Neostempellina Reiss

Description

Introduction

Small larvae, 3-4 mm long.

Dorsal Head

Dorsal surface of head finely or coarsely granulated. S3 simple or bifid.

Antenna

Antenna 5 segmented, on tall pedestal with pronounced distal spur and accessory multispined process; basal segment equal to, shorter or slightly longer than flagellum; segment 2 equally long or slightly longer than segment 3, somewhat wedge-shaped, with apical style and pair of large, opposite Lauterborn organs. Ring organ and weak seta placed proximally on basal segment. Blade arising distally on basal segment, extending to or beyond antennal apex. Lauterborn organs placed apically on segment 2 on moderately long pedicels, not reaching the apex of the antenna.

Labrum

S I comb-like, bases fused; S II plumose, situated on tall pedestal; S III simple, seta-like; S IV present. Labral lamella well developed. Pecten epipharyngis 3 separate, distally serrated scales. Premandible bifid; brush well developed.

Mandible

Dorsal tooth pale; apical and 2 inner teeth brownish. Seta subdentalis long, curved, extending beyond dorsal tooth. Seta interna consisting of 4 strongly plumose branches. Pecten mandibularis with well several developed lamellae, partly extending past median margin of mandible.

Mentum

Median tooth pale, rounded; 6 pairs of lateral teeth present, more or less of same size or third and forth laterals slightly larger. First pair more or less fused with median tooth. Ventromental plates fanshaped, separated medially by width of 3-4 mental teeth, about as wide as mentum or more narrow. Seta submenti simple.

Body

Posterior parapods with simple claws only. Procercus strongly sclerotized with several spines and projections in addition to anal setae.

Notes

Taxonomic Notes

Neostempellina larvae can easily be separated from all other chironomids by the combination of spur and multispined process on the antennal pedestal. The larva of Neostempellina thienemanni (the type species) was described originally as belonging to Stempellinella montivaga (Thienemann), but this was based on an erroneous association (Reiss, 1984). Larvae belonging to N. reissi have the pecten epipharyngis comprising three apically serrated scales.

Ecological Notes

Four species are known from the Holarctic and one is described from the Afrotropical region (Ekrem and Reiss, 1999). All known larva construct transportable cases which are strongly curved and with a exterior smooth surface. The anterior case opening is approximately twice the size of the posterior opening.

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