identifier	taxonID	type	CVterm	format	language	title	description	additionalInformationURL	UsageTerms	rights	Owner	contributor	creator	bibliographicCitation
03AA23621471FF84FF28AC37FEEDABE2.text	03AA23621471FF84FF28AC37FEEDABE2.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Onthophagus chevrolati Harold 1869	<div><p>Onthophagus chevrolati species group.</p><p>This group is diagnosed by the male having no clypeal horn (Figs. 5.17 –18); male clypeus transverse, with clypeal keel reduced or absent and long frontal keel; female clypeus less transverse with strong and forward-arched clypeal keel; male protibia apex having short setae (Figs. 1.45 –55), male pronotum unarmed forming a large gibbosity (Figs. 5.17 –18), and well-developed males presenting small head horns (Figs. 5.17 –18). Zunino &amp; Halffter (1988: 23) characterized this species group based on the male and female genitalia.</p><p>Zunino &amp; Halffter (1988) established the  O. chevrolati species group by joining the Boucomont (1932) “1 er Groupe” and “9 e Groupe” and based on proposals and species relationships previously suggested by Boucomont (1932), Howden et al. (1956), Howden &amp; Cartwright (1963), and (Howden (1973). Palestrini &amp; Zunino (1986) considered this group a vicariant from elements distributed at present in the Chinese Transition Zone (Stegmann 1930; Müller 1977; Palestrini et al. 1985). The  O. chevrolati species group was later subdivided into several species lines and complexes by Halffter et al. (2019). It comprises 59 species (Appendix 1), of which four are included in this analysis, representing the most speciose Western Hemispheric group. It is noteworthy how this group has undergone rapid speciation, primarily associated with the Mexican mountains.</p><p>Our mtDNA barcode analysis has recovered the  O. chevrolati species group (Figs. 1–2). Halffter et al. (2019) proposed the  O. cyanellus species complex within this species group, which is recovered in our barcode tree (Figs. 1–2). The existence of the  O. cyanellus species complex is supported by the unique long and slender metafemur present in  O. cyanellus Bates (Fig. 1.46). Although the present analysis is not all-encompassing, the tree recovers the existence of three of the 10 species complexes proposed by Halffter et al. (2019); the  O. brevifrons species complex ( O. brevifrons Horn and  O. subtropicus Howden &amp; Cartwright), the  O. chevrolati species complex ( O. cochisus Brown), and the  O. cyanellus species complex ( O. cyanellus Bates). In their phylogenetic analysis, Emlen et al. (2005) recovered the  O. chevrolati species group represented by  O. cochisus . This species group is also strongly supported by the other gene trees presented in this study, where the bootstrap study (Fig. 8) registers a bootstrap value of 91. A more comprehensive analysis might later recover more species complexes. All cave-dwelling and nest-dwelling species have a strongly bent male protibial apical spur; all other species have the typical straight apical spur (Figs. 1.45 –55). The  O. chevrolati species group is distributed from southern United States of America to Panama.</p></div>	https://treatment.plazi.org/id/03AA23621471FF84FF28AC37FEEDABE2	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Kohlmann, Bert;Solís, Ángel	Kohlmann, Bert, Solís, Ángel (2025): A review of the species groups of the Western Hemisphere Onthophagus Latreille (Coleoptera: Scarabaeidae: Scarabaeinae) using COI barcoding and gene trees. Zootaxa 5604 (4): 401-447, DOI: 10.11646/zootaxa.5604.4.1, URL: https://doi.org/10.11646/zootaxa.5604.4.1
03AA23621471FF81FF28ABCBFF71A9C4.text	03AA23621471FF81FF28ABCBFF71A9C4.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Onthophagus clypeatus	<div><p>Onthophagus clypeatus species group.</p><p>This group is diagnosed by males having a clypeal horn (Fig. 5.3); frons of male and female with two horns; male protibia long and slender, with a tuft of long setae at the apex (Figs. 1.79 –90); metatibial apex with short thick setae, alternating with thin setae of the same length as the thick setae, or longer, but never more than 2.5 times the size of the thick setae (Fig. 5.5); anteriosuperior region of male and female pronotum with two medial keels or humps; pronotum and elytral interstriae smooth with feeble punctures, with metallic luster (evanescent in  O. andersoni Howden &amp; Gill and  O. grataehelenae Kohlmann &amp; Solís); pygidium finely punctate.</p><p>The present barcode study suggests that the original  O. clypeatus species group that Zunino &amp; Halffter (1981, 1997) established comprises three species groups ( O. clypeatus,  O. dicranius, and  O. nasutus). Several taxa formerly considered to belong to this group (Table 3) now belong to the newly established  O. nasutus species group (Table 4, Figs. 1–2). This situation would be the second time a species group is derived from the  O. clypeatus group, the first one being the separation of the  O. dicranius and  O. mirabilis species groups by Howden &amp; Gill (1993) from the  O. clypeatus species group sensu Zunino &amp; Halffter (1981, 1997).</p><p>......continued on the next page</p><p>......</p><p>continued on the next page</p><p>Zunino &amp; Halffter (1981) first established the  O. mirabilis species complex within the  O. clypeatus species group. This first  O. mirabilis species complex (sensu Zunino &amp; Halffter 1981) consisted of  O. micropterus Zunino &amp; Halffter,  O. subcancer Howden,  O. mirabilis Bates, and  O. neomirabilis Howden. However, Howden &amp; Gill (1993), Génier &amp; Howden (1999), and Génier (2017) did not include  O. micropterus in either their  O. mirabilis species group or species complex. Howden &amp; Gill (1987) subsequently divided the  O. clypeatus species group into two species complexes,  O. belorhinus and  O. nasicornis –  O. nasutus, and considered them part of the  O. praecellens –  O. rhinolophus –  O. clypeatus species group. Chamé-Vázquez &amp; Sánchez-Hernández (2022) considered that the  O. belorhinus species complex to consist of  O. andersoni Howden &amp; Gill, 1987,  O. belorhinus Bates,  O. grataehelenae Kohlmann &amp; Solís,  O. istmenus Moctezuma, Sánchez-Huerta, &amp; Halffter, and  O. tacanensis Chamé-Vázquez &amp; Sánchez-Hernández. Subsequently, Howden &amp; Gill (1993) separated an  O. dicranius and an  O. mirabilis species group from the  O. clypeatus species group.