Females, however, cannot currently be identified to species with any reliability. Male adults of the North American species can generally be identified using keys provided by Traver ( 1935) and Burks ( 1953), using a combination of color patterns and genitalic morphology. Similar species groups have been proposed for the Palearctic species ( Kluge 1987). solitaria (McDunnough) (e.g., Traver 1935). diabasia Burks and apulla group that includes H. patoka Burks an elegantula group that includes H. Nonetheless, based on characters of the genitalia the species have been divided into a flavescens group that includes H. No analytical hypothesis of the relationships among the North American species of Heptagenia has been proposed. In North America, 12 species have been recently recognized, although some of these may prove to be synonymous. Species reported as Heptagenia from Southeast Asia are actually members of other genera ( Wang and McCafferty 2004, Webb et al. Mayflies of the genus Heptagenia Walsh (Heptageniidae: Heptageniinae) are distributed throughout the Holarctic biogeographic realm. diabasia is placed as a junior subjective synonym of H. elegantula (Eaton) differed from each other by only 1.1% these two alleged species show a clinal pattern in larval abdominal coloration and there are no structural differences between the semaphorants. Interspecific sequence divergence based on K2P distance ranged from 8.9–20.0%. Intraspecific sequence divergences based on Kimura-2-parameter (K2P) distance ranged from 0–1.1%. was compared with those of 12 specimens representing eight other North American species of Heptagenia. A 630 bp partial sequence of the mitochondrial gene cytochrome oxidase 1 (COI) from three specimens of H.
Larvae are differentiated from other North American Heptagenia Walsh by a pair of large, rectangular pale markings on abdominal tergum 4, and the combination of having the posterior margin of the abdominal terga with bluntly pointed spines less than half the length of the fine setae, small blunt spines on the posterior margin of the caudal filaments, and numerous rows of setae laterally on the ventral surface of the labrum. is described from larvae, a male subimago, a female adult, and eggs collected from large rivers in the west-central portion of North America. A new mayfly species, Heptagenia whitingi Webb & McCafferty n.sp.
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