Eusarsiella falx Kornicker 1992

Eusarsiella falx

ETYMOLOGY.—From the Latin falx (sickle, scythe).

HOLOTYPE.—MNHN Os 454, undissected adult female in alcohol with choniostomatid egg case in marsupium (visible through shell).

TYPE LOCALITY.—Sta 8-DR, 19 Mar 1977, W Glorioso Islands, 11°29′12″S, 47°18′12″E, depth 250 m.

PARATYPES.—Sta 8-DR: 3 undissected adult females in alcohol. Sta 72-DS: USNM 193782, 1 partly dissected A-1 male in alcohol; USNM 193783, 1 undissected A-1 female in alcohol; USNM 193784, 1 undissected ovigerous female in alcohol; Paris, 3 undissected adult females. Sta 104-DR: Paris, 2 undissected specimens in alcohol. Sta 120-DS: USNM 193710, 1 adult female on slide and in alcohol, 1 undissected adult female, and 1 undissected juvenile in alcohol.

DISTRIBUTION.—Sta 8-DR, W Glorioso Islands, depth 250 m. Sta 72-DS: NNE north reef, Mayotte, depth 300–350 m. Sta 104-DR, N Île du Lys, Glorioso Islands, depth 330–550 m. Sta 120-DS, SE Glorioso Islands, depth 335–390 m. Known depth range 250–550 m.

DESCRIPTION OF ADULT FEMALE (Figures 84–86a–k).—Carapace oval in lateral view with long slender caudal process projecting posteroventrally (Figures 84, 85a, 86a); posterodorsal part of valves bulbous with anterior end of dorsal margin of bulb extending laterally at midlength of dorsal margin of valve (Figure 86b). Valves without prominant rostrum or incisur but with minute overlap at midheight of ventral margin indicating position of rostrum (not shown).

Ornamentation: Surface of valves with abundant round shallow fossae with bare bottoms (Figure 84); area between fossae with numerous short bristles with fairly parallel sides; most bristles with pointed tips, but very few with tips either blunt or with minute bulbs. Lateral surface of valves with few very long slender bristles with stout ribbed bases (not shown); anterior edge of valves with long bristles with stout ribbed bases (Figure 84); similar bristles sparsely distributed along ventral margin. Surface of valves with gelatinous coat covering short bristles.

Infold: Anterior infold with small bristle at inner margin just ventral to valve midheight (Figure 86c). Infold of caudal process with 7 or 8 small bristles forming row across base (Figure 86d); 2 setal bristles near outer edge of infold just dorsal to caudal process; 2 bristles at inner edge of infold just anterior to caudal process.

Selvage: Broad lamellar prolongation with smooth outer edge along anterior (Figure 86c), ventral, and posterior valve margins, and forming flap at distal end of caudal process (dashed in Figure 86d).

Central Adductor Muscle Attachments (Figure 85a): Comprising about 13 small oval attachments.

Carapace Size (specimen oriented so that caudal process does not enter into height measurement): MNHN Os 454, holotype, length with caudal process 1.73 mm, length without caudal process 1.46 mm, height 1.37 mm; USNM 193710, length with caudal process 1.86 mm, length without caudal process 1.74 mm, height 1.41 mm. Sta DR-8, 3 specimens: length with caudal process 1.75 mm, length without caudal process 1.55 mm, height 1.37 mm; length with caudal process 1.63 mm, length without caudal process 1.55 mm, height 1.37 mm; length with caudal process 1.63 mm, length without caudal process 1.50 mm, height 1.34 mm. Sta 72-DS, 2 specimens: ovigerous, length with caudal process 1.38 mm, length without caudal process 1.35 mm, height 1.09 mm; nonovigerous, length with caudal process 1.56 mm, length without caudal process 1.32, height 1.17 mm.

First Antenna (Figure 85b): 1st joint bare. 2nd joint with spines forming rows along dorsal and ventral margins, and on lateral surface near ventral margin, and 1 long dorsal bristle with long proximal hairs and short distal spines. 3rd and 4th joints fused; 3rd joint short with 2 long bristles (dorsal bristle with long proximal hairs and short distal spines; ventral bristle with long hairs becoming shorter distally along bristle). 4th joint long, with 2 bristles, both with short distal hairs or spines (ventral bristle more than twice length of dorsal bristle). Sensory bristle of 5th joint with minute filament proximal to midlength and terminal spine. 6th joint fused to 5th, with small bare medial bristle. 7th joint: a-bristle more than twice length of bristle of 6th joint, with short marginal spines; b-bristle longer than a-bristle, bare except for terminal spine; c-bristle about same length as sensory bristle of 5th joint, with 2 distal and 1 subterminal minute filaments, and terminal spine. 8th joint: d-and e-bristles shorter than c-bristle, bare with blunt tips; f-bristle about same length as d- and e-bristles, bare except for terminal spine; g-bristle about same length as c-bristle, with 3 small marginal filaments (proximal longer).

