Genus Tetreres Caullery, 1913

Type species

Hermella varians Treadwell, 1901; by original designation.

Diagnosis

Operculum with lobes partially fused. Two rows of opercular paleae. Outer paleae arranged in semicircles, blades straight, flat. Few (4–5) cylindrical inner paleae in single short row on ventral side of operculum, with blades straight, flat. One pair of large nuchal hooks with tips pointing inwards towards the prostomium. Tentacular filaments arranged in single rows (simple). Median organ small, conical at dorsal junction of opercular lobes. Palps grooved, longer than operculum. Four parathoracic segments (Kirtley 1994; Capa et al. 2012).

Key to species of Tetreres Caullery, 1913 from the Caribbean Sea

1. Outer paleae lanceolate, six times as long as wide, with long slender tip (Fig. 18A–B) ................... ........................................... T. israeli sp. nov. Northeast United States Virgin Islands, 4180 m depth

– Outer paleae oblong, three times as long as wide (Fig. 21A–B) ...................................................... 2

2. With about ten thin tentacular filaments on each opercular lobe ........................................................ ...................... T. varians (Treadwell, 1901) . Mayagüez, Harbor, Puerto Rico, 177.4–219. 5 m depth

– With five broad tentacular filaments on each opercular lobe (Fig. 20D) ............................................ ................................................ T. oscari sp. nov. Southeastern Key West, Florida, 288–378 m depth