Cypridinodes relax Kornicker ex Kornicker & Thomassin 1998

Cypridinodes relax

ETYMOLOGY.—From the Latin relax (loosen, slacken, unbend).

HOLOTYPE.—Ovigerous female on slide and in alcohol.

TYPE LOCALITY.—BT-620.

PARATYPES.—BT-620: USNM 194216, ovigerous female on slide and in alcohol; USNM 194225, partly dissected ovigerous female; USNM 194226, partly dissected adult male. BT-779: USNM 194218, adult male on slide and in alcohol.

DISTRIBUTION.—See type specimens, above.

DESCRIPTION OF ADULT FEMALE (Figures 11–14a–f).—Carapace with convex ventral and dorsal margins (Figure 11a); anterior margin of rostrum convex (Figure 11a,d): caudal process small, triangular, with straight or convex posterior edge (Figure 11f,g); neither valve with lunate process ventral to incisur (Figure 11a–c,e); edge of anteroventral corner of valve with 0–7 short bristles (bristles shown on Figures 11e, 14d).

Ornamentation: Surface appearing smooth without fossae or reticulations.

Infold: Rostral infold with about 27 bristles, some bifurcate, and pair of additional bristles near inner end of incisur (Figure 11d); anteroventral and ventral infold with narrow list with posterior end at ventral end of caudal process (Figure 11f); ventral list from point at anterior of valve to caudal process stout on both valves, but stouter and closer to valve edge on right valve than on left; anteroventral infold of right valve (from incisur to anterior end of stout part of list) with single row of about 65 bristles; left valve with about same number of anteroventral bristles, but some distal to list, and with about 10 additional bristles along anterior end of stouter part of list (Figure 11e; not all bristles shown). Infold of caudal process with 25–29 digitate striated processes and several slender bristles (Figure 11f,g; not all shown); on right valve only, small bristle present at inner edge of infold near ventral end of caudal process (Figure 11g). Posterior and dorsal edges of caudal process with 8–14 minute bristles and many short straight pore canals (Figure 11f,g).

Selvage: Lamellar prolongation with narrow striations and smooth outer edge present along dorsal edge of rostrum anterior to hinge and along anterior margin of rostrum (not shown). Prolongation absent along dorsal edge of incisur; prolongation along ventral edge of incisur broad, narrowly striated, and with indistinct pustules (striations and pustules not shown in Figure 11c,e); incisur narrow for short distance just anterior to anteroventral corner of valve, then broadens along ventral margin (Figure 11c); outer edge of prolongation along anteroventral and ventral margins minutely serrate; prolongation absent along posterior and dorsal edges of caudal process in vicinity of short straight pore canals.

Hingement: Same as male.

Carapace Size (length, height in mm): BT-620: holotype, 2.75, 1.92; USNM 194216, 2.76, 1.95; USNM 194225, 2.79, 2.02.

First Antenna (Figure 11h,i): 1st joint bare. 2nd joint with spines. 3rd joint with oblique distal margin, few rows of lateral spines, spinous proximal dorsal bristle, and terminal ventral bristle. 4th joint with medial spines near ventral margin (not shown), 2 distal bristles (1 ventral, 1 dorsal). Sensory bristle of 5th joint with 9 long slender filaments followed by 3 shorter and slenderer filaments and bifurcate tip. 6th joint with short medial bristle. 7th joint: a-bristle longer than bristle of 6th joint, with few short spines; b-bristle about 4 times length of a-bristle, with 5 short filaments; c-bristle about longer than bristle of 5th joint, with 9 filaments and bifurcate tip. 8th joint: d- and e-bristles about same length as sensory bristle of 5th joint, bare with blunt tips; f-bristle shorter than c-bristle, with 9 filaments and bifurcate tip; g-bristle similar to c-bristle.

Second Antenna: Protopodite with small medial bristle (Figure 12a). Endopodite 3-jointed (Figure 12a): 1st joint with 4 proximal bristles (1 long, 3 short) and 1 long spinous bristle near midlength; 2nd joint long bare; 3rd joint short with long terminal filament. Exopodite: bristle of 2nd joint reaching well past 9th joint, with 1 slender ventral spine followed by 8 stouter spines, and 3 hair-like dorsal spines (Figure 12b); bristles of joints 3–8 with natatory hairs, no spines; 9th joint with 4 bristles (1 short dorsal, 1 medium, 2 long), all with natatory hairs; joints 2–8 with stout basal spines increasing in length on distal joints (spine of 8th joint about twice length of 9th joint); 9th joint with lateral spine about length of joint; joints 3–8 with minute spines along distal edges.

