(Panephemeroptera Euephemeroptera Euplectoptera Posteritorna - Baetisca/f2=g1)

Nomen hierarchicum: Baetisca/f2=g1 [f:1900; g:1862] (sine Prosopistoma; incl. Balticobaetisca).

In circumscription fits:

fam. Baetiscidae: Staniczek & Bechly 2002: 7

Baetisca/f2=g1: Kluge 2004: 68

References. Staniczek & Bechly 2002: *; Kluge 2004: * * *.

Autapomorphies of Baetisca/f2=g1.

(1) Prosternum has a bispinate projection between leg bases; this projection is prominent in imago and subimago (Staniczek & Bechly 2002: Fig.8), but indistinct in larva.

(2) Hind wing is nearly round (Kluge 2004: Fig.17:C)

(3) Imaginal and subimaginal paracercus is vestigial, non-segmented (Pescador & Peters 1974: Fig.24D; Staniczek & Bechly 2002: Fig.10). Non-unique apomorphy (see Index of characters [2.3.22]). 

Plesiomorphies of Baetisca/f2=g1 (unlike Prosopistoma/f1=g2).

In larva (known for Baetisca/f3=g2 only): Mouth apparatus is non-specialized: labrum is not widened; mandible has normal form, with mola and prostheca; superlinguae are present; maxilla [see Posteritorna (7)] has 3 canines and 6-8 dentisetae (Kluge 2004: Fig.17:G-H) (number of dentisetae varies individually); anterior-lateral lobes of submentum [see Posteritorna (7)] are not large, situated dorsad of the rest part of labium and do not cover it; glossae and paraglossae are separated one from another (Eaton 1883-1888: Pl.52:5-10; Pescador & Berner 1981: Fig.5a-f)

In imago and subimago: Fore wing has complete venation, including all branches and intercalaries of RS (with RSa2 arising from RSa), symmetrical bifurcation of MA near middle of wing with intercalary iMA, crossveins and intercalaries; hind wing with bifurcation of MP near middle of wing and with crossveins; costal projection is situated at a distance from base (Kluge 2004: Fig.17:B-C). Legs are functional; tarsus is 5-segmented, 1st tarsal segment is fused with tibia, longer than 2nd; claws are ephemeropteroid [except for male fore legs - see Baetisca/f3=g2 (5) below]. Moult to subimago takes place in both sexes. At least in Baetisca/f3=g2 eyes of male are large, indistinctly separated to two portions; mesonotal suture is distinct, transverse, stretches backward medially (Kluge 2004: Fig.17:D-E)

Size. Fore wing length 616 mm. 

Age and distribution. Palaeogene (see Balticobaetisca) recent. Recently in Nearctic only (see Baetisca/f3=g2).

The taxon Baetisca/f2=g1 is divided into:

1. extinct plesiomorphon Balticobaetisca

2. Recent taxon Baetisca/f3=g2

2.1. Fascioculus 

2.2. Baetisca/f4=g3