A new genus and tribal placement for Ceneus speculiferus Fairmaire, 1879, comments on Grundmannius, Mirachlaenius and Stenoodes, and a key to the Oriental and Australasian genera of Chlaeniina

The Fijian endemic species Prosopogmus speculiferus (Fairmaire, 1879) originally described in the tribe Pterostichini Bonelli, 1810 as Ceneus speculiferus, is reviewed. Morphological evidence places the species in the tribe Chlaeniini Brullé, 1834 and a new genus is proposed to accommodate it with the following new combination Lapitachlaenius speculiferus (Fairmaire, 1879) n. comb. A second species endemic to Vanuatu is also assigned to the genus L. specularis (Emden, 1937) n. comb. The new genus is distinguished from all other currently recognized genera of subtribe Chlaeniina Brullé, 1834 by its elytron having a medial, mirror-like area, interval 3 with large, foveate setiferous punctures, and interval 8 interrupted near the level of the elytral plica. Additionally, the pronotum disc has broad and shallow paramedial, parenthesis-like impressions that join the baso-lateral impressions. These autapomorphic morphological features provide evidence that Lapitachlaenius n. gen. is a derived member of the subtribe. Grundmannius Basilewsky, 1965, originally placed in subtribe Callistina Laporte, 1834 and recently included in Lachnophorini LeConte, 1853, is returned to Chlaeniini, and placed in the subtribe Chlaeniina. The first female of the rarely collected Mirachlaenius barbarae Facchini, 2011 was studied and its morphological characters are also presented. The pygidial glands, genital, and reproductive apparatus are described. Mirachlaenius barbarae has a distinct dorsal lobe of pygidial gland reservoir and a reservoir junction channel linking the main reservoir with the efferent duct. This pygidial gland configuration is unlike any previously reported for Chlaeniini. The genus Stenoodes Basilewsky, 1953 was recently moved to Chlaeniini, though its original placement was in the tribe Oodini La Ferté-Sénectère, 1851. The original placement is restored based on the modifications of elytral intervals 8 and 9 – present in Stenoodes and other oodines but absent in chlaeniines. A key to Oriental and Australasian genera of Chlaeniina is provided.