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 sturmi ( Jekel, 1865 ) Figs 3 , 5A–B Geotrupes (Ceratotrupes) sturmii Jekel, 1865: 543 . Geotrupes (Ceratotrupes) mniszechi Jekel, 1865: 544 ( Fig. 5C–D ). Geotrupes sturmi – Gemminger & Harold 1869: 1085 . — Bates 1887: 112 . Geotrupes mniszechi – Gemminger & Harold 1869: 1083 . — Bates 1887: 113 . Ceratophyus (Ceratotrupes) sturmi – Boucomont 1902: 11 . Ceratophyus ( Ceratotrupes ) mniszechi – Boucomont 1902: 11 . Ceratotrupes sturmi – Boucomont 1912: 20 . — Blackwelder 1944: 220 . — Halffter & Martínez 1962: 155 . — Howden 1964: 47 ; 1974: 569 ; 2003: 100 . — Zunino 1984: 109 . — Trotta-Moreu et al. 2008: 42–43 , 48, 54. — Trotta-Moreu & Lobo 2010: 46 . Ceratotrupes mniszechi – Boucomont 1912: 20 . — Blackwelder 1944: 220 . — Halffter & Martínez 1962: 153 , 155, 157. — Howden 1964: 47 ; 1974: 569 . — Zunino 1984: 109 . Diagnosis Within the genus, C. sturmi is here considered to be related to C. gonzaloi sp. nov. , and it can be separated by the following diagnostic characters: posterior edge of pronotum with a thin, medial margin ( Fig. 3A, C ); clypeal horn slender, laterally narrower, tip obtuse ( Fig. 3A, D ); pronotal projection narrower, with convergent sides ( Fig. 3A, D ); elytral interstriae unpunctured. Furthermore, the male genitalia exhibit a series of clear morphological differences: distal tip of right ventral lobe of phallobase curved medially ( Fig. 3J ); shorter branch of the bifurcation of the right lobe of the phallobase longer than in C. gonzaloi ( Fig. 3L ); different shape of the parameres ( Fig. 3F ; arrows indicate the main differences); in lateral view, left paramere with a distinct lobe beneath the apical spur ( Fig. 3G ). It is noteworthy that C. sturmi and C. gonzaloi share with C. bolivari the presence of an apical, acute tooth on left paramere. Type material examined Holotype of C. sturmi MEXICO • ♂ ; “ Juquila [printed] / Mexico , Salle Coll. [printed] / 844 [green label, printed] / Sp. figured. [printed] / Ceratotrupes Sturmi Jekel , male symbol [handwritten] / Ceratotrupes sturmi Jekel , type apud Sallé [handwritten] / B.C.A. Col., II(2)., Geotrupes sturmi [printed] Jek / Holotype [white label with red border, printed]”; NHML . Holotype of C. mniszechi MEXICO • ♂ ; “Collection Mniszech [printed] / Ex-Musaeo VAN LANSBERGE [printed] / Geotr. (Ceratotrupes) Mniszechi Jekel [green label, handwritten] / Holo TYPUS Ceratotrupes mniszechi Jek [red label, handwritten except TYPUS, printed]”; MNHN . Additional material examined MEXICO – Oaxaca • 1 ♂ ; “ 20 mi S of Juchatengo , Rt. 131 . 6000’ alt. 27–30 May 1971 . H.F. Howden leg.”; CMNC 00031072 • 1 ♀ ; same collection data as for preceding; CMNC 00031071 • 1 ♂ ; “ Oaxaca , km 164.5, carr. 131 , Oax.–Pto. Escondido . 1800–2000 m a.s.l. 24–26 Jun. 1995 . A. Perez and J. Blackaller leg. Bosque de Encino, en excremento [oak forest, in excrement]”; http://id.luomus.fi/NC.04; FMNH • 1 ♂ , 1 ♀ ; “ Cerro del Vidrio , 1800 m a.s.l. 26 May 2004 . G. Nogueira leg. / Ceratotrupes sturmi Jekel, 1866 , M.A. Morón det. Mayo 2007 ”; http://id.luomus.fi/NC.05, http://id.luomus.fi/NC.06; FMNH • 1 ♂ ; “Rm 164.5, carr. Oaxaca–Puerto Escondido . 1500–1650 m a.s.l. 17–20 Jun. 1993 . coprotrampa [coprotrap]. L. Delgado leg.”; CEMT • 1 ♀ ; same collection data as for preceding; CEMT • 15 ♀♀ ; “ Oaxaca , 4 km S of Lachao. 16°12.1´N , 97°08.17′ W . 1710 m a.s.l. 1–24 Jun. 2006 . D. Curoe leg.”; CEMT • 3 ♂♂ ; same collection data as for preceding; CEMT • 1 ♂ ; “km 164.5 carr. Oaxaca–Puerto Escondido. 17–20 Jun. 1993 . 