Sinodrepanus tsaii Masumoto, Yang & Ochi, 2004

Montanaro, Giulio, 2024, New or poorly known species of Sinodrepanus Simonis, 1985 (Coleoptera: Scarabaeidae: Oniticellini), with the first identification key for the genus, Zootaxa 5537 (4), pp. 577-595 : 589-590

Sinodrepanus tsaii Masumoto, Yang & Ochi, 2004

Sinodrepanus tsaii : Masumoto, Yang & Ochi, 2004: 360 (original description); Roggero et al., 2015: 154, 156, 159

Type locality: Huanshan , Taiwan .

Type material examined. None.

Additional material examined (2♂♂). Taiwan: Taoyuan City, Fuxing, Northern Cross-Island Highway , Flight Interception Trap, 3.vii–9.vii.2018, Y.H. Ho & Y.C. Huang legit [ GMOC] .

Diagnosis. Masumoto et al. (2004) separated S. tsaii from the closely allied S. besucheti using four characters: i) the clypeus noticeably bidentate and reflexed in front (feebly bidentate in S. besucheti ); ii) the genae more strongly produced laterally; iii) the pronotum more widely produced postero-laterally; and iv) the differently shaped genitalia. I was able to examine two non-type males of S. tsaii from Taiwan and compare them with several males of S. besucheti (see Table 1). The only significant differences I could identify are in the shape of the clypeus of major males and in the pronotal shape, although the latter is rather feeble. Importantly, I could not spot any difference in male genitalia, both in the shape of aedeagus and lamella copulatrix. These structures are very important for species diagnosis, since they usually differ also between externally very similar taxa. These observations cast some doubt on the validity of S. tsaii as a full species. This taxon may rather be considered a diverging island population or a subspecies of S. besucheti , which is widespread in China. However, given the limited number of specimens I was able to study, I refrain for the moment from any formal taxonomic proposal.

Distribution. The species appears to be endemic to Taiwan ( Masumoto et al. 2004).