Comprehensive Description

provided by Smithsonian Contributions to Zoology
Cypridina dentata (Müller, 1906)

Pyrocypris dentata Müller, 1906:20, pl. 2: figs. 17–21.–1912:17, 18.

Cypridina dentata.—Poulsen, 1962:265, fig. 123.

HOLOTYPE.—None selected; 3 syntypes (2 males, 1 female).

SYNTYPE LOCALITIES.—Malay Archipelago, Siboga Expedition: Sta 40 (1 female, 1 male), 2 Apr 1899, Paternoster Island near Kawassing, plankton, 12 m; sta 66 (1 male), 7 May 1899, bank between Bahuluwang and Tabolungan, plankton, 8–10 m.

MATERIAL.—Enewetak lagoon: Midwater trawl off Bokandretok Island: USNM 193658, 1 A-1 male in alcohol. Sta B, plankton trap 10, night, coral rubble substrate: USNM 193655A, 1 A-1 male in alcohol; USNM 193655B, 1 A-1 female in alcohol; USNM 193656, 1 A-1 male on slide and in alcohol.

DISTRIBUTION.—Malay Archipelago (Poulsen, 1962:267) and Enewetak Atoll.

DESCRIPTION OF A-1 MALE (Figures 12, 13).—Carapace elongate with convex ventral and dorsal margins (Figure 12a,c); maximum height at midlength. Rostrum with dorsal corner angular in lateral view (Figure 12a–c), more rounded in medial view (Figure 12d), and with concave anterior margin and pointed ventral comer; caudal process elongate with rounded tip. Anteroventral edge of valve with 13 or 14 bristles along inner edge lateral to transparent lamellar prolongation of selvage (Figure 12a,c,e,g); between 1st and 2nd bristles a fairly large tooth (formed by ventral end of concave rib extending from inner end of incisur to anteroventral valve edge) followed by 4–6 smaller teeth (Figure 12e,g); about 30 narrow sutures perpendicular to valve edge in vicinity of bristles but not forming serrations along edge (Figure 12e). Outer surface of valves with 3 or 4 slender bristles along anteroventral margin near edge ventral to incisur (Figure 12e).

Infold: Rostral infold with 3 bristles forming row paralleling anterior edge of rostrum (upper bristle missing in Figure 12d), 2 bristles near inner end of incisur, and 1 small bristle proximal to their bases. Anteroventral infold (inward from bristles along edge) with 6 or 7 short bristles (Figure 12g); ventral infold with few widely separated bristles. List of anterior edge of caudal process forming narrow bar covered by broad transparent flap with long nonarticulated triangular serrations along posterior edge (USNM 193656 with 17 on right valve, 10 on left) (Figure 12f,h); flap also with small pores and bristles on outer surface; additional spines and triangular processes between flap and outer edge of caudal process (Figure 12f,h).

Selvage: Similar to that of C. spina described herein.

Central Adductor Muscle Attachments (Figure 12c): Comprising many closely spaced ovoid scars (not all scars illustrated).

Carapace Size: USNM 193655A, length 1.47 mm, height 0.82 mm; USNM 193656, length 1.44 mm, height 0.84 mm; USNM 193658 (shell distorted), length 1.40 mm, height 0.70 mm.

First Antenna (Figure 13a): 1st joint bare. 2nd joint with abundant medial spines forming rows. 3rd joint with 2 bare bristles (short dorsal and longer ventral (tip of ventral bristle broken off on illustrated limb)). 4th joint with 2 bare bristles (1 ventral, 1 dorsal). Sensory bristle of 5th joint with 2 short proximal filaments followed by 1 longer slender Filament, 5 long stout filaments, 2 short slender filaments, and bifurcate tip. 6th joint with short bare medial bristle near dorsal margin. 7th joint: a-bristle bare, slightly longer and stouter than bristle of 6th joint; b-bristle about half length of sensory bristle of 5th joint, with 4 short proximal filaments; c-bristle about twice length of sensory bristle of 5th joint, with 8 short slender filaments, some with spines (only proximal part of bristle shown in illustrated limb); minute papilla present on joint edge just dorsal to b-bristle. 8th joint (bristles not shown): d- and e-bristles long, bare, with blunt tips (d-bristle about same length as sensory bristle, e-bristle shorter); f-bristle with tip broken off on USNM 193656, remaining part about same length as c-bristle, with 8 marginal filaments, some with spines; g-bristle about 1/3 longer than c-bristle, with 9 or 10 marginal filaments, some with spines.

