Anuncotendipes Cranston

Description

Introduction

Small larvae, to 3mm long.

Dorsal Head

A single sclerite, narrowed between bases of SIVa sensillae.

Antenna

Antenna 6 segmented, basal segment shorter than flagellum, 2nd segment subequal to 3rd, terminal segments small. Blade arises in mid-segment 2, reaching subapex of flagellum, accessory blade absent. Lauterborn organs shorter than short style. Antennal seta absent.

Labrum

SI seta slender, seta; SII more than 2x as long as SI, SIII very small, seta-like; SIVa long, 3-segmented, with SIVb attached at base. No chaetae. Labral lamellae absent. Pecten epipharyngis a single triangular scale with median projecting spine. Premandible with 5 teeth, brush weak.

Mandible

Mandible lacking dorsal tooth, with strong apical tooth and 2 small inner teeth. Seta subdentalis slender reaching basal tooth. Seta interna with 5-6 simple branches. Pecten mandibularis quite strong.

Mentum

Mentum with pale rounded broad median tooth, flanked by 4 pairs of dark lateral teeth, the outermost perhaps comprising two fused teeth. Ventromental plates widely separated, fan-shaped, 2-2.5 times as wide as high, finely striate, with crenulate anterior margin. Setae submenti simple.

Maxilla

Palp about as long as first antennal segment.

Body

Anterior parapods with dense fine claws, all with at least one inner tooth, perhaps serrate. Procercus weakly pigmented, bearing apical setae the longest 2 of which extend at least half body length.

Notes

Taxonomic Notes

Larval Anuncotendipes key with the Harnischia-complex of genera. The larvae of Anuncotendipes key to Saetheria Jackson in the Holarctic keys, differing from this and the rather similar Paracladopelma larva in the very elongate procercal setae, the absence of elongate chaetae flanking the SII setae, and the presence of only four pairs of dark lateral mental teeth flanking the broad pale middle tooth.

Ecological Notes

Pupal exuviae of Anuncotendipes australotropicus have been found in small numbers in several shaded rainforest streams of the Australian Wet Tropics at a range of elevations and seasons. Despite conventional searching by washing rocks, kicking and stirring sediments and picking through leaf packs, no candidate larvae were found until searching was concentrated on two streams in the Cape Tribulation area. Here pupal exuviae and pharate adults were drifting in higher densities during the extended wet season than ever encountered elsewhere. Flows were so high that direct observations were difficult or impossible. Eventually larvae were found associated with clay boulders, probably quite close to the rapidly flowing water surface. The elongate procercal setae may act as anchorage. Pupae were non-tubicolous and active in the water column in the laboratory, and appeared to be so in the creeks, presumably living in virtually hygropetric conditions.

Anuncotendipes kakadu is known from pristine streams in Kakadu National Park, Northern Territory, Australia.

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