</p><p>Zunino &amp; Halffter (1997) separated the  O. clypeatus species group into three species complexes:  O. clypeatus,  O. mirabilis, and  O. nasicornis . However, Zunino &amp; Halffter (1997) continued to consider the  O. dicranius and  O. mirabilis species groups of Howden &amp; Gill (1993) as part of the  O. clypeatus species group and the  O. dicranius species complex as part of the  O. clypeatus species complex (sensu Zunino &amp; Halffter 1997). Afterwards, Kohlmann &amp; Solís (2001) merged the  O. dicranius and  O. mirabilis species complexes into a single  O. dicranius species group, separate from the  O. clypeatus species group. Génier (2017) redefined the  O. dicranius species group and Rossini &amp; Génier (2024), proposed two subgroups within the  O. clypeatus species group:  O. clypeatus and  O. nasutus . The list of species pertaining to the  O. clypeatus species group as proposed by Rossini &amp; Génier (2024) matches the one proposed in this study. However, Rossini &amp; Génier (2024) did not provide any definition of what a subgroup is (new terminology) and its hierarchical level relative to previously accepted taxonomic usage in  Onthophagus of the hierarchical terms: species group, species line, and species complex (Zunino &amp; Halffter 1981, 1997; Halffter et al. 2019; see definitions below in  O. dicranius species group discussion). Interestingly, the present analysis (Figs. 1–2) does not register the existence of any species complexes within the  O. clypeatus species group. The bootstrap analysis also recovers the  O. clypeatus species group with a bootstrap value of 54 (Fig. 8).</p><p>Palestrini &amp; Zunino (1986) considered in their phyletic analysis that the  O. clypeatus species group is the most primitive one of the Western Hemisphere. In their global analysis of the  Onthophagus, Breeschoten et al. (2016) suggested a stem origin of the group about 20.5 Mya with a bootstrap value of 99, the oldest for Western Hemispheric  Onthophagus, and a recent crown origin of around 3 Mya with a bootstrap value of 100. Moctezuma et al. (2024) considered a stem origin of the group around 24 Mya and a crown origin of around 11.5 Mya. Emlen et al. (2005) and Schwery &amp; O'Meara (2021) also considered the  O. clypeatus species group the first to have appeared for the Western Hemispheric  Onthophagus . The Costa Rican Caribbean–Pacific vicariance pattern represented by the  O. limonensis –  O. coriaceoumbrosus and  O. nemorivagus –  O. propraecellens endemic species pairs (Figs. 1–2, 8–9), suggest that species formation must have occurred before the 8–6 Mya period, when Talamanca became a well-defined mountain range, separating the Caribbean and Pacific Southern Central American slopes (Kohlmann et al. 2024; Solís et al. 2024). This point is discussed below in more detail in the “Biogeography” section. Finally, the greatest intragroup genetic distance range (10.2%) recorded in this study suggests that the  O. clypeatus species group is old in origin. The  O. clypeatus species group is distributed from Mexico to Bolivia (Zunino &amp; Halffter 1997).</p></div>	https://treatment.plazi.org/id/03AA23621471FF81FF28ABCBFF71A9C4	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Kohlmann, Bert;Solís, Ángel	Kohlmann, Bert, Solís, Ángel (2025): A review of the species groups of the Western Hemisphere Onthophagus Latreille (Coleoptera: Scarabaeidae: Scarabaeinae) using COI barcoding and gene trees. Zootaxa 5604 (4): 401-447, DOI: 10.11646/zootaxa.5604.4.1, URL: https://doi.org/10.11646/zootaxa.5604.4.1
03AA2362147BFF8EFF28AEB8FE9CAC02.text	03AA2362147BFF8EFF28AEB8FE9CAC02.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Onthophagus crinitus	<div><p>Onthophagus crinitus species group*.</p><p>This group is diagnosed by the male having no clypeal horn and with two curved horns at the vertex (Fig. 5.6); male protibia apex with a tuft of long setae (Fig. 1.56); metafemur long and slender, bicolored, dark brown at apices and light brown at the center (Fig. 2.56); long dorsal pubescence.</p><p>Based on external morphology and genitalia, Rossini et al. (2018a) proposed that  O. crinitus Harold is related to the  O. gazellinus species group. The present mtDNA barcode study (Figs. 1–2) and the gene tree analyses (Figs. 8–9) weakly support this genital morphology-based proposal (clade node value of 9). Boucomont (1932), in his  Onthophagus species groups study, established a “6 e Groupe” composed of  O. crinitus and  O. lebasi Boucomont. According to him, this group is characterized by setose species with long pubescence and the male having long and slender protibiae. Subsequently, Zunino &amp; Halffter (1997) considered  O. lebasi a member of the  O. landolti species group. The maximum-likelihood analyses (Figs. 8–9) suggest that  O. lebasi represents an indepent clade with a weak relation to Eastern Hemispheric species. The  O. crinitus species group is distributed from Mexico to Colombia.</p></div>	https://treatment.plazi.org/id/03AA2362147BFF8EFF28AEB8FE9CAC02	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Kohlmann, Bert;Solís, Ángel	Kohlmann, Bert, Solís, Ángel (2025): A review of the species groups of the Western Hemisphere Onthophagus Latreille (Coleoptera: Scarabaeidae: Scarabaeinae) using COI barcoding and gene trees. Zootaxa 5604 (4): 401-447, DOI: 10.11646/zootaxa.5604.4.1, URL: https://doi.org/10.11646/zootaxa.5604.4.1
03AA2362147BFF8EFF28AC68FCB7AAFB.text	03AA2362147BFF8EFF28AC68FCB7AAFB.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Onthophagus curvicornis Latreille 1812	<div><p>Onthophagus curvicornis species group*.</p><p>This group is diagnosed by a male protibial apex with some short setae (Figs. 1.1-7); pronotum hornless; apical and internal margin of male protibia with a bulge ending in an acuminate projection (Figs. 1.1-7); male protibial spur downward bent at apex (Figs. 1.1-7); metafemur very short and stout (Figs. 2.1-7); apex of parameres poorly developed and defined.</p><p>Rossini et al. (2018a) recognized the  O. curvicornis species complex within the  O. hircus species group based on morpho-anatomical traits observed on the external body and genital organs. This relationship is recovered in the present study, supporting its hierarchy as a species group and not at a species complex level. Our study of the protibiae shows that the  O. curvicornis species group has a protibial acuminate apex (Fig. 1.1–7), whereas it is obsolete or with an obtuse tooth in the closely related  O. hircus species group (Fig. 1.8 –15).</p><p>In their  Onthophagus study, Emlen et al. (2005: fig. 4) recovered the  O. curvicornis species group based on  O. acuminatus Harold,  O. incensus Say, and  O. stockwelli Howden &amp; Young with a bootstrap support of 100 for the tree branch. Breeschoten et al. (2016) suggested a stem age of the group of around 14 Mya with a bootstrap value of 95. Schwery &amp; O'Meara (2021) also recovered an  O. curvicornis species group with a bootstrap support of 24. The present bootstrap analysis (Fig. 8) registers a clade node support of 35. At present, according to Rossini (2021) and Rossini et al. (2018a), eleven species are considered to belong to this new group (Table 7). In addition, six new species have been identified within this species group by Rossini et al. (2018a) and await description. This species group is distributed from the northern United States of America to northern Peru (through northern Venezuela), and two species from southeastern Brazil to northern Uruguay.</p></div>	https://treatment.plazi.org/id/03AA2362147BFF8EFF28AC68FCB7AAFB	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Kohlmann, Bert;Solís, Ángel	Kohlmann, Bert, Solís, Ángel (2025): A review of the species groups of the Western Hemisphere Onthophagus Latreille (Coleoptera: Scarabaeidae: Scarabaeinae) using COI barcoding and gene trees. Zootaxa 5604 (4): 401-447, DOI: 10.11646/zootaxa.5604.4.1, URL: https://doi.org/10.11646/zootaxa.5604.4.1
