Mayfly Species Epeorus punctatus

Source: Contribution to the taxonomy of Eastern North American Epeorus Eaton (Ephemeroptera: Heptageniidae)

Diagnosis: Larvae of Epeorus punctatus are differentiated from those of all other North American Epeorus species by the following combination of characters: the lamellae of the first pair of gills are not enlarged anteriorly; the apex of the hind femur has a bluntly pointed projection; the setae of the subdorsal row on each femur are simple; and the dorsal and ventral posterolateral spines of the abdomen are subequal in length. Epeorus punctatus appears to be most similar to Epeorus subpallidus. Male adults of Epeorus punctatus are most reliably differentiated from those of Epeorus subpallidus by the absence of lateral spines on the penes. Additionally, the abdominal terga of Epeorus subpallidus are darkened only medially on the posterior margin and there are not any dark markings laterally; in Epeorus punctatus there is a dark line along the entire posterior margin of each abdominal tergum that broadens laterally and there are also small, dark lateral maculae. The thorax of Epeorus subpallidus is a pale yellowish brown whereas that of Epeorus punctatus is a dark chestnut brown. Larvae of Epeorus punctatus are smaller in size than those of Epeorus subpallidus; the femoral flanges of the former are bluntly pointed rather than sharply pointed; and the pair of small pronotal protuberances of Epeorus subpallidus are absent in Epeorus punctatus.