Isacanthon, Pacheco & Vaz-de-Mello, 2019

Pacheco, T. L. & Vaz-de-Mello, F. Z., 2019, New dung beetle genus and species from a cave in the Espinhaço mountain rangeı Brazil (Coleoptera: Scarabaeidae: Scarabaeinae), Journal of Natural History 53 (19), pp. 1247-1253 : 1248-1249

Isacanthon Pacheco and Vaz-de-Mello gen. Nov.

Diagnosis

Body very flattened, surface with microsculpture between ocellate punctuation, punctures with setae, clypeus with two teeth appearing to originate beneath clypeal margin, eyes slightly visible in dorsal view, elytra with eight striae, pseudoepipleuron large and with one stria, mesoventrite short, carina between mesoventrite and metaventrite almost straight, prolegs with anterior trochantofemoral pit, protibiae with three distinct teeth on external margin, metatibiae with one distinct tooth at its basal two-fifth, and aedeagus with asymmetrical parameres.

To exclude the possibility that this genus can be confused with Paracanthon see the following characters: clypeus with two teeth appearing to originate beneath clypeal margin ( Isacanthon ) or originating from leading margin of clypeus ( Paracanthon ), hypomeron with ( Paracanthon ) or without ( Isacanthon ) carina parallel to the margin of the dorsal surface of pronotum, and by presence ( Isacanthon ) or absence ( Paracanthon ) of the unique armature of metatibiae. From Paracryptocanthon is distinguished by clypeus with two teeth ( Isacanthon ) instead of six ( Paracryptocanthon ), pygidium in vertical ( Isacanthon ) or horizontal ( Paracryptocanthon ) position, eyes entirely visible ( Isacanthon ) or not ( Paracryptocanthon ) dorsally, and the presence ( Isacanthon ) or absence ( Paracryptocanthon ) of the spur on metatibiae. The entirely visible eyes ( Isacanthon ) or not ( Cryptocanthon ) in dorsal view, parameres asymmetrical ( Isacanthon ) or not ( Cryptocanthon ), and much larger size separate it from Cryptocanthon . Finally, the presence of just one stria ( Isacanthon ) instead three ( Tesserodoniella ) on pseudoepipleuron, together with all previously mentioned characters under previous diagnoses, differentiate the new taxon from Tesserodoniella .

As only one species is known so far, the description of the new genus and the new species shall be seen as equivalent.

Etymology

The prefix Isa is named after Isac da Silva Lara, grandfather of the first author. Canthon Hoffmannsegg, 1817 is a large New World genus of Scarabaeinae, with several (not necessarily phylogenetically related) derivatives, all lacking expanded meso- and metatibiae.

Type species

Isacanthon mariaelinae Pacheco and Vaz-de-Mello sp. nov., here designated.

This genus can be separated from other Neotropical genera by modifying couplet 34 of Vaz-de-Mello et al. (2011) key as follows:

34 (33) Length of metatarsomere 1 greater than combined length of metatarsomeres 2–3 .... ............................................................................................................................................... 34A

– Length of metatarsomere 1 shorter than combined length of metatarsomeres 2–3 ... ................................................................................................................................................... 35

34A (34) Clypeal teeth appearing to originate on clypeal margin. Hypomeron with posterior carina parallel to edge. If elytra with ocellate puncture, without microsculpture between punctuation. Metatibiae without distinct tooth at their two-fifth. Widely distributed across the Atlantic Forest in Brazil and Argentina.. ....................... ........................................................................................................................................... Paracanthon

– Clypeal teeth appearing to originate beneath clypeal margin. Hypomeron without posterior carina parallel to edge ( Figure 1 (a)). Elytra with ocellate puncture, with microsculpture between punctuation. Metatibiae with distinct tooth at their twofifth ( Figure 1 (b)). Know only from one place in the Espinhaço mountain range, southeastern Brazil.. ..................................... .................................... Isacanthon new genus

Figures

Figure 1. Isacanthon mariaelinae sp. nov. (a) Lateral view. (b) Dorsal view. (c) Right view of the aedeagus. (d) Left view of the aedeagus. Scar bars: (a,b) 500 mm; (c,d) 500 μm.