Second Antenna: Prolopodite with small distal medial bristle with few minute marginal spines (Figure 13b). Endopodite 1-jointed with 4 bristles (2 small anterior bristles followed by 1 slightly longer and stouter bristle, and 1 longer bristle) and 1 distal filament about 4 times length of shortest bristle (Figure 13c). Exopodite: 1st joint with few dorsal spines along concave margin; bristle of 2nd joint reaching to about 6th joint, with 11 slender ventral spines (distal spine longer than others) (Figure 13d); bristles of joints 3–8 with natatory hairs but no spines; 9th joint with 3 bristles (2 long with natatory hairs, 1 short, dorsal, bare); joints 3–8 with slender basal spines increasing in size on distal joints; spine of joint 8 slightly longer than half length of 9th joint; 9th joint with lateral spine about 2/3 length of joint; 2nd joint with few minute spines along ventral margin; joints 2–8 with indistinct spines forming row along distal margin.

Mandible (Figure 13e,f): Coxale endite well developed, spinous, with 2 stout terminal spines, 1 on each side of small triangular process; small bristle near base of endite. Basale: ventral margin with 2 small ringed a-bristles, 1 small bare b-bristle, 2 c-bristles (proximal small, distal long spinous), and 2 d-bristles (proximal small, distal long with rings of long spines); dorsal margin with 3 bristles (1 distal to midlength, bare, 2 terminal (lateral bare, medial with short spines)); medial surface with few spines near dorsal margin; lateral surface with few proximal hairs near ventral margin. Exopodite about same length as dorsal margin of 1st endopodial joint, hirsute, with terminal hirsute triangular pad and 2 subterminal bristles (distal stouter and shorter). 1st endopodial joint with 4 ventral bristles (1 minute, bare, others longer, spinous). 2nd endopodial joint: ventral margin with few proximal spines, 2 single weakly ringed distal bristles, and paired terminal bristles (medial sclerotized unringed; lateral slenderer, weakly ringed); dorsal margin with indistinct spines, 4 long spinous ringed bristles, 1 shorter spinous ringed bristle proximal to long bristles, 0 or 1 short bristle (with short spines) medial to proximal of long bristles, and 1 short unringed bristle (with long spines) medial to 2nd long bristle. 3rd endopodial joint with 3 equilength unringed claws (dorsal bare, others with proximal ventral teeth) and 4 ringed bristles (2 medial near ventral margin (ventral of these small, bare, other longer, bulbous proximal to ringed spinous part and with short segment without rings near tubular tip (not shown)), 1 terminal (near ventral margin) and long with S-shaped proximal part, and 1 lateral dorsal) (Figure 13f).

Maxilla (Figure 13g): Endite I with 6 bristles; endite II with 4 or 5 bristles; endite III with 5 bristles. Coxale with plumose dorsal bristle. Basale with 2 short distal bristles (1 ventral, 1 at midwidth). Exopodite broad, hirsute, with 3 bristles (proximal and middle bristle with long marginal hairs, other bare). 1st endopodial joint with bifurcate cutting tooth, 1 ringed alpha-bristle with long marginal hairs, 2 ringed beta-bristles (medial stout pectinate, lateral slender bare, about half length of outer), and dorsal hairs forming rows. 2nd endopodial joint with 3 slender bare ringed a-bristles, 2 small ringed b-bristles (posterior smaller and pectinate proximally, anterior hirsute), 2 ringed c-bristles, and 3 pectinate d-bristles (posterior ringed distally, others unringed).

Fifth Limb (Figure 13h,i): Epipodite with 33 hirsute bristles. Anterior tooth-like process of protopodite absent. Endite I with 5 bristles; endite II with 4 short terminal bristles, 1 minute terminal spine-like bristle, and 1 minute proximal anterior bristle; endite III with 6 bristles (not all endite bristles shown in Figure 13i). 1st exopodial joint: main tooth with proximal peg with serrate margin and 5 cuspate teeth (largest tooth with 13 small cusps forming row); spinous ringed bristle proximal to peg (Figure 13h); anterior side with 2 adjacent ringed bristles (both with long proximal hairs, inner bristle twice length of outer) and 1 hirsute bristle closer to epipodite (this bristle could be on protopodite) (Figure 13i). 2nd exopodial joint with 3 pectinate unringed a-bristles, 3 pectinate b-bristles including stout b-bristle (with long proximal spines) near inner lobe of 3rd joint (small posterior bristle unringed, others ringed)(rings not shown in Figure 13h), posterior c-bristle ringed, with long proximal spines, and anterior d-bristle ringed, with long spines on proximal half (Figure 13i). 3rd exopodial joint: inner lobe with 3 bristles (1 short, ringed, proximal (with long proximal and short distal spines), 1 short, unringed, pectinate, terminal, and 1 longer ringed terminal (with short marginal spines)); outer lobe hirsute, with 2 short ringed bare bristles. 4th and 5th joints fused, hirsute, with 3 ringed bristles (1 short with few indistinct spines, 2 longer with short spines); low rounded node between long and short bristles (node not shown in Figure 13i).