Mandible (Figure 12c–e): Coxale endite spinous with 2 stout terminal spines with minute peg between them; coxale with small bristle near base of endite. Basale: ventral margin with 2 small a-bristles, 1 small b-bristle with base lateral, 2 c-bristles (longer with few indistinct short spines), and 2 d-bristles (longer with wreaths of long spines and short spines distal to last wreath); dorsal margin with 1 distal and 2 terminal bristles, all with short spines; medial surface with few rows of distal indistinct spines near dorsal margin. Exopodite about same length as dorsal margin of 1 st endopodial joint, hirsute, with 2 bristles (proximal slightly longer and with indistinct short spines). 1st endopodial joint with 4 ventral bristles (1 minute bare medial, 1 short medial with short spines, 2 long stout with short and long spines). 2nd endopodial joint narrows at about length (in vicinity of proximal ventral bristle); ventral margin spinous, with 2 single ringed bare bristles with slender tubular tips and paired terminal bristles (medial unringed sclerotized, broader, longer; lateral ringed and with slender tubular tip); dorsal margin with 7 long spinous ringed bristles (Figure 12c), 2 short ringed distal bristles with short marginal spines, 6 short proximal bristles with stout spines and proximal rings (Figure 12d), 10 or 11 short proximal unringed bristles (with indistinct slender anterior spines) with bases slightly medial to bases of the short bristles with stout spines, and 2 short bristles (with indistinct slender anterior spines and proximal rings) proximal to most bristles; medial surface with rows of spines. 3rd endopodial joint (Figure 12e) with short dorsal part bearing 2 ringed bare bristles (lateral bristle longer, claw-like with pointed sclerotized tip; shorter bristle medial and with tubular tip), and longer ventral part bearing 2 unringed claws (medial about longer, both with proximal ventral teeth), 2 long ringed ventral bristles (with few proximal ventral spines) with tubular tips, and 1 minute ringed bare ventral bristle with tubular tip. (Rings and spines of many bristles not shown.)

Maxilla (Figure 12f–k): Endite I with about 8 bristles (Figure 12f); endite 11 with 5 bristles (Figure 12g), endite III with 1 proximal and 6 terminal bristles (Figure 12g (proximal bristle not shown)). Precoxale with dorsal fringe of hairs (not shown). Coxale with ringed bare dorsal bristle (Figure 12h). Basale with ringed ventral bristle with few indistinct spines (Figure 12h). Exopodite elongate with 3 ringed bristles (1 short bare subterminal; 2 long terminal (1 bare, other with few long spines)) (Figure 12h). 1st endopodial joint with 2 ringed alpha-bristles (1 long bare except for long hairs near hooked tip (with or without minute tooth proximal to hooked tip), 1 shorter with long proximal spines), and 3 ringed beta-bristles (inner bristle short slender bare, 2 outer bristles stouter and longer and with recurved marginal teeth) (Figure 12i). 2nd endopodial joint with 4 a-bristles (3rd from anterior pectinate, others bare) (Figure 12j), 3 pectinate ringed b-bristles, 3 ringed c-bristles (inner short bare, others with long curved teeth), and 3 stout pectinate d-bristles (posterior ringed, others unringed) (Figure 12k). (Rings not shown on all bristles.)

Fifth Limb: With 3 endites (not all bristles shown on endites II and III in Figure 13a). Anterior process of protopodite short with rounded tip (stippled in Figure 13b,c). Exopodite: anterior side of 1st joint with row of 3 closely spaced bristles (inner ringed, short, slender, with long proximal hairs; middle and outer bristles stout, with distal rings and long proximal and short distal spines) and 1 or no bristle closer to protopodial process (Figure 13b,c); main tooth comprising proximal triangular peg (with few indistinct spines at tip) and 6 cuspate teeth (Figure 13a); bristle with long proximal spines proximal to triangular peg. 2nd joint with posterior c-bristle with short spines (Figure 13a), anterior d-bristle with long proximal hairs (Figure 13c,d), 4 ringed pectinate a-bristles (Figure 13a) (the longest a-bristle could be a b″-bristle), 5 ringed pectinate b′-bristles (Figure 13e), and 4 b″-bristles (3 with very large teeth and mostly unringed) (Figure 13f). 3rd joint (Figure 13d): inner lobe with 3 bare bristles (1 proximal short ringed, 2 longer terminal, ringed only in proximal half, and with curved tips); outer lobe hirsute, with 2 ringed bristles with indistinct spines and slender tips. 4th and 5th joints fused, with total of 5 ringed bristles (3 on inner corner (1 with stout spines, others bare or with few indistinct spines), and 2 on outer corner (1 with stout spines, other bare or with few indistinct spines)) (Figure 13d).

