Protohemiphlebiidae fam. nov., a stem hemiphlebioid damselfly from Cretaceous amber in Kachin

Hemiphlebiidae are the most basal lestomorphan family following the latest phylogenetic analysis of the Zygoptera: this unique damselfly family today contains one relict species found in the wetlands of Australia. It was, however, very diverse and widespread during the Mesozoic. Nevertheless, very few species were known, obscuring the origination and early evolution of the family. Here we propose a new stem hemiphlebioid taxon (Protohemiphlebiidae Zheng, Jarzembowski and Nel, fam. nov.) based on a new genus and two species: Protohemiphlebia zhangi Zheng, Jarzembowski and Nel, sp. nov. and Protohemiphlebia meiyingae Zheng, Jarzembowski and Nel, sp. nov. The new family shares the characteristics of both Hemiphlebiidae and Coenagrionoidea, but it is more closely related to Hemiphlebiidae in having the pterostigma with a 'star-shaped' microsculpture and AA originating from the wing base slightly distal of Ax0. Protohemiphlebia Zheng, Jarzembowski and Nel, gen. nov. is further considered to belong to the stem group of Hemiphlebioidea, instead of belonging to the Hemiphlebiidae, in possessing pretibial combs and a weakly kinked RP1 below the Pt brace. The new damselflies will help to calibrate the origin of Hemiphlebiidae, which could be earlier than the current oldest records in the Kimmeridgean (Late Jurassic).