Synasterope browni Kornicker & Iliffe 2000

Synasterope browni

ETYMOLOGY.—The species is named in honor of Roland Brown, Smithsonian Institution, who has been of considerable assistance in facilitating research in the Department of Invertebrate Zoology.

HOLOTYPE.—USNM 194469, adult female on slide and in alcohol.

TYPE LOCALITY.—Sta 95-005, transect BB, Exuma Sound, Bahamas, depth 96 m.

PARATYPES.—None.

DISTRIBUTION.—Collected only at type locality, in baited trap.

DESCRIPTION OF ADULT FEMALE (Figures 45–47).—Carapace oval with evenly rounded anterior and posterior margins; dorsal margin more convex than ventral margin (Figure 45a).

Infold: Obscure on slides, but appearing to have relatively few bristles on infold of rostrum (Figure 45d). Approximate number of flap-like bristles and small bristles on broad posteroventral list shown in Figure 45e. No processes observed between broad posteroventral list and valve edge. Each valve with 2 large ?glands containing closely spaced light amber-colored globules present in space between inner surfaces of anteroventral infold and outer shell (Figure 45b,c).

Selvage: Posterodorsal curvature of right valve with short segment of fringed lamellar prolongation (Figure 45e).

Central Adductor Muscle Attachments (Figure 45a,f): Comprising about 8 ovoid attachments.

Carapace Size (length, height in mm): USNM 194469, 0.80, 0.50, height 63% of length.

First Antenna (Figure 45g,h): 1st joint with long lateral spines. 2nd joint with row of short lateral spines near distal margin, spinous dorsal bristle, and without lateral bristle. 3rd and 4th joints combined shorter than wide; 3rd joint with small ventral bristle and 6 dorsal bristles (2 single bristles with long spines, 2 paired bristles (lateral with short spines, medial with long spines), and 2 paired bristles with short spines); 4th joint with 1 terminal ventral bristle and 1 terminal dorsal bristle with short spines; suture separating 4th and 5th joints convex. Sensory bristle of 5th joint with 6 terminal filaments. Medial bristle of 6th joint long with short spines. 7th joint: a-bristle claw-like, concave dorsally, with proximal dorsal spines; b-bristle with 3 long dorsal filaments; c-bristle long with 4 or 5 filaments. 8th joint: d-bristle represented by minute peg; e-bristle reaching tip of sensory bristle of 5th joint, bare with blunt tip; f-bristle oriented dorsally, with 3 marginal filaments; g-bristle long with 4 marginal filaments. Filaments of sensory bristle of 5th joint and filaments of 7th and 8th joints each with minute terminal papilla.

Second Antenna (Figure 45i,j): Protopodite with small distomedial bristle, and with few rows of medial spines in distodorsal corner. Endopodite 3-jointed with long terminal filament. Exopodite: bristle of 2nd joint reaching 8th joint, with slender ventral spines; bristles of joints 3–8 with slender ventral spines and natatory hairs; 9th joint small, with 2 bristles (1 about length of bristle of 8th joint and with natatory hairs, 1 short with small spines); joints 2 and 3 with small spines along distal medial margin; lateral side of exopodite obscured, but some joints with minute spines along distal margins (spines not shown), basal spines not observed (obscured), but not large if present.

Mandible (Figure 46a,b): Coxale endite broken off both limbs of USNM 194469. Basale endite with 3 spinous end bristles, glandular peg, 2 dwarf bristles (one length of other), and 2 triaenid bristles (one close to base) with 3 pairs of spines proximal to terminal pair (terminal pair well developed, about length of bristle). Basale: ventral margin with U-shaped boss near midlength; dorsal margin with 2 subequal terminal bristles with short spines. Exopodite about length of dorsal margin of 1st endopodial joint, with rounded hirsute tip and 2 short subterminal bristles (exopodite of right limb of USNM 194469 larger than that of left limb (compare Figures 46a and 46b). 1st endopodial joint with 3 long ventral bristles (2 with long spines, 1 with short spines). 2nd endopodial joint: ventral margin with 3 terminal bristles with short marginal spines; dorsal margin with a-, b-, c-, d-, f-, and g-bristles (c-bristle with slightly stouter base than b- and d-bristles), and with 1 short bristle proximal to a-bristle; medial surface of joint with 4 cleaning bristles in row between b- and c-bristles but closer to c-bristle. 3rd endopodial joint with slightly curved claw with ventral and dorsal spines, and with 5 spinous bristles.

Maxilla (Figure 46c,d): Epipodite triangular, short, hirsute at tip. Endite I with 4 bristles (3 long, 1 short); endite II with 3 long bristles. Basale: medial surface with 1 short proximal bristle near ventral margin, and 2 short bristles (proximal near midwidth, distal closer to dorsal margin); lateral surface with 1 short proximal bristle near midwidth; ventral margin with long stout spinous terminal bristle; medial surface and dorsal margin spinous. 1st endopodial joint with short bare alpha-bristle and long bare beta-bristle; 2nd joint with long terminal bare bristle reaching past tip of beta-bristle.

