A taxonomic review of the endemic Mexican genus Ceratotrupes Jekel, 1865 (Coleoptera: Geotrupidae: Ceratotrupini), with the description of an unexpected new species from the Sierra Madre del Sur Author Arriaga-Jiménez, Alfonsina C63A2853-E857-4683-A5AE-626D2387A352 Insect Ecology Lab, School of Environmental and Rural Sciences, University of New England, Armidale NSW 2351, Australia. aarriaga@une.edu.au Author Zunino, Mario A1EE6CAE-8FC5-413B-9984-625DF6C4C486 Instituto de Ecología A. C., Invited researcher, Carretera antigua a Coatepec 351, Xalapa 91070, Veracruz, Mexico. mariozunino@hotmail.it Author Halffter, Gonzalo CF2EF74E-878A-4BC8-82A2-01F669049650 Deceased 11 March 2022. Former address: Aldama Street 17, Centro, 91500 Coatepec, Veracruz, Mexico. Author Escobar-Hernández, Fernando 0F5EFB92-6896-4E9D-A3E3-6DB3F33B762A Red de Ecoetología, Instituto de Ecología, INECOL A. C. Xalapa, México, Carretera antigua a Coatepec 351, El Haya, Xalapa 91070, Veracruz, Mexico. fernando.escobar@inecol.mx Author Rossini, Michele 2698881E-C265-42DB-8A8E-0BE3A5BDDB97 Finnish Museum of Natural History (LUOMUS), University of Helsinki, Pohjoinen Rautatiekatu 13, Helsinki, 00014, Finland. & Department of Agronomy, Food, Natural resources, Animals and Environment (DAFNAE), University of Padova, Via dell'Università 16, 35020, Legnaro (PD), Italy. text European Journal of Taxonomy 2023 2023-07-24 885 1 20 journal article 57492 10.5852/ejt.2023.885.2183 f1935cd8-83c6-45fd-aac5-8c6659a934aa 2118-9773 8177540 A928AB6A-0029-4CEA-B941-C2238643835A Ceratotrupes fronticornis ( Erichson, 1847 ) Fig. 1 Geotrupes fronticornis Erichson, 1847: 727 . Geotrupes ( Ceratotrupes ) fronticornis – Jekel 1865: 541 ; Geotrupes fronticornis – Gemminger & Harold 1869: 1082 . — Bates 1887: 112 . Ceratophyus ( Ceratotrupes ) fronticornis – Boucomont 1902: 11 . Ceratotrupes fronticornis – Boucomont 1912: 20 . — Blackwelder 1944: 20 . — Halffter & Martínez 1962: 151 . — Howden 1964: 45 ; 2003: 100 . — Zunino 1984: 107–109 . — Blackaller 1993: 22 . — Navarrete-Heredia et al. 2001: 49 . — Martínez & Trotta-Moreu 2010: 130 . — Trevilla-Rebollar et al. 2010: 487 . — Trotta-Moreu & Lobo 2010: 46 . — García et al. 2011: 184 . — Ramírez-Restrepo & Halffter 2016: 213–214 . Diagnosis This species can be separated from other members of the genus by having lateral edges of pronotum curved, anterior angles truncate in males, cephalic horn of male strongly compressed laterally, posteriorly not sulcate. Material examined MEXICO – Distrito Federal • 1 ♂ ; “ Contreras Jul. 2003 M.C. Halffter leg.”; CEMT • 1 ♀ ; same collection data as for preceding; CEMT . – Jalisco • 1 ♂ ; “ Concepción B. Aires , Paso Hondo 12 Jun. 2003 Curoe, Nogueira leg.”; CEMT • 1 ♀ ; same collection data as for preceding; CEMT . – México • 1 ♂ ; “km 45 cam. a Temascaltepec 2360 m a.s.l. Sep. 1971 pine-oak forest Martínez leg.”; CMNC 00031019 . – Michoacán • 1 ♂ ; “ Huajúmbaro 2160 m a.s.l. 13 Aug. 1999 G. Nogueira leg.”; CEMT • 1 ♀ ; same collection data as for preceding; CEMT • 1 ♂ ; “ Los Azufres 19°49′55″ N , 100°39′41″ W 2916 m a.s.l. 2 Jul. 2005 past. Pinus . cow dung. Cabrero and Trotta leg.”; CEMT • 1 ♀ ; same collection data as for preceding; CEMT • 1 ♀ ; “ 13 mi. W of Hidalgo 12 Jul. 1963 . F.D. Parker and L.A. Stange leg.”; CMNC 00031006 • 1 ♂ ; “ 70 km E of Morelia , Mil Cumbres 9000’ a.s.l. 8–10 Sep. 1969 . pine-oak forest. S. and J. Peck leg.”; CMNC 00031009 . – Morelos • 1 ♂ ; “ Cuernavaca , Colonia del Bosque Jul. 1987 . excr. de caballo [horse droppings] J. Blackaller leg.”; CEMT • 1 ♂ ; “ Cuernavaca , Colonia del Bosque Jul. 2008 . S. Boucher leg.”; CEMT • 1 ♀ ; “ Cuernavaca , km 55 carr. México 