1550–1650 m a.s.l. coprotrampa [coprotrap]. L. Delgado leg. / Ceratotrupes sturmi (Jek.) / DET. H.F. HOWDEN ”; CMNC 00031062 • 1 ♀ ; same collection data as for preceding”; CMNC 00031067 . Redescription of the male COLOUR . Body black with purple iridescence, especially on both dorsal and ventral sides; dorsally, tegument shining, pronotal disc occasionally weakly silky; antennal segments brown, antennal club yellow. HEAD . Clypeus obtusely triangular and elongated, with a medial, high and triangular horn; from posterior side, horn narrow and longitudinally sulcate, tip narrowly rounded; clypeal punctation dense, coarse and superficial; genae squared, with elevated and acuminate angle, genal punctation obsolete; 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 finely margined at middle, lateral edges weakly curved from posterior angles to midline, straight and convergent from midline to anterior angles; anterior angles obtusely squared; pronotal disc unpunctured, sides with strong and coarse punctures sparsely distributed from posterior to anterior angles; in lateral view, anteromedial projection curved upward apically; in dorsal view, projection with sides convergent apically, tip narrowly emarginated at middle. Elytral interstriae slightly convex, unpunctured, apex of elytra with distinct but shallow punctation. Ventral side of thoracic sclerites (i.e., pro-, meso- and metasternum) with long, yellowish setae. LEGS . Protibiae robust, with six 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 (among the examined material, only one specimen shows four entire carinae on both meso- and metatibiae); femora unmodified, with long yellowish setae. Fig. 3. Ceratotrupes sturmi ( Jekel, 1865 ) (CMNC) . A–B . Dorsal habitus of male (A) and female (B). C . Details of head and prothorax; arrows indicate posteromedial edge of pronotum margined. D . Details of cephalic horn and pronotal projection of male. E . Aedeagus in dorsal view. F . Parameres in dorsal view; arrows indicate main differences between C. sturmi and C. gonzaloi sp. nov. G . Right paramere in lateral view; arrow indicates lobe beneath apical spur. H . Tergite. I . Pleurotergites. J . Phallobase in ventral view; arrow indicates curved margin of ventral lobe. K . Phallobase in dorsal view. L . Phallobase in lateral view; arrow indicates long bifurcation. M . Internal sac (is) and median struts (ms) in dorsal view. N . Internal sac and median struts in lateral view. Sexual dimorphism Female specimens have the clypeal horn distinctly shorter and clearly depressed posteriorly; from above, the clypeal horn is triangular-shaped, apex almost reaching clypeal edge; anteromedial pronotal protuberance callus-like and transverse, depressed on superior side and close to anterior pronotal edge. Remarks This species was originally described using the specific epithet “ sturmii ”, which is probably the derived genitive form of the Latinization “Sturmius” ( Jekel 1865 ). Nonetheless, later authors, from Gemminger & Harold (1869) to today’s publications, indicated the same species as “ sturmi ”. According to Art. 31.1 of the ICZN (1999) , the original spelling of the species-group name must be preserved. However, Art. 33.3.1 suggests that an “incorrect subsequent spelling” must be maintained if in prevailing use in the literature, which is the case for Ceratotrupes sturmi . Jekel (1865) described C. sturmi and C. mniszechi on two specimens from the Sallé and Mniszech collections and today deposited in the NHML and MNHN, respectively. In addition, the author mentioned the generic “ Mexico ” as type locality of the two species. The holotype of C. mniszechi does not have any label saying “ Mexico ”. However, Jekel’s handwritten label (“Collection Mniszech”) and the match between the morphology of the specimen and its original description remove any doubt to its identity ( Fig. 5C–D ). At the same time, the holotype of C. sturmi has a label indicating “ Mexico . Salle Coll.” and a second saying “Juquila”, a locality near Oaxaca ( Fig. 5A–B ). Probably the latter was added subsequently to the description of the species. At the moment, there is no evidence that indicates who might have attached this label to the holotype . Nonetheless, the morphology of the holotype matches perfectly with specimens recently collected in the mountains around Oaxaca (cephalic horn slender; pronotal projection clearly narrower distally; pronotal posterior edge with margin).