Taxonomy of the Mexican species of Belonuchus Nordmann (Coleoptera: Staphylinidae) Author Márquez, Juan 0000-0001-5423-3545 marquezorum@gmail.com Author Asiain, Julieta 0000-0002-7958-4779 asiainae@yahoo.com text Zootaxa 2022 2022-06-10 5152 1 1 129 http://zoobank.org/92e9dd85-6cc6-4602-bd7c-c51f49ceef47 journal article 10.11646/zootaxa.5152.1.1 1175-5326 6630873 92E9DD85-6CC6-4602-BD7C-C51F49CEEF47 Belonuchus bidens Sharp, 1885 Figs. 4e, f , 10e , 11e , 12h , 15m , 19d , 23a , 30a Belonuchus bidens Sharp, 1885: 430 . Total body length in males 12.1 mm (range 9.5–13.0 mm), in females 11.3 mm (range 9.9–12.2 mm ). Black on head (except mouthparts), antennomeres 4–10 or 4–11, pronotum, visible abdominal segments 1–4, and anterior half (or slightly more) of fifth. Reddish on mouth parts, antennomeres 1–3 and sometimes the apical segment, elytra, scutellum, sterna, legs, from basal half (or basal third) of fifth visible abdominal segment to genital segment. Prosternum with variation from black to reddish. Apical antennomere reddish, paler than anterior antennomeres and with different texture. Head : transverse, ratio length/width in males 0.71 (range 0.50–0.82), in females 0.79 (range 0.77–0.82); with posterior corners and postero-dorsal part somewhat convex. Dorsal surface with sulcate longitudinal midline visible in anterior half of head; front foveate near anterior margin, in males this foveate area is placed between the two rather short cephalic projections at internal side of each antennal insertion ( Fig. 10e ). Eyes large, slightly more than 0.5 times the cephalic lateral length, not protruding laterally. Antennomere 4 elongate, 5 as long as wide, 6–10 transverse. Mandibles longer than head in males (ratio 1.26, range 1.10–1.48) and shorter than head in females (ratio 0.90, range 0.84–0.97); each with two small, moderately separated teeth (basal and middle); mandibular channel slightly developed, with external margin slightly separated from internal margin, internal margin like impressed line, markedly extending anteriad of middle tooth. Apical palpomere of maxillary and labial palpi 1.25 to 1.48 times longer than preapical palpomere. Head slightly wider than pronotum in males (ratio 1.14, range 1.06–1.18), and almost equally wide in females (ratio 1.03, range 0.95–1.07). Thorax : each dorsal row of pronotum with five punctures; pronotum almost as long as wide (ratio in males 1.04, range 1.00–1.14, in females 1.07, range 1.00–1.11) and almost as wide at anterior corners as at posterior corners (ratio in males 1.08, range 1.06–1.12, in females 1.03, range 1.03–1.05). Scutellum and elytra with fine punctures and setae moderately dense. Prosternum with area near to anterior margin slightly elevated and delimitated backward by a faintly impressed transverse line. Intercoxal process of mesoventrite shield-shaped, rather broad and with obtuse-angled tip; transverse discal ridge almost parallel to margin of intercoxal process, not meeting margin of process laterally ( Fig. 11e ). Profemur of males with external and internal margins well differentiated and each with row of spines; external margin curved downward near apex, distinctly narrowed and forming kind of notch where protibia would fit; external row of spines initiating slightly before base and reaching initial part of curvature, with fewer spines than on internal margin; spines on internal margin initiating from base, where there are additional non-aligned spines, but row of spines continuing until apex ( Fig. 12h ). Metafemur of males with two rows of large and dark spines on ventral surface, internal row well aligned from base until apical third, external row not clearly aligned because of additional, non-aligned spines at base. Tarsomeres dorsally flattened. Abdomen : first three visible tergites with posterior basal transverse carina well developed; adjacent area slightly depressed and narrow, with moderately dense wide-superficial punctures that are decreasing toward posterior margin, combined with fine, moderately dense punctures; fourth visible tergite with punctures similar to that of previous tergites, visible tergites 5–6 only with fine, moderately dense punctures. Visible sternites 1–4 with similar punctures as on tergites 1–4, but with denser wide-superficial punctures; sternites 5–6 only with fine punctures. Male pregenital sternite slightly emarginate at posterior margin, with long setae at sides and shorter, finer setae at center ( Fig. 15m ). Male genital sternite short (2.26 times longer than wide), very asymmetrical, anterior portion occupying 29% and posterior portion 71% of its length, apical emargination deep ( Fig. 19d ). Abdominal styli pale, but with apical third darker, slender, with lateral margin slightly curved. Aedeagus : length 1.65 mm ; rounded shape in basal half