Synasterope psitticina (Darby 1965)

Synasterope psitticina (Darby, 1965)

Cylindroleberis psitticina Darby, 1965:31–33 [part], pl. 19: fig. 6, pl. 20: figs. 1,2,5,8.

HOLOTYPE.—UMMP 48801 (University of Michigan, Museum of Paleontology), adult female on slides.

TYPE-LOCALITY.—Offshore Sapelo Island, Georgia. Slides containing holotype bear the number 1071, which might be the station number. Depth range of the species given by Darby (1965: 32) is 45 to 405 feet; however, his material in-eluded more than one species.

MATERIAL.—Darby (1965) described and illustrated a female (holotype, UMMP 48801) and a male (paratype, UMMP 48802). I received both specimens for study from Dr. Robert V. Kesling. The female holotype does not bear a long lateral bristle between the b- and c-bristles of the 2nd endopodial joint of the mandible. Therefore, I have referred the species to the genus Synasterope Poulsen, 1965. The male paratype is not adult as stated by Darby, but instead is a juvenile male (probably an A-1 instar). The specimen bears a long lateral bristle between the b- and c-bristles of the 2nd endopodial joint of the mandible. Therefore, I refer it here-with to the genus Parasterope Poulsen, 1965, and designate it Parasterope species.

SUPPLEMENTARY DESCRIPTION OF MAXILLA OF HOLOTYPE (Figure 11).—Endite I with 1 short and 3 long bristles; endite II with 3 long bristles. Dorsal margin of basale with 1 short proximal bristle and 1 distal bristle reaching beyond distal end of basale (both bristles with bases on hirsute medial side of basale); ventral margin of basale with 1 short proximal bristle, 1 minute distal bristle, and 1 long terminal bristle (lateral surface with 1 short proximal bristle). Endopodite 2-jointed: 1st joint with short dorsal bristle and long β-bristle; end joint with long terminal bristle.

Synasterope psitticina (Darby, 1965)

Cylindroleberis psitticina Darby, 1965:31 [part], pl. 19: fig. 6, pl. 20: figs. 1, 2, 5, 8.

Synasterope psitticina.—Kornicker, 1974a: 18, fig. 11.

HOLOTYPE.—UMMP 48801, adult female on slides, length 1.80 mm.

TYPE-LOCALITY.—Continental shelf off Sapelo Island, Georgia. Depth range of the species given by Darby (1965:32) is 45 to 405 feet (13.7 to 123 m), but his material included more than 1 species. The exact depth of the holotype is unknown.

MATERIAL.—Holotype.

DISTRIBUTION.—Known only from type-locality.

SUPPLEMENTARY DESCRIPTION OF ADULT FEMALE HOLOTYPE (Figure 28).—Carapace elongate with evenly rounded anterior and posterior and slightly convex ventral and dorsal margins (see Darby, 1965, pl. 19: fig. 6).

Infold: Obscure on slides but seemingly of general type found in genus; posterior list not unusually wide.

Size: Holotype, UMMP 48801, length 1.80 mm, height 0.57 mm (Darby, 1965:32).

First Antenna (Figure 28a; also see Darby, 1965, pl. 20: fig. 1): 1st joint with medial and lateral spines and minute, bifurcate, medial projection on distal margin. 2nd joint with medial spines, 1 short, lateral, distal bristle, and 1 long, spinous, dorsal bristle. 3rd and 4th joints quadrate, separated by suture less distinct medially than laterally; distal margin of 4th joint concave; 3rd joint with 1 small bristle on short ventral margin, and 6 dorsal bristles; 4th joint with 2 slender ventral bristles and 1 stouter dorsal bristle. Sensory bristle of 5th joint with 6 terminal filaments. 6th joint with long medial bristle with faint marginal spines. 7th joint: a-claw bare, about same length as combined 5th and 6th joints; b-bristle about 1 times length of a-claw, with 3 marginal filaments; c-bristle longer than f-bristle, and reaching well past distal end of sensory bristle of 5th joint, with about 5 marginal filaments. 8th joint: d-bristle represented by minute peg; e-bristle slightly longer than a-claw, bare with blunt tip; f-bristle bent dorsally, with 4 marginal ventral filaments; g-bristle about same length as c-bristle, with 5 marginal filaments.

