Chernovskiia Sæther

Description

Introduction

Moderate to large-sized slender larvae, to 8 mm long.

Dorsal Head

Narrow-headed, elongate, sclerites not described.

Antenna

Antenna very long, with 7 weakly sclerotised segments, basal segment as long as 2nd or 2nd and 3rd segments combined. Ring organ not visible. Blade arising subproximally on 3rd segment, not extending to apex of antenna. Lauterborn organs lacking. Antennal seta absent. Style strong, on segment 5.

Labrum

SI seta short, seta-like; SII elongate, robust blade, SIII short, seta-like; SIVa 3 segmented, long, with SIVb a blade arising from base of SIVa. Labral lamellae absent. Pecten epipharyngis a single scale. Premandible with 3 teeth, brush absent.

Mandible

Mandible distinctive with very elongate sickle-like apical tooth, lacking dorsal tooth, with or without single inner tooth. Seta subdentalis absent. Seta interna absent. Pecten mandibularis absent.

Mentum

Mentum pale, weakly to strongly concave, with broad flat, or triangular median tooth flanked by 4-5 pairs of lateral teeth. Ventromental plates 1.0-1.5 times as wide as high, with few very coarse striae.

Maxilla

Palp elongate, as long as first 4 antennal segments combined.

Body

Anterior body segments apparently subdivided, making apparent 20 body segments (needs verification). Posterior parapods long, tapering with a few apical claws. Procercus very short. Anal tubules elongate.

Notes

Taxonomic Notes

The strongly curved mandible with very long apical tooth and strongly concave mentum with heavily striated and coarsely crenate ventromental plate will separate larvae of Chernovskiia from all others. Sæther (1977b) describes the larvae of C. orbicus and C. macrocera. Ferrarese (1984) gives an excellent description of C. macrocera.

Ecological Notes

Larvae of Chernovskiia macrocera are known from sand of deep rivers, sometimes with overlying muddy substrates. In the River Po, Italy, Ferrarese (1984) observed flow of 800-1800 m3/sec, and 7-10 ppm O2. Other records are from lakes, and an undescribed species from Western Australia occurs in sandy substrates of brown-water streams.

The genus is Holarctic, Australian and possibly Afrotropical in distribution.

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