Plesiomorphon Tridentiseta (or Baetis/fg1)

(Panephemeroptera Euephemeroptera Euplectoptera Anteritorna - pm.Tridentiseta)

Nomen hierarchicum: Baetis/fg1 [fg:1815] (incl. Siphlonurus, Dipteromimus, Ameletus, Metretopus, Acanthametropus, Ametropus, Metamonius, Oniscigaster, Ameletopsis, Rallidens).

Nomen circumscribens: Tridentiseta Kluge & Studemann & Landolt & Gonser 1995: 105. 

In circumscription fits:

superfam. Siphlonuroidea: McCafferty 1997: 95

infraordo Pisciforma: Kluge & Studemann & Landolt & Gonser 1995: 105 (non Pisciforma McCafferty 1991a)

grex infraordines Tridentiseta Kluge & Studemann & Landolt & Gonser 1995: 105

Tridentiseta = Baetis/fg1: Kluge 2000: 247

plesiomorphon Tridentiseta = Baetis/fg1: Kluge 2004: 71

References. Kluge & al. 1995: * *; Kluge 1998: *; 2004: * * *.

Plesiomorphies of Tridentiseta. Unlike Bidentiseta, maxilla usually has 3 dentisetae [see Anteritorna (2)] (Kluge 2004: Fig.3:E, 22:D, 25:D, 28:B,D, 31:A,E, 32:E, 36:A). Exceptions are made by Ameletus/fg1 (Kluge 2004: Fig.20:C), Acanthametropus/fg1 (Kluge 2004: Fig.23:B) and some Tetramerotarsata, whose maxillae have less number of dentisetae. Homology of maxillary parts and systematic position of Ameletopsis/fg1 (Kluge 2004: Fig.34:D) are unclear; here we conditionally attribute this taxon to Tridentiseta. In selected individuals seta proximad of 3rd dentiseta has the same shape as 2nd an 3rd dentisetae, so total number of dentisetae looks as increased to 4; sometimes other setae of this (inner-dorsal) row have similar shape (see below, plesiomorphies of Tetramerotarsata).

Size. Fore wing length 224 mm.

Age and distribution. Jurassic (see Anteritorna INCERTAE SEDIS) recent; world-wide.

Status and systematic position of Tridentiseta. Here we unite all Anteritorna not belonging to Bidentiseta, in a taxon Tridentiseta; probably in future paraphyly of Tridentiseta will be clarified and this taxon will be disbanded. Earlier, the groups attributed to Tridentiseta were placed into one of larger paraphyletic taxa Schistonota McCafferty & Edmunds 1979 (uniting Tridentiseta, Branchitergaliae, Pinnatitergaliae and Leptophlebia/fg1) or Costatergalia Kluge 1989 (uniting Tridentiseta and Branchitergaliae). A taxon, which circumscription is close to Tridentiseta, is Pisciforma McCafferty 1991; unlike Tridentiseta, Pisciforma do not include Vetulata, but include Pseudiron, thus being polyphyletic (Kluge 1998).


The taxon Tridentiseta (or Baetis/fg1) is divided into 11 directly subordinate taxa:

(A) Holarctic taxa: 

1. Siphlonurus/fg1

2. Dipteromimus

3. Ameletus/fg1

4. Metretopus/fg1

5. Acanthametropus/fg1 

6. Ametropus

(B) widely distributed taxa:

7. Tetramerotarsata, or Baetis/fg2

8. Nesameletus/f1=Metamonius/g1

(C) Amphinotic taxa: 

9. Vetulata, or Oniscigaster/fg1

10. Ameletopsis/fg1 

11. Rallidens