Tomarus Erichson, 1847

López-García, Margarita M., Gasca-Álvarez, Héctor J. & Amat-García, Germán, 2015, The scarab beetle tribe Pentodontini (Coleoptera: Scarabaeidae: Dynastinae) of Colombia: taxonomy, natural history, and distribution, Zootaxa 4048 (4), pp. 451-492 : 476

Tomarus Erichson, 1847

Tomarus Erichson, 1847: 95 . Type species: Tomarus maimon Erichson, 1847: 96 .

Ligyrus Burmeister, 1847: 542 . Type species: Scarabaeus gibbosus De Geer, 1774: 322 . Ligyrodes Casey, 1915: 172 . Type species: Scarabaeus relictus Say, 1825: 194 .

Euligyrus Casey, 1915: 185 (as subgenus). Type species: Scarabaeus ebenus De Geer, 1774: 317 . Grylius Casey, 1915: 189 (as subgenus). Type species: not designated.

Anagrylius Casey, 1915: 204 (as subgenus). Type species: Heteronychus tumulosus Burmeister, 1847: 101 . Ligyrellus Casey, 1915: 206 (as subgenus). Type species: not designated.

Diagnosis. This genus can be differentiated from other genera of the tribe by having an apically attenuated clypeus, with two small teeth on the anterior margin; frontoclypeal region with two tubercles or transverse carina, interrupted or not; and tibiae generally tridentate. The coloration is black to piceous, rarely red. Additionally, the species of the genus have the ocular canthus glabrous and the basal marginal bead absent.

Distribution. Tomarus is the most diverse and widespread genus in Pentodontini , with 30 species distributed from the United States of America to Argentina ( Endrödi 1969; Ratcliffe 2003; López-García et al. 2014). Twelve species are restricted to South America, and 11 are found in Colombia.

Remarks. The genus name Tomarus has been considered by some authors ( Endrödi 1985; Escalona & Joly 2006) as a junior synonym and a subgenus of Ligyrus for a long time, but Ratcliffe (2003) argued that Tomarus is the correct name by priority. The controversy emerged because both genera were described in the same year by Erichson and Burmeister, but with a difference of five months. Escalona & Joly (2006) indicated that Ligyrus has become a commonly used name due to its agricultural importance, and it should be validated. However, despite the generalized use of Ligyrus , we agree with Ratcliffe (2003) that the priority principle should be applied. Recently, Morón & Grossi (2015) indicated that both Ligyrus and Tomarus should be distinct genera, based on the number of teeth on the outer margin of the mandibles. However, a single character should not be used to delimit genera, and further analysis is needed to support such taxonomic change.