Namtokocoris Sites, a new genus of Naucoridae (Hemiptera: Heteroptera) in waterfalls of Indochina, with descriptions of six new species

Abstract

A new genus with six new species of Naucoridae inhabiting waterfalls of Indochina are described from a decade of aquatic insect collections in Thailand and Vietnam. Namtokocoris Sites NEW GENUS is diagnosed by a pair of prominent scutellar protuberances, the prosternal midline bears an expansive, thin, plate-like carina, the forelegs of both sexes have a one-segmented tarsus apparently fused with the tibia, and a single claw. Prominent linear series of stout hairs occur on the hemelytra, although this attribute is not unique within the subfamily. Despite the lack of sexual dimorphism in the forelegs, this new genus is a member of the subfamily Laccocorinae, an assignment based on other characters consistent with this subfamily. Character states of this genus are compared with those of other Asian genera of Laccocorinae. The type species, Namtokocoris siamensis Sites NEW SPECIES, is widely distributed from northern through eastern Thailand in waterfalls of several mountain ranges. Namtokocoris khlonglan Sites NEW SPECIES was collected only at Namtok Khlong Lan at Khlong Lan National Park. Namtokocoris minor Sites NEW SPECIES was collected at two waterfalls near the border with Burma in Kanchanaburi Province and is the smallest species known. Namtokocoris akekawati Sites NEW SPECIES occurs in waterfalls from Kanchanaburi Province south to Ranong Province along the Burmese border. In Vietnam, Namtokocoris dalanta Sites NEW SPECIES was collected in Thac Dalanta near Da Lat in Lam Dong Province. Namtokocoris kem Sites NEW SPECIES was collected from Thac Kem, a limestone waterfall in Pu Mat National Park in Nghe An Province, as well as in Nan Province of northern Thailand. Few characters are available to distinguish among the species; however, genitalic features are reliably diagnostic.