(Panephemeroptera Euephemeroptera Euplectoptera Anteritorna Bidentiseta Branchitergaliae
Heptagennota Pentamerotarsata Radulapalpata 

Nomen hierarchicum: Heptagenia/f6=g5 [f:1901; g:1863] (sine Ecdyonurus; incl. Kageronia)

In circumscription fits:

 gen. Heptagenia: Kluge 1983b: 16 (unpublished); 1988: 292;

 grex genn. Heptagenia: Tomka 1991: 121;

 Heptagenia/f6=g5: Kluge 2004: 168.

References. Kluge 1986: *; 1987a: * *; 1988: * *; Tomka 1991: *; Kluge 1993: * *; 2004: * * * *.

Characters of Heptagenia/f6=g5 of unclear phylogenetic status. 

(1) Mandibles [usually with left setiform prostheca and irregular setation on median margin see Heptagennota (7)] have uniform shape of incisors in majority of representatives: incisor of each mandible is thin, its apex bears 3 denticles more or less brought together, and inner side bears a row of smaller denticles (Kluge 2004: Fig.54:E-F). Only in rare cases, when incisor is thickened (particularly, in Dacnogenia) it has another form.

(2) On maxilla ventral row of setae [see Branchitergaliae (1)] is parallel to inner margin and apically is slightly curved laterally (Kluge 2004: Fig.55:H) (unlike Cinygma, Paegniodes, Epeorus/fg1, where this row is not curved; unlike Rhithrogena/fg2, where it is curved stronger; unlike Ecdyonurus/fg1, where this row is transformed to a field of irregular setae).

(3) Vestige of 3rd segment of maxillary palp (see Plesiomorphies of Heptagenia/f5=g4) is small, usually curved (Kluge 2004: Fig.55:H) (unlike Ecdyonurus/fg1, where this vestige is larger, and unlike other Radulapalpata, where it is not expressed).

(4) Imaginal prosternum has characteristic shape: it always has a distinct transverse ridge, and surface behind this ridge is concave (Kluge 2004: Fig.56:A-B). Among Heptagennota examined, similar shape of prosternum occurs only in Pseudiron, Bleptus and selected Ecdyonurus/fg1; in other Heptagennota there prosternum is entirely convex, without transverse ridge.

Plesiomorphies of Heptagenia/f6=g5. Larval femora [flattened see Heptagennota (1)] have no regular row of long stout setae on outer margin: stout setae (long clavate or short spine-like) are situated on outer margin of femur irregularly (Kluge 2004: Fig.54:H, 55:B-C). Imaginal and subimaginal median impression of mesothoracic furcasternum is strongly narrowed anteriorly, metathoracic nerve ganglion is situated in its posterior part (Kluge 2004: Fig.56:C-D) (unlike Ecdyonurus/fg1). Median titillators of penis [see Pentamerotarsata (5)] are always well-developed.

Size. Fore wing length 616 mm.

Age and distribution: Palaeogene (see Kageronia) recent; Holarctic, Oriental Region and Central America; dominate in Holarctic. 

The taxon Heptagenia/f6=g5 is divided into:

1. Kageronia

2. Heptagenia/f7=g6
2.1. Heptagenia/f8=g7

2.2. Dacnogenia/g(1)

2.3. Stenonema/fg1