Enigmocarnus chloropiformis gen. et sp. nov., and parallel evolution of protandrial symmetry in Carnidae (Diptera)

Enigmocarnus chloropiformis Buck gen. et sp. nov. is described on the basis of a single male from east central Texas. The phylogeny of Carnidae is analyzed based on a matrix of 25 morphological characters, and a key to the World genera of Carnidae is presented. The new genus is characterized by a reduced head chaetotaxy (bristles short and mostly pale), notable gray pruinosity of the body, and a unique configuration of pregenital sclerites (the protandrium), which precludes placement of this species in any previously described genus of Carnidae. Enigmocarnus possesses a nearly symmetrical protandrium like Carnus and Meoneura, but the position of sternite 7 indicates that symmetry evolved independently and on a different path. The protandrial peculiarities exhibited by Enigmocarnus are discussed in the framework of Carnoidea relationships.