Second Antenna: Protopodite with short, distal, medial bristle, but without medial spines. Endopodite fairly short, weakly 3 jointed, about length of 1st exopodial joint, with terminal bristle reaching to about middle of 3rd exopodial joint. Exopodite: bristle of 2nd joint reaching to 7th or 8th joint, with ventral spines, but no natatory hairs; bristles of joints 3–5 with natatory hairs and few small ventral spines; bristles of joints 6–8 with natatory hairs, no spines; 9th joint with 3 bristles (1 long with natatory hairs, 2 shorter, either bare or with few short hairs); joints 2–8 with slender spines forming row along distal margin; 9th joint with 2 lateral spines (larger of these about same length as 9th joint); basal spines absent.

Mandible (Figure 28b–d; also see Darby, 1965, pl. 20: fig. 2): Coxale endite: small medial bristle present at base of ventral branch; ventral branch with proximal ventral hairs and spines forming 3 oblique rows; tip of branch with 2 or 3 minute teeth; ventral margin of dorsal branch with 2 pointed processes followed by 2 or 3 low rounded processes and main spine (remainder of branch obscure). Basale endite with 4 end bristles, 3 triaenid bristles, 2 dwarf bristles, and small glandular peg; dorsal margin of basale with 1 short midbristle, and 2 long, subequal, subterminal bristles (both reaching just past distal end of 1st endopodial joint); lateral side of basale with spines forming rows near dorsal margin; medial side of basale with 1 minute bristle near base of endite. Exopodite about length of dorsal margin of 1st endopodial joint, hirsute, with 2 short subterminal bristles. 1st endopodial joint with 3 long, spinous, ventral bristles. 2nd endopodial joint: ventral margin with 3 spinous distal bristles; dorsal margin with 1 short proximal bristle, and bristle-like a-, b-, c-, and d-bristles (c-bristle bare, others with marginal spines); medial side with 1 short cleaning bristle between a-and b-bristles, 1 cleaning bristle between b- and c-bristles, 4 cleaning bristles forming oblique row near base of c-bristle, 1 spinous bristle just distal to base of d-bristle, and faint spines forming rows near ventral margin; lateral side with 1 long spinous bristle between c- and d-bristles, but none between b- and c-bristles. End joint with straight bare claw and 5 bristles (medial of these short).

Maxilla (Figure 28e; also see Kornicker, 1974a:19 fig. 11): Endite I with 1 short and 3 long bristles; endite II with 3 long bristles, and stout hairs forming row near base of bristles. Epipodial appendages with pointed tip reaching to about middle of dorsal margin of basale. Basale: medial side spinous and hirsute, with 1 proximal and 1 longer distal bristle (“dorsal bristles”); ventral margin with 1 short proximal bristle, 1 minute distal bristle, and 1 long, spinous, terminal bristle. Endopodite: 1st joint with 1 short anterior bristle and 1 long beta bristle; 2nd joint with long terminal bristle (tip broken off on illustrated limb).

Sixth Limb (Figure 28f): Anterior margin with upper and lower sutures representing endites, each with 1 bristle; lateral flap with marginal hairs, 1 short, slender, distal bristle, and 1 minute, proximal, spine-like bristle (on right limb only); anterior end of skirt with 5 short bristles; ventral and posteroventral margin with more than 13 bristles (posterior corner of right limb of holotype fragmented; whole limb probably had 3 or 4 additional bristles on posterodorsal corner; only anterior half of left limb of holotype present on slide).

Seventh Limb: 6 bristles in proximal group (3 on each side); 6 bristles in distal group (3 on each side); each bristle with 2–4 bells. Terminus consisting of opposing combs, each with 10 or 11 spinous teeth.

Furca (Figure 28g; also see Darby, 1965, pl. 20: fig. 8): Each lamella with 9 claws (posterior 2 of these bristle-like, oriented backwards); claw 1 of right lamella anterior to claw 1 of left lamella; claws 1–7 with long teeth interspersed with groups of short teeth along posterior margins (not all shown on illustrated limb); lamella following claws projecting slightly and with minute marginal teeth.

Bellonci Organ (Figure 28h; also see Darby, 1965, pl. 20: fig. 5): Elongate with rounded tip.

Eyes: Medial eye well developed, bare (Figure 28h). Lateral eyes: none present on slides of holotype; according to Darby (1965:32) lateral eyes of female absent or very reduced.

Genitalia (Figure 28j; also see Darby, 1965, pl. 20: fig. 8): Oval sclerotized ring on each side of body anterior to furca.

Posterior of Body: Slide somewhat obscure, but posterior apparently evenly rounded, without thumb-like process.

Y-Sclerite (Figure 28i; also see Darby, 1965, pl. 20: fig. 8): Typical for genus.