Thienemanniola Kieffer

Description

Introduction

Small larva, up to about 5 mm long. Head capsule brown, abdomen whitish.

Dorsal Head

Dorsal surface of head with fine granulation on clypeus and numerous wart-like processes on posterior 1/3. S3 simple on small tubercle.

Antenna

Antenna 5 segmented; mounted on prominent pedestal with strong, triangular spur distally; basal segment about as long as flagellum, with proximal ring organ and strong seta; distally with long blade extending to or slightly beyond antennal apex; segment 2 somewhat wedge-shaped, shorter than segment 3, bearing style and pair of sessile Lauterborn organs distally.

Labrum

S I plumose, not comb-like, bases fused; S II long, blade-like, simple, situated on long pedestal; S III simple, setalike; S IV present. Labral lamella well developed. Pecten epipharyngis overlain by epipharyngeal chaetulae. Premandible deeply bifid distally, with additional rounded tooth on inner side and well developed brush.

Mandible

Dorsal tooth, apical tooth and 2 inner teeth present, all brown. Seta subdentalis very long, slender. Seta interna consisting of 3 plumose branches. Pecten mandibularis with 8–10 strong lamellae.

Mentum

Median tooth trifid, central part broadly rounded, outer parts lower and very narrow; with 5 pairs of lateral teeth, varying slightly in size, arranged somewhat obliquely so that anterior margin of mentum is weakly concave. Ventromental plates pointed internally, widely separated, only about 3/4 width of mentum.

Body

Posterior parapods reduced, with about 10 simple hooks. Procercus unusually well developed, backwardly directed and with tuft of very strong apical setae, some distally divided. Anal tubules reduced.

Notes

Taxonomic Notes

Thienemanniola is very distinctive, coming closest in its morphology to Stempellina. However the characteristically shaped mentum, unusually well developed procerci and reduced posterior parapods together serve to distinguish the larvae from all other Chironominae.

Ecological Notes

Thienemanniola is confined to standing waters, including lakes and carp ponds.

Thienemanniola is monotypic, with T. ploenensis Kieffer recorded from several countries in central Europe.

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