Actinoseta chelisparsa Kornicker 1958

Actinoseta chelisparsa Kornicker, 1958

Actinoseta chelisparsa Kornicker, 1958:244, figs. 43A–L, 46:10A,B, 69A–F, 70A–I; 89H,J,P,Q; 1981a:192, figs. 9o, 11e, 16d, 17e, 72–77, pls. 52–58.

HOLOTYPE.—Ovigerous female, length 2.42 mm, height 1.92 mm (lost).

TYPE-LOCALITY.—Bimini, Bahamas.

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

DISTRIBUTION.—Atlantic Ocean: Florida, Bahamas, Virgin Islands, Bonaire, Curacao, Belize, Panama, Venezuela. Gulf of Mexico: Florida, Texas. Known depth range 1–34 m.

DIAGNOSIS.—Carapace oval in lateral view with small rostrum; left valve overlapping right along posterior and dorsal margins; posterior margin forming angle near midpoint; 3 or 4 low nodes in posterodorsal part of valve (Figure 48).

First Antenna: 8th joint with d-bristle at least length of e-bristle.

Furca: Each lamella with 3 stout claws followed by space and then 2 or 3 short spinous bristles without annulae.

Actinoseta chelisparsa Kornicker, 1958

Actinoseta chelisparsa Kornicker, 1958:244, figs. 43a–l, 46:10a,b, 69a–f, 70a–i, 89h,j,p,q; 1981:192, figs. 9o, 11e, 12c, 16d, 17e, 72–77, pls. 52–58.

HOLOTYPE.—Ovigerous female (lost).

TYPE LOCALITY.—Bimini, Bahamas.

MATERIAL.—Exuma Sound: Sta 94-018, transect AA, USNM 194471, 2 specimens in alcohol.

DISTRIBUTION.—Wall off Lee Stocking Island, Exuma Cays, Sta 94-018, depth 67 m.

Actinoseta chelisparsa Kornicker, 1958

Actinoseta chelisparsa Kornicker, 1958:244, figs. 43A–L; 46:10A,B; 69A–F; 70A–I; 89H,J,P,Q.

HOLOTYPE.—Ovigerous female, length 2.42 mm, height 1.92 mm (lost).

PARATYPE.—USNM 122898, 1 juvenile female, length 1.65 mm, height 1.32 mm, sta 60–1 (Kornicker, 1958:244).

TYPE-LOCALITY.—Bimini, Bahamas.

MATERIAL.—Bahama Islands: USNM 122898, juvenile female, paratype from Bimini; USNM 150283, adult female, sta 57, Andros Island. Bonaire: USNM 150294, ovigerous female, and 1 specimen, USNM 157795, sta 1560; 1 ovigerous female and 1 juvenile, from sta 1567. Florida: USNM 152493, 1 adult female, off Fort Pierce, Gosnold Cruise 222, sta 0262b; USNM 156714, 1 juvenile female, Card Sound. Carrie Bow Cay, Belize: USNM 157177, adult male, sta AC-CBC-20; USNM 157175, 1 juvenile, sta AC-CBC-26; USNM 157185, juvenile male, sta AC-CBC-31; USNM 157176, juvenile male, sta AC-CBC-34; USNM 157181, juvenile, sta AC-CBC-43; USNM 157180, 3 juveniles, USNM 157184, juvenile male, sta AC-CBC-47; USNM 157179, juvenile, sta AC-CBC-56; USNM 157174, juvenile, USNM 157178, adult male, sta AC-CBC-58. Panama, Atlantic Ocean, sta 179, subsample B, 1 juvenile female, USNM 157764. Curaçao: 1 ovigerous female, sta 1457, USNM 157796; 1 ovigerous female, sta 1453a, USNM 157797; 1 specimen, sta 1460, USNM 157798; 1 specimen, sta 1460A, USNM 157799. Venezuela: USNM 157648, 1 adult female.

DISTRIBUTION (Figure 71).—Bimini, Andros Island, Bahamas; Carrie Bow Cay, Belize; Card Sound and off Fort Pierce, Florida; Bonaire; Curaçao; Venezuela; Canal Zone, Panama, Atlantic Ocean. Depth intertidal to 34 m.