03AA2362147BFF8FFF28AAE0FF71AA43.text	03AA2362147BFF8FFF28AAE0FF71AA43.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Onthophagus dicranius Bates 1887	<div><p>Onthophagus dicranius species group.</p><p>This group is diagnosed by males having a clypeal horn (Fig. 5.2); male protibia long and slender, with a tuft of long setae at apex (Figs. 1.67 –78); metatibial apex with short, thick setae, alternating with thin setae of the same length as the thick setae, or longer, but never more than 2.5 times the size of the thick setae (Fig. 5.5); pronotum and elytral interstriae rough with coarse punctures, without metallic luster; pygidium with large coarse punctures, giving the impression of looking like a honeycomb.</p><p>The  O. dicranius and  O. mirabilis species groups were initially established by Howden &amp; Gill (1993). Through a parsimony phylogenetic analysis, they proposed the hypothesis that they both represented sister groups. Subsequently, Génier &amp; Howden (1999) redefined the limits of their  O. mirabilis species group through another parsimony phylogenetic analysis. Later, Kohlmann &amp; Solís (2001) considered both species groups to form one, the  O. dicranius species group. Finally, Génier (2017) established a conceptual framework for species groups and complexes, thus assigning the status of species complex to the two previous species groups and integrating them into the  O. dicranius species group.</p><p>Génier (2017: 2) defined a species group as having: "a broader scope and encompass species that possess one or more synapomorphies and may have very distinctive external morphologies" and a species complex as: "a group of closely related species that are very similar in appearance to the point that the boundaries between them are often unclear, as seen in the external morphology of the males." Interestingly, Zunino &amp; Halffter (1981) had already defined a species group and a species complex. According to Zunino &amp; Halffter (1981: 100) a species group is: “un raggruppamento omogeneo, con valore filetico, di rango infrasubgenerico. Il termine è quindi equivalente ad Artengruppe dei tassonomi di lingua tedesca”; whereas a species complex is defined as: “Nel caso in cui siano riconoscibile nell'ambito di un gruppo di specie più raggruppamenti di rango inferior, che rappresentano l'esito di altrettante linee evolutive distinte, indichiami tali raggruppamenti come «complessi di specie” (translation: a homogeneous grouping, with phyletic value, of infrasubgeneric rank). The term is therefore equivalent to the “Artengruppe” of German-speaking taxonomists. In contrast, a species complex is defined as: “In the event that they are recognizable in the ambit of a group of species, more groupings of lower rank, which represent the result of as many distinct evolutionary lines, we refer to these groupings as species complexes”. Génier's (2017) usage seems to have won the day over Zunino &amp; Halffter's (1981) usage, possibly because of them having written it in Italian and it not having been repeated and translated into Spanish or English in their subsequent works (Zunino &amp; Halffter 1988, 1997, 2019).</p><p>The  O. dicranius species group is recovered by the present mtDNA barcoding analysis (Figs. 1–2), as well as by the bootstrap analysis (21) (Fig. 8). The  O. dicranius and  O. clypeatus species groups are considered to be sister groups at a 49-bootstrap value (Fig. 8). Interestingly and according to the barcode (Figs. 1–2), bootstrap (Fig. 8), and partitioned (Fig. 9) analyses, members of what were initially considered species belonging to the  O. dicranius species complex ( O. dicranius Bates) and the  O. mirabilis species complex ( O. orphnoides Bates and  O. solisi Howden &amp; Gill) coalesce into what can be considered a single  O. dicranius species complex at a bootstrap value of 33. This fact would negate the existence of an  O. mirabilis species complex, as Kohlmann &amp; Solís (2001) and Génier (2017) proposed. More specimens are needed to resolve this situation.</p><p>The barcode (Figs. 1–2), bootstrap (Fig. 8), and partitioned (Fig. 9) analyses suggest the existence of a second and new species complex, the  O. micropterus species complex at a 73-bootstrap value, comprising four species ( O. dorsipilulus Howden &amp; Gill,  O. humboldti Kohlmann, Solís &amp; Alvarado,  O. micropterus Zunino &amp; Halffter, and  O. quetzalis Howden &amp; Gill) (Figs. 1–2). This last species complex originated and diversified in the Costa Rican–  Panamanian mountains . The analyses support the removal of  O. micropterus from the  O. dicranius species complex, as Delgado &amp; Mora-Aguilar (2019) suggested, forming an  O. micropterus species complex within the  O. dicranius species group. However, Delgado &amp; Mora-Aguilar (2019) did not reassign  O. micropterus to any specific grouping.</p><p>Of note are the results of the barcode analyses. According to the greatest interspecific and intergroup genetic distances in this study, these are concentrated between the  O. dicranius and  O. chevrolati species groups. This would support, according to previous evidence, that  O. dicranius, together with  O. clypeatus, its suggested sister group, are the oldest Western Hemispheric species groups, whereas  O. chevrolati would represent the most recent species group in the Western Hemisphere. The  O. dicranius species group is distributed from Mexico to Ecuador (Génier 2017).</p></div>	https://treatment.plazi.org/id/03AA2362147BFF8FFF28AAE0FF71AA43	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Kohlmann, Bert;Solís, Ángel	Kohlmann, Bert, Solís, Ángel (2025): A review of the species groups of the Western Hemisphere Onthophagus Latreille (Coleoptera: Scarabaeidae: Scarabaeinae) using COI barcoding and gene trees. Zootaxa 5604 (4): 401-447, DOI: 10.11646/zootaxa.5604.4.1, URL: https://doi.org/10.11646/zootaxa.5604.4.1
