Tetreres varians (Treadwell, 1901)

Opercular lobes partially fused (with deep indentation on ventral margin), operculum longer than wide. Operculum with distal end slope absent (opercular disc perpendicular to longitudinal axis). Form of tentacular filaments simple (unbranched). Oral plates absent. Palps longer than operculum. Medial organ (cirrus) at dorsal junction of lobes absent. Number of outer paleae 30; arrangement of outer paleae in semicircles. Angle of blades and axis of shafts straight; blade of outer paleae flat. Outer paleae denticles on lateral margins absent. Distal margins of outer paleae smooth. Outer paleae medial plume absent. Middle paleae absent. Number of inner paleae 4 pairs; inner paleae giving the appearance of 1 row. Arrangement of inner paleae in short line on ventrum, angle of blades and axis of shafts straight; blade of inner paleae cylindrical, like spines. Inner paleae with internal fusiform outline present. Medial organ present. Nuchal spines or hooks present; number of nuchal spines or hooks 1 pairs; tip shape of spines bent, hooklike. Limbation on hooks absent. Neuropodia on segment 1 with 1 pair(s) of cirri. Neurochaetae on segment 1 present. Number of lateral lobes on segment 2: 4 pair(s). Number of parathoracic segments 2. Thoracic branchiae absent. Parathoracic neurochaetae only capillary. Branchiae in posterior abdominal segments present. Dorsal papillae present.

Description generated from: Hutchings, P.A., Capa, M., & Peart, R. 2012. Revision of the Australian Sabellariidae (Polycheata) and description of eight new species. Zootaxa, 3306: 1-60.

Additional references:
Treadwell, Aaron L. 1901. The Polychaetous annelids of Porto Rico. Bulletin of the United States Fish Commission, 20(2): 181-210.
Kirtley, David W. 1994. A review and taxonomic revision of the family Sabellariidae Johnston, 1865 (Annelida; Polychaeta). Volume Science Series number 1. 1-223. Sabecon Press. Vero Beach, FL.