Belonuchus rufisternus, Márquez & Asiain, 2022

Márquez, Juan & Asiain, Julieta, 2022, Taxonomy of the Mexican species of Belonuchus Nordmann (Coleoptera: Staphylinidae), Zootaxa 5152 (1), pp. 1-129 : 43-44

Belonuchus rufisternus sp. nov.

http://zoobank.org/NomenclaturalActs/e422a463-d3d7-42f2-988d-b5eeda8c0bda

Figs. 3g , 11c , 15k , 18m , 22d , 26b

Total body length 12.05 mm. Black on head, antennae, pronotum, scutellum, posterior 2/3 of sixth visible abdominal segment and abdominal styli. Reddish on elytra, mesoventrite, metaventrite, legs, first five visible abdominal segments and anterior third of sixth. Brown on mandibles (irregularly), maxillary and labial palpi, prosternum and genital segment.

Head: transverse, ratio length/width 0.74. Dorsal surface with sulcate longitudinal midline visible in anterior half of head; front foveate between antennal insertions. Eyes nearly 0.5 times the cephalic lateral length, not protruding laterally. Antennomeres 4–5 elongate, 6 as long as wide, 7–10 transverse. Mandibles 1.3 times longer than head; each with two teeth, basal tooth notably bigger than middle tooth; mandibular channel well developed, external and internal margins moderately separated at base, internal margin carinate, extending forward beyond level of middle tooth. Apical palpomere of maxillary and labial palpi almost 1.25 times longer than preapical palpomere. Head 1.3 times wider than pronotum.

Thorax: each dorsal row of pronotum with six punctures; pronotum slightly longer than wide (ratio 1.09) and slightly wider at anterior corners than at posterior corners (ratio 1.1). Scutellum with punctures denser than on elytra, latter with moderately dense punctation. Prosternum with area adjacent to anterior margin elevated and delimited behind by a transverse, slightly depressed line. Intercoxal process of mesoventrite shield-shaped, its apex acute, slightly acuminate; transverse discal ridge slightly visible, not meeting margin of intercoxal process laterally ( Fig. 11c ). Profemur with external row of spines initiating near basal third, spines small to medium sized, sparse, before apex with a space without spines, as if one or two spines were missing, and ending at apex with one or two spines; with four to five apical spines at internal margin longer than external spines. Metatrochanter modified like a hook, elongate at base, but at apex making a 90-degree turn to end in acute downward point, longer than 1/3 and shorter than 1/2 the length of metafemur; metafemur with internal margin curved at level of overlap with hook and slightly beyond; metatibia with internal side curved in anterior third. Tarsomeres flattened dorsally.

Abdomen: first three visible abdominal tergites with posterior basal transverse carina well developed, adjacent area slightly depressed, with wide-superficial punctures denser at sides than at center, on remaining surface only with fine, moderately dense punctures; visible tergite 4 with wide-superficial punctures denser in anterior half than in posterior half, in latter area combined with fine punctures which cover also the remaining tergites. Visible sternites 1–4 with wide-superficial punctures denser than on tergites, combined with fine punctures; remaining sternites with both types of punctures, but few dense. Male pregenital sternite with weak, broadly arcuate emargination at posterior margin ( Fig. 15k ). Male genital sternite moderately elongate (2.58 times longer than wide), very asymmetrical, anterior portion occupying 35% and posterior portion 65% of its length; apical emargination very deep ( Fig. 18m ). Abdominal styli slender.

Aedeagus: length 1.5 mm; elongate shape; apex moderately acute; sides converging almost homogeneously from base to apex; basal half moderately wider than apical half; internal sac visible ( Fig. 22d ).