DESCRIPTION OF ADULT FEMALE (Figures 72–75, Plates 52–55).—Carapace oval in lateral view with small rostrum (Figures 72, 73a, Plates 52a, 54a,b); left valve overlapping right along posterior and dorsal margins; 3 or 4 low nodes present in posterodorsal part of valve (Plate 52a,b); posterior margin forming angle at midpoint.

Ornamentation: Small fossae with minute processes forming inner ring near edge and spines at bottom abundant over valve surface (Plates 52a,e, 54c, 55a,d); some fossae filled with debris and Drewite (aragonite needles) (Plate 52g,k); surface of valve with pavement of discs with various diameters (Plates 52a-c,e-j, 53b,c, 54); pavement on some specimens covers fossae (Plate 54d,f); edges of discs appearing broken on some discs and complete on others (Plates 52i, 53c); bristles emerging from both open and closed pores scattered over valve surface and along anterior, ventral, and posterior margins (Plates 52g, 53c,d); some bristles with pore near base (note aragonite needles on valve surface) (Plate 53c,d). USNM 150294 brown, USNM 150283 white; (On a broken edge of USNM 150294 the brown layer is seen to be beneath 2 shell layers). A reticulate pore (Plate 55b,c) and fibrous structure observed where outer layer of shell missing (Plate 55b,e).

Hinge Teeth: Intermeshing wedge-shaped teeth along dorsal and posterodorsal margins and external to ligament present on each valve (Plate 53e–g).

Infold: Broad along anterior, ventral, and posterior margins; anterodorsal infold with 50 short and 19 long bristles forming row parallel to valve margin; about 7 minute bristles present between row of long and short bristles and anteroventral valve margin; anteroventral infold with 6 short and several minute bristles; ventral infold with about 25 short bristles near inner margin of infold; posterior infold near inner margin with about 14 stout tubular bristles composed of 3 or 4 tubes (Plate 53j); 1 slender bristle terminating in 3 branches present posterior to each stout tubular bristle (Plate 53j,k); about 50 short tubes present between the stout tubular bristles, up to 6 tubes between each bristle (Plate 53j,l); about 59 short bristles forming row on posterior infold just within edge of valve (Plate 53j); list with lamellar prolongation present near middle of ventral infold.

Central Adductor Muscle Attachment Scars: Consisting of bundles of individual muscles (Plate 53h,i); about 30 minute attachment areas forming cluster visible from outside of valve (Figure 73e).

Size: USNM 150283, length 2.30 mm, height 1.80 mm; USNM 150294, length 2.29 mm, height 1.73 mm; USNM 157794, length 2.29 mm, height 1.72 mm; USNM 157796, length 2.05 mm, height 1.53 mm; USNM 157797, length 1.97 mm, height 1.46 mm; USNM 157648, length 1.97 mm, height 1.48 mm.

First Antenna (Figure 73b,d): 1st joint with spines and hairs on medial and lateral surfaces; 2nd joint with spines along ventral and dorsal margins and 4 dorsal bristles; 3rd joint with 1 terminal bristle on ventral margin and 1 midbristle and 2–3 terminal bristles on dorsal margin; 4th joint with 1 stout terminal bristle on dorsal margin and 2 short terminal bristles on ventral margin; sensory bristle of 5th joint with 5 short filaments and 4 long terminal filaments including stem; 6th joint minute with 1 short medial bristle. Seventh joint: a-bristle forming a stout claw; b-bristle longer than a-bristle, with 3 minute marginal filaments (only 2 visible in Figure 73b) and bifurcate tip; c-bristle slightly longer than sensory bristle of 5th joint, with about 6 short marginal filaments and bifurcate tip. Eighth joint: d-bristle slightly shorter than e-bristle, about same length as a-bristle, both bare; f-bristle bent dorsally, with 3 marginal filaments and bifurcate tip; g-bristle about same length as c-bristle, with 3 distal marginal filaments and bifurcate tip.

