Taxonomic notes on the rare ant genus Chrysapace with description of a new species from Brunei (Hymenoptera: Formicidae: Dorylinae)

Abstract: The genus Chrysapace Crawley, 1924 is one of the rarest and poorly known lineages in the ant subfamily Dorylinae, currently composed of only three extant valid species from the Oriental Realm. There is some taxonomic obscurity concerning the distinction between two of the three valid species, C. sauteri (Forel, 1913) and C. costatus (Bharti & Wachkoo, 2013), resulting from previous unavailability of C. sauteri type material and inconsistency in descriptions provided in previous literature. In the present study, we examined the C. sauteri syntype and the C. costatus holotype as well as newly collected material and vouchers used in previous literature. Although both of the species agreed well with each other in most morphological characters of the worker, we tentatively retain the separation of these species based on differences in the head sculpture, eye and ocelli sizes. The worker, queen, and male of C. sauteri, and the worker of C. costatus are here redescribed with the first provision of COI DNA barcode data. In addition, C. merimbunensis Yamada & Eguchi sp. nov. is described from Brunei based on workers and males from a single colony. A key to valid Chrysapace species is also provided.

Key words: Hymenoptera, Formicidae, Chrysapace costatus, Chrysapace merimbunensis, Chrysapace sauteri, male genitalia, Brunei, Oriental Realm