Thienemann, 1936
Body
Small larvae up to 5 mm long. Living larvae may be greenish. The anterior and posterior parapods are separate and bear rows of claws. Procercus and two pairs of anal tubules present (Wiederholm, 1983; Moller Pillot, 1984b).
Head
The head length is 0.27-0.34 mm in Dutch species (Moller Pillot, 1984b). The 3 eyes are fused but discernable Parak gr bathophila head 8.
Antenna
The antenna consists of five segments. The blade is shorter than the flagellum. Lauterborn organs are weak or absent.
Mentum
The mentum has one median tooth Parak gr bathophila mentum (P. gracillima 2) and 6 pairs of lateral teeth (P. gracillima 5). The first pairs of laterals is yellow (in P. bathophyla) and stand very close to the median tooth. The ventromental plates are distinct but do not cover lateral teeth. The beard is absent. In very worn specimens the first lateral teeth may be absent Parak gr. bath mentum worn.
Labrum
The pecten epipharyngis consists of three subequal scales. SI is branched or palmate, weak labral lamellae may be present. The premandible has one or two apical teeth and a broad basal tooth (Wiederholm, 1983; Moller Pillot, 1984b).
Mandible
The mandible has an apical tooth and 3 inner teeth. The seta interna has simpel branches (Wiederholm, 1983).
Differential characteristics
The branched or palmate SI and the mentum with 6 pairs of lateral teeth, without beard Parak gr bathophila mentum separate Parakiefferiella from all other Orthocladiinae.
Diversity
European species: 6 or 7
Treated species:
Parakiefferiella bathophila
Parakiefferiella cf. coronata
Parakiefferiella cf. gracillima