Neozavrelia Goetghebuer in Goetghebuer & Thienemann

Description

Introduction

Small larvae, up to 4 mm long.

Antenna

Antenna 5 segmented; placed on low pedestal without apical projection; basal segment about as long as flagellum, with proximal ring organ and seta about 1/2 way along. Segment 2 slightly wedge-shaped, about as long as segment 3, sometimes not sclerotized distally, bearing style and opposite Lauterborn organs. Blade arising from tip of basal segment. Lauterborn organs medium to large, placed on broad pedicels which may extend beyond antennal apex, usually somewhat shorter.

Labrum

SI comb-like, short compared with those of most Tanytarsini, bases fused; SII plumose, situated on tall pedestal; SIII small, sim ple; SIV present. Labral lamella well developed. Pecten epipharyngis consisting of 3 distally toothed plates. Premandible distally bifid, with additional pale slender tooth laterally and well developed brush.

Mandible

Dorsal tooth brown or yellowish; apical tooth and 2 inner teeth similar in colour. Seta subdentalis long, slender. Seta interna with 4 plumose branches. Pecten mandibularis well developed, with many long lamellae.

Mentum

Median tooth rounded or weakly crenate; with 4 or 5 pairs of lateral teeth, regularly decreasing in size laterally; fifth pair of lateral teeth modestly protruding to very small. Ventromental plates very close together medially, about 1.2x width of mentum.

Body

Claws of posterior parapods all more or less simple hooks.

Notes

Taxonomic Notes

Larvae of Neozavrelia superficially resemble those of Cladotanytarsus in several respects, notably the shape of antennal segment 2. They may easily be distinguished, however, by the longer pedicels of the Lauterborn organs, bifid mandible and absence of fine serrations on inner margin of the claws of the posterior parapod. Three of the European species described as larvae. Neozavrelia bernensis has large Lauterborn organs on pedicels which do not reach the antennal apex, whereas N. fuldensis and N. luteola, have smaller Lauterborn organs with pedicels extending well beyond antennal apex (Thienemann 1942a, Fittkau 1954b, Reiss 1968a). An undescribed larva with very small fifth lateral teeth is known from southern Germany.

Ecological Notes

The larvae of Neozavrelia are said to be cold stenothermic, in Europe principally occurring in limestone rich waters in mountainous regions but also known from River Fulda in central Germany and from chalk-streams in s. England. In Australia species are associated with seepages that are cool, but certainly not cold (Cranston, 1998). Larvae are recorded from hygropetric situations, as well as lakes (N. longappendiculata) and rivers.

The genus is known from western Palaearctic, Middle East (Saudi Arabia), Oriental regions (Mongolia, Afghanistan and SW China), Australia (Cranston, 1998) and at least one undescribed species from North America. At least ten species are known, of which 5 definitely associated larvae have been described.

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