Variability. Total body length in males 11.0 mm (range 8.9–12.1 mm), in females 10.8 mm (range 9.8–11.7 mm); ratio length/width of head in males 0.77 (range 0.7–0.85), in females 0.85 (range 0.81–0.89); ratio mandibular length/cephalic length in males 1.56 (range 1.33–1.83), in females 0.82 (range 0.72–0.92); ratio cephalic width/pronotal width in males 1.23 (range 1.09–1.33), in females 1.09 (range 1.06–1.14); ratio length/width of pronotum in males 1.13 (range 1.11–1.2), in females 1.15 (range 1.10–1.21); ratio anterior width/posterior width of pronotum in males 1.02 (range 0.91–1.07), in females 1.01 (range 1.00–1.07); aedeagus length 1.32 (1.25–1.4). In smaller males, the posterior trochanters are very similar to those of females, with only a small apical spine. The apical antennomere may be lighter than the previous ones. The number of punctures in the dorsal rows of pronotum varies by one or maximum two punctures more or less than the normal six. The sixth visible abdominal segment usually has the basal 2/3 black and 1/3 reddish, but the reddish part can occupy up to about 1/2.

Taxonomic comments. Belonuchus rufisternus was separated from B. apiciventris after extensive review of the material, and in previous publications where the studied specimens were included, they were not distinguished. Therefore, the species with which B. rufisternus can be most confused is B. apiciventris and its main differences can be found under taxonomic comments for that species. It may also be confused with B. tepoztecus due to its great similarity in size and color pattern but they can be distinguished using the taxonomic comments of the latter species.

Etymology. The name is a combination of “rufus” and “sternum”, which refers to the reddish color of the mesoventrite and helps to distinguish it from B. apiciventris , which has a black mesoventrite.

