Actinoseta jonesi Kornicker 1981

Actinoseta jonesi Kornicker, 1981

Actinoseta jonesi Kornicker, 1981a, figs. 9p, 85–87, pls. 62–65.

HOLOTYPE.—USNM 157636, ovigerous female.

TYPE-LOCALITY.—West of Punta Charagata, Isla Cubaque (S. of Isla de Margarita), Venezuela, depth less than 1.5 m.

MATERIAL.—No new material.

DISTRIBUTION.—Collected only at type-locality.

DIAGNOSIS.—Carapace similar to that of A. monambon except without the 3 minute processes in the posterdorsal part of the valve present in many specimens of that species (Figure 50).

First Antenna: d-bristle of 8th joint only about length of e-bristle.

Asteropella Kornicker, 1975

TYPE-SPECIES.—Asteropella mortenseni Poulsen, 1965, by subsequent designation, Kornicker, 1975.

DISTRIBUTION.—Gulf of Mexico, Atlantic and Pacific Oceans in vicinity of North, Central, and South America between latitudes of about 37°30′N and 41°48′S. Known depth range intertidal to 57 m.

COMPOSITION.—This genus contains the following species in the study area: A. agassizii (Fritz Müller, 1870), A. monambon (Kornicker, 1958), A. punctata Poulsen, 1965, A. mortenseni Poulsen, 1965, A. maclaughlinae Kornicker, 1981, A. kalkei, new species, and A. pax, new species.

Actinoseta jonesi

ETYMOLOGY.—The species is named for Dr. Meredith L. Jones, who collected the specimens from Venezuela.

HOLOTYPE.—USNM 157636, ovigerous female, on slides and in alcohol.

TYPE-LOCALITY.—Station M-9, Venezuela.

PARATYPES.—From same samples as holotype: adult females, USNM 157635, 157637, 157649, 157650.

NON-TYPES.—USNM 157700, 11 unopened specimens, 2 right valves and 1 left valve.

DISTRIBUTION (Figure 71).—Known only from type-locality. Depth intertidal to 1.5 m.

DESCRIPTION OF ADULT FEMALE (Figures 85–87, Plates 62–65).—Carapace oval in lateral view, with relatively small rostrum having lower edge forming right-angle (Figure 85a,b, Plate 62a); left valve larger than right; in dorsal view, anterior slightly more acuminate than posterior (Plate 63a).

Ornamentation: Surface of each valve with numerous round-to-irregular platelets (Plates 62a-c, 63b); surface between platelets with smooth areas, possibly representing places where platelets were once present (Plate 62b-d), oval crustose areas (Plate 62b-e), smaller reticulate structures (Plate 62d,e), and shallow fossae with about 5 minute papillate processes around the edge (Plates 62b,c, 63c,d); papillate bristles emerging from open pores with low narrow rim sparsely distributed over valve surface (Plate 62c,d,f); some bristles emerging from closed pores (Plate 63b).

Hingement: Teeth and sockets forming row along dorsal margin outside of ligament on each valve (Plates 63a,b,e,f, 64a,f); teeth and sockets of left valve bearing papillae (Plate 64a,f).

Infold: Normal for genus (Plates 63e, 64b-d, 65b-e).

Selvage: Narrow selvage along anterior margin of rostrum serrate (Plates 64b,e, 65a).

Size: USNM 157636, length 2.16 mm, height 1.65 mm; USNM 157635, length 2.05 mm, height 1.58 mm; USNM 157637, length 2.21 mm, height 1.37 mm; USNM 157649, length 2.13 mm, height 1.68 mm; USNM 157650, length 2.12 mm, height 1.61 mm.