03AA2362147AFF8FFF28AAA8FA83A84B.text	03AA2362147AFF8FFF28AAA8FA83A84B.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Onthophagus eulophus Bates 1887	<div><p>Onthophagus eulophus species group*.</p><p>This group is diagnosed by a slightly emarginate clypeus; apical and internal male protibial margins projected (Figs. 1.23 –25); male protibial apex with some short setae (Figs. 1.23 –25); male protibial spur strongly bent inwards (Figs. 1.23 –25); male pronotum with a horn or a plate-like horn, which is level or turned upwards, never bent downwards.</p><p>Although no species of this group could be included in the mtDNA analysis, this aggregation is established based on a characteristic set of morphological characters, like having apical and internal male protibial margins projected and a male protibial spur strongly bent inwards (Figs. 1.23 –25). Moreover, contrary to the  O. mexicanus species group that have long and slender male protibiae (Figs. 1.26 –28), this group has short and stout male protibiae (Figs. 1.23 –25). All species of this group seem to be associated with rodent nests; this behavior is supported by the shortened male protibiae and bent male protibial spurs (Moctezuma &amp; Halffter 2021; Moctezuma et al. 2023). We consider that this group includes eight species (Table 7). Zunino &amp; Halffter (1997) and Moctezuma &amp; Halffter (2021) consider these species part of the  O. mexicanus species group. The  O. eulophus species group is primarily distributed in the mountains of the southwestern United States of America and along the Mexican Pacific mountain slopes, except for  O. totonacus Moctezuma &amp; Halffter, which lives along the Mexican Gulf piedmont.</p></div>	https://treatment.plazi.org/id/03AA2362147AFF8FFF28AAA8FA83A84B	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Kohlmann, Bert;Solís, Ángel	Kohlmann, Bert, Solís, Ángel (2025): A review of the species groups of the Western Hemisphere Onthophagus Latreille (Coleoptera: Scarabaeidae: Scarabaeinae) using COI barcoding and gene trees. Zootaxa 5604 (4): 401-447, DOI: 10.11646/zootaxa.5604.4.1, URL: https://doi.org/10.11646/zootaxa.5604.4.1
03AA2362147AFF8CFF28A850FEEBAEEB.text	03AA2362147AFF8CFF28A850FEEBAEEB.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Onthophagus gazellinus Bates 1887	<div><p>Onthophagus gazellinus species group.</p><p>This group is diagnosed by the male having no head horns (Figs. 5.7–8); male protibial apex with a tuft of long setae resembling a fine-pointed paintbrush (Figs. 1.57 –58); pronotum with four transversely aligned tubercles along a straight carina (Figs. 5.7–8), base unrimmed; metafemur light brown with fine punctures (Figs. 2.57 –58); at the excavated posterior pronotal margin a line of 5–6 large, ocellate punctures with one short, stiff, upward pointing seta, punctures disappearing towards middle of the pronotal margin; apex of elytra and pygidium with long, erect setae.</p><p>Boucomont (1932) initially established this species group as his “10 e Groupe” and was supported by Kohlmann &amp; Solís (2001) under the name of  O. gazellinus species group. This group contains, at present, only two species,  O. gazellinus Bates and  O. onthochromus Arrow (Table 7). Boucomont (1932) defined the group as having large species with long erect setae at the end of the elytra and on the pygidium; male head unarmed and female with two carinae; thorax base not rimmed; coloration light, elytral points brown. This species group is distributed from Nicaragua to Brazil.</p></div>	https://treatment.plazi.org/id/03AA2362147AFF8CFF28A850FEEBAEEB	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Kohlmann, Bert;Solís, Ángel	Kohlmann, Bert, Solís, Ángel (2025): A review of the species groups of the Western Hemisphere Onthophagus Latreille (Coleoptera: Scarabaeidae: Scarabaeinae) using COI barcoding and gene trees. Zootaxa 5604 (4): 401-447, DOI: 10.11646/zootaxa.5604.4.1, URL: https://doi.org/10.11646/zootaxa.5604.4.1
03AA23621479FF8CFF28AEF0FACCAD07.text	03AA23621479FF8CFF28AEF0FACCAD07.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Onthophagus hecate (Panzer 1794)	<div><p>Onthophagus hecate species group*.</p><p>This group is diagnosed by the apical and internal male protibial margin projected (Figs. 1.39 –44); male protibial spur bent downwards (Figs. 1.39, 1.41 –44); male protibial apex with some short setae (Figs. 1.39 –44); male pronotum with a bifurcate projection bent downwards or level (Figs. 5.12 –13).</p><p>A distinct  O. hecate species group is recovered by the barcode and gene tree analyses (Figs. 1–2, 8–9) with a bootstrap value of 70 and is formed by  O. hecate (Panzer),  O. medorensis Brown, and  O. orpheus (Panzer) . This group is distributed in the eastern half of the United States of America and southeastern Canada. Several other species may pertain to this group. This species group and rodent nests have a strong but not exclusive relationship. The mtDNA barcode tree topology (Figs. 1–2, 6) suggests that  O. hecate blatchleyi Brown should be elevated to species status. Brown (1925, 1927, 1929) initially suggested a relationship between  O. cynomysi Brown,  O. hecate,  O. medorensis, and  O. orpheus .</p><p>Emlen et al. (2005) have shown prolific evolutionary lability in the horn gain and loss processes shown by  Onthophagus worldwide. Emlen et al. (2005: fig. 4) estimated a Bayesian posterior probability of 100 for the  O. orpheus –  O. hecate tree clade. Emlen et al. (2005: fig. 5) proposed for the case of  O. orpheus and  O. hecate the loss of head horns, still showing rudimentary bumps at the base of the head, suggesting that full head horns may have been present in ancestral populations. At the same time, Emlen et al. (2005: fig. 7) proposed an independent gain event of pronotal horns for  O. orpheus and  O. hecate . These independent gain/loss processes seem to have confused previous taxonomists into considering the  O. hecate species group as part of the  O. mexicanus species group.</p></div>	https://treatment.plazi.org/id/03AA23621479FF8CFF28AEF0FACCAD07	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Kohlmann, Bert;Solís, Ángel	Kohlmann, Bert, Solís, Ángel (2025): A review of the species groups of the Western Hemisphere Onthophagus Latreille (Coleoptera: Scarabaeidae: Scarabaeinae) using COI barcoding and gene trees. Zootaxa 5604 (4): 401-447, DOI: 10.11646/zootaxa.5604.4.1, URL: https://doi.org/10.11646/zootaxa.5604.4.1
