Aphroteniinae Brundin

Description

Introduction

Small, to very small, <2 mm, yellowish-white or grey. Head large to very large in relation to body length (from 9-10% to near 20% body length in Paraphrotenia), squat, wider than long; pale cream to yellow. Eye spots single.

Dorsal Head

Comprised of a single often crenulate to rugose sclerite.

Antenna

Slightly shorter than mandible to very short, 4 segmented; basal segment squat; segments 2-4 rather longer, more or less subequal in length; segment 3 never annulate. Ring organ visible only if 1st segment is long. Blade slightly shorter  than flagellum. Lauterborn organs apparently absent, but antenna with style on apex of 2nd segment, well-developed, at least as long as 3rd segment. 

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

Generally large, study and multi-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 2-4 long well sclerotised, sickle-shaped lamellae. Outer margin  with 1 seta at base of hypocondyle and 2 setae close together on margin.

Mentum

With well sclerotised, smoothly concave anterior margin that is continuation of hypostomal margin; ventromentum with scale-like incisions; dorsomental wall comprising 2 medially-separated bands of sclerotised teeth.

Maxilla

Palp well-developed, nearly as long as antenna, 3 segmented, with 4 apical sensory peg, without Ring organ; stipes well developed and linked by ligament to mandibular condyle. Elongate cardolacinia extending medially from palpiger along hypostomal/mentum margin, and bearing cardinal setae SM3 and 4.

Body

Anterior parapods fused basally, crowned with simple claws; posterior parapods also well developed, may have basal papillae. Surface smooth to uniquely modified with papillae, to plumose scales. Procercus elongate to very elongate (7x width), subapically with 2 strong setae, apically with brush of 4-5 setae of heterogeneous lengths, at least 1 as long as 3 segments. Body setae simple and well developed.

Notes

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