Fifth Limb (Figure 46e): Comb (right limb USNM 194469): lateral side with stout spinous exopodial bristle reaching past end of comb, 1 short slender bifurcate bristle ventral to base of stout bristle (tip of both branches broken off on illustrated limb), 1 pair of bristles and 1 single bristle closer to ventral margin, 1 single bristle proximal to paired bristles and almost on ventral margin, and 1 proximal and 2 distal bristles almost on ventral margin; anterodorsal tip of comb with long hairs.

Sixth Limb (Figure 47a): Small indistinct medial bristle near proximal anterior corner. Anterior margin with slender bristle at upper endite and longer spinous bristle at lower endite. Skirt: anterior end with 3 spinous ventral bristles; lateral flap with slender hirsute anterior bristle; ventral margin posterior to midlength with 9 spinous bristles; posterior edge of skirt slightly concave.

Seventh Limb (Figure 47b): Proximal group with 5 or 6 bristles (2 or 3 on each side), each with 2–4 bells; distal group with 6 bristles (3 on each side), each with 2–4 bells. Terminus with opposing combs, each with 8 spinous teeth.

Furca (Figures 46f, 47c): Each lamella with 9 claws; posterior 4 claws bristle-like but not ringed (2 bent backward); claws 1–5 with teeth along posterior edge (not shown), some longer than others; claw 1 with distal anterior spines; right lamella anterior to left by width of base of claw 1.

Bellonci Organ (Figure 46g): Elongate, broad near midlength, with rounded tip.

Eyes: Medial eye without pigment, bare (Figures 46g, 47d). Lateral eye well developed with brown pigment and 15 ommatidia (Figure 45a,j,k).

Lips (Figure 47d,e): Upper lip comprising 2 hirsute lobes on each side of saddle; minute anterior spine on each lobe; saddle not visible in lateral view (Figure 47e) but observed in anterior view (Figure 47d). Lower lip a hirsute flap on each side of mouth.

Genitalia (Figures 45a, 47c,f): Oval with sclerotized peripheral rim, present on each side anterior to furca.

Brush-like Organ: Not observed, but could have been torn off during dissection.

Posterior of Body (Figure 47f): Posterodorsal corner spinous and forming right angle; posterior margin with few long hairs at midheight.

Gills: Seven on each side reaching just past posterior of body (2 shown in Figure 47f).

Y-Sclerite (Figures 47f 52g): Without ventral branch.

Eggs: USNM 194469 with small unextruded eggs (3 shown in Figure 45l; 1 shown in Figure 47f); diameter of 3 eggs 0.07 mm, 0.10 mm, 0.10 mm.

COMPARISONS.—The new species, S. browni, differs from S. setisparsa (Kornicker, 1958), the only other species of the genus reported in the Bahamas, in having many more ventral and posteroventral bristles on the 6th limb (nine compared to at most two or three for S. setisparsa), and also in having a much shorter bristle at the anterior tip of the 6th limb. Synastrope browni differs from S. cushmani Kornicker, 1974, S. williamsae Kornicker, 1986, and S. psitticina (Darby, 1965) in having well-developed lateral eyes. The 1st antenna of S. browni differs from that of S. serrata Poulsen, 1965, in lacking a lateral bristle on the 1st joint. The 6th limb of S. browni differs from that of S. longiseta Poulsen, 1965, in not having two long bristles at the anterior tip of the skirt and also differs by having many more bristles along the ventral and posteroventral edge (nine compared to four or five for S. longiseta). The stem proximal to the terminal filaments of the sensory bristle of the 5th joint of the 1st antenna is much longer in S. longiseta and S. implumis Poulsen, 1965, than it is in S. browni.

Parasterope Kornicker, 1975

TYPE SPECIES.—Asterope Mülleri Skogsberg, 1920; subsequent designation by Kornicker (1975:401).

COMPOSITION AND DISTRIBUTION.—Members of the genus are widespread between latitudes of about 55°N to 65°S with a depth range from intertidal to 4303 m (Kornicker and Caraion, 1974:7). Two species of Parasterope, P. muelleri (Skogsberg, 1920) and P. extrachelata Kornicker, 1958, have been reported previously from the Bahamas. Four additional species of the genus have been reported from the eastern Atlantic: P. longungues Poulsen, 1965, from about 900 m off St. Croix, U.S. Virgin Islands; P. pollex Kornicker in Bowman and Kornicker, 1967, which is widespread along the North American coast of the Atlantic and Gulf of Mexico; P. zeta Kornicker, 1986b, on the continental shelf of Texas; and P. hulingsi Baker, 1978, on the continental shelf off North Carolina and Georgia (Kornicker, 1986b).