03AA23621479FF8CFF28AD6CFC62A84B.text	03AA23621479FF8CFF28AD6CFC62A84B.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Onthophagus hircus Billberg 1815	<div><p>Onthophagus hircus species group.</p><p>This group is diagnosed by a male protibial apex with some short setae (Figs. 1.8 –15); apical and internal margin of male protibia obtuse or with obsolete tooth (Figs. 1.8 –15) ( O. confusus has long male protibiae with internoapical tooth distinct and acuminated); male protibial spur downward bent at the apex (Figs. 1.8 –15); pronotum without horns; metafemur very short and stout (Figs. 2.8 –15); apex of parameres poorly developed and defined.</p><p>Zunino &amp; Halffter (1997) established an  O. hirculus species group, later renamed  O. hircus by Rossini et al. (2018a). Although Zunino &amp; Halffter (1997) do not mention it, this group is based on and corresponds to the “5 e Groupe” of Boucomont (1932), to which they erroneously incorporated  O. crinitus . In the Rossini et al. (2018a, 2018b) study of the  O. hircus species group, the authors established five species complexes:  O. curvicornis,  O. hircus,  O. ophion,  O. osculatii, and  O. rubrescens . The present analysis recovers an  O. hircus species group formed by species of the  O. hircus,  O. osculatii, and  O. rubrescens species complexes. The  O. curvicornis species complex is elevated to a group level in this study, as suggested by the present mtDNA analyses. No members of the  O. ophion species complex could be analyzed. The present analysis needs to contain a significant enough sample of analyzed species to validate all the proposed  O. hircus species complexes. This group presents a distribution from Mexico to the peripheral Amazonian basin of South America, including the Lesser Antilles.</p><p>Interestingly, Emlen et al. (2005: fig. 4) recovered an  O. hircus –  O. nasutus clade in their phylogenetic analysis, thus suggesting a relationship between the two species groups. The present barcoding analysis (Figs. 1–2) recovers the same relationship, whereas the bootstrap (Fig. 8) and the partition (Fig. 9) analyses suggest the  O. nasutus species group as a sister group to the  O. clypeatus –  O. dicranius species groups. A more comprehensive analysis is needed. Breeschoten et al. (2016) register an  O. hircus species group with a bootstrap value of 61 with an estimated crown age of approx. 10.5 Mya and a stem age of approximately 14 Mya. Schwery &amp; O'Meara (2021) recovered also an  O. hircus species group with a bootstrap support of 74. Moctezuma et al. (2024) proposed a stem value of around 17.5 Mya for the species group and a crown value of around 11 Mya.</p></div>	https://treatment.plazi.org/id/03AA23621479FF8CFF28AD6CFC62A84B	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Kohlmann, Bert;Solís, Ángel	Kohlmann, Bert, Solís, Ángel (2025): A review of the species groups of the Western Hemisphere Onthophagus Latreille (Coleoptera: Scarabaeidae: Scarabaeinae) using COI barcoding and gene trees. Zootaxa 5604 (4): 401-447, DOI: 10.11646/zootaxa.5604.4.1, URL: https://doi.org/10.11646/zootaxa.5604.4.1
03AA23621479FF8DFF28A850FAA5AFCB.text	03AA23621479FF8DFF28A850FAA5AFCB.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Onthophagus hoepfneri Harold 1869	<div><p>Onthophagus hoepfneri species group*.</p><p>This group is diagnosed by no male head horns present (Fig. 5.14); male protibial apex with some sparse short setae subequal to apical spur (Figs. 1.59 –66); pronotum with a small pointed or rounded anterior-pronotal projection (Fig. 5.14); with coarse punctures in metafemur (Figs. 2.59 –66).</p><p>We propose, based on the barcode and morphological analyses, that this species group includes, at present, besides  O. hoepfneri Harold, four more species,  O. coscineus, Bates,  O. oklahomensis Brown,  O. pennsylvanicus Harold, and  O. tuberculifrons Harold. Using a phylogenetic analysis, Emlen et al. (2005: fig. 2, bootstrap support of 79) had already obtained a branch formed by  O. coscineus and  O. pennsylvanicus . At the same time, because of the low support values indicated by the maximum-likelihood tree (Fig. 8), more species groups might emerge from the  O. hoepfneri branch once more species are included. These maximum-likelihood analyses suggest the existence of at least two clades within this species group, one formed by  O. coscineus and  O. tuberculifrons, another by  O. hoepfneri,  O. oklahomensis, and  O. pennsylvanicus . More specimens are needed to clarify this situation. Boucomont (1932) placed  O. hoepfneri in his “8 e Groupe”, which corresponds to the  O. landolti species group, and  O. oklahomensis,  O. pennsylvanicus, and  O. tuberculifrons in his “12 e Groupe”;  O. coscineus was unassigned.</p><p>The relationship of the  O. hoepfneri species group with the  O. crinitus species group suggested in this study (Figs. 1–2) was expected. In another maximum-likelihood genetic analysis, Emlen et al. (2005: fig. 4, Bayesian posterior probability of 99) obtained a branch formed by  O. crinitus and  O. pennsylvanicus . The Emlen et al. (2005) analysis and the present barcode (Figs 1–2) and partition (Fig. 9) analyses suggest a close relationship between these two groups. Schwery &amp; O'Meara (2021) also recovered a mixed  O. hoepfneri –  O. crinitus clade with a bootstrap support of 9. The  O. hoepfneri species group is distributed from the United States of America to Ecuador.</p></div>	https://treatment.plazi.org/id/03AA23621479FF8DFF28A850FAA5AFCB	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Kohlmann, Bert;Solís, Ángel	Kohlmann, Bert, Solís, Ángel (2025): A review of the species groups of the Western Hemisphere Onthophagus Latreille (Coleoptera: Scarabaeidae: Scarabaeinae) using COI barcoding and gene trees. Zootaxa 5604 (4): 401-447, DOI: 10.11646/zootaxa.5604.4.1, URL: https://doi.org/10.11646/zootaxa.5604.4.1
03AA23621478FF8DFF28AFD0FCA4AAD7.text	03AA23621478FF8DFF28AFD0FCA4AAD7.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Onthophagus landolti Harold 1880	<div><p>Onthophagus landolti species group.</p><p>This group is diagnosed by the male having no head horns (Fig. 5.14); male protibial apex with a tuft of long setae (Figs. 1.31 –38); pronotum with a small central protuberance (Fig. 5.14); metafemur brown to black with coarse punctures (Figs. 2.31 –38).</p><p>This species group has been studied recently by Arriaga-Jiménez et al. (2020), within which they established the  O. anthracinus species complex. According to Arriaga-Jiménez et al. (2020), the  O. landolti species group comprises the following species complexes:  O. anthracinus,  O. lecontei –  O. subopacus, and  O. mariozuninoi, plus 18 unassigned taxa to species complexes. The  O. landolti species group was established by Zunino &amp; Halffter (1997) and is based on the Boucomont (1932) “8 e Groupe”. The species of this group have long, slender, and bent male protibiae with a tuft of long setae at their apex (Figs. 1.31 –38).</p><p>In their  Onthophagus analysis, Emlen et al. (2005: fig. 4) indicated that a branch formed by  O. coscineus and  O. knulli Howden &amp; Cartwright (a member of the  O. landolti species group) has a sister relationship with a branch formed by  O. orpheus and  O. hecate (no Bayesian posterior probability reported), thus supporting a relationship between the  O. landolti and  O. hecate species groups as suggested by this barcode study (Figs. 1–2).  