Second Antenna (Figure 73c): Protopodite with spinous medial bristle and hairs along ventral and dorsal margins and on medial surface. Endopodite 3-jointed: 1st joint short with 7–8 proximal and 8–10 distal bristles; 2nd joint elongate, tapered, with 10 short bristles along ventral margin; 3rd joint short with long terminal bristle. Exopodite: 1st joint with short, recurved, terminal spine on medial side; bristles of joints 2–8 with natatory hairs; bristles of joints 2–5 also with slender ventral spines; 9th joint with 3 bristles (2 long, 1 short) with natatory hairs; no basal spines present.

Mandible (Figure 74a): Coxale endite with long hairs on ventral margin proximal to ventral branch; minute medial bristle near base of ventral branch; ventral branch with spines forming 8 oblique rows and tip with 2 minute ventral teeth and minute hairs dorsal to teeth on small projection; ventral margin of dorsal branch with 2 small pointed processes followed by 3 larger rounded processes; main spine short with slender spines forming row proximally near its base; margin between main spines and tip of branch serrate; hirsute dorsal bristle with base slightly proximal to tip of branch; dorsal margin of branch serrate. Basale: endite with 9 end bristles, 1 proximal triaenid bristle with 1 set of the paired teeth long, reaching tip of bristle, and 5 short bristles; middle of ventral margin of basale with 3 triaenid bristles and 1 longer bristle with long proximal and short distal spines; medial surface of basale with 1 minute bristle near middle of ventral margin and spines forming clusters on dorsal half; dorsal margin of basale with about 11 proximal bristles, some with bases on lateral side, 4 short subterminal bristles, and 2 long, stout, terminal bristles. Exopodite hirsute, reaching past distal end of 1st endopodite joint, with 2 ventral bristles (proximal of these reaching distal end of 2nd endopodite joint, with short marginal spines; other bristle shorter, bare). Endopodite: 1st joint with 5 spinous bristles forming ventral row with bases on medial surface; 2nd joint with numerous bristles on dorsal margin and on medial surface near dorsal margin, including 2 stout triaenid bristles; ventral margin with 3 long terminal bristles; medial surface with long hairs forming rows; end joint with 3 claws and 3 bristles.

Maxilla (Figure 74b,c): Epipodial appendage hirsute, reaching middle of dorsal margin of basale. Protopodite with 2 endites: proximal endite with 5 long bristles; distal endite with 4 long, 1 medium, and 2 short bristles. Basale: medial surface near dorsal margin with bristles forming 3 groups: proximal group with 7–9 bristles; middle group with 3–4 bristles, distal group with 5 bristles; small bump present at terminal end of dorsal margin; medial surface near ventral margin with 4–6 short proximal bristles, 2 slightly longer distal bristles, and 1 very long, spinous, terminal bristle; medial surface spinous, with 10–11 additional short bristles scattered over surface. Exopodite minute (not forming lobe), with 2 short spinous bristles, the shorter bristle about half the length of longer proximal bristle. Endopodite: 1st joint spinous with 3 short anterior bristles and long spinous beta-bristle; end joint with 2 long and 4 shorter spinous bristles.

Fifth Limb (Figure 74d): Dorsal margin of comb with long hairs along anterior margin; lateral surface with long, spinous, exopodial bristle reaching just past end of comb, 6 short bristles near ventral margin proximal to base of long bristle, and 3 short bristles dorsal and proximal to base of long bristle.

Sixth Limb (Figure 74e,f): Medical surface of anterior margin of proximal anterior part of limb (trunk) with single row of 6 or 7 short bristles dorsal to 4 longer spinous bristles; 3 or 4 short bristles present inward from the long bristles; horizontal suture not reaching anterior end of limb present ventral to the long bristles; about 4 long medial bristles present between suture and broad distal part of limb (skirt); lateral flap of skirt with 3 slender hirsute bristles; anterior end of skirt medial to flap with about 11 bristles; ventral margin of limb posterior to flap with 6–8 long spinous bristles; medial surface of skirt with abundant minute bristles (not all shown on Figure 74e); posterior end of skirt overlapping ventral part, without bristle or with 1 spinous bristle on dorsal margin between posterior tip of skirt and trunk of limb; limb hirsute; no epipodial bristle.

