide-superficial punctures; remaining tergites with fine, moderately dense punctures and setae. Abdominal sternites with punctures and setae similar to that on tergites, although with denser wide-superficial punctures on first three sternites. Male pregenital sternite with weak, broadly arcuate emarginate at posterior margin ( Fig. 15h ). Male genital sternite short (2.4 times longer than wide), very asymmetrical, anterior portion occupying 31% and posterior portion 69% of its length, apical emargination deep ( Fig. 18b ). Abdominal styli slender and black at apex.

Aedeagus: length 1.25 mm; cone-shaped; apex moderately acute; basal half notably wider than apical half, both in ventral and lateral view, mainly in basal third where it is rounded; internal sac visible ( Fig. 21b ).

Variability. The holotype is a small specimen in comparison with the average of the remaining analysed specimens: the mandibular length is slightly shorter than the cephalic length, the spines of anterior tibiae less numerous and short, the posterior trochanters modified like a spine or short hook, and the posterior femora and tibiae slightly curved. In larger specimens, the mandibles are longer than the head, the spines of the anterior femora are more numerous and larger, the posterior trochanters are modified like a hook and slightly longer, and the posterior femora and tibiae are more curved. Total body length in males 10.30 mm (range 8.8–11.4 mm), in females 10.17 (range 8.7–12.1 mm); head a little convex dorsally in large specimens and more convex in small specimens; wider than long in males (ratio 0.795, range 0.72–0.90), as in female (ratio 0.836, range 0.87–0.96); males with mandibles longer than head (ratio 1.28, range 1.13–1.48); females with mandibles shorter than, or almost as long as head (ratio 0.88, range 0.76–1.04); males with head wider than pronotum (ratio 1.175, range 1.07–1.30), females with head almost as wide as pronotum (ratio 1.05, range 0.93–1.28); pronotum slightly longer than wide in males (ratio 1.12, range 1.06–1.18) and in females (ratio 1.17, range 1.11–1.23); in both sexes, pronotum almost as wide at anterior corners as at posterior corners (ratio in males 1.02, range 1.00–1.07, in females 1.01, range 1.00–1.06); with five or six punctures in each dorsal row of the pronotum.

Taxonomic comments. This species is very similar to B. tepoztecus , it is only possible to distinguish them by the male characters; females of both species from Morelos State (the only place where males of B. tepoztecus are known) are indistinguishable, while females from other localities out of Morelos, based on the geographic distribution of males, can be assigned to B. apiciventris . This latter species has the row of spines of anterior tibiae interrupted before apex, as if one or two spines are missing, trochanters of posterior legs modified like wide hooks, pregenital sternite emarginate at posterior margin and a different shape of the genital sternite and aedeagus; while B. tepoztecus has the rows of spines of anterior tibiae continuous, without interruption until apex, trochanters of posterior legs are modified like hooks, slenderer than in B. apiciventris , pregenital sternite without emargination at posterior margin, and genital sternite and aedeagus are different than in B. apiciventris . Also, B. apiciventris can be confused with B. rufisternus , which is distinguished from B. apiciventris with difficulty. In B. apiciventris the anterior half of the mesoventrite is black, the dorsal rows of pronotum are normally composed of five punctures, the male pregenital sternite is emarginate at posterior margin, and the male genital sternite and aedeagus are different than that of B. rufisternus . While in B. rufisternus , the whole mesoventrite is reddish, the dorsal rows of the pronotum usually include six punctures, the male pregenital sternite without emargination at posterior margin, and has a different male genital sternite and aedeagus.

Type material examined: Holotype (male, NHM): “ Philonthus apiciventris Type D. S. Juquila, Mex. Höge (in the plaque with the specimen) / Type / Juquila , Mexico, Hoege / Sharp Coll. 1905-313 / B.C.A. Col. I.2. Philonthus apiciventris Sharp / Sharp Coll. 1905-313 / Holotype ”. Additional material examined (67 males, seven females): Mexico: Estado de México: “77 M, NE de Temascaltepec, 2150 m, bosque de pino-encino, N19°5.05’, W100°0.03’, sobre hongos Boletaceae , 29-IX-1999, A. Newton y M. Thayer cols.” (m 2, MAAS) . Michoacán: “autopista México - Morelia , km 194, bosque de encino, 218 m, en cadáver de ratón, 20-IX-2001, J. Márquez col.” (m 1, MAAS) . Morelos: “ Tlayacapan, San José de los Laureles , camino a Amatlán , bosque de pino, 1930 m, N18°58’8”, W99°0.25 ”, NTP-80 (calamar), 1 a VIII-1995 (m 1, MAAS) . “ Tlayacapan, San José de los Laureles , Loc-1, N18°58’33”, W99°00’47”, 2000 m, bosque de pino-encino, NTP-80, 1 a 30-VIII-1995, J. Márquez col.” (m 22, MAAS) . Same data, except: “ 1 a 30-XI-1996 ” (m 2, MAAS) . Same data, except: “ 1 a 30-IX-1995 ” (m 16, MAAS) . Same data, except: “ 1 a 30-X-1995 ” (m 5, MAAS) . Same data, except: “ 1 a 30-XII-1995 ” (m 1, MAAS) . Same data, except: “ 1-V-1995 ” (m 1, MAAS) . Same data, except: “ 1-30-VII-1995 ” (m 1, MAAS) . Same data, except: “ 1 a 30-IX-1995 ” (m 6, MAAS) . Oaxaca: “ Santiago Yosondua, camino a Sta. Ma. Yolotepec , 2398 m, bosque de pino-encino, N16°51’13”, W97°33’43.6”, en hongos, 10-VII-2005, J. Asiain y J. Márquez cols.” (m 7, f 6, CC-UAEH) . “ Santiago Yosondua, camino a la Cañada de Garnica , 2299 m, bosque de pino-encino, N16°52’26.9”, W97°37’44.4”, en excremento caballar, 12-VII-2005, J. Asiain, S. Bautista, R. Bautista y J. Márquez cols.” (m1, CC-UAEH) . “ La Cascada, camino El Vergel , bosque encino, 1917 m, N16°50’46.6”, W97°34’47.5”, NTP-80 calamar, 12-VII-2005, J. Asiain, S. y R. Bautista, J. Márquez cols.” (f 1, CC-UAEH) .

Figures

FIGURE 2. Dorsal view of males of: a) Belonuchus alternans (syntype, NHM©), b) B. alternans, c) B. apiciventris, d) B. cariniventris (lectotype), e) B. colon, f) B. confusus (holotype), g) B. julietitae (paratype), h) B. linuzensis (paratype). 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 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 18. Male genital sternite of: a) Belonuchus altenans, b) B. apiciventris, c) B. cariniventris, d) B. colon, e) B. confusus, f) B. julietitae, g) B. magnistylus, h) B. linuzensis, i) B. metafemoralis, j) B. oxyporimimus, k) B. oxyporinus, l) B. pulcher, m) B. rufisternus, n) B. singularis, o) B. tenuistylus. Scale bars = 0.5 mm.

FIGURE 21. Ventral (left) and lateral (right) view of the aedeagus of: a) Belonuchus alternans, b) B. apiciventris, c) B. cariniventris, d) B. colon, e) B. confusus, f) B. julietitae, g) B. linuzensis, h) B. magnistylus, i) B. metafemoralis. Scale bar = 0.5 mm (all figures).

FIGURE 26. Geographical distribution in Mexico and Guatemala of: a) Belonuchus alternans, B. apiciventris, B. magnistylus; b) B. cariniventris, B. confusus, B. julietitae, B. rufisternus, B. singularis and B. zunilensis.