Aphroteniella Brundin

Description

Introduction

Larva to 2.2 mm long, with head pale, c. 10% body length. Body cream-coloured, dorso-ventrally flattened.

Dorsal Head

A single smooth sclerite.

Antenna

Short, 4-segmented, basal segment squat without ring organ; segments 2 stout, shorter than 3+4, each of which more or less subequal in length. Blade shorter than flagellum. Lauterborn organs absent. Style on apex of 2nd segment, well-developed, reaching antennal apex.

Labrum

SI seta adjacent basally, comprising long, slender setae each arising from slender pedestal; SII large and broader, arising from low pedestal, SIII anteriorly placed near midline of head, one anterior to the other (ie not bilaterally symmetrical); SIVA and B thin setae. Labral rod close to SIVB, strongly developed on pedestal. Chaetae, chaetulae, spinulae and premandibles absent.

Mandible

Large, sturdy and 7-toothed, outside of dominant apical tooth are 1-3 teeth, middle one being longest; inner teeth 3-4, short. Pecten mandibularis absent. Seta subdentalis clearly dorsal, simple/lanceolate, extending to near apical tooth. Seta interna may be represented on dorsolateral mandible by 4 long well sclerotised, sickle-shaped lamellae.

Mentum

Well sclerotised, smoothly concave anterior margin; ventromentum with scale-like incisions; dorsomental wall comprising 2 medially-separated bands of sclerotised teeth.

Maxilla

Palp nearly as long as antenna, 3 segmented, with short and broad basal segment, slender 2-segmented flagellum, and 2 large club-shaped sensory rods; without ring organ.

Body

Anterior parapods fused basally, crowned with simple claws. Body surface with closely set tubercles or papillae, many with small hooklets. Body setae simple. Posterior parapods well developed with papillae extending onto proximal surface. Procercus smooth, elongate, c. 7% as high as wide, subapically with 2 strong setae, apically with brush of 5 setae of various lengths, one of which is as long as 3 abdominal segments.

Notes

Taxonomic Notes

Distinguished from other Aphroteniinae by the tuberculose body, developed as papillae which may bear hooklets. The body setae are simple. The antenna is 4-segmented but very short, in contrast to the 3-segmented antenna ofAphrotenia and the longer (=mandible length) of Paraphrotenia. The head is c. 10% of the body length in Aphroteniella, in contrast to the >15% in Paraphrotenia.

Ecological Notes

Larvae are found in generally cool running waters, but all stages of an Australian species has been found in 24-29 C water in tropical Northern Territory and also in the perched Lake Boomanjin, s. Queensland. Two species are described from Australia, one (unnamed) from South America.

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