Second Antenna (Figure 85c): Protopodite bare. Endopodite 2-jointed: 1st joint with 2 short bare proximal anterior bristles; 2nd joint small with long terminal bristle with short marginal spines and terminal spine. Exopodite: 1st joint with small recurved medial terminal tubular bristle; bristle of 2nd joint long, with few long proximal dorsal hairs, then 12 short nub-like ventral spines followed by 4 long slender ventral spines, then distal ventral and dorsal natatory hairs; bristle of joint 3 with few long proximal dorsal hairs, then 12 nub-like spines followed by 4 long slender ventral spines, then ventral and dorsal natatory hairs; bristle of joint 4 with few long proximal dorsal hairs, then 10 ventral nub-like spines followed by 5 long slender ventral spines, then ventral and dorsal natatory hairs; bristles of joints 5 and 6 each with few long proximal dorsal hairs, then 7 ventral spines (some nub-like) followed by ventral and dorsal natatory hairs; bristles of joints 7 and 8 each with few proximal ventral hairs, then 5–7 ventral spines (bristle of 7th joint with only 1 nub-like spine, bristle of 8th joint with none) followed by ventral and dorsal natatory hairs. 9th joint with 2 bristles: ventral long with natatory hairs, no spines; dorsal short with short hairs. Joints 2–6 with minute spines forming short distal row. (The small nub-like ventral spines on some bristles may be an aberrance but are on both limbs of USNM 193710.)

Mandible (Figure 85d): Coxale endite represented by stout spine with 2 minute spines at tip. Coxale with long hairs and spines along ventral surface. Basale: ventral margin with 3 ringed bristles with bases on medial side just proximal to sclerotized internal boss and 3 small bristles distal to boss (1 medial, 2 lateral); dorsal margin with 1 small pointed spine-like bristle distal to midlength and 2 terminal (medial minute spine-like, lateral longer, weakly ringed). 1st endopodial joint: medial surface with spines forming rows, slender spines forming row in distal dorsal corner, and small spine-like bristle at base of long ventral claw; proximal dorsal edge of claw with minute perpendicular internal lineations (Figure 85d). 2nd endopodial joint with stout ventral claw and small dorsal bristle. 3rd endopodial joint with stout terminal claw, and 2 small bristles at base (1 dorsal, 1 longer ventral).

Maxilla (Figures 85e, 86e–h): Precoxale and coxale with dorsal fringe (Figure 85e). Endite I with 6 bristles (Figure 86e); endite II obscured on mounted specimen but with 4 bristles visible (Figure 86f); endite III with 6 bristles (Figure 86g). Coxale with short bare dorsal bristle. Basale with short bristle (with widely separated marginal spines) near base of exopodite. Exopodite small with 2 bristles (long spinous bristle more than twice length of short bare bristle) (Figure 85e). 1st endopodial joint with distal spines along anterior margin, 1 alpha-bristle (1 tooth proximal to ringed part, slender spines along ringed part), and 1 beta-bristle (few teeth proximal to ringed part, short spines along ringed part). 2nd endopodial joint with 2 slender ringed a-bristles with minute indistinct spines (posterior bristle longer), 1 slender bare ringed c-bristle, and 5 stout terminal pectinate bristles.

Fifth Limb (Figure 85f): Single endite with 1 bare bristle. 1st exopodial joint with 2 spinous bristles (spines stouter and longer on longest bristle). 2nd to 5th exopodial joints almost completely fused, but comprising 2 lobes with 4 terminal bristles on inner lobe and 1 proximal and 5 terminal bristles on outer lobe (proximal bristle could have base on inner lobe), both lobes hirsute.

Sixth Limb (Figure 85g): Single endite with 3 bare bristles (1 medium, 2 short). End joint with 11 or 12 spinous bristles along ventral margin and 2 hirsute posterior bristles. Posterior edge of limb and lateral and medial sides near posterior edge hirsute.

Seventh Limb (Figure 85h): Each limb with 2 proximal bristles (1 on each side on same or different segments; each with 4 or 5 bells) and 6 terminal bristles (3 on each side, each with 3–8 bells). Terminus with opposing combs, each with 6 or 7 teeth (not all shown).

Furca (Figure 86i): Each limb with 5 claws; claw 1 nonarticulated, others articulated; posterior margin of each claw with many slender teeth between few stout teeth; margin of lamellae following claw 5 with 3 or 4 teeth on right lamella and 5 or 6 on left; medial hairs at base of claw 1; anterior margins of right and left lamellae with few minute spines (more on right). Right lamella anterior to left by about width of base of claw 1.

Bellonci Organ (Figures 85i,j, 86j): Elongate, broadening distally, with broadly rounded tip.

Eyes: Medial eye bare, with brown pigment (Figures 85i,j, 86j). Lateral eye with light brown pigment, with 4 or 5 small light amber-colored ommatidia (Figure 85j).

Upper Lip (Figure 85i): With rounded projecting tip.