O. knulli has since been synonymized with  O. durangoensis Balthasar by Arriaga-Jiménez et al. (2020). This last species is a member of the  O. anthracinus species complex. On the other hand, Breeschoten et al. (2016) recovered in their study an  O. landolti clade with a bootstrap support value of 99 and suggested a stem origin of the group of approximately 17 Mya. The present barcode (Figs. 1–2), bootstrap (Fig. 8), and partition (Fig. 9) analyses also suggest the existence of an  O. landolti species group with a bootstrap value of 19. This low support node value suggests a similar situation as the one observed for the  O. hoepfneri species group. It is highly possible that more species groups shall emerge from the  O. landolti species group, once more species are added to the analysis. This group is distributed from the United States of America to Peru (Zunino &amp; Halffter 1997).</p></div>	https://treatment.plazi.org/id/03AA23621478FF8DFF28AFD0FCA4AAD7	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Kohlmann, Bert;Solís, Ángel	Kohlmann, Bert, Solís, Ángel (2025): A review of the species groups of the Western Hemisphere Onthophagus Latreille (Coleoptera: Scarabaeidae: Scarabaeinae) using COI barcoding and gene trees. Zootaxa 5604 (4): 401-447, DOI: 10.11646/zootaxa.5604.4.1, URL: https://doi.org/10.11646/zootaxa.5604.4.1
03AA23621478FF8DFF28AADCFC71A917.text	03AA23621478FF8DFF28AADCFC71A917.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Onthophagus marginatus	<div><p>Onthophagus marginatus species group*. This</p><p>group is diagnosed by a pale antennal club; head frons with a strong carina; elytral intervals having a median row of tubercles each bearing a strong seta; distal edges of the elytra have contrasting pale markings (brown in  O. fragosus); the pygidium has distinct setiferous umbilicate punctures; males with a brush of fused long hair at the distal end of the protibiae. Its two species live in Cuba.</p><p>Although no species of this group could be included in the mtDNA analysis, this aggregation is established based on a characteristic set of morphological characters mentioned in the diagnosis. The group is composed at present by  O. marginatus Laporte and  O. fragosus Génier &amp; Howden. The first species is widely distributed on the island; the second has been collected in litter on an isolated patch of moist forest (650-935 m a.s.l.) (Matthews 1966; Génier &amp; Howden 2014).</p><p>There is also a third species in the Greater Antilles living in Hispaniola,  O. albicornis Palisot. Matthews (1966) is of the opinion that the species of the Greater Antilles are derived from a common ancestor. This might be so because  O. albicornis shares with the two Cuban species the following characters: distal edges of the elytra have contrasting pale markings (brown in  O. fragosus); the antennal clubs are white while alive, turning yellowish when dead; prominent brush of fused setae emerging from the distal end of the male foretibia. Génier and Howden (2014) indicated that the protibiae of  O. fragosus lacked the apical setal brush. However, photographs provided by Andrew Smith of the male  O. fragosus clearly shows the existence of this structure.</p></div>	https://treatment.plazi.org/id/03AA23621478FF8DFF28AADCFC71A917	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Kohlmann, Bert;Solís, Ángel	Kohlmann, Bert, Solís, Ángel (2025): A review of the species groups of the Western Hemisphere Onthophagus Latreille (Coleoptera: Scarabaeidae: Scarabaeinae) using COI barcoding and gene trees. Zootaxa 5604 (4): 401-447, DOI: 10.11646/zootaxa.5604.4.1, URL: https://doi.org/10.11646/zootaxa.5604.4.1
03AA23621478FF8AFF28A91CFA92AC03.text	03AA23621478FF8AFF28A91CFA92AC03.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Onthophagus mexicanus Bates 1887	<div><p>Onthophagus mexicanus species group.</p><p>The males of this group have a slightly emarginate clypeus ( O. mexicanus), or a small clypeal projection ( O. championi), or a distinct vertical clypeal horn protrusion present in  O. guatemalensis and  O. pseudoguatemalensis (Fig. 5.11); slender male protibiae (Figs. 1.26 –28); apical and internal male protibial margin acuminate (Figs. 1.26 –28); male protibial apex with some short setae (Figs. 1.26 –28); male pronotum with a plate-like projection, distally more-or-less distinctly emarginated at middle (Fig. 5.11).</p><p>Zunino &amp; Halffter (1988) established this species group based on the Boucomont (1932) “7 e Groupe”. Zunino &amp; Halffter (1997) later defined this group, giving a detailed morphological characterization. Interestingly and opposed to this study, they considered that contrary to groups such as  O. clypeatus and  O. landolti, this group had a robust internal homogeneity that did not allow for the separation of species groups. Bates (1887) described in the Biologia Centrali-Americana for the first time an  O. mexicanus species group comprised of  O. championi Bates,  O. eulophus Bates,  O. guatemalensis Bates, and  O. mexicanus Bate s. Moctezuma &amp; Halffter (2021) considered that the group included at least 18 species. We consider the existence of only four species in this group (Appendix 1). The present analysis proposes the idea that at least three new species groups previously considered to form part of the  O. mexicanus species group exist within:  O. eulophus,  O. hecate, and  O. velutinus (Figs. 1–2). The present barcode and gene tree analyses (Figs. 1–2, 8–9) suggest a very close relationship between the  O. mexicanus and  O. velutinus species groups with a bootstrap support of 93, while the  O. hecate species group is distantly related. The  O. mexicanus species group is distributed in the mountains from northwestern Mexico to Costa Rica.</p></div>	https://treatment.plazi.org/id/03AA23621478FF8AFF28A91CFA92AC03	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Kohlmann, Bert;Solís, Ángel	Kohlmann, Bert, Solís, Ángel (2025): A review of the species groups of the Western Hemisphere Onthophagus Latreille (Coleoptera: Scarabaeidae: Scarabaeinae) using COI barcoding and gene trees. Zootaxa 5604 (4): 401-447, DOI: 10.11646/zootaxa.5604.4.1, URL: https://doi.org/10.11646/zootaxa.5604.4.1