and elongate in apical half; apex wide at sides, with a minute median projection; basal half notably wider than apical half; internal sac visible, with characteristic shape ( Fig. 23a ). Variability . In addition to the variation in the measurements and ratios indicated in the description, it was observed, in both males and small females, that antennomeres 5–10 may be transverse instead of as long as wide. In some specimens the punctures of scutellum are denser than on elytra. Females do not have the apex of the anterior tibiae widened and curved to form a notch. Taxonomic comments . Belonuchus bidens is differs from the rest of species of rufipennis group by its unique coloration pattern, in which the elytra, scutellum, legs and last two visible abdominal segments (fifth only the posterior half) are reddish and the rest of the body is black; additionally, the males have two projections in the form of short horns on the frons, next to the antennal insertions. The aedeagus and genital sternite are also rather distinctive in this species. The syntypes of this species were not studied, but we analyzed some photos of these specimens ( Fig. 4e ; NHM, shared by M. Chani Posse), which together with the information of the original description ( Sharp 1885 ) allowed us to identify this species. Material examined ( 34 males , 21 females ): Mexico : Hidalgo : “Chapulhuacán Arroyo Blanco, bosque tropical subcaducifolio , 239 m , N21°09.286’ , W99°00.331’ , NTP-80 #2 (calamar), 30-III a 06-IV-2009 , J. Márquez , M. Rivero , M. Torres , M. Vargas y J. Sánchez cols.” (1, CC-UAEH ). Same data, except: “NTP-80 #3 (calamar)” (3, CC-UAEH ). “ Huautla , 2 km NW de Tohuaco Amatzintla , N21°07´23” , W98°16´51” , bosque tropical subcaducifolio, trampa cebada con champiñones, 17 a 28-IV-2015 , R. Ramírez y J. Márquez cols.” (2, CC-UAEH ). “ Huehuetla , Rio Blanco , 588 m , UTM (WG-384), 14 94809, NTP-80 (calamar), 1 a 30-V-2010 , C. Berriozábal col.” (22, CC- UAEH ). “La Misión, Lomas del Pericón , bosque mesófilo de montaña, 1377 m , N21°6.0’ 46.0”, W99°6.0’ 15.6”, trampa de intercepción de vuelo #1, 26-VIII a 9-IX-2011 , J. Márquez col.” (1, CC-UAEH ). Puebla : “Tlacuilotepec, cerca del río San Marcos , N20°19’22.5” , W98°02’35.4” , bosque tropical subcaducifolio, trampa con fruta, 13 a 25- X-2018 , J. Márquez y J. D. Silva cols.” (m 1, CC-UAEH ). Same data, except: “NTP-80, 17-VII a 19-VIII-2018 , J. D. Silva-Hurtado col.” (3, CC-UAEH ). “ Xicotepec de Juárez , Cañada de Patla , bosque mesófilo de montaña perturbado, 11-IX-1994 , en tronco caído, J. Márquez col.” (1, MAAS ). “ Xicotepec de Juárez , Hidroeléctrica Patla, bosque mesófilo de montaña perturbado, en necrotrampa temporal (calamar), 27-III-1998 , O. Pérez col.” (2, MAAS ). “ Xicotepec de Juárez , Hidroeléctrica Plata , selva mediana , 457 m , en plantas, 5-X-2002 , J. Asiain y J. Márquez cols.” (1, MAAS ). Same data, except: “ 487 m , en inflorescencia de plátano, 6-III-2002 .” (1, MAAS ). San Luis Potosí : “ Xilitla , Las Pozas de James , N21°23’55.7” , W98°56’6.7” , bosque tropical subperenifolio, 585 m , bajo rocas a orilla del río, 16-VII-2007 , J. Asiain y J. Márquez cols.” (1, CC-UAEH ). Veracruz : “Catemaco, Estación Biológica “Los Tuxtlas”, en frutos podridos, 20 al 24-II-1994 , J. Márquez col.” (1, MAAS ). Same data, except: “caminando” (1, MAAS ). “ Catemaco , Pipiapan , N18°27´ , W95°03´ , feb-march, 1991, M. A. Morón , ex carrion trap ” (1, IEXA ). “ Córdoba , San Rafael Calería , Ojo de Agua , selva mediana subcaducifolia , 1127 m , en lima podrida, Q. Santiago y J. Márquez cols.” (1, MAAS ). “ Córdoba , San Rafael Calería , Ojo de Agua , selva mediana subcaducifolia , 1127 m , en lima podrida, Q. Santiago y J. Márquez cols.” (1, MAAS ). “ Córdoba , San Rafael Calería , Ojo de Agua , N18°57’15” , W96° ,56’24”, selva mediana subcaducifolia , 1127 m , NTP-80 (calamar), 20-III a 17-IV-1999 , Q. J. Santiago , J. Márquez y J. Asiain cols.” (2, MAAS ). “ Córdoba , Cuauhtémoc , 940 m , 24-VI-1992 , NTP-80, R. Hernández col.” (1, IEXA ). “ Ilamatlán , Xococapa , bosque tropical subperenifolio , 388 m , N20°48’24.9” , W98°20’24.7” , NTP-80 (calamar) # 3, 13-VIII a 10-IV-2006 , F. Ramírez col.” (1, CC-UAEH ). Same data, except: “ 397 m , N20°48’24.0” , W 98°20’24.6” , NTP-80 #4, 05-III a 01-IV-2006 .” (1, CC-UAEH ). Same data, except: “ 362 m , N20°48’20.3” , W98°20’31.5” , NTP-80 #2” (1, CC-UAEH ). “ Totutla , Mata Oscura , Rancho Zacuapan , N19°12’23” , W96°50’32” , 869 m , naranja podrida, 18-V-1999 , J. Asiain , Q. Santiago y J. Márquez cols.” (1, MAAS ). Same data, except: “ 24- II-1994 ” (1, MAAS ). Same data, except: “en mandarina podrida, 18-V-1999 ” (2, MAAS ). “ Xico , km 1.2 camino a cascadas de Texolo , cultivo de café, en plátano en descomposición, 12-XI-1997 , Q. Santiago col.” (1, QJSJ ) .