Seventh Limb (Figure 74g): Each limb with 49–51 bristles, 24–26 bristles on each side; each segment with not more than 1 bristle on each side (except rarely; only 1 segment on specimen examined with 2 bristles on one side and 1 on the other); each bristle with up to 7 bells and without marginal spines; terminus consisting of opposing combs, each with about 15 teeth consisting of 5 alate middle teeth with 5 spinous teeth on each side.

Furca (Figure 75a,i): Each lamella with 3 stout claws followed by space and then 2 or 3 short spinous bristles without annulae; each claw with lateral and medial row of teeth along concave margin; minute tooth present on lamellae near inner corner of base of claw 1; teeth grouped with each group consisting of stout tooth and 1–4 smaller teeth.

Eyes: Medial eye bare, pigmented (Figure 75b); lateral eye smaller than medial eye, pigmented, with about 16 ommatidia (possibly more) (Figure 75c,d).

Rod-shaped organ (Figure 75b): Elongate, broadening towards middle and then tapering to rounded tip, suture may be present near proximal end.

Upper Lip (Figure 75b,c): Consisting of left and right hirsute lobes without spines, each with lateral hirsute flap.

Posterior (Figure 75f,g): Elongate hirsute dorsum present; posterior margin between dorsum and furca hirsute. Gills well developed. The dorsum on USNM 150294, which is an ovigerous female, was ventral to the eggs, as if it were holding the eggs to keep them from falling out of the shell when the valves are spread.

Y-Sclerite (Figure 75h): Unbranched.

Eggs: USNM 150294 with 11 eggs in marsupium; USNM 157794, 157796, 157797, each with 8 eggs in marsupium; USNM 157648 with 17 eggs in marsupium.

DESCRIPTION OF ADULT MALE (Figures 76, 77).—Carapace similar to that of adult female but smaller (Figure 76).

Size: USNM 157178, length 1.73 mm, height 1.31 mm; USNM 157177, right valve, length 1.71 mm, height 1.25 mm.

First Antenna (Figure 77a,b): 1st joint with hairs and spines on medial and lateral surfaces. 2nd joint with spines on medial and lateral surfaces, ventral margin, and proximally on dorsal margin; also, with 4 or 5 dorsal bristles. 3rd joint: short ventral margin with 1 subterminal bristle; longer dorsal margin with 1 midbristle and 2 terminal bristles. 4th joint with 3 bristles (1 dorsal, 2 ventral (1 very small)). Sensory bristle of long 5th joint with 4 short proximal filaments and dividing distally into 2 branches, each with 2 long filaments. Medial bristle of short 6th joint small. 7th joint: a-claw about same length as combined joints 5–8, tip of claw rounded; b-bristle reaching past tip of a-claw, with 3 proximal filaments and bifurcate tip; c-bristle reaching just past tip of sensory bristle of 5th joint, with about 8 filaments including stem. 8th joint: d-bristle slender, not quite reaching tip of a-claw; e-bristle stout, slightly longer than b-bristle; f-bristle bent dorsally, with 6 or 7 filaments including stem; g-bristle about same length as c-bristle, with 8 filaments including stem.

Second Antenna (Figure 77c): Protopodite with distal medial bristle, otherwise bare. Endopodite 3-jointed: 1st joint short, with 1 or 2 proximal and 1 distal bristles; 2nd joint long, with 5 or 6 distal, ventral bristles (2 or 3 annulate, 2 with few annulae distally, 1 without annulae); 3rd joint recurved, with 1 bristle proximally on dorsal margin, about 9 teeth along ventral margin, and long, terminal, pointed process with few spines at tip; teeth on knob-like process proximal to tip with minute spines along edges. Exopodite: 1st joint with small medial bristle on terminal margin; bristles of joints 2–8 with spines along part of ventral margin and with natatory hairs; 9th joint with 3 bristles, all with natatory hairs (long ventral bristle with ventral spines; dorsal bristle very short).

