(Panephemeroptera Euephemeroptera Euplectoptera Anteritorna Bidentiseta Furcatergaliae  
Fimbriatotergaliae Caenotergaliae Caenoptera Caenis/f3=g1
MadecocercusCaenis/f4=g2TillyardocercusCaenis/f5=g3 - Clypeocaenis/fg1)

Nomen hierarchicum: Clypeocaenis/fg1 [f:2013; g:1978] (incl. Amercaenis

In circumscription fits:

 Clypeocaenis/g1: Kluge 2004: 289

References. Provonsha & McCafferty 1985: *; Kluge 2004: * *

Autapomorphies of Clypeocaenis/fg1.

(1) Larval fore legs and mouthparts are specialized as filtering (Soldan 1978: Fig.28; Provonsha & McCafferty 1985: Fig.16; 1995: Fig.35): Tibia and tarsus with long setae on inner and sometimes on dorsal side (non-unique apomorphy see Index of characters [1.2.32]). Maxilla with apical field of long dense setae; canines [initially three see Plesiomorphies of Caenotergaliae] are slender and more or less fused together; dentisetae [two see Bidentiseta (1)] are weak and indistinguishable among setae. 3rd segment of maxillary palp has numerous long setae [and can be fused with 2nd segment see Clypeocaenis/fg2 (1) below]. Labial palp has 2nd segment shortened and 3rd segment elongate, with numerous long setae (in Amercaenis and Clypeocaenis/g3 the 2nd segment is several times shorter than 3rd, only in Barnardara they are subequal).

(2) Y-shaped rib of gill operculum is modified: median rib [which stretches longitudinally from antero-median angle to posterior margin see Caenotergaliae (1) and Caenoptera (18)] is more or less expanded in median direction; it can be slightly expanded (Kluge 2004: Fig.88:JK), or forms a wide plate reaching median margin (Soldan 1978a: Fig.13).

(3) Plumose microtrichia on ventral side of gill operculum [see Caenis/f3=g1 (1)] are more or less reduced and directed not strictly perpendicular to margin, but obliquely (somewhat similar to Brachycercus/f1=g3); in ridens [Caenis] a regular row of multipointed microtrichia is retained, while oligosetosa [Clypeocaenis] has irregular stripe of very small, mainly bipointed microtrichia (other species have not been examined).

Size. Fore wing length 25 mm.

Distribution. Possibly, Arctogea (Holarctic, Oriental and Afrotropical Regions).

The taxon Clypeocaenis/fg1 is divided into:

1. plesiomorphon Amercaenis

2. Clypeocaenis/fg2
2.1. plesiomorphon Barnardara

2.2. Clypeocaenis/fg3