03AA2362147FFF8AFF28AC68FD7BA93B.text	03AA2362147FFF8AFF28AC68FD7BA93B.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Onthophagus nasutus Guerin-Meneville 1855	<div><p>Onthophagus nasutus species group*.</p><p>This group is diagnosed by a male having a clypeal horn (Fig. 5.1); female frons never with a horn (either unarmed or with simple straight carina); male protibia short and stout, with a broad brush of setae at the apex subequal in length to the apical spur (Figs. 1.16 –22); metatibial apex, with short thick setae, alternating with other thin and long setae three times or more the length of the thick setae (Fig. 5.4); female anterosuperior region of pronotum simple, never carinate.</p><p>The species forming this group were initially considered part of the  O. clypeatus species group by Boucomont (1932), Zunino &amp; Halffter (1981, 1997), and Kohlmann &amp; Solís (2001). Zunino &amp; Halffter (1981), when first establishing the existence of the  O. clypeatus species group, indicated that the species belonging to the  O. nasutus species group might belong to another (unnamed) group. They considered the following species as part of this possible different group:  O. carpophilus Pereira &amp; Halftter,  O. nasicornis Harold,  O. nasutus Guérin-Méneville, O.  sharpi Harold,  O. tapirus Sharp, and  O. rostratus Harold. Subsequently, Howden &amp; Gill (1987) considered the existence of an  O. nasicornis –  O nasutus species complex within the  O. clypeatus species group. Delgado &amp; Deloya (1990) proposed an  O. nasutus line, separate from an  O. clypeatus and  O. mirabilis species lines, all three lines forming part of an  O. clypeatus species group. Although their taxonomic discussion is not clear, they proposed within this  O. nasutus line, an  O. nasutus species complex formed by:  O. atriglabrus,  O. nasicornis,  O. nasutus, and  O. villanuevai . Later, Zunino &amp; Halffter (1997) maintained this  O. nasutus species group as the  O. nasicornis species complex, a part of the  O. clypeatus species group. Subsequently, Delgado et al. (2006) excluded the  O. nasicornis species complex from the  O. clypeatus species group (sensu Zunino &amp; Halffter 1997) based on the lack of tubercles and horns on the vertex of males without formally establishing a species group. Finally, Rossini &amp; Génier (2024) established two subgroups,  O. clypeatus and  O. nasutus, as part of the  O. clypeatus species group. Whereas Rossini &amp; Génier (2024) give a complete list of the species belonging to their  O. clypeatus subgroup, they did not specify any species for their  O. nasutus subgroup.</p><p>The mtDNA barcode and maximum-likelihood analyses recover this group. The barcode analysis (Figs. 1–2, 6) suggests a relationship with the  O. hircus species group. Emlen et al. (2005: fig. 4) and Schwery &amp; O'Meara (2021: fig. 1) also suggested this same relationship. In contrast, the bootstrap and partition analyses propose a relationship with the  O. clypeatus –  O. dicranius species groups with a low node support value of 9. Unlike most Western Hemispheric  Onthophagus, this species group is not coprophagous but, instead, frugivorous, mycophagous, necrophilous, and saprophagous.</p><p>The Emlen et al. (2005: fig. 4) phylogenetic tree showed that  O. sharpi Harold ( O. nasutus species group) falls within a branch composed of  O. haematopus Harold and  O. marginicollis Harold (both species members of the  O. hircus species group) with bootstrap support of 88; therefore, supporting the results presented in Fig. 1 and Fig. 2, where  O. hircus and  O. nasutus appear as sister species groups. Emlen et al. (2005: fig. 6a) considered that  O. sharpi gained a clypeal horn in an independent evolutionary process from the  O. clypeatus species group. This species group is distributed from Mexico to Ecuador.</p></div>	https://treatment.plazi.org/id/03AA2362147FFF8AFF28AC68FD7BA93B	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Kohlmann, Bert;Solís, Ángel	Kohlmann, Bert, Solís, Ángel (2025): A review of the species groups of the Western Hemisphere Onthophagus Latreille (Coleoptera: Scarabaeidae: Scarabaeinae) using COI barcoding and gene trees. Zootaxa 5604 (4): 401-447, DOI: 10.11646/zootaxa.5604.4.1, URL: https://doi.org/10.11646/zootaxa.5604.4.1
03AA2362147FFF8BFF28A920FB90AC97.text	03AA2362147FFF8BFF28A920FB90AC97.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Onthophagus velutinus Horn 1875	<div><p>Onthophagus velutinus species group*.</p><p>This group is diagnosed by a pronotal disc distinctly tuberculate; clypeus slightly emarginate; surface of pronotum and (or) elytra finely alutaceous. Male with two straight and erect horns at vertex (Figs. 5.19 –20); male protibia short and stout (Figs. 1.29 –30); male protibial spur inwardly bent at apex (Figs. 1.29 –30); male protibial apex with some short setae (Figs. 1.29 –30); metafemur long and slender (Figs. 2.29 –30); male pronotum with a well-developed central gibbosity (Figs. 5.19 –20); apex of parameres well developed and defined. Females with carina of vertex nearly straight.</p><p>Zunino &amp; Halffter (1997: 159) included  O. velutinus Horn as part of the  O. mexicanus species group without giving any justification for this decision. Later, Zunino (2003) considered  O. cartwrighti Howden to be in an incertae sedis species group. Subsequently, Moctezuma &amp; Halffter (2019) suggested that  O. cartwrighti should be included within the  O. mexicanus species group due to its close relationship to  O. velutinus . We disagree with these opinions because these species have a different Bauplan (from the German, Bauplan (s.) [Baupläne, pl.], body plan, a suite of characters shared by a group of phylogenetically related animals at some point during their development; Willmore 2012) from the  O. mexicanus species group.</p><p>While the mtDNA analyses suggested a relationship between the  O. velutinus and  O. mexicanus species groups (Figs. 1–2, 8–9), the external morphological Bauplan between these two groups is entirely different. The  O. velutinus species group, contrary to the  O. mexicanus species group, does not have pronotal horns and no short and thick metafemora (Figs. 2.29 –30) and presents very characteristic and almost parallel long vertex horns (Figs. 5.19 –20). Howden &amp; Cartwright (1963: 107) indicated that  O. velutinus is quite distinct from other Western Hemispheric  Onthophagus species and seemed restricted to  Neotoma Say &amp; Ord ( Rodentia:  Cricetidae) nests. We suggest that  O. cartwrighti and  O. velutinus form a new species group, the  O. velutinus species group, distributed in the Southwestern United States of America and the Baja California Peninsula.</p></div>	https://treatment.plazi.org/id/03AA2362147FFF8BFF28A920FB90AC97	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Kohlmann, Bert;Solís, Ángel	Kohlmann, Bert, Solís, Ángel (2025): A review of the species groups of the Western Hemisphere Onthophagus Latreille (Coleoptera: Scarabaeidae: Scarabaeinae) using COI barcoding and gene trees. Zootaxa 5604 (4): 401-447, DOI: 10.11646/zootaxa.5604.4.1, URL: https://doi.org/10.11646/zootaxa.5604.4.1
