Postasterope messingi Kornicker 1986

Postasterope messingi

ETYMOLOGY.—The species is named for one of its collectors, Dr. Charles G. Messing.

HOLOTYPE.—USNM 156715, I ovigerous female on slide and in alcohol.

TYPE-LOCALITY.—Key Biscayne side of Bear Cut, Florida Keys, 2–4 m.

NON-TYPES.—USNM 158386, 158390, 158389, 157894, 4 adult males; USNM 158604, 11 adult males. All from Abaco Island, Bahamas.

DISTRIBUTION.—Key Biscayne, Florida; Abaco Island, Bahamas. Known depth range 2–4 m.

DESCRIPTION OF ADULT FEMALE (Figures 41, 42). Carapace elongate with evenly rounded anterior and posterior margins and only slightly convex ventral and dorsal margins (Figure 41a–c); deep incisur below middle of anterior margin.

Ornamentation: Surface smooth with sparsely distributed long bristles.

Infold (Figure 41d,e): Infold of incisur ventral to rostral ridge with about 9 small bristles forming row; rostral infold with about 21 bristles forming row just within valve edge, and about 25 bristles (mostly small) posterior to row of bristles near edge; anteroventral infold with about 3 bristles. Ventral infold with 2 lists joining at their posterior ends to form broad posterior list; bare upper list extending from near inner end of incisur to inner edge of ventral end of wide posterior list; lower list with wide lamellar prolongation (stippled in Figure 41d,e); anterior end of lower list intersecting valve edge near anterior end of ventral margin; posterior end of lower list joining outer edge of wide posterior list at its ventral end. Ventral infold with few bristles between upper and lower lists; posterior list with very faint, transparent, flap-like bristle and few simple bristles near inner edge; outer edge of posterior list with minute spine-like processes on or near edge (difficult to resolve with × 40 objective); a few small bristles present proximal to posterior edge of posterior list; outer edge of posterior list continues ventrally intersecting lower edge of valve.

Central Adductor Muscle Attachments (Figure 41a): Consisting of about 10 individual oval scars.

Size: USNM 156715, length 1.16 mm, height 0.61 mm.

First Antenna (Figure 42a): 1st joint spinous. 2nd joint with medial spines and 1 spinous dorsal bristle. 3rd and 4th joints forming square; joints separated by suture on lateral side; 3rd joint with minute ventral bristle and 6 spinous dorsal bristles; 4th joint with stout, spinous, dorsal bristle, 2 slender ventral bristles, and slightly concave distal margin. Sensory bristle of 5th joint with 6 long terminal filaments. Medial bristle of 6th joint long, spinous. 7th joint: a-claw short, stout, bare; b-brist.le stout, about twice length of a-claw, with 3 long marginal filaments near middle; c-bristle about 3 times length of a-claw, slightly longer than sensory bristle of 5th limb, with 5 short marginal filaments. 8th joint: d-bristle, absent; e-bristle bare, slightly shorter than b-bristle, tip blunt; f-bristle bent dorsally, about same length as b-bristle, with 3 or 4 short marginal filaments; g-bristle slightly shorter than c-bristle, with 6 short marginal filaments.

Second Antenna (Figure 41f): Protopodite: short spines forming rows along dorsal margin and dorsal half of medial surface; distal medial bristle minute. Endopodite 3-jointed: suture between 2nd and 3rd joints weak; 1st and 2nd joints bare; 3rd joint with long terminal bristle with blunt tip. Exopodite: distal medial bristle of 1st joint not observed, if present extremely small; bristle of 2nd joint extending past 9th joint, with ventral spines; bristles of joints 3–8 long, with natatory hairs and minute, widely spaced, ventral spines; 9th joint with 3 bristles (1 short, bare, 1 medium with natatory hairs, 1 long with natatory hairs and few ventral spines); basal spines fairly small (spine on 8th joint about length of 9th joint); lateral spine of 9th joint about same length as basal spine of 8th joint.

Mandible (Figure 42b): Coxale endite: minute medial bristle present at base of ventral branch; ventral branch with spines forming 4 oblique rows, and with pointed tip with few short spines; ventral margin of dorsal branch with 4 low nodes followed by short main spine (tip of branch obscure on limbs examined); long bristle on dorsal margin of branch set well back from tip of branch. Basale: endite with 4 spinous end bristles, 3 trianeid bristles (with 3 pairs of marginal teeth excluding terminal pair), 1 dwarf bristle, and glandular peg; ventral margin of basale with 1 triaenid bristle near endite; dorsal margin with 2 terminal bristles (lateral of these about length of other). Exopodite hirsute, about length of dorsal margin of 1st endopodial joint, with 2 subterminal bristles. 1st endopodial joint with 3 long, spinous, ventral bristles. 2nd endopodial joint: ventral margin with 3 long spinous bristles; dorsal margin with 1 short proximal bristle and stout, spinous, a-, b-, c-, and d-bristles; medial side with 7 cleaning bristles between b- and c-bristles (1 individual bristle and 6 bristles forming row), and 1 short spinous bristle just distal to the d-bristle; lateral side with 1 long bristle between b- and c-bristles and c- and d-bristles. 3rd joint with stout dorsal claw and 5 spinous bristles (4 long, 1 short).

