Parasterope antyx Kornicker 1989

Parasterope antyx

Parasterope species A.—Komicker, 1985:410–412 [part, excluding specimens from sample DS-60 referred to Parasterope styx, herein].

ETYMOLOGY.—From the Greek antyx (edge, rim, or frame).

HOLOTYPE.—Ovigerous female, length 1.44 mm, in alcohol, MNHN Os 256, Muséum National d'Histoire Naturelle, Paris, France.

TYPE LOCALITY.—BIOGAS I, R.V. La Perle, west of Bay of Biscay, 47°39′N, 8°11′48″W, 1560 m, sta Hors-Zone, sample DS-14, 10 Aug 1972.

PARATYPES.—BIOGAS I, R.V. La Perle, sta Hors-Zone: sample DS–14 (same sample as holotype), 1 ovigerous female on slide and in alcohol (USNM 157977; carapace lost) + 1 ovigerous female (USNM 193252) + 1 A-1 male (USNM 193253) + 2 adult females + 1 A-1 female (MNHN 9s 257).

DISTRIBUTION.—West of Bay of Biscay, 1560 m.

DESCRIPTION OF ADULT FEMALE (Figures 55, 56).—Carapace ovoid in lateral view with broadly rounded posterior margin; incisur ventral to midheight (Figure 55a, d).

Infold (Figure 55b,c): Rostral infold with bristles between list and anterodorsal margin of valve and total of 7 bristles on list and between list and incisur (Figure 55b; not all bristles shown on illustration); 1 bristle present at inner end of incisur; anteroventral infold with 5 bristles (Figure 55b; not all bristles shown on illustration); ventral infold between broad anteroventral infold and anterior end of broad posteroventral list with 9–11 bristles. Broad posteroventral list with 18–20 flap-like bristles and 9 or 10 minute bristles (not more than 2 minute bristles between each pair of flap-like bristles); no bristles or processes present between broad posteroventral list and edge of valve (Figure 55c); right valve only with small bristle near posterior juncture just dorsal to end of broad posteroventral list.

Selvage: Broad lamellar prolongation (with long fringe) along inner half of lower margin of incisur. Short segment with long fringe present near posterior juncture of hinge of right valve just anterior to single bristle. Elsewhere lamellar prolongation narrow and without marginal fringe.

Size: Holotype, length 1.44 mm, height 1.10 mm; USNM 157977, length 1.47 mm, height 1.09 mm. USNM 193252, ovigerous female, length 1.47 mm, height 1.06 mm. BIOGAS I, DS-14: 2 adult females without eggs, length 1.46 mm, height 1.04 mm, length 1.40 mm, height 1.07 mm.

First Antenna (Figure 55e): 1st joint with medial hairs. 2nd joint with lateral and dorsal spines and 2 spinous bristles (1 dorsal, 1 lateral). 3rd joint with well-defined distal margin, 7 bristles (1 small, ventral, 6 spinous, dorsal), and few dorsal hairs. 4th joint with concave distal margin and 3 bristles (2 ventral, 1 dorsal). 5th joint with fairly short, stout, sensory bristle with 6 long terminal filaments; lateral surface of joint with few minute spines forming row in distal dorsal corner. 6th joint with fairly long bare medial bristle. 7th joint: a-bristle claw-like, with proximal dorsal spines; b-bristle longer than a-bristle, with 3 distal marginal filaments excluding stem; c-bristle long, with short marginal filaments (tip broken off on illustrated limb). 8th joint; d-bristle missing; e-bristle only slightly longer than b-bristle, bare with blunt tip; f-bristle bent dorsally, with 4 short marginal filaments excluding stem; g-bristle longer than f-bristle, with short marginal filaments (tip broken off on illustrated limb).

Second Antenna (Figure 55f): Protopodite with few minute medial spines forming rows near dorsal margin and with small, distal, medial bristle. Endopodite 3-jointed: 1st and 2nd joints bare; 3rd joint well defined, with long terminal filament. Exopodite: 1st joint bare; bristle of 2nd joint just reaching 9th joint, with slender, indistinct, ventral spines; bristles of joints 3–8 with natatory hairs; 9th joint with 3 bristles (2 long with natatory hairs, 1 short, bare); basal spines absent; 9th joint with small lateral spine with few minute spines at tip; joints 2 and 3 and possibly others with indistinct minute spines forming row along distal margins.

