Georthocladius Strenzke



Medium-sized larvae, up to 9 mm long.


Antenna about 1/2 the mandible length; 5 segmented; segments 4 and 5 longer than segment 3. Blade extending well beyond terminal antennal segments. Lauterborn organs absent. Style well developed and bulbous.


Labrum with SI weakly serrate; SII long and broad; SIII simple and fine; SIV well developed. Labral lamellae simple, rounded, and weakly sclerotized. A pair of spines present in center of labral margin, at least in Georthocladius s.str., situated above middle of 3 subequal scales of pecten epipharyngis. Premandible with 1 apical tooth and broad inner tootn; brush absent.


Apical tooth shorter than combined width of 2 or 3 (in G. (Atelopodella) Sæther) inner teeth; apical part of mola often strongly sclerotized and giving the impression of an additional tooth. Seta subdentalis broad or normal (in G. (Atelopodella)). Seta interna with 6-7 mostly plumose branches.


Mentum with 1 domed median and 4 pairs of lateral teeth present; with outermost tooth more or less bifid or notched or with divided median tooth and 5 pairs of lateral teeth (or 4 teeth with outermost strongly bifid in G. (Atelopodella). Ventromental plates weak, not extending beyond outermost lateral teeth; beard absent.


Maxilla with tetrahedral lamella of palpiger developed as 4 or 5 spines. Galear lamellae small and triangular. Most lacinial chaetae weakly serrate. Appendix seta absent.


Body with anterior parapods divided and bearing claws. Posterior parapods absent in G. (Atelopodella); slender, digitiform, with small but distinct claws or claws vestigial with 1 strong, 0-1 medium, and 0-3 weaker anal setae; procercus absent. G. (Atelopodella) with procercus consisting of 2 nearly contiguous low plates with 2-3 hair-like setae probably representing lateral setae of procercus and not anal setae. Anal tubules very long, 2 to 4 times as long as the posterior parapods, with numerous annulations.


Ecological Notes

Larval Georthocladius are terrestrial (as the name derives) and semiterrestrial in seepages, Sphagnum, water-logged peats and leaf litter. One undescribed Nearctic species is lotic. The larval diagnosis is based on one species only.

The genus is Palaearctic (G. luteicornis) and several species are described from North America. The western European species may be parthenogenetic.

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