New and notable records of flatheaded mayfly species (Ephemeroptera: Heptageniidae) from Texas, USA

Data from recent collections of Ephemeroptera from Texas reported here include new state records of the Heptageniidae species Heptagenia elegantula (Chihuahuan Province), H. diabasia (Kansan Province), Leucrocuta aphrodite (Balconian and Texan Provinces), and Rhithrogena plana (Chihuahuan Province). Other Texas species reported from particular biotic provinces in Texas for the first time include Maccaffertium terminatum (Tamaulipan Province), Stenacron interpunctatum (Austroriparian and Kansan Provinces), and Stenonema femoratum (Balconian Province). The 13 known species of Texas Heptageniidae have primarily eastern and midwesten North American faunal affinities; however, the new records of H. elegantula and R. plana involve the first Texan heptageniids with western North American affinities.