Tetreres terribilis, Hutchings & Capa & Peart, 2012

Hutchings, Pat, Capa, María & Peart, Rachael, 2012, 3306, Zootaxa 3306, pp. 1-60 : 48-51

Tetreres terribilis n. sp.

Figs 6B, 27, Table 5

Material examined. Holotype: NTM W4994 *, FRV Soela , cruise 06/85 st. 5: 17.xi.1985, S of Saumarez Reef , Marian Plateau, 22˚40.0'S, 154˚05.5'E to 22˚42.5'S, 154˚05.9'E, 416–419 m, collected with a lobster trawl. Specimen posteriorly incomplete with 15 chaetigers, 35 mm in length, 6 mm in width.

Description. Holotype robust, laterally flattened body, preserved animal pale yellow colourless except for dark brown nuchal hooks. Operculum with two partially fused lobes, as long as wide with deep indentation on ventral margin, laterally compressed ( Fig. 27A). Outer paleae, 40 pairs, arranged in semicircles, stout, golden, flattened, blades with three transverse thecal bands and asymmetrical pointed tips ( Fig. 27A). Inner row of paleae with three pairs of paleae arranged as a short ventral line on each inner margin of the opercular lobes, about one quarter length of outer paleae. One pair of flat and strongly curved nuchal spines without limbation ( Fig. 25C). Opercular papillae, 14 pairs, triangular, almost as long as outer paleae ( Fig. 27A, B). Dorsal papilla, digitiform, located between nuchal spines ( Fig. 27C). Palps, thick, rounded, with crenulated margins about one third longer than operculum. Median and median ridge present. Eye spots not observed, as difficult to separate lobes. Tentacular filaments, simple, nine pairs. Segment 1 (chaetiger 1) with neuropodial cirri on either side of buccal organ, elongate and tapering and a fascicle of capillaries. Segment 2 (chaetiger 2) with well fascicle of neuropodial capillaries, three elongate narrow lateral lobes present. Branchiae from segment 2, extending to chaetiger 13, last two chaetigers lacking branchiae, long thin flattened, meeting mid dorsally. Segments 3–6 (parathoracic) with two types of notochaetae inserted transversely, eight stout lanceolate with frayed tips and much shorter finer capillaries inserted in between. First parathoracic notopodia very small about one quarter size of subsequent ones which increase in size posteriorly. Notochaetae consist of two rows of five large lanceolate chaetae and short fine capillaries respectively. Segments 3–6 (parathoracic segments) with only one kind of neurochaetae, six capillaries. Abdomen incomplete. Abdominal neuropodia with compact fascicle of long capillaries arranged in two tiers with expanded fine tips, thecae expanded and margins appear denticulate. Notopodia erect expanded tori with transverse row of uncini with two rows of teeth, each row with 7–8 teeth. Cauda missing in holotype.

Remarks. Tetreres terribilis n. sp., is characterised by the presence of outer paleae with flattened blades symmetrical tips and transverse thecal bands a feature only shared with T. perryi ( Kirtley, 1994) , however it should be noted that the latter species is poorly described with only an illustration of the outer paleae and a comment that the nuchal looks are large with sharply recurvedd tips (Table 5). These two species are distinguished by the shape of the tip of these outer paleae with a pointed tip in the new species and a long spike in T. perryi , and the presence of an internal fusiform outline in T. terribilis n. sp., absent in T. perryi (Table 5). The only species described from nearby localities to Marian Plateau is T. robustus Lechapt & Kirtley, 1998 at depths of 440–450 m off New Caledonia. This species was described as having a larger number of outer paleae (70–80 pairs) but with a smooth surface, lacking thecal bands but they can be separated by the number of lateral lobes on segment 2, being three in T. terribilis n. sp. and four in T. robustus .

Distribution. Known only from type locality, Marion Plateau in depths of 416– 419 m.

Habitat. Substrate unknown, appears to be a solitary species.

Etymology. The name of this species terribilis refers to the large size of the species and which is much larger than any other material examined and if complete would represent a very scary animal.