Euchone scotiarum Hartman 1978

"Euchone scotiarum n. sp.
Figs. 40a-40f

Material. Weddell Sea, in 412-654 m: Station 68­1 (2 specimens); 69-2 (1 specimen); 69-8 (holotype, USNM 47091); 69-10 (1 specimen).

Description. The holotype, from station 69-8, is 7.5 mm long and 0.5 mm wide anteriorly and consists of eight thoracic and eight abdominal setigers, the last three comprising the caudal funnel, which is followed by a narrow tapering triangular pygidial lobe enclosing the anal pore. Large ova are crowded in setigers 5-11. The tentacular crown, preserved in the tube and somewhat compressed, is long and attenuated: each half is composed of three radioles (Figure 40a). Pinnules are in paired series attached along the inner side of the radiole to near the distal tip.

Radioles are transversely annular along their length (Figure 40b); the pinnules are much more slender and minutely ciliated up to their tips. The ventralmost radiole is thick, simple, and distally coiled; it is annular on its outer side, resembles the others, and is densely ciliated on its inner oral side (Figure 40c).

The collar consists of a pair of expanded pouchlike dorsal lobes separated by a middorsal cleft and a pair of long ventral lobes medially divided (Figure 40a). The first, or collar, segment is shortest; setigers 2 and 3 are also short, and setiger 4 is 1¹/2 times as long as setiger 3. Thereafter, the setigers are long and cylindrical through the rest of the thorax and the abdominal region to the last three setigers, which are short and involved in the caudal funnel.

An opaque band of cilia encircles the body posterior to the setal fascicles of setiger 2 (Figure 40(d).

Thoracic notosetae are of one kind; they are lim­bate, and the upper ones are longest (Figures 40d, 40e). Spatulate setae are lacking. Thoracic neurosetae are present from the second setiger and consist of long-shafted acicular spines terminating in thick fangs surmounted by small denticles (Figur 40f). Abdominal setigers have short slender capillary neurosetae and short avicular notosetae.

Remarks. Euchone scotiarum belongs to a smal group of species in which the caudal funnel comprise the last three setigers. It differs from all others in the unique development of the collar membrane notably the pouchlike dorsal lobes separated by middorsal cleft.”

(Hartman, 1978)