Thienemann, 1926
Body
Small to medium sized larvae up to 7 mm long. Living larvae may be blue to purple. The anterior parapods are separate. The two posterior parapods bear rows of claws. The setae on the abdomen are simpel and shorter than half the length of the segment. Procercus and two pairs of anal tubules present (Wiederholm, 1983; Moller Pillot, 1984b).
Head
Antenna
The antenna consists of four or five segments Euk claripennis antenna. Segment 4 may be longer or subequal to segment 3. The blade is shorter than the flagellum. Lauterborn organs are present.
Mentum
The mentum has one Euk brevicalcar mentum or two median teeth Euk claripennis mentum and 5 pairs of lateral teeth (rarely 4 or 6 pairs). The ventromental plates are weak. The beard is absent.
Labrum
The pecten epipharyngis consists of three scales, SI is usually simpel, sometimes bifid or branched and the premandible has one apical tooth (Wiederholm, 1983; Moller Pillot, 1984b).
Mandible
The mandible has an apical tooth and 3-4 inner teeth. The seta interna has simpel, serrate of plumose branches. The mola with 1 - 5 spines Tvet calvescens mandible (Wiederholm, 1983).
Differential characteristics
The combination of a mentum with 5 pairs of lateral teeth, weak ventromental plates, mandible with 3-4 inner teeth and spines on the mola, simpel SI and procercus present separate Eukiefferiella from all other Orthocladiinae except Tvetenia. Eukiefferiella differs from Tvetenia in having inconspicuous body setae while they are very distinct in Tvetenia Tvet discoloripes body setae.
Diversity
European species: 21
Treated taxa:
Species-group Eukiefferiella gr. fittkaui
Eukiefferiella brevicalcar
Eukiefferiella claripennis
Eukiefferiella clypeata
Eukiefferiella gracei
Eukiefferiella ilkleyensis