Type material (68 males, 56 females): Holotype (male, CC-UAEH) : “ México: Morelos, Tlayacapan, camino a Santa Catarina, Loc. 4, N18°57’13”, W99°00’15”, selva tropical caducifolia, 1550 m, NTP-80, 1 a 30-XII-1996, J. Márquez col.” . Paratypes: Mexico: Chiapas: “carretera Tuxtla Gutiérrez-San Cristobal de las Casas , km 30.7, selva mediana perturbada, 961 m, N16°45’, W92°57’, NTP-80 calamar, 20-IX al 3-XII-1999, J. Márquez col.” (m 2, f 3, MAAS) . Morelos: “ Cuernavaca, camino a Mexicapa, bosque de pino, NTP-80 calamar, Zona 1, 25-IV-1993, A. Soria, C. Cabello y E. Córdoba cols.” (f 1, MAAS). Same data, except: “ 1 a 30 VI-1993 ” (f 2, MAAS). “Tepoztlán, Ocotitlán, Cueva del Diablo , 20-XII-1977, L. Jiménez ” (m 2, MAAS) . Same data, except: “ 20-XII-1977, R. Badillo ” (m 1, f 1, MAAS). Same data, except: “ C. Martínez ” (m 3, MAAS) . Same data, except: “ 7-I-1977, J. Palacios ” (m 1, f 1, MAAS). Same data, except: “ 4-XII-1977 ” (f 1, MAAS). Same data, except: “ 4-VI-1978, M. Ortíz ” (m 1, MAAS) . Same data, except: “ 21-V-1978, M. R. Martínez ” (m 2, MAAS) . Same data, except: “ 17-VI-1978, C. Valdez ” (m 1, MAAS) . Same data, except: “ 20-XII-1977, G. Meneses ” (m 1, MAAS) . Same data, except: “ 15-X- 1977, D. López ” (f 1, MAAS). Same data, except: “ 1-XII-1977, M. Morales ” (f 1, MAAS). Same data, except: “ 20- XII-1977, J. Vázquez ” (f 1, MAAS). Same data, except: “ 21-V-1978, A. García ” (f 1, MAAS). Same data, except: “ 21-V-1978, M. E. Vera ” (f 1, MAAS). Same data, except: “ 4-VI-1978 ” (f 1, MAAS). Same data, except: “ 21-V- 1978, G. Muños ” (f 1, MAAS). Same data, except: “ 4-VI-1978, G. Borja ” (f 1, MAAS). “Tlayacapan, San José de los Laureles, Loc-1, N18°58’33”, W99°00’47”, 2000 m, bosque de pino-encino, NTP-80 (calamar), 1-30-X-1995, J. Márquez col.” (f 1, MAAS). Same data, except: “Loc-3, N18°58’29”, W99°01’25”, 1700 m, bosque mesófilo de montaña, NTP-80, 1 a 30-XII-1995, J. Márquez col.” (m 13, f 5, MAAS). Same data, except: “ 1 a 30-X-1995 ” (m 2, CC-UAEH) . Same data, except: “ 1-30-IV-1996 ” (m 1, f 2, MAAS). Same data, except: “ 1 a 30-VIII-1996 ” (m 1, CC-UAEH) . Same data, except: “ 1 a 30-XI-1996 ” (m 3, f 4, MAAS). Same data, except: “ 1 a 30-I-1996 ” (m 3, CC-UAEH) . Same data, except: “ 1 a 30-VI-1996 ” (m 1, CC-UAEH) . “ Tlayacapan, camino a Santa Catarina , N18°57´13”, W99°00´15”, 1550 m, Loc-4, selva tropical caducifolia, 1-30-VII-1995, K. Villavicencio y J. Márquez cols.” (m 1, MAAS) . Same data, except: “ 1-30-VIII-1995 ” (m 1, MAAS) . Same data, except: “ 1-30-X-1995 ” (m 1, f 2, MAAS). Same data, except: “ 1-30-XI-1995 ” (f 2, MAAS). Same data, except: “ 1-28-II-1996 ” (f 1, MAAS). Same data, except: “ 1-30-IX-1996 ” (f 1, MAAS). Same data, except: “ 1-30-XII-1996 ” (m 7, f 2, MAAS). Same data, except: “ 1 a 30-III-1996 ” (m 2, CC-UAEH) . Same data, except: “ 1 a 30-VIII-1996 ” (m 3, CC-UAEH) . Same data, except: “ 1 a 30-IV-1996 ” (m 2, CC-UAEH) . Same data, except: “ 1 a 30-IX-1996 ” (m 5, CC-UAEH) . Same data, except: “ 1 a 30-V-1996 ” (m 1, CC-UAEH) . Same data, except: “ 1 a 30-I-1996 ” (m 1, CC-UAEH) . Same data, except: “ 1 a 30-II-1996 ” (m 2, CC-UAEH) . “ Tlayacapan , N18°58’29”, W99°01’44”, 1685 m, Loc-5, cultivos de temporal, NTP-80, 1 a 30-IX-1996, J. Márquez col.” (m 2, CC-UAEH) . Oaxaca: “ Candelaria Loxicha, Portillo del Rayo , Finca Dos Ángeles, 1100 m, bosque tropical y cafetal, NTP, VI-1990, C. Deloya López col./ IEXA 5320261” (m 1, IEXA) . Same data, except: “Finca El Encanto, 750 m / IEXA 5320261” (m 1, IEXA) .

Figures

FIGURE 3. Dorsal view of males of: a) Belonuchus magnistylus (paratype), b) B. metafemoralis (paratype), c) B. oxyporimimus (paratype), d) B. pulcher (paratype), e) B. oxyporinus (holotype, NHM©), f) B. oxyporinus, g) B. rufisternus (holotype), h) B. singularis (holotype). Scale bars = 2.5 mm.

FIGURE 11. Mesoventrite of males of: a) Belonuchus cariniventris, b) B. oxyporinus, c) B. rufisternus, d) B. tepoztecus, e) B. bidens, f) B. jalappensis, g) B. longitarsus, h) B. ephippiatus, i) B. dichrous, j) B. flavipennis, k) B. platypterus, l) B. juanmorronei, m) B. iridescens. Red arrow: intercoxal process of the mesoventrite, blue arrow: transverse discal ridge, green arrow: longitudinal carina in anterior half.

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 22. Ventral (left) and lateral (right) view of the aedeagus of: a) Belonuchus oxyporimimus, b) B. oxyporinus, c) B. pulcher, d) B. rufisternus, e) B. singularis, f) B. tenuistylus, g) B. tepoztecus (at center detail of the paramere), h) B. trochanterinus, i) B. zunilensis. 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.