Mandible (Figure 56a,b): Coxale endite: ventral branch with abundant slender spines along ventral margin forming rows, and tip with 2 minute spines; dorsal branch with small bristle near base of ventral branch and with 6 processes proximal to main spine of ventral margin, each process with 2 or 3 small terminal spines; tip of branch with short terminal spine; bristle on dorsal margin near tip hirsute; dorsal margin of branch opposite ventral processes with indistinct serrations. Basale: endite with 4 end bristles, 1 dwarf bristle, glandular peg, and 1 triaenid bristle with about 13 paired spines proximal to terminal pair; ventral margin without bristles; dorsal margin with 2 terminal bristles; medial surface with long slender hair-like spines; lateral surface with slender spines near ventral margin. Exopodite reaching about distance of dorsal margin of 1st endopodial joint, hirsute distally and wth 2 short subterminal bristles. 1st endopodial joint with 3 ventral bristles. 2nd endopodial joint: ventral margin with 3 terminal bristles; dorsal margin with stout a-, b-, c- and d-bristles (a-bristle bare, others with marginal spines not shown on illustrated limb); slender lateral bristle present between b- and c-bristles; dorsal margin with 1 short bristle proximal to a-bristle; 2 cleaning bristles present medial to base of b-bristle; 4 cleaning bristles forming oblique row between b- and c-bristles; 1 long bristle present just medial and distal to d-bristle; 1 long lateral bristle present between c- and d-bristles; medial surface with spines forming rows. End joint with stout terminal claw with ventral spines and 5 bristles (tip of claw missing on illustrated limb).

Maxilla (Figure 56c): Endite I with 4 bristles (3 long, 1 short); endite II with 3 long bristles. Epipodite with pointed hirsute tip reaching to about middle of dorsal margin of basale. Basale: spinous; ventral margin with 1 backward-pointing bristle near middle, 1 minute distal bristle, and 1 long hirsute terminal bristle; medial side near dorsal margin with 1 short proximal bristle; lateral side with 1 short slender proximal bristle. 1st endopodial joint spinous, with short dorsal bristle near middle and 1 long slender terminal bristle. End joint with long bare terminal bristle. (Maxilla of holotype and USNM 157977 examined.)

Fifth Limb (Figure 56d,e): Lateral side of comb with stout hirsute exopodial bristle reaching past end of comb, 2 slender bristles ventral to base of stout bristle, and 4 bristles near ventral edge of comb (1 long, 3 short).

Sixth Limb (Figure 55g): Trunk with small pointed medial bristle in proximal anterior corner; anterior with upper and lower sutures representing endites, each with short bristle; lateral flap of skirt hirsute but without bristles; anterior tip of skirt with 2 slender bristles; ventral and posteroventral margin with 18 hirsute bristles; posteroventral margin of skirt broadly curving; limb hirsute.

Seventh Limb (Figure 56f): Each limb with 12–14 bristles comprising 6 or 7 in proximal group (3 or 4 on each side) and same in distal group; longer of the bristles with 3 bells, shorter with 1 or 2 bells; terminus with 2 opposing combs, each with about 9 finger-like teeth with few indistinct spines.

Furca (Figure 55i): Each lamella with 8 claws of which posterior 2 bristle-like; right lamella slightly anterior to left.

Bellonci Organ (Figure 55h): Elongate, thinning near midlength but without well-defined suture; tip rounded.

Eyes: Lateral eyes absent. Medial eye bare and without pigment (Figure 55h).

Upper Lip (Figure 56g,h): Each lobe with 3 spines and hairs; saddle between lobes with stout anterior spine. Lower lip represented by broad rounded hirsute flap on each side of mouth.

Posterior of Body (Figure 55i): Long hairs present near midheight and near posterodorsal corner; without thumb-like dorsum. Gill-like structures poorly defined except at distal end.