Sixth Limb (Figure 13g): With 4 epipodial bristles. Endite I with 3 bristles (2 short medial, 1 long terminal); endite II with 5 bristles (2 short medial, 2 long terminal, and 1 minute medial near bases of long bristles); endites III and IV each with 1 hirsute medial bristle and 2 long terminal bristles with minute medial bristle between them. End joint hirsute, posteriorly extended, with 22 anteroventral bristles (many with bases on medial side), 5 posteroventral bristles with bases on medial side some distance from ventral margin, and 2 broad plumose posterior bristles (only proximal parts shown).

Seventh Limb (Figure 13h–j): Terminal segment with 4 ventral bristles (with 3–5 bells) and 3 bristles proximal to teeth (1 on one side, 2 on other, each with 3–5 bells). Proximal bristles comprise 5 or 6 on ventral side and 7 on dorsal jaw side; all bristles with 3 bells. Total number of bristles 19 or 20. Stout dorsal jaw with marginal row of 7 stout pointed teeth (not all shown), and 4 slender indistinct teeth on each end of row. Comb with 7 long teeth (terminal tooth longest) and 8 shorter teeth (4 on each side), all teeth with rounded tips; small pointed process projecting inward within arc of teeth (Figure 13i).

Furca (Figure 14a,b): Each lamella with 7 claws; claw 2 either nonarticulated (Figure 14a) or weakly articulated (faint suture at base of claw (Figure 14b)). All claws with row of teeth along posterior edges, some teeth slightly stouter than others; claws 1–5 with medial row of teeth; medial row of claw 1 with about 25 teeth of which distal 8 teeth larger; right lamella anterior to left by about width of base of claw 1. (Not all teeth shown on claws.)

Bellonci Organ (Figures 13k, 14e,f): Cup-shaped or cylindrical.

Eyes: Medial eye unpigmented, bare (Figures 13k, 14e,f). Lateral eye about larger than medial eye, with 16 amber-colored ommatidia with black pigment between them (Figures 11a, 13l).

Upper Lip (Figure 14c): Anterior part with 4 short pairs of processes followed by 1 longer pair (in lateral view each pair appears as single process). Posterior part with elongate pointed tusks without glandular processes (each tusk with row of stout lateral hairs near posterior edge), and a posterior proximal serrate process with 5 teeth; hirsute rounded process present between serrate process and mouth (not shown).

Genitalia: Not observed.

Posterior of Body: Evenly rounded, bare.

Y-Sclerite (Figure 14a): Typical for subfamily.

Pigmentation: Black pigment in lateral eyes.

Eggs: Holotype with 38 colorless eggs (some with faint eyes and developing, incipient antennae visible, membrane absent) in marsupium, length (mm) of 3 typical eggs: 0.31, 0.30, 0.31. USNM 194216 with 31 amber-colored eggs (without eyes) in marsupium, length of typical egg excluding membrane: 0.34 mm. USNM 194225 with 15 amber-colored eggs in marsupium, length of typical egg (with visible eyes and antennae) including transparent membrane: 0.41 mm; excluding membrane: 0.345 mm.

DESCRIPTION OF ADULT MALE (Figures 14g–j, 15): Carapace similar in shape to that of adult female (Figure 14g).

Ornamentation: Surface appearing smooth without reticulations; small bilobed pores present but sparse.

Infold: Rostral infold with about 20 bifurcate bristles, and pair of additional bristles near inner end of incisur; list similar to that of adult female. Infold of right valve (from incisur to anterior end of stout part of list) with about 49 bristles mostly along list but some distal to it; left valve with about 55 bristles similarly distributed plus about 7 bristles along anterior end of stouter part of list. Infold of caudal process with 23–26 processes and several slender bristles (Figure 14i,j (not all processes or bristles shown)). Posterior and dorsal edges of caudal process with 6–8 minute bristles and many short straight pore canals (not shown).

Selvage: Similar to that of adult female.

Hingement: Bar dorsal to rostrum of right valve fits into elongate socket of left valve (not shown). Dorsal margin of right valve with bar with knob at posterior end (Figure 14j).

Vestment: 3 or 4 widely separated small bristles present on vestment of posteroventral part of valve proximal to inner end of infold (not shown).

Carapace Size (length, height in mm): BT-620: USNM 194226, 2.38, 1.71. BT-779: USNM 194218, 2.34, 1.77.