Mandible: Coxale endite: small bristle present near base of ventral branch; ventral branch with proximal hairs and spines forming 6 oblique rows, and tip with 3 minute teeth (dorsal of these with few spines); dorsal branch with 5 low teeth along ventral margin, short main spine, hirsute terminal bristle, and few serrations along dorsal margin. Basale endite and ventral margin of basale fragmented on specimen examined; dorsal margin of basale with 3 short proximal bristles and 1 short and 2 long terminal bristles; medial surface of basale with spines forming rows. Exopodite hirsute, tip reaching just past distal end of 1st endopodial joint, with 2 distal bristles. Endopodite: 1st joint with 5 ventral bristles; ventral margin of 2nd joint with 3 long spinous bristles forming single group; dorsal margin and medial surface of 2nd joint with numerous bristles (2 of the cleaning bristles with broad marginal spines); medial surface of 2nd joint with spines forming rows; end joint with 3 long claws (all with ventral teeth), 2 short ventral bristles, and 1 long lateral bristle.

Maxilla: Endopodite: 1st joint with 1 short dorsal bristle and 1 long beta-bristle; end joint with 5 bristles.

Sixth Limb (Figure 77d): 1 short, annulate, medial bristle present in anterodorsal corner; anterior margin of trunk above single anterior suture with 8 bristles; anterior tip of skirt in vicinity of lateral flap with about 10 bristles; ventral margin of skirt posterior to lateral flap with 5 bristles; posterior end of skirt hirsute, with rounded tip without bristle; medial side of skirt with 5 minute bristles near ventral margin, 2 near middle of limb, and 1 just ventral to anterior suture separating trunk and skirt; no epipodial bristles present.

Seventh Limb: Single limb examined with 21 bristles, 9 on 1 side, 12 on other (some bristles could be missing); each segment with not more than 2 bristles, 1 on each side: each bristle with up to 5 bells; terminus consisting of opposing combs, each with 11 teeth consisting of 5 alate middle teeth and 3 spinous teeth on each side of middle teeth.

Furca (Figure 77e): Each lamella with 3 stout claws followed by space and then 1 or 2 short bristles without annulae; distribution of teeth along claws similar to those of adult female.

Eyes (Figure 77f): Medial eye bare, pigmented; lateral eye smaller than medial eye, pigmented, with about 17 ommatidia.

Rod-shaped Organ (Figure 77f): Elongate, broadening towards middle and then tapering to rounded tip; suture near middle.

Upper Lip (Figure 77f), Posterior of Body (Figure 77g), Y-Sclerite (Figure 77g): Similar to those of adult female.

Copulatory Organ: Small.

DESCRIPTION OF JUVENILE FEMALE PARATYPE (Plates 56–58).—Carapace similar in shape to that of adult female and with 3 or 4 low nodes in posterodorsal part of valve (Plate 56a).

Ornamentation: Small fossae with minute processes forming inner ring near edge and spines at bottom abundant over valve surface (Plates 56a,b,d,f-h,l, 57a-d); surface of valve with pavement of discs with various diameters (Plate 56a,d,f,l); edges of discs appearing broken on some discs and complete on others (Plate 56c,l); small shallow fossae forming row along anterodorsal margin of valve near edge (Plate 57d,h); bristles emerging from both open and closed pores scattered over valve surface and along anterior, ventral, and posterior margins (Plates 56b,d-f,i-k, 57a,d,g,h); some bristles with pore near base (Plates 56e,i, 57g), and some bifurcate (Plate 56j).

Hinge Teeth: Intermeshing wedge-shaped teeth along dorsal and posterodorsal margins and external to ligament present on each valve (Plates 57d-f,i 58a-c).

Infold: Broad along anterior, ventral, and posterior margins (Plate 57i); anterodorsal infold with bristles forming row (Plate 57i-k); bristles also present along anteroventral margin (Plate 57l); list along posterior infold with stout tubular bristles composed of 3 or 4 tubes (Plate 58c-f); pore at base of tubular bristle with 4 compartments (observed where bristle partly broken off at base) (Plate 58f,g).

Size: USNM 122898, length 1.65 mm, height 1.32 mm.