03AA2362147EFF88FF78ADA5FA0DADDC.text	03AA2362147EFF88FF78ADA5FA0DADDC.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Onthophagus	<div><p>Key to Western Hemispheric  Onthophagus species groups</p><p>We provide a preliminary identification key for the different species groups. Current diagnoses for the groups will require more species to stabilize the characters that define the aggregations. On the other hand, many morphological characters suggested by the COI groupings have not been customarily used for the Western Hemispheric  Onthophagus systematics, like protibial and metafemoral shapes, protibial apical setae, protibial apical projections, apical metatibial setae, and the position of the horns.</p><p>The key is based mostly on males. There are no general invariant external morphological differences between both sexes, these can vary from species group to species group, we indicate here the more common ones. Males usually have the head horned or tuberculate and (or) the pronotum with horns or other protuberances; in many cases males have long and slender protibiae with a short apical spur and an apical brush or tuft of setae. Females have generally the head carinate and sometimes the pronotum with a carina or other minor elevation; in many cases females have short and thick protibiae with a long apical spur and never with an apical brush of setae.</p><p>Identification key to the Western Hemispheric  Onthophagus species groups</p><p>1 Elytral intervals with a median row of tubercles each bearing a strong seta; pygidium with distinct umbilicate punctures, Cuba .........................................................................  O. marginatus species group</p><p>- Elytral intervals without median row of tubercles; pygidium without distinct umbilicate punctures..................... 2</p><p>2 Male protibia apex with a brush or tuft of long setae (Figs. 1.31 –38, 1.56–58, 1.67–90).............................. 3</p><p>- Male protibia apex with some short setae smaller or subequal to the length of the apical spur (Figs. 1.1 –15, 1.16–22, 1.23–30, 1.39–55, 1.59–66).................................................................................... 7</p><p>3 Males with clypeal horn (Figs. 5.1–3)..................................................................... 4</p><p>- Males without clypeal horn............................................................................. 4</p><p>4 Pronotum and elytral interstriae smooth with feeble punctures, with metallic luster (poorly defined in  O. andersoni and  O. grataehelenae); pygidium finely punctate.............................................  O. clypeatus species group</p><p>- Pronotum and elytral interstriae rough with coarse punctures, without metallic luster; pygidium with large coarse punctures, giving the impression of looking like a honeycomb.....................................  O. dicranius species group</p><p>5 Male with two curved horns at vertex (Fig. 5.6); dorsum with very long setae..................  O. crinitus species group</p><p>- Male with no head horns; dorsum with small setae or with long, erect setae at elytral apex and pygidium............... 6</p><p>6 Pronotum with four transversely aligned tubercles along a straight carina (Figs. 5.7–8); metafemur light brown with fine punctures (Figs. 2.57 –58); excavate posterior pronotal margin with a line of large, ocellate punctures (disappearing towards middle) and with one short, stiff, upward-pointing seta; apex of elytra and pygidium with long, erect setae.............................................................................................  O. gazellinus species group</p><p>- Pronotum with a small central protuberance (Fig. 5.9 –10); metafemur brown to black with large punctures (Figs. 2.31 –38); excavate posterior pronotal margin impunctate, surface smooth; apex of elytra and pygidium glabrous or with or short setae.................................................................................  O. landolti species group</p><p>7 Males with clypeal horn (Figs. 5.1); metatibial apex, with short, thick setae, alternating with other thin and long setae three times or more the length of the thick setae (Fig. 5.4).......................................  O. nasutus species group</p><p>- Males without clypeal horn; metatibial apex, with short, thick setae of equal length (Fig. 5.5)......................... 8</p><p>8 Male pronotum with a plate-like horn (Figs. 5.11 –13)........................................................ 9</p><p>- Pronotum unarmed or with a small anteropronotal projection or gibbosity........................................ 11</p><p>9 Apical and internal male protibial margin projected like a round pointed spur (Figs. 1.23 –25, 1.39–43)................ 10</p><p>- Apical and internal male protibial margin projected like a thin pointed spur (Figs. 1.26 –28)....  O. mexicanus species group</p><p>10 Male protibial spur bent downwards, strongly so in  O. cynomisi (Figs. 1.39 –43).................  O. hecate species group</p><p>- Male protibial spur strongly bent inwards (Figs. 1.23 –25).................................  O. eulophus species group</p><p>11 Male pronotum with a small, pointed or rounded anteropronotal projection (Fig. 5.14); males without head horn.........................................................................................  O. hoepfneri species group</p><p>- Male pronotum with no small conical central pronotal projection present; males with head horns (Figs. 5.15 –16), if head horn small, then pronotum with a large central gibbosity (Figs. 5.17 –18) ............................................. 12</p><p>12 Male pronotum with a large, central gibbosity and usually with well-marked, small lateral tubercles (Figs. 5.17 –18); well-developed males with small head horns (Figs. 5.17 –18)..................................  O. chevrolati species group</p><p>- Male pronotum without large, central gibbosity and limited only between cephalic horns; males with well-developed head horns (Figs. 5.15 –16)................................................................................. 13</p><p>13 Disc of pronotum distinctly tuberculate; male protibial spur inwardly bent at apex (Figs. 1.29 –30); metafemur long and slender (Figs. 2.29 –30); apex of parameres well developed and defined; inhabitant of  Neotoma nests.....  O. velutinus species group</p><p>- Disc of pronotum without tubercles; male protibial spur downward bent at apex (Figs. 1.1 –15); metafemur short and stout (Figs. 2.1 –15); apex of parameres poorly developed; not an inhabitant of  Neotoma nests.................................. 14</p><p>14 Apical and internal margins of male protibia with acuminate tooth and short protibia (Figs. 1.1–7)...................................................................................................  O. curvicornis species group</p><p>- Apical and internal margins of male protibia obtuse with a short male protibia (Figs. 1.8 –15), or long protibia with apical and internal margin with acuminate tooth ( O. confusus)........................................  O. hircus species group</p></div>	https://treatment.plazi.org/id/03AA2362147EFF88FF78ADA5FA0DADDC	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Kohlmann, Bert;Solís, Ángel	Kohlmann, Bert, Solís, Ángel (2025): A review of the species groups of the Western Hemisphere Onthophagus Latreille (Coleoptera: Scarabaeidae: Scarabaeinae) using COI barcoding and gene trees. Zootaxa 5604 (4): 401-447, DOI: 10.11646/zootaxa.5604.4.1, URL: https://doi.org/10.11646/zootaxa.5604.4.1