First Antenna (Figure 15a): Joints 1, 2, 5, and 6 similar to those of adult female. 3rd joint with medial and ventral spines and 2 spinous bristles (dorsal proximal, ventral terminal). 4th joint with medial spines near ventral margin, stout ventral spines, and 2 distal bristles (ventral spinous, dorsal shorter with few indistinct spines). 7th joint: a-bristle longer than bristle of 6th joint, with short spines; b-bristle about 6 times length of a-bristle, with short proximal filament with large sucker (with marginal fringe) followed by a slender filament with small triangular process proximal to row of 5 or 6 small round suckers, then a second slender filament (with small triangular process proximal to row of 5 small round suckers) adjacent to a small bare filament, followed by a small bare filament; c-bristle with short stout proximal filament with large sucker (with marginal fringe) followed by a slender filament with row of 5 small round suckers (with triangular process proximal to row of 5 small round suckers), then a short bare filament adjacent to a longer slender filament, followed by 6 narrow filaments. 8th joint with d- and e-bristles long, bare; f- and g-bristles long stout, each with 10 or 11 filaments, some with 2–4 small spines. (3rd and 4th joints of male differ from those of female in having numerous ventral spines.)

Second Antenna: Protopodite similar to that of adult female. Endopodite differs from that of adult female in having a minute round ventral protuberance adjacent to distal bristle of 1st joint. Exopodite: 1st joint with ventral and dorsal spines (on USNM 194218 spines better developed on right limb); exopodite otherwise similar to that of adult female.

Mandible: 2nd endopodial joint: ventral margin with medial unringed terminal bristle longer than that of adult female (extending past 3rd joint) (Figure 15b). Dorsal margin with 7 long spinous ringed bristles, 2 short ringed distal bristles with short spines, 7 short proximal bristles with stout spines and proximal rings, 11 short proximal unringed bristles (with indistinct slender anterior spines) with bases slightly medial to bases of short bristles with stout spines, and 2 short bristles (with indistinct slender anterior spines and proximal rings) proximal to most bristles. Limb otherwise similar to that of adult female.

Maxilla: All 3 bristles of exopodite with few long spines. Long alpha-bristle of 1st endopodial joint of each limb with tooth proximal to tip. Anterior a-bristle of 2nd endopodial joint about length of adjacent bristle. Limb otherwise similar to that of adult female.

Fifth Limb: Epipodite with 51 bristles. Anterior side of 1st endopodial joint of both limbs with row of 3 bristles plus 1 bristle near protopodial tooth. b″-bristles of 2nd exopodial joint similar to those of adult female (Figure 15c). Remaining bristles of exopodial joints similar to those of adult female.

Sixth Limb: Endite I with 2 or 3 bristles (1 or 2 short proximal, 1 long terminal). End joint with 17 anteroventral bristles, 3 posteroventral bristles with bases on medial surface some distance from ventral margin, and 2 broad plumose posterior bristles. Limb otherwise similar to that of adult female.

Seventh Limb (Figure 15d): Except for having only 6 proximal dorsal bristles, bristles similar to those of adult female. Total number of bristles 18 or 19. Stout dorsal jaw with marginal row of about 7 stout teeth (some alate), and 5 or 6 slender teeth at each end of row (exact number and shape of teeth difficult to resolve). Comb with 6 or 7 long teeth and 8 shorter teeth (4 on each side). Small pointed process projecting inward within arc of teeth.

Furca (Figure 15e): Each lamella with 6 claws; claw 2 either nonarticulated or with indistinct suture at base of claw. Teeth on claws similar to those of adult female (not shown).

Bellonci Organ (Figure 15f): More cylindrical than that of adult female.

Eyes: Medial eye unpigmented, bare (Figure 15f). Lateral eye large (about same size as that of adult female), with 19 amber-colored ommatidia and black pigment between them (Figures 14g, 15g).

Upper Lip (Figure 15h): Similar to that of adult female.

Genitalia (Figure 15e,i): Elongate lobes on each side of body anterior to furca.

Posterior of Body (Figure 15j): With about 5 lobes dorsal to dorsal end of girdle, bare.

Y-Sclerite (Figure 15j): Similar to that of adult female.

Pigmentation: Black pigment in lateral eyes, and minute areas of brown pigment in upper lip.

COMPARISONS.—Cypridinodes relax is similar to C. minuta Poulsen, 1962. According to Poulsen (1962:304) both valves of C. minuta have a very shallow bulge ventral to the incisur, with about 23 hairs (bristles) along the edge of the bulge. The bulges are absent on C. relax, and no more than 5 marginal bristles were observed on valves of C. relax. Three of the b″-bristles of the 2nd exopodial joint of the 5th limb of C. relax bear a few very large teeth compared to only two bristles for C. minuta. The serrate process posterior to the tusks of the upper lip of C. minuta appears more rounded in lateral view than that of C. relax. The valves of both C. relax and C. acuminata Skogsberg, 1920, are without bulges ventral to the incisur, but the latter species is much larger and has many more bristles on the 7th limb. The right valve of C. relax differs from that of C. strophinx in lacking a lunate process ventral to the incisur. The b″-bristles of the 5th limb of C. parallax, new species, differ from those of C. relax in not having a few very large teeth.