Maxilla (Figure 42c): Epipodial appendage hirsute, with slender tip reaching just past middle of dorsal margin of basale. Endite I with 4 bristles (3 long and 1 short); endite II with 3 long bristles. Basale: dorsal margin with 1 short distal bristle; medial side with 1 short proximal bristle; ventral margin with 1 short proximal bristle and 1 long, spinous, terminal bristle; lateral side with 1 short proximal bristle. Endopodite: 1st joint with short anterior bristle and long beta-bristle; end joint with long, spinous, terminal bristle.

Fifth Limb: Not clearly observed on specimen examined, but seemingly typical for genus.

Sixth Limb (Figure 41 g): Medial side with small spine in proximal anterior corner; anterior margin with upper and lower bristle; anteroventral corner of skirt with 2 short hirsute bristles; ventral margin without bristles; posterior corner with 1 short hirsute bristle; narrow lateral flap without bristles; hairs present along anterior end of lateral flap and along anterior, ventral, and posterior margins of remaining part of limb.

Seventh Limb (Figure 42d): Each limb with 6 proximal bristles (3 on each side) and 6 terminal bristles (3 on each side); each bristle with 3 or 4 distal bells. Terminus consisting of opposing combs, each with about 15 spinous teeth.

Furca (Figure 41h): Each lamella with 8 or 9 claws; posterior 2 or 3 claws tending to be bristle-like, but not bent backwards on specimen examined; teeth present along posterior margins of most claws.

Bellonci Organ (Figure 41i): Elongate without suture, tip rounded.

Eyes: Medial eye hirsute, pigmented (Figure 41i). Lateral eyes about same size as medial eye, each with black pigment and about 17 ommatidia (Figure 41i).

Lips (Figure 41j): Upper lip consisting of 2 hirsute lobes, each with 2 anterior spines. Lower lip with hirsute lateral flap on each side of mouth.

Posterior of Body (Figure 41h): With spinous, thumb-like, dorsal process.

Y-Sclerite: Normal for subfamily.

Eggs: USNM 156715 with 10 eggs in marsupium.

DESCRIPTION OF ADULT MALE (Figures 43, 44).—Carapace elongate with overhanging rostrum (Figure 43a,f); bristles forming vertical row near posterior end of valve.

Infold (Figure 43b,c): In general, similar to that of female.

Size: USNM 158386, length 1.16 mm, height 0.97 mm; USNM 158390, length 1.23 mm, height 0.64 mm; USNM 157894, length 1.19 mm, height 0.60 mm; USNM 158389, length 1.16 mm, height 0.60 mm; USNM 158604 (11 specimens, 2 measured) length 1.13 mm, height 0.55 mm, length 1.18 mm, height 0.59 mm.

First Antenna (Figure 44a): 1st joint bare. 2nd joint with small lateral spines and long medial hairs near ventral margin, and 1 spinous dorsal bristle. 3rd joint with small bristle on short ventral margin, and 1 spinous bristles on long dorsal margin. Dorsal margin of 4th joint with stout spinous bristle; ventral margin with few short spines and 2 terminal bristles; 5th joint short, with well-defined sutures separating the 5th and 6th joints; sensory bristle with abundant filaments, terminal filaments stouter than others; dorsal edge of 5th joint with 2 processes (proximal process longer than other). 6th joint: medial bristle spinous, with base near dorsal margin; dorsal margin with 4 low processes. 7th joint: a-claw short, bare, on pedestal; b-bristle with 2 short proximal filaments with few marginal spines, and 3 longer distal filaments, bristle more than twice length of a-claw; c-bristle very long, tip broken off on specimen examined, 15 filaments on remaining part. 8th joint: d-bristle missing; e-bristle reaching past a-claw, bare with blunt tip; f-bristle very long, tip broken off on specimen examined, 17 filaments on remaining part; g-bristle longer than b-bristle, with about 7 filaments.

