Coffmania Hazra & Chaudhuri

Description

Introduction

Small-medium larvae, up to 6 mm long. Brown with cephalic margin blackish-brown brown to darker brown, distal half of mandible, apical 1/3 of ligula, dark brown. Capsule longish-oval, cephalic index 0.64-0.70. Dorsally DP dorsal to S8, posterior to S5, S7 close to S8; ventrally SSm, S10 and S9 aligned at 45° to antero-ventral axis, VP immediately posterior to S10. SSm, S5, S7 and S10 multi-branched, S8 simple, short, S9 simple, strong.

Antenna

Half head length, AR: 3.4-3.9; basal segment c10-12 times as long as basal width, Ring organ at base of apical 1/3. Blade bifid, broad outer branch subequal to thin inner branch. Peg sensilla very short, perhaps absent, style extending to apex of 3rd segment of antenna.

Mandible

Uniformly gently curved, basal 1/2 strongly broadened, distal 1/2 blackish brown. strongly narrowed in apical 1/2, almost 3x as long as broad; Apical tooth parallel-sided 2.5x as long as basal width, 1/4 length of mandible. Basal tooth / mola insignificant, not protruding beyond inner margin of mandible which bears long seta subdentalis; no evidence of accessory tooth. Ventrolateral setae approximated on outer margin of basal 1/2 of mandible; seta 1 a small, peg, 2 simple, 3 divided; gap between setae 2 and 3 c 2x as great as that between setae 1 and 2; Ring organ situated proximal to seta 3.

Maxilla

Basal segment of palp about 4x as long as wide, with ring organ at base of apical 1/3; b seta 3- segmented, middle segment 2x as long as basal or apical segments.

Body

Without fringe of swim setae. Anal tubules slender, shorter than half length of posterior parapod, spindle-shaped, about 5x as long as basally wide. Subbasal seta of posterior parapod simple. Procercus about 3x as long as wide, with 7-12 anal setae. Claws of posterior parapod simple; larger claws with small points on inner margin; all claws pale.

Notes

Taxonomic Notes

Coffmania very closely resembles Conchapelopia (q.v.) as a larva, the major differences lying in the male genitalia (Hazra and Chaudhuri, 2000, Niitsuma 2008b). Larvae may be separable by the narrow pseudoradula in Coffmania (c 10% of the width of M-Appendage, with granulation in 5-8 closely adjacent, parallel rows) compared to Conchapelopia (>20% of the width of M-Appendage, with granulation in at least 8 rows).

Ecological Notes

Larvae of the two Coffmania species described from the Darjeeling-Sikkim Himalayas in India came from algal mats and bottom sediments in springs (Hazra and Chaudhuri, 2000). Near identity of the quite common south Indian larva and pupa “Pentaneurini sp. 1” of Roback and Coffman (1989) to that of C. animispina suggests that Coffmania may be widely distributed in India. Coffmania insignis appears common in lotic waters in Japan (Niitsuma, 2008b). Unreared larvae from small creeks and drains in Singapore conform to this generic diagnosis (P.S. Cranston pers. obs.).

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