Y-Sclerite (Figure 55i): Typical for subfamily.

Eggs: Holotype and USNM 157977, each with 5 eggs in marsupium; USNM 193252 with 6 eggs.

DESCRIPTION OF A-1 MALE (Figure 57).—Carapace similar in shape to that of adult female but not as high relative to length (Figure 57a).

Size: USNM 193253, length 1.20 mm, height 0.90 mm.

First Antenna: 2nd joint with dorsal spines and 2 bristles (1 dorsal, 1 lateral near dorsal margin). 3rd joint with fairly well-defined distal margin and 5 bristles (1 small, ventral, 4 spinous, dorsal). 4th joint with concave distal margin and 2 bristles (1 ventral, 1 dorsal). Sensory bristle of 5th joint with no proximal filament and 6 terminal filaments. 6th joint with long medial bristle. 7th joint: a-bristle claw-like, about same length as bristle of 6th joint, with proximal ventral spines; b-bristle slightly longer than a-bristle, with 3 distal filaments excluding stem; c-bristle long with short filaments (tip of bristle broken off on limb examined). 8th joint: d-bristle represented by minute peg with rounded tip; e-bristle about same length as b-bristle, bare with blunt tip; f-bristle bent dorsally, with short marginal filaments (tip of bristle broken off on limb examined); g-bristle similar to c-bristle (tip of bristle broken off on limb examined), a-bristle of adult appearing as inner claw almost reaching midlength of a-bristle; bristles and filaments of adult visible within limb.

Second Antenna (Figure 57b): Protopodite similar to that of adult female. Endopodite 3 jointed: 1st and 2nd joints short, bare; 3rd joint elongate with tapering tip and long proximal filament. 3rd joint of adult male endopodite visible inside 3rd joint. Exopodite similar to that of adult female.

Mandible: Ventral branch of coxale endite with slender spines forming 4 or 5 oblique rows. 2nd endopodial joint with 1 cleaning bristle medial to base of b-bristle, and 3 cleaning bristles forming row between b- and c-bristles. Limb otherwise similar to that of adult female. Claw of end joint of adult male appearing inside claw of A-1 male and reaching about its length.

Maxilla: Proximal dorsal bristle and proximal lateral bristle, both of basale, not observed. Minute distal bristle on ventral margin of basale also not observed. Limb otherwise similar to that of adult female.

Fifth Limb (Figure 57c): Similar to that of adult.

Sixth Limb: Similar to that of adult female except for having only 14 or 15 posteroventral bristles on the skirt.

Seventh Limb: With 8 bristles, 4 in proximal group, 2 on each side, and same in distal group; bristles tapering distally and with 1 or 2 bells. Terminus tapering to narrow tip with opposing combs, each with few thumb-like bare teeth.

Furca (Figure 57d): Each lamella with 7 claws; claws 6 and 7 bristle-like.

Eyes: Lateral eyes absent.

Upper Lip, Posterior of Body (Figure 57d), Y-Sclerite (Figure 57d): Similar to those of adult female.

COMPARISONS.—Few species of Parasterope are without lateral eyes. The new species P. antyx differs from P. annomata Kornicker, 1975a:427 in not having a distal bristle on the dorsal margin of the basale of the maxilla and in not having bristles on the infold between the posteroventral list and valve edge. Parasterope antyx seems closely related to P. longungues Poulsen, 1965:382, but differs in being much smaller, in having 2 endite bristles on the trunk of the 6th limb, and in having fewer flap-like bristles on the broad list of the posteroventral infold. Parasterope antyx differs from P. styx Kornicker, 1975a:432 in having only 2 anterior bristles on the trunk of the 6th limb.

DISTRIBUTION.—Members of this genus are widespread between latitudes of about 43°N to 73°S and depths of 1–4450 m (Koricker and Caraion, 1974:23; Kornicker, 1974, fig. 4). The known depth range in and west of the Bay of Biscay is 2147–2906 m. The known northern limit is extended slightly to about 47.5°N.