Eurypylus rousei (Darby 1965)

Eurypylus rousei (Darby, 1965)

Sarsiella rousei Darby, 1965:37, pl. 25: figs. 10–12; pl. 26: figs. 1–3.

HOLOTYPE.—UMMP 48811, female on slides.

TYPE-LOCALITY.—Continental shelf off Georgia. Darby (1965:37) includes a paratype (UMMP 48812) in his locality data for the species: “Taken from 77 to 96 feet of water, offshore, salinity of about 32 parts per thousand. July and August.”

MATERIAL.—See “Station Data with Specimens Examined.”

DISTRIBUTION.—Continental shelf off Georgia (Figure 1). Depth range 11–29.3 m (Table 1).

SUPPLEMENTARY DESCRIPTION OF ADULT FEMALE (Figures 11–13).—USNM 158208: Carapace oval in lateral view with short caudal process with rounded edge (Figure 11); anterior smoothly rounded but rostrum and location of incisur indicated by minute lateral lip visible at high magnification (10–40× objective) (Figure 12c at 40× objective). Surface with weakly developed U-shaped ridge visible on right valve of USNM 158208 (Figure 12a) and only in part on left valve (Figure 11).

Ornamentation (Figures 11–12a,d): Surface with fairly large shallow fossae (Figure 11); surface between fossae with numerous short stout processes visible at low magnification (10× objective); abundant slender bristles with broad flat tip visible at higher magnification along valve edge (Figure 12d drawn with 50× objective); short slender pointed bristles and long slender pointed bristles, some of the latter with broad proximal part, sparsely distributed over valve surface; surface of valve coated with gelatinous transparent substance (the jell covers all except the long narrow pointed bristles, Figure 12b).

Infold (Figure 12b): Minute bristle usually present on anterior infold of Sarsiellinae not observed on either valve (Figure 12c). Infold of caudal process with 6 small bristles forming row; 2 additional small bristles (ventral of the 2 stouter than other and with blunt tip) at inner edge of infold of caudal process (Figure 12b). Posterior infold with 2 setal bristles (Figure 12b).

Selvage (Figure 12b): Broad lamellar prolongation with smooth outer edge present along free margins, and forming square edge at caudal process.

Size: USNM 158208, length 1.19 mm, height 0.93 mm.

First Antenna (Figure 13a): First joint bare. Second joint with 1 dorsal bristle with faint marginal spines. Third and fourth joints fused; short third joint with 2 bristles, 1 ventral, 1 dorsal; long fourth joint with short dorsal bristle and 2 long ventral bristles. Sensory bristle of long fifth joint with 2 minute filaments (1 proximal, 1 just distal to middle). Sixth joint minute, fused to fifth with 1 short medial bristle near dorsal margin. Seventh joint: a-bristle about twice length of bristle of sixth joint; b-bristle narrow, bare, less than twice length of a-bristle; c-bristle slightly longer than sensory bristle of fifth joint, with 2 minute marginal filaments. Eighth joint: d- and e-bristles well developed, about twice length of b-bristle, with blunt tips; f-bristle slightly shorter than c-bristle, bare; g-bristle very slightly longer than f-bristle, with 2 minute marginal filaments. Tips, of b-, c-, f-, and g-bristles, as well as sensory bristle of fifth joint, with distal end tapering to blunt tip without spine (tips of these bristle not nearly as broad and flat as tips of d- and e- bristles).

Second Antenna (Figure 13b): Protopodite bare. Endopodite with single joint bearing 2 short, bare, proximal, anterior bristles, and small terminal protuberance with long spinous bristle (bristle missing on left limb of USNM 158208). Exopodite: elongate first joint with fairly large distal medial bristle with blunt tip; bristle of second joint fairly long, reaching well past ninth joint, with about 35 stout ventral spines followed by natatory hairs; bristles of joints 3–8 with proximal stout ventral spines and distal natatory hairs; ninth joint with 2 bristles (1 long with slender ventral spines and distal natatory hairs, 1 short with small faint marginal spines); middle joints with minute faint spines forming row along distal lateral margins.

