Omorgus zumpti (Haaf, 1957)

Omorgus zumpti (Haaf, 1957) View in CoL

We have reason to be cautious that the Trogidae in Lanner Gorge Cave (see below) had correctly been identified as Omorgus zumpti , as reported by Braack (1989). We could not track down any trogid voucher specimens from Braack’s study. Rather, in both the TMSA and the SANC we found four Lanner Gorge Cave specimens— resultant from three separate collection events—which are Omorgus lindemannae ; their collecting details are presented above. We hence propose that Braack’s (1989) beetles may rather have been Omorgus lindemannae , or that both Omorgus zumpti and Omorgus lindemannae co-occur in Lanner Gorge Cave. We did not trace any specimens truly being Omorgus zumpti from Lanner Gorge Cave, but that species is present on the Nyandu Sandveld, only some 30 km from the cave ( Scholtz, 1980).

Omorgus zumpti View in CoL and Omorgus lindemannae View in CoL are similar species ( Scholtz, 1980). The Trogidae View in CoL from Lanner Gorge Cave were in the period between August 1983 and March 1988 identified by trogid specialist Clarke H. Scholtz. At that stage, Omorgus lindemannae ( Petrovitz, 1975) View in CoL was known—under the synonymic name Trox (Omorgus) glaber Scholtz, 1980 View in CoL —from only Tanzania. The first record of Omorgus lindemannae View in CoL outside Tanzania, and inside South Africa, was presented by Pittino (2005).

SOUTH AFRICA: LIMPOPO. Braack (1989) surveyed Lanner Gorge Cave, a remote cave in the far north of the Kruger National Park, and described its macro-arthropod fauna. He estimated that more than 2,400 adult individuals of Omorgus zumpti were simultaneously present on the cave floor, mostly in the twilight zone. This beetle species is widespread in southern Africa, but rarely collected ( Scholtz, 1980). Lanner Gorge Cave is inhabited by a large, permanent colony of fruit bats, the entire cave floor being covered with bat guano, in its proximal half more than a metre deep ( Braack, 1989). Despite the abundance of bat guano, Braack (1989) did not report any interaction between the Trogidae and the guano, but rather reported that adult beetles were on several occasions observed feeding on dead bats. He reported this circumstance both in his text and in a schematic representation of trophic interactions in the cave (his Figure 2). We consider it unlikely that the Trogidae would not feed on the abundance of bat excrement, hence we suggest that Omorgus zumpti perhaps indeed is bat-guanophilic, while clearly being a troglophile.