Neoennearthron mindanaonus Souza-Gonçalves & Lopes-Andrade 2024, comb. nov.

Neoennearthron mindanaonus (Chûjô, 1966) comb. nov. Fig. 2A–D Octotemnus mindanaonus Chûjô, 1966: 530 (original description). Comments. From the island of Mindanao, Philippines. It was originally described as possessing eight antennomeres. However, the holotype has nine antennomeres (Fig. 2B). Species of Octotemnus Mellié, 1847 all have eight antennomeres, short prosternum with incomplete, acute prosternal process, subconical procoxae projected beyond the level of the prosternum, and all tibiae with a row of spines from the apical edge to at least the apical one-third of the outer edge (Kawanabe 1993, 2002; Lawrence 2016), characteristics not observed in this species. The holotype fits well within the limits of the genus Neoennearthron Miyatake, 1954 in the possession of 9-segmented antennae, serrate outer protibial edge with a single tooth at the apex, short, biconcave prosternum with strongly curved prosternal process (which is narrow, but not laminate), vestiture of very short, fine hairs, dual, confuse elytral punctation, relatively simple, non-spinose meso- and metatibial apices, and produced and narrowly rounded anterior pronotal angles (Kawanabe 1994; Lawrence 2016). The specimen seems to be a female due to the lack of anterior pronotal projections and a sex patch at the first abdominal ventrite, and it is similar to females of other Neoennearthron species. Neoennearthron sakaii Kawanabe, 1994 was also described from the Philippines but from Luzon island. Interestingly, a diagnostic feature of N. sakaii is the presence of microscopic radial incisions surrounding each pronotal puncture, which can be seen in the holotype of N. mindanaonus. Neoennearthron sakaii may be a synonym of N. mindanaonus, and it would be important to compare males and females of Neoennearthron from the Mindanao and Luzon islands to evaluate this possibility. Besides Neo. mindanaonus and Neo. sakaii, the genus includes three other described species: Neo. bicarinatum Miyatake, 1954, Neo. hisamatsui Miyatake, 1959 and Neo. meridionale Lawrence, 2016. The genus Neoennearthron occurs in the Australian region, Chinese transition zone, and Indo-Malayan transition zone.