First Antenna (Figures 85c,d): 1st joint: lateral side with long hairs near ventral margin and short spines forming rows on dorsal half; medial side with long hairs near ventral margin. 2nd joint: ventral margin with long hairs; dorsal margin with proximal and distal hairs, 3 proximal bristles, and 1 distal bristle. 3rd joint: short ventral margin with 1 bristle; long dorsal margin with 1 bristle near middle and 2 terminal. 4th joint: long ventral margin with 3 terminal bristles (2 long, 1 minute); short dorsal margin with 1 long terminal bristle. 5th joint: sensory bristle with 3 or 4 short marginal filaments and branching distally, with bifurcate tip on each branch. 6th joint with short medial bristle. 7th joint: a-bristle clawlike, smooth; b-bristle about one-third longer than a-bristle, with 4 marginal filaments and bifurcate tip; c-bristle reaching past tip of sensory bristle of 5th joint, with 5 marginal filaments and bifurcate tip. 8th joint: d-bristle about one-tenth length of e-bristle, with blunt tip; e-bristle much stouter than d-bristle, slightly longer than a-bristle, bare with blunt tip; f-bristle bent dorsally in proximal section, about same length as b-bristle, with 4 or 5 ventral filaments and bifurcate tip; g-bristle about same length as c-bristle, with 6 marginal filaments and bifurcate tip.

Second Antenna (Figure 85e): Protopodite with spines along ventral and dorsal margins and on medial surface, and 1 distal medial bristle with terminal spine. Endopodite 3 jointed: 1st joint with 10–16 proximal and 4–7 distal bristles; 2nd and 3rd joints fused; 2nd joint elongate, with 3–6 short ventral bristles; 3rd joint short with long terminal bristle with blunt tip. Exopodite: 1st joint with minute spine on distal margin; bristle of 2nd joint very long, with natatory hairs and slender ventral spines; bristles of joints 3–8 with natatory hairs and slender ventral spines; 9th joint with 3 bristles (2 long with natatory hairs and ventral spines, 1 short, dorsal, with only natatory hairs); no basal spines or spines forming row along distal margins of joints 2–8. The distribution of bristles on the 1st and 2nd endopodial joints of 5 specimens is tabulated below.

Mandible (Figure 85f–h): Coxale endite: minute bristle present near base of ventral branch; ventral branch with proximal hairs forming rows, spines forming 5 oblique rows, and tip with 3 minute teeth; ventral margin of dorsal branch with 3 nodes proximal to main spine; 6 stout spines present near base of main spine; main spine with slender teeth along both margins; margin distal to main spine with small teeth followed by hairs and then long bristle; dorsal margin of dorsal branch serrate. Basale endite: tip with 4 end-type bristles; ventral margin with 5 triaenid bristles (proximal of these with single pair of very long teeth between rows of smaller teeth); dorsal margin with 5 dwarf bristles (distal of these much longer than others). Basale: ventral margin with 2 triaenid bristles with 1 pair of very long teeth, 1 longer triaenid bristle with 1 pair of teeth only slightly longer than others, and 1 long, distal, spinous bristle; medial surface spinous, with 2 minute bristles near ventral margin; dorsal margin with clump of about 15 proximal bristles and 5 or 6 distal bristles (3 or 4 short and 2 very long). Exopodite spinous, reaching past distal end of 1st endopodial joint, with 2 ventral bristles. Endopodite: 1st joint with 6 ventral bristles; ventral margin of 2nd joint with 3 distal bristles; dorsal margin and medial side near dorsal margin of 2nd joint with numerous bristles (2 of the cleaning bristles with broad distal spines, Figure 85h); medial surface with long slender spines forming rows; end joint with 3 long claws (dorsal of these shorter than others and with ventral spines), 1 long lateral bristle, and 1 short ventral bristle.

