Platysmittia Sæther

Description

Introduction

Small larvae, up to 4.9 mm long. Cream-coloured with orange to olive-orange thoracic markings, head capsule amber.

Antenna

Antenna slightly shorter to subequal to length of mandible; 6 segmented; segment 4 longer than third; segment 6 very thin, difficult to distinguish. Blade long, extending beyond flagellum apex; accessory blade present. Lauterborn organs as long, or slightly longer than segment 3.

Labrum

Labrum with SI dissected, with 2-4 branches; remaining S setae simple; SII quite long and stout. 4-5 pairs of simple chaetulae, 3-4 spinulae. Pecten epipharyngis consisting of 3 slender spines, 6 chaetulae laterales, 2 apically notched chaetulae basales. Premandible bifid; brush absent.

Mandible

Apical tooth shorter than combined width of 3 inner teeth. Outer, inner and molar surfaces smooth. Seta subdentalis small, notched apically. Seta interna with 7 simple to weakly serrate branches.

Mentum

Mentum with paired broad median teeth divided by broad U-shaped notch; 5 pairs of lateral teeth present; fourth pair smaller than fifth. Ventromental plate well developed with indication of weak smaller plates dorsal to main plates; beard absent.

Maxilla

Maxilla well developed, with pecten galearis present. with fine shallow serrations. Anterior lacinial chaeta shortest, broadest of 4-5 lacinial chaetae. Galea with about 5 lamellae.

Body

Body with anterior and posterior parapods divided, well developed with anterior parapod claws smooth or bluntly serrate; posterior claws smooth. Procercus about as long as wide, bearing 7 subequal anal setae. Anal tubules shorter than parapods, ventral pair digitiform with 1 median constriction. No conspicuous body setae.

Notes

Taxonomic Notes

Diagnosis after Jacobsen (1998).

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