Second Antenna: Protopodite bare except for small, medial, distal bristle (Figure 43g): endopodite 3-jointed (Figure 43h): 1st joint elongate, bare; 2nd joint elongate with 3 distal ventral bristles (distal of these about length of others); 3rd joint elongate, reflexed on 2nd, and with 1 long proximal bristle with blunt tip; tip of joint pointed and with ridges. Exopodite: joint 1 elongate with distal lateral hairs forming rows; 2nd joint about 2 times as long as 3rd joint; remaining joints decreasing gradually in size; joints 3–8 with minute basal spines; 9th joint with small, pointed, lateral spine about length of joint; bristle of 2nd joint with few, faint, ventral spines and natatory hairs; bristles of joints 3–8 with long bristles with natatory hairs, no spines; 9th joint with 4 bristles (1 short, 3 long), all with natatory hairs; joints 2–8 with minute spines forming row along distal margin and long hairs forming row on distal dorsal corner.

Mandible (Figure 44b,c): Coxale endite with small medial bristle at base of ventral branch; ventral branch with spines in 4 oblique rows, and tapered tip; dorsal branch with 4 processes along ventral margin proximal to small main spine; tip of branch pointed; dorsal margin with bristle (broken on illustrated endite) set back from tip and few serrations (Figure 44c). Basale endite with 4 end-type bristles, 3 triaenid bristles with 4 or 5 paired spines excluding terminal pair, 1 dwarf bristle, and a glandular peg. Basale: dorsal margin with 2 long terminal bristles; ventral margin with 1 small triaenid bristle with 3 or 4 paired spines excluding terminal pair; U-shaped sclerotized process to which muscle is attached present just distal to base of small triaenid bristle. Exopodite short, reaching to about middle of dorsal margin of 1st endopodial joint, hirsute, with 2 small subterminal bristles. 1st endopodial joint with 3 long spinous bristles. 2nd endopodial joint: ventral margin with 3 terminal spinous bristles; dorsal margin with 2 proximal bristles, bare a-bristle, and spinous b-, c-, and d-bristles; lateral side with a long bristle between b- and c-bristles and another between c- and d-bristles; medial side with spines forming rows, 5 cleaning bristles (1 just distal to base of b-bristle, 4 forming row just proximal to base of c-bristle), and 1 spinous bristle adjacent to base of d-bristle. End joint with straight claw with ventral teeth, and 5 bristles (medial of these short).

Maxilla (Figure 43i): Epipodial appendage with hirsute tip reaching to about middle of dorsal margin of basale. Endite I with 4 bristles (3 long, 1 short); endite II with 3 long bristles. Basale: dorsal margin hirsute, with 1 proximal and 1 distal bristle (both with medial bases); ventral margin with 1 proximal bristle and 1 long, spinous, terminal bristle; lateral side with 1 short proximal bristle. 1st endopodial joint with 1 short anterior bristle and 1 long beta-bristle; end joint with terminal bristle about longer than beta-bristle.

Fifth Limb: Obscure on specimen examined but typical for genus.

Sixth Limb (Figure 43j): Small medial spine in anterior proximal corner; anterior margin with 1 bristle at both upper and lower sutures (lower bristle much longer than upper bristle); anterior corner of skirt with 2 bristles (posterior of these about length of other); lateral flap hirsute but without bristles; ventral margin of skirt hirsute but without bristles; posteroventral corner of skirt with no or 1 bristle.

Seventh Limb: Each limb with 6 bristles in proximal group (3 on each side) and 6 in distal group (3 on each side); each bristle with 3 or 4 bells. Terminus with opposing combs, each with about 9 spinous teeth.

Furca (Figure 43e): Each lamella with 8 claws; posterior 2 or 3 claws bristle-like but not oriented backwards.

Bellonci Organ (Figure 43d): Elongate, broadening near middle, with rounded tip.

Eyes: Medial eye unpigmented, with dorsal hairs (Figure 43d). Lateral eye larger than medial eye, amber color, with 20 ommatidia (Figure 43d). (Lateral eye was probably black prior to preservation.)

Upper Lip (Figure 43d): Each lobe hirsute but without spines; anterior spine on saddle between lobes; hirsute lateral flap on each side of mouth.

Copulatory Organ: Fairly small, consisting of several lobes, at least 1 with bristles.

Posterior of Body (Figure 43e): With short, hirsute, thumb-like process.

Y-Sclerite: Typical for subfamily.

COMPARISONS.—The new species P. messingi differs from P. barnesi and P. corrugata in having a triaenid bristle on the ventral margin of the mandibular basale, and also in having a smaller carapace. The carapace is also smaller than that of P. abaco, which also differs in having 3 instead of 4 bristles on endite I of the maxilla.