Onthophagus oaxacanus Zunino and Halffter

Höglinger, Marc, Huber, Andrea & Eichler, Klaus, 2019, Entwicklung Medizintechnik 2019 bis 2030: stationäre Rehabilitation & amp; stationäre Psychiatrie, The Coleopterists Bulletin 73 (3), pp. 535-550 : 541

Onthophagus oaxacanus Zunino and Halffter

The type specimens of O. oaxacanus were collected by Howden and Peck (1971) with carrion and dung-baited pitfall traps. This former subspecies of O. pseudundulans was elevated to species level by Halffter et al. (2019). The basic differences that distinguish O. oaxacanus from O. undulans are a bronze color, a deep, thick pronotal sculpture, and impressed elytral striae. Also, the male of O. oaxacanus has the clypeal apex evenly rounded, a strong, distinct, trapezoidal frontal carina, a basal margin slightly sinuate at the middle and evanescent laterally, and the pronotal prominence without a trace of intermediate tubercles.

Onthophagus oaxacanus ( Fig. 6 ) is found in the Sierra Madre del Sur in Guerrero and Oaxaca. The previously known localities in Oaxaca are Juchatengo and Suchixtepec , both with difficult access. The scarce material collected makes the distribution limits of this subspecies unclear. However , the recent collection of this species in the Sierra Norte and Sierra Sur of Oaxaca expand its known distribution in Oaxaca ( Fig. 9 ). It is a coprophagous species that inhabits oak-pine forests, gallery forests, and acahual. It is found from 2,100 to 2,900 m elevation and even up to 3,170 m (Zunino and Halffter 1988) .

This species was assessed by the IUCN Red List (2017) along with O. undulans , as they were considered subspecies and hence the evaluation was made at the species level. Therefore, O. undulans sensu lato was assessed as Vulnerable, based on an EOO of about 1,420 km 2 ( Favila et al. 2017a). However, considering the new status of both taxa as species, both should be considered Endangered because as separate species they occupy different mountains and smaller areas. Considering the currently known distribution of O. oaxacanus (AOO = ∼ 32 km 2; EOO = ∼ 4,400 km 2), it must be considered as Endangered B1 (EOO = <5,000 km 2) or B2b(iii) (continuing decline observed based on estimated, inferred, or projected AOO). It also must be considered that its habitats are high mountain environments and that climatic changes and anthropogenic modifications could put this species at a higher risk if the number of known locations, AOO, or EOO decline. Our research suggests that more exploration is needed to provide a more detail assessment for this species as well as for O. undulans .

Figures

Fig. 6. Onthophagus oaxacanus. A) Illustration of female, B) Illustration of male, C) Female, dorsal habitus, D) Male, dorsal habitus.

Fig. 9. Known distribution of Onthophagus species in Oaxaca, Mexico.