Lauterborniella Thienemann & Bause

Description

Introduction

Small larvae, up to 4 mm long. Pale red larvae. Transportable case in shape of spectacle case, with broad opening at each end.

Dorsal Head

Frontal apotome with slightly convex anterior margin, separate clypeus and labrum present, remaining labral area variably fragmentary. Clypeus wider than width of anterior frontal apotome.

Antenna

Antenna with 6 segments, segments 3 and 4 long. Lauterborn organs large, alternate on apex of 2nd, and on short pedestal subapically on 3rd segment, with long style. Ring organ near base of segment 1, seta present. Blade extending beyond flagellum, accessory blade very short.

Labrum

SI with bases fused, plumose on one side; SII lamelliform, plumose on one side only; SIII short, slender; SIV normally developed. Seta premandibularis simple, slender. Labral lamellae undivided, relatively broad, short. Pecten epipharyngis tripartite, each plate with several finger-like teeth distally. Premandible with 3 distal teeth, 1 short, blunt inner tooth, with beard.

Mandible

Mandible with very strong dorsal tooth; apical tooth no stronger than 2 inner teeth, all teeth pale brown. Pecten mandibularis with apical lamellae stronger than basal, extending beyond apex of mandible. Seta subdentalis very long and broad, almost reaching tip of apical tooth, distal margin with several pointed teeth. Seta interna inserted on dorsal surface, 4-branched.

Mentum

Mentum with all teeth brown with double, protruding median teeth, 6 pairs of lateral teeth on each side, 1st small. 2nd high, remainder diminishing in size laterally. Ventromental plates 80% as wide as mentum, almost triangular in shape, very narrowly separated medially, with smooth anterior margin, striae restricted to basal part Setae submenti plumose.

Body

Lateral tubules long, slender, filamentous and distally produced. Segment 11 dorsomedially with large, anally-directed hump. Segments 11 and 12 bent ventrally. Short procercus with 2 short and 5 very long anal setae.

Notes

Taxonomic Notes

Amongst the Holarctic genera of Chironomini only the larvae of Lauterborniella and Zavreliella construct transportable cases and have a dorsal hump on segment 11. Lauterborniella has a slit-like opening to its case, short, pointed lateral tubules, a clypeus, distally toothed seta subdentalis and feathered seta submenti.

Ecological Notes

Larvae of Lauterborniella are mobile amongst submerged vegetation in small bodies of standing water.

The genus has a Holarctic distribution, with one species, L. agrayloides. A further occurrence of this species is known from southern Chile. All other species referred to Lauterborniella in the literature belong either to Zavreliella or Stelechomyia or their generic affinities are not clear.

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