“Eurydice bathypelagica n. sp.
Figs. 6A-6M and 7A-7N
Description. Blind. Anterior border of cephalon rounded; first segments of antenna 1 protrude from under cephalon and second segments branch at right angles from first to form antennae. Antenna 1 peduncular third segment longer than segments 1 and 2 combined. Flagellum of 3 articles almost as long as second peduncular segment; second article longest. Antenna 2 fifth peduncular article slightly longer than fourth; fourth segment longer than segments 1-3 combined. Flagellum of 8 articles, slightly shorter than peduncular segments 4-5 combined. Antenna 2 extends caudally to about midlength of peraeonal segment IV. Clypeus notched. Hypopharynx bilobed and covered with sensory hairs. Mandibles with three teeth on incisor processes; setal row with about seven setae; molar processes with sawlike teeth on upper edge. Triarticulate palp with inner row of setae on segment 2, apical segment with about four setae. Exopod of maxilla 1 with seven large toothlike setae and one sensory seta; endopod with three large specialized setae on apex. Maxilla 2 with four large sensory setae on inner lobe; two long toothed setae each on middle and outer lobes. Pa1p of maxilliped only slightly wider than endite; endite about as long as first palp segment, with no coupling hooks.
Peraeon with regularly convex lateral margins; coxal extensions with pointed posterolateral corners on all. Peraeopods I-VII with bases of about same length; peraeopod I about two-thirds length of peraeopod VII; basis of peraeopod I only slightly shorter than length of propodus to merus distance; that of peraeopod VII about two-thirds length; all others of intermediate lengths.
Pleon triangular in dorsal view; shorter than broad, anterior part being broadest. Posterolateral edges slightly turned underneath margin. Posterior margin with particular series of setae and teeth (Figure 6A). Pleopod 1 with endopod slightly wider than exopod. Pleopod 2 with male stylet slightly longer than exopod, with apex produced into acute point; endopod narrower than exopod. Pleopod 2 of female similar to that of male, but with no stylet. Pleopods 3, 4, and 5 with endopod narrower than two-segmented exopod. Uropod with exopod about two-thirds length and two-thirds width of exopod; both flat with plumose fringing setae. The name bathypelagica, from the Greek, represents the habitat of the species.
Measurements. Holotype male, 8 mm long; allotype female, 11 mm long; all males (2), 8 and 9 mm long, average 8.5 mm; all females (6), 7.4-11.4 mm long, average 10.1 mm.
Type locality. 10-930: 70°09'S, 110°06'W; 70°08°S, 109°31'W; 1391 m. Holotype male and allotype female.
Distribution and size. 10-812 (one female, 9 mm); 10-839 (one male, 9.6 mm); 10-852 (one female, 7.4 mm); 11-930 (one male, 8 mm; one female, 11 mm); 11-940 (one female, 10.2 mm); 11-944 (one female, 11.4 mm); 12-1007 (one female, 11.1 mm). All specimens were collected between 55° and 111°W and 55° and 71°S or in a region close to the Drake Passage off southern South America.
Affinities. The species is similar to the other blind species of the genus, E. caeca Hansen, 1916, which was taken from the North Atlantic in a `young fish trawl' with 1800 m of wire out. Only one specimen (male, 7.1 mm long) was recorded by Hansen. The pleon of E. caeca has a rounded posterior margin, and there are small spines projecting from the margin that are visible in dorsal view. Spines are not visible in dorsal view on the posterior pleonal margin of the more pointed pleotelson on the new species. In E. caeca the flagellum of antenna 1 has four flagellar articles, the two middle ones very much longer than the two end ones. On the flagellum of the new species there is only one long article between two shorter ones. The peraeopods of the new species lack the second spine from the distal edge on the propodus on peraeopods II—VII, or at least there is a gap without spines on the inner edge of the propodus in the new species that is not indicated in Hansen's illustrations of E. caeca. The species are remarkably alike in other respects and perhaps someday will be considered different at only the subspecies level if intermediate specimens are found.
Ecology. The specimens, like E. caeca Hansen, are most probably truly bathypelagic, being essentially pigmentless and without eyes. Only one or two specimens were taken at any one station, but the species was taken at seven stations. They were taken in the depths between 824 and 3111 m at least 964 m from the bottom, which is below the depth of most light penetration and above the bottom to such an extent as to exclude a completely benthic existence.”
(Schultz, George, 1977: 75-79)