Genitalia (Figure 86i,k): Round sclerotized ring on each side of body anterior to base of furca.

Anterior of Body (Figure 85i): Midline of anterior of body between medial eye and upper lip without anterior process, but a triangular process present lateral to midline on anterior edge of sclerotized rim of socket for base of mandible.

Posterior of Body (Figure 86k): Bare.

Y-Sclerite (Figure 86k): Typical for subfamily.

Eggs: USNM 193710 with 2 large unextruded eggs; USNM 193784 with 2 eggs in marsupium (Figure 86a).

Parasites: Holotype and 3 paratypes (from same sample as holotype) with choniostomatid ovisacs in marsupium; the valves were not opened but the ovisacs are visible through shell (eggs of the ostracode may also be present but could not be identified with certainty). USNM 193710 with 2 choniostomatid ovisacs in marsupium.

DESCRIPTION OF A-1 MALE (Figure 86l–p).—Carapace with more truncate posterior margin than that of adult female (Figure 86l), but with similar bristles on outer surface.

Carapace Size: USNM 193782, length with caudal process 1.19 mm, length without caudal process 1.01 mm, height 0.85 mm.

First Antenna: Ventral bristle of 4th joint just reaching distal margin of 8th joint; limb otherwise similar to that of adult female, but filaments of bristles of end joints not counted.

Second Antenna: Protopodite and exopodite similar to those of adult female except for bristles having pointed spines (no nub-like spines as on some female bristles). Endopodite 2-jointed (Figure 86m): 1st joint similar to that of adult female; 2nd joint larger than that of adult female and with 2 bristles (anterior bristle short).

Mandible, Maxilla, Fifth and Sixth Limbs: Not examined in detail, but appearing similar to those of adult female.

Seventh Limb (Figure 86n): Well developed, with 2 tapered proximal bristles (1 on each side), each with 3 bells, and 4 tapered terminal bristles (2 on each side), each with 3 or 4 bells. Terminus with opposing combs.

Furca, Bellonci Organ, Upper Lip, Anterior and Posterior of Body, and Y-Sclerite: Similar to those of adult female.

Eyes (Figure 86o): Medial eye similar to that of adult female. Lateral eye with light browm pigment and indistinct ommatidia.

Genitalia (Figure 86p): Comprising 2 small lobes (1 with 1 or 2 minute bristles) on each side of body.

Remarks: The specimen was identified as male by its genitalia. The endopodite of the 2nd antenna indicates that the endopodite of the adult male will be 2-jointed and not prehensile. The 7th limb indicates that the limb of the adult male will be well developed and have terminal combs.

DESCRIPTION OF A-1 FEMALE (Figure 86q).—Carapace similar in outline to that of A-1 male and with similar bristles on outer surface (Figure 86q).

Carapace Size: USNM 193783, length with caudal process 1.28 mm, length without caudal process 1.04 mm, height 0.93 mm.

First Antenna: Ventral bristle of 4th joint about 1 times length of 5th joint; limb otherwise similar to that of adult female.

Second Antenna, Mandible, Maxilla, Fifth and Sixth Limbs, Furca, Bellonci Organ, Eyes, Upper Lip, Anterior and Posterior of Body, and Y-Sclerite: Not examined in detail but appearing similar to those of adult female.

Seventh Limb: Similar to that of A-1 male.

Genitalia: Not developed.

COMPARISONS.—The following combination of characters distinguishes female E. falx from females of other species of Eusarsiella. Shell: large size of shell (length 1.38–1.86 mm including caudal process, 1.32–1.74 excluding caudal process), absence of ribs on carapace, elongate caudal process, row of 7 or 8 bristles across base of infold of caudal process. Appendages: ventral bristle on 3rd joint of 1st antenna unusually long (length 52% of combined lengths of joints 2–8 measured at midwidth), ventral margin of 4th joint of 1st antenna with only 1 bristle, endopodite of 2nd antenna with small 2nd joint bearing long terminal bristle (length of bristle 90% length of endopodite (including both joints)). Based on study of the A-1 male, the adult male of E.falx probably will not have a prehensile endopodite of the 2nd antenna, and the 7th limb will be well developed with bristles and terminal teeth.

Chelicopia Kornicker, 1958

Chelicopia Kornicker, 1958:253.—1986a:28.—Poulsen, 1965:56.

TYPE SPECIES.—Chelicopia arostrata Kornicker, 1958:253, monotypy.

DISTRIBUTION.—Bahama Islands; Pacific coast of El Salvador; Scammon Lagoon, Baja California, Mexico; Tasman Sea off the west coast of South Island, New Zealand; Lizard Island, Australia; Mozambique Channel. Known depth range 1–768 m.

COMPOSITION.—Including 2 new species described herein the genus comprises 8 species, but 2 of them C. kornickeri McKenzie, 1965:69, and C. rotunda (Hartmann, 1959:199) may be junior synonyms of C. arostrata Kornicker, 1958:253 (see “Remarks” below).