Maxilla (Figure 86a): Epipodial appendage with pointed hirsute tip reaching past middle of dorsal margin of basale. Endite I with 3 long bristles; endite II with 2 long bristles; endite III with 3 stout bristles of unequal length; 5 small bristles present near bases of stout bristles of endite III. Basale: dorsal margin with 14 or 15 proximal bristles with bases on medial side, 3 bristles distal to middle, and 5 distal bristles; medial side with 2 or 3 proximal and 2 distal bristles; ventral margin with 7 short bristles, 1 longer, spinous, distal bristle, and 1 very long terminal bristle. Exopodite represented by 1 short bristle. Endopodite: 1st joint spinous, with 2 proximal anterior bristles and 1 long spinous beta-bristle; end joint with 5 or 6 bristles.

Fifth Limb (Figure 85i): Lateral side of comb with 3 small proximal bristles near dorsal margin, 1 long, stout, spinous, exopodial bristle, 2 minute bristles just ventral to base of stout bristle, and 6 small bristles proximal and ventral to base of stout bristle; tip of comb with long hairs; ventral margin with spinous bristles forming 2 rows.

Sixth Limb (Figure 87a): Anterior margin with short suture separating trunk and skirt; anterior margin of trunk with about 15 bristles, all with bases on medial side; lateral flap with 4 spinous bristles; ventral margin of skirt with about 11 bristles at anterior end and 7 long bristles along middle part; medial side of limb with abundant hairs and many minute bristles with slender spine at tip; posterior end of skirt hirsute, rounded, without bristles; no epipodial bristles.

Seventh Limb: Each limb with about 47 bristles, 23 or 24 on each side; each bristle with up to 6 bells; each joint generally with 2 bristles, 1 on each side; terminus with opposing combs, each with about 16 spinous teeth (Figure 85j).

Furca (Figure 87b): Each lamella with 3 main pectinate claws followed by 3 small bristles; a small tooth present on lamella near inner corner of base of claw 1; anterior bristle of left lamella slightly closer to claw 3 than anterior bristle of right lamella; a few short spines present along anterior edge of lamella; long medial hairs present on lamella near bases of claws 1 and 2.

Rod-shaped Organ (Figure 86b): Elongate, broadening near middle, with rounded tip; a suture may be present proximal to middle.

Eyes (Figure 86b): Medial eye bare with dark brown pigment; lateral eye smaller than medial eye, pigmented dark brown making ommatidia difficult to count, possibly about 9.

Upper Lip (Figure 86b): Each lobe with anterior spine and many hairs; hirsute lateral flap present on each side of mouth.

Posterior (Figure 86c): Posterior of body hirsute; dorsum fingerlike, with tip consisting of posterior spinous lobe and bare anterior process.

Eggs: USNM 157636 with all 18 well-developed eggs (bearing lateral eyes) in marsupium; USNM 157635—13 eggs; USNM 157637—18 eggs; USNM 157649—15 eggs.

COMPARISONS.—The new species, Actinoseta jonesi, differs from previously described species of the genus in that the d-bristle of the 1st antenna is only about one-tenth the length of the e-bristle. The carapace of A. jonesi does not have ridges that are present on the carapace of A. hummelincki, and does not have the 3 minute processes in the posterodorsal part of the valve present on many specimens of A. chelisparsa. The rostral projection of A. jonesi is generally slightly less than that of A. chelisparsa. The fossae appear to be more abundant and deeper on valves of A. chelisparsa than on A. jonesi.

Actinoseta jonesi er en art av slekten Actinoseta i familien Cylindroleberididae som er den ene av fem familier innenfor ordenen Myodocopida, under klassen av muslingkreps som er små krepsdyr. Denne familien har 23 slekter og 70 arter. Mye av den tidlige forskningen, inklusive beskrivelsen av Myodocopida-gruppen, er gjort av den norske marinbiologen og havforskeren Georg Ossian Sars.

Gruppen Cylindroleberididae har arter med mykt skall (carapax) på overkroppen (thorax) og lang ytter-gren (i stedet for lang inner-gren) på andre antenne-par. Det særegne for artene er at antennen sitter på et feste med en nebb-liknende utvekst (rostrum). Individene er små.