Onthophagus bidentatus Drapiez, 1819

Solís, Ángel & Kohlmann, Bert, 2023, New synonyms and records of Costa Rican and Panamanian dung beetles (Coleoptera: Scarabaeidae: Scarabaeinae), Insecta Mundi 2023 (972), pp. 1-21 : 6

Onthophagus bidentatus Drapiez, 1819 and Onthophagus marginicollis Harold, 1880

Onthophagus bidentatus ( Fig. 14 ) was described by Drapiez in 1819 from French Guiana. Medina and Pulido (2009) report it from the Colombian Orinoquia. Rossini et al. (2016) report it from Panama, Trinidad and Tobago, Brasil, Peru, and Suriname. Rossini et al. (2016) also write that this is a common species in open habitats but rare in transitional forested areas. It also has been cited for Ecuador ( Chamorro et al. 2018). Recently, Taboada-Verona et al. (2019) have reported its presence in Sucre, Colombia.

Rossini et al. (2018) indicate that O. bidentatus belongs to the O. hircus complex, part of the O. hircus species group. Onthophagus marginicollis Harold, 1880 ( Fig. 15 ) is also a member of this complex, and we here analyze the distribution of both species for Costa Rica. In the case of Costa Rica, O. bidentatus had not been previously reported. However, its presence has now been confirmed, and Costa Rica apparently represents the northernmost occurrence of this species ( Fig. 16 ).

Figure 16 shows clearly that O. bidentatus is distributed in the Pacific Rain Forest of southern Costa Rica, plus isolated localities in the Nicoya Peninsula. These localities usually represent rainforest patches in the deep gorges of the Nicoya mountains, where the broken terrain maintains damp and stable rainforest patches. On the other hand, O. marginicollis is distributed along the Pacific and Caribbean coasts ( Fig. 17 ). Interestingly, the two species are sympatric along the Pacific coast ( Figs. 16–17 ). They can be collected in the same trap or manure, apparently coexisting even though they occupy the same niche, living in open or disturbed habitats.

Figures

Figures 12–17. 12) Color pie-chart of the northern Caribbean P. pyrois populations, northward of the 10° N latitude line, n = 462. 13). Color pie-chart of the southern Caribbean P. pyrois populations, southward of the 10° N latitude line, n = 203.14). Male Onthophagus bidentatus. 15). Male Onthophagus marginicollis. 16). Known distribution of O. bidentatus. 17). Known distribution of O. marginicollis.