Mandible (Figure 13c): Coxale endite consisting of short stout spine in proximal ventral corner; ventral margin of coxale with long hairs. Basale: medial side with 4 small bristles near ventral margin (3 proximal, 1 distal) and 1 minute proximal bristle on ventral margin; dorsal margin with 1 small subterminal bristle. Exopodite absent. First endopodial joint with medial spines and 2 minute medial bristles near base of stout ventral claw; ventral claw with minute faint proximal spines on anterior margin. Second endopodial joint with 2 small subterminal bristles on dorsal margin, and stout ventral claw. End joint with stout terminal claw and 3 minute bristles at base of claw (2 ventral, 1 dorsal).

Maxilla (Figures 13d,e): Three endites present with total of about 15 spinous and pectinate bristles. Precoxale with fringe of hairs. Coxale with dorsal bristle. Basale with bristle near exopodite. Exopodite with 2 bristles (Figure 13e). Endopodite (Figure 13d): first joint with pectinate alpha- and beta-bristles; second joint with 2 subequal a-bristles, 1 short c-bristle, and 5 pectinate end bristles.

Fifth Limb (Figure 13f): Epipodial appendage with about 30 bristles. Single endite with 1 short bristle. First exopodial joint with 2 spinous bristles; exopodial joints 3–5 fused, hirsute, with total of 5 spinous bristles.

Sixth Limb (Figure 13g): Single endite with 3 short bristles. End joint with 10 spinous anterior bristles (one of the bristles with spear-like tip), followed by short space and 2 stout hirsute bristles.

Seventh Limb: Not observed (lost?).

Furca (Figure 13h): Each lamella with 5 claws decreasing in size posteriorly along lamella; claws 1 and 2 fused to lamella and with rounded tips; claws 3–5 separated from lamella by suture and with pointed tips; claws 1–3 with teeth visible along posterior margins, and with slender hairs along anterior margins; anterior of lamella with few hairs; lamella following claws with few minute spines.

Bellonci Organ (Figure 13i,j): Elongate, broadening distally, with rounded tip.

Eyes: Medial eye bare, with brown pigment (Figure 13i,j). Lateral eye about same size as medial eye, with 5 ommatidia and brown pigment (Figure 13j).

Upper Lip (Figure 13j): Helmet shaped, projecting anteriorly.

Posterior of Body (Figure 13h): Bare.

Genitalia (Figure 13h): Consisting of sclerotized ring on each side of body anterior to furca.

Y-Sclerite: Typical for family.

SUPPLEMENTARY DESCRIPTION OF HOLOTYPE (Figure 14).—(UMMP 48811, adult female.) Carapace (Figure 14a,b) similar to that of USNM 158208.

Infold: Not examined.

Size: Length 1.26 mm, height 0.96 mm (Darby, 1965:37).

First Antenna (Figure 14c,d): Differs from USNM 158208 in having 3 ventral bristles on fourth joint of right limb (2 on left limb), and slightly shorter b-bristle on seventh joint.

Second Antenna (Figure 14e): Protopodite and endopodite similar to USNM 158208. Exopodite: bristle of second joint with 29 ventral spines followed by natatory hairs; exopodite otherwise similar to USNM 158208.

Mandible, Maxilla, Fifth and Sixth Limbs (Figure 14f–i): Similar to USNM 158208.

Seventh Limb (Figure 14j): Six bristles in terminal group (3 on each side); 2 bristles in proximal group (1 on each side); each bristle with up to 5 bells. Terminus with opposing combs, each with 3–5 teeth.

Furca (Figure 14k): Tips of claws 1 and 2 broadly pointed, not rounded; limb otherwise similar to USNM 158208. (Darby 1965:37, did not mention that both claws 1 and 2 are fused to lamellae of this species.)

Bellonci Organ Eyes (Figure 14l), upper Lip, Posterior of Body: Similar to USNM 158208.

Parasarsiella Poulsen, 1965

Parasarsiella Poulsen, 1965:70.

TYPE-SPECIES.—Sarsiella globulus Brady, 1887, monotypy.

COMPOSITION.—Only the type-species is known.

DIAGNOSIS.—Each lamella with more than 5 claws; only claw 1 fused to lamella; claw 3 longer and stouter than claw 4.

DISTRIBUTION.—Between the Canary Islands and Cape Verde Islands at depths of 932–2333 m. Off Frederiksted, St. Criox, U.S. Virgin Islands, at unknown depth.