Angulorostrum segonzaci Kornicker 1981

Angulorostrum segonzaci

ETYMOLOGY.—The species is named for Dr. M. Segonzac, Museum National d'Histoire Naturelle (CENTOB), Paris, France, who supplied the specimens.

HOLOTYPE.—Adult female in alcohol, Museum National D'Histoire Naturelle, Paris (MNHN Os 12).

PARATYPE.—USNM 158133, ovigerous female, R/V Thalassa, sta X 342, continental slope north of Spain, Bay of Biscay.

TYPE-LOCALITY.—R/V Thalassa, sta Y 400, continental slope west of the northern end of Portugal.

DESCRIPTION OF ADULT FEMALE (Figures 1–11).—Carapace elongate with straight hingeline; greatest height anterior to middle; ventral margin convex; elongate rostrum with lateral overlap having rounded anterior end; caudal process prominent (Figures 9, 10a-c,e).

Ornamentation (Figures 9, 10e): Surface with abundant shallow fossae and few long hairs; hairs more abundant along ventral and anterior margins of valve (Figure 10e).

Infold (Figure 10b,c): Rostral infold with 4 bristles; 1 bristle present just ventral to inner end of incisur; anteroventral infold with about 7 ridges paralleling valve margin; infold of caudal process with 6 flat hirsute bristles forming row along list, and 1 or 2 small bristles near inner margin of infold.

Selvage (Figure 10b): Selvage with broad fringed lamellar prolongation along anterior and ventral margin; fringed lamellar prolongation narrower along posterior margin;

Size: USNM 158133, length 1.36 mm, height 0.75 mm; USNM 158135, length 1.42 mm, height 0.82 mm.

First Antenna (Figure 10d,f): 1st joint bare. 2nd joint spinous, with 1 spinous dorsal bristle. 3rd joint with 3 spinous bristles, 2 dorsal, 1 ventral. Long 4th joint spinous, with 4 spinous bristles, 1 dorsal, 3 ventral. Sensory bristle of long 5th joint with 5 marginal filaments. Minute 6th joint with 1 short spinous bristle. 7th joint: a-bristle spinous, almost twice length of bristle of 6th joint; b-bristle about one-third longer than a-bristle, with 2 short filaments, 1 proximal, 1 distal; c-bristle almost as long as sensory bristle of 5th joint, with 5 marginal filaments. 8th joint: d- and e-bristles long, bare, with blunt tips; f-bristle shorter than e-bristle, with 2 filaments, 1 proximal, 1 distal; g-bristle longer than f-bristle with 4 or 5 marginal filaments.

Second Antenna Figure 10g): Protopodite bare. Endopodite 2-jointed: 1st joint with 1 short bare bristle; 2nd joint with 1 long spinous ventral bristle and 1 short spinous terminal bristle. Exopodite: long 1st joint with small medial bristle on terminal margin; bristle of short 2nd joint reaching past end of 9th joint, with 1 proximal hair, otherwise bare; bristles of joints 3–8 only about one-third longer than bristle of 2nd joint, with a few proximal hairs, otherwise bare; 9th joint with 3 bristles (2 about same length as combined joints 2–9, other short), all with short marginal hairs; joints 2–8 with fairly long spines forming row along distal margin.

Mandible (Figure 10h): Coxale endite pectinate, hirsute, bifurcate at tip, without bristle near base. Basale: dorsal margin with 3 spinous bristles (1 distal to middle, 2 terminal); ventral margin, with 1 subterminal bristle; medial surface spinous, with 5 bristles near ventral margin (1 near middle, 4 proximal); lateral surface spinous, with 4 spinous bristles forming row near ventral margin. Exopodite hirsute, about one-half length of dorsal margin of 1st endopodial joint, with 2 subterminal bristles. 1st endopodial joint with medial spines and 3 ventral bristles. 2nd endopodial joint: medial surface spinous; dorsal margin with 6 bristles near middle; ventral margin with 4 spinous bristles forming 2 distal groups, 2 bristles in each group. End joint with 3 claws (dorsal of these small, bare, others long, spinous) and 3 bristles.

Maxilla (Figure 10i): 3 endites present, each with 6 or 7 bristles (not shown on illustrated limb). Precoxale and coxale with dorsal fringe of long hairs; coxale with single dorsal bristle. Basale with 2 or 3 bristles. Exopodite short, with 3 bristles (2 long, 1 short). Endopodite: 1st joint with 1 alpha-bristle and 2 beta-bristles; 2nd joint with about 6 additional claws and bristles.

Fifth Limb (Figure 11a-d): Endite I with 2 bristles; endite II with 5 bristles; endite III with about 9 bristles (not all shown on illustrated limb). Exopodite: 1st joint with main tooth consisting of 3 pectinate teeth followed by smooth peglike tooth (distal pectinate tooth with triangular anterior tooth); 1 spinous bristle proximal to peglike tooth; anterior side of 1st joint with 2 slender bristles near middle (not shown on illustrated limbs) and 1 small bristle near outer corner. 2nd joint with large squarish tooth with 3 small processes along inner margin; posterior side of joint with 3 bristles forming group (long bristle in middle, shorter bristles on each side) and proximal long bristle. 3rd joint with 3 bristles on inner lobe and 2 on outer lobe. 4th and 5th joints fused, with total of 5 bristles.

Sixth Limb (Figure 11e): Endite I small, with 3 bristles; endite II with 3 terminal bristles; endite III broad, with 7 terminal bristles; endite IV narrower than 4th, with 5 terminal bristles; end joint not projecting posteriorly with 5 spinous bristles followed by 3 hirsute bristles (1 short, 2 long); 1 short spinous bristle in place of epipodial appendage.

Seventh Limb (Figure 11f): Proximal group with 2 or 3 bristles (1 or 2 on each side); terminal group with 6 bristles (3 on each side); each bristle with marginal spines and up to 5 bells. Terminus consisting of comb of 6 or 7 teeth opposite 3 pegs forming row (inner peg longer than others).

Furca (Figure 11g): Each lamella with 9 claws, all separated from lamella by suture, and all decreasing in length and width posteriorly along lamella; claw 1 with single large tooth distal to middle of claw; claws 1–7 with small teeth of various lengths along posterior margins; long hairs present along anterior margin of lamellae and on lamellae following 9th claw.

Bellonci Organ (Figures 10d, 11h): Elongate but not much longer than width of 1st joint of 1st antenna, with 4 proximal segments and pointed tip.

Eyes: Medial eye small, unpigmented (Figures 10d, 11h). Lateral eyes absent.

Upper Lip (Figure 10d): Typical for family.

Genitalia (Figure 11g): Oval sclerotized area on each side of body anterior to furca.

Eggs: USNM 158133 with 1 egg in marsupium.

COMPARISONS.—The new species A. segonzaci differs from the previously described species of the genus in the shape of the carapace, especially in the rostrum, which projects anteriorly and ventrally a considerable distance from the valve's edge. The endopodite of the female 2nd antenna of A. segonzaci differs from the endopodites of A. monothrix and A. costatum in having 2 bristles on the 2nd joint.