31 Aug. 1958 . bajo estiércol de caballo [under horse manure] W.M.W. Gibson leg. / H. and A. Howden Collection ex. A. Martínez coll.”; CMNC 00031003 ” • 1 ♀ ; same collection data as for preceding; CMNC 00031052 . – Querétaro • 1 ♀ ; “ Amealco Aug. 1957 G. Halffter leg. / H. and A. Howden Collection ”; CMNC 00031022 • 1 ♀ ; same collection data as for preceding; CMNC 00031023 • 1 ♂ ; same collection data as for preceding; CMNC 00031024 • 1 ♂ ; same collection data as for preceding; CMNC 00031025 • 1 ♂ ; same collection data as for preceding; CMNC 00031050 . Redescription of the male COLOUR . Body black, sometimes with purplish to bluish tinges on elytra; dorsally, tegument feebly shining; antennal segments dark brown, antennal club blackish to dark brown. HEAD . Clypeus obtusely triangular, longitudinally crossed by a medial, high and triangular horn, either projected forward or raised vertically; from posterior side, horn basally narrow and apically thicker, tip narrowly rounded; clypeal punctation dense and superficial; genae squared; frons smooth, unpunctured, with two oblique ridges along inner side of eyes. THORAX . In lateral view, pronotum weakly convex; in dorsal view, posterior edge of pronotum completely margined, lateral edges almost straight and parallel from posterior angles to midline, convergent towards anterior angles; anterior angles squared, and transversally truncated; pronotal disc with isolated and simple punctures, scattered and slightly deeper punctation near lateral and anterior edges; in lateral view, anteromedial projection slightly curved upward apically; in dorsal view, projection with sides convergent apically, tip emarginated at middle. Elytral interstriae slightly convex, unpunctured. Ventral side of thoracic sclerites (i.e., pro-, meso- and metasternum) with long, yellowish setae. LEGS . Protibiae robust, with seven external teeth, ventral side with a longitudinal, crenulated carina; apical spur long and slender; meso- and metatibiae respectively with 3 and 4 entire, transversal carinae on posterior side; femora unmodified, with long yellowish setae. Sexual dimorphism Female specimens have clypeal horn distinctly lower; from above, the clypeal horn is triangular-shaped; pronotal punctation simple and strong, scattered on disc, gradually denser near lateral and anterior edges; anteromedial pronotal protuberance callus-like and transverse, depressed on superior side and close to anterior pronotal edge; anterior angles simply curved. Ecology and biogeography This species inhabits mixed pine-oak forests and meadows located between 1850 and 3000 m a.s.l. It is known from a few localities distributed across the southern Trans-Mexican Volcanic Belt, and small populations scattered across the Balsas basin (e.g., some specimens were collected in Ario de Rosales, Michoacán , and Chalma, Mexico State ). Finally, C. fronticornis extends its distribution westward in the northern part of the Sierra Madre Occidental (Los Altares Durango ). Howden (2003) recorded this species from Canelas, Sinaloa , and Talpa de Allende, Jalisco . The eastern limit of its area of distribution seems to be located in the southern borders of Mexico City , between San Lorenzo Acopilco and Cumbres del Ajusco National Park, with the easternmost record in Chalco, Mexico State , close to the Iztaccíhuatl-Popocatépetl National Park. Recently, C. fronticornis was recorded from Mexico City ( Ramírez-Restrepo & Halffter 2016 ). Ceratotrupes fronticornis and C. bolivari are sympatric in the area between Mexico City and the southern border of the State of Mexico , as well as in Tapalpa, Jalisco and Durango , Sierra Madre Occidental ( Fig. 6 ).