Sixth Limb (Figure 13j,k): With 1 small bare epipodial bristle. Endite I with 2 small proximal medial bristles and 1 long terminal bristle (Figure 13j); endite II with 1 small proximal medial bristle, 1 small subterminal medial bristle, and 1 long terminal bristle; endite III with 1 small medial subterminal bristle and 2 long terminal bristles; endite IV with 1 short medial subterminal bristle and 1 long terminal bristle (Figure 13k). End joint with 7 bristles (4 anterior separated by space from 1 short bristle, then short space and 2 posterior hirsute bristles) (Figure 13k); medial surface of limb hirsute; lateral side with spines along ventral edge of end joint.

Seventh Limb (Figure 13l,m): Each limb with 8 bristles: 2 weakly developed proximal bristles (1 on each side, without bells), and 6 terminal (3 on each side: 2 weakly developed without bells, and 1 with rings and 2 bells). Terminus elongate with small peg at base and 4 terminal teeth.

Furca (Figure 13n–p): Each lamella with 8 claws; claw 2 nonarticulated, remaining claws articulated; claw 4 slightly narrower than claw 3; claws 2 to 8 decreasing gradually in length and width; all claws with teeth forming lateral and medial row along posterior edges (Figure 13o,p); claw 1 with several large distal teeth in medial row (Figure 13o); claws 1–3 with anterior hairs; claw 1 of right lamella anterior to claw 1 of left lamella by width of claw measured at its base.

Bellonci Organ (Figure 12i): Short, not well defined.

Eyes: Medial eye unpigmented, bare (Figure 12i). Lateral eye about twice length of medial eye, with 13 amber-colored ommatidia on surface and 3 small ommatidia beneath the surface ommatidia at dorsal end of eye; largest ommatidium placed 4th in middle row (counting from ventral end) (Figure 12j). No pigmentation between ommatidia.

Upper Lip (Figure 12k): With 2 unpaired anterior processes and 2 pairs of posterior processes. Each anterior unpaired process with glandular opening at tip; anterior of paired processes bifurcate at tip, each branch with 1 or 2 glandular openings at tip; posterior of paired processes elongate, with 4 glandular openings along posterior edge and 1 at tip.

Genitalia: Comprising 2 lobes anterior to furca (Figure 13q); an oval sac on each side of body proximal to lobes interpreted to be testes (Figure 13r).

Posterior of Body: Evenly rounded, bare.

Y-Sclerite (Figure 13n): Typical for subfamily.

Pigmentation: None in carapace or appendages.

DESCRIPTION OF A-1 FEMALE (Figure 14).—Shape of carapace similar to that of A-1 male except caudal process marginally shorter (Figure 14a). Anteroventral edge of valve with 17 or 18 bristles (more than on A-1 male) along inner edge lateral to transparent lamellar prolongation of selvage (Figure 14b,c); teeth between anterior 2 bristles not projecting past valve edge as on A-1 male; anterior 17 or 18 teeth along edge oblique, remainder vertical to edge (Figure 14b,c).

Infold: Bristles of rostrum, anteroventral and ventral margins not all counted but, in general, similar to those of A-1 male. Infold of caudal process similar to that of A-1 male (USNM 193655B with about 16 spines on right valve (Figure 14d), and 14 on left (Figure 14e).

Carapace Size: USNM 193655B, length 1.24 mm, height 0.73 (smaller than A-1 male).

First Antenna: Joints 1–4 and 6 similar to those of A-1 male. Sensory bristle of 5th joint with 2 slender proximal filaments followed by 4 longer and stouter filaments, 2 short slender filaments, and bifurcate tip (Figure 14f). 7th joint b-bristle bare; remaining bristles of 7th joint as well as those of 8th joint not examined in detail but, in general, similar to those of A-1 male.

Second Antenna: Protopodite and endopodite similar to those of A-1 male (Figure 14g). Bristle of 2nd exopodial joint with 9 or 10 slender spines; exopodite otherwise similar to that of A-1 male.

Mandible, Maxilla, and Fifth Limb (Figure 14h): Similar to those of A-1 male.

Sixth Limb (Figure 14i): Endite I with 1 short proximal medial bristle and 1 long spinous terminal bristle. Limb otherwise similar to that of A-1 male.

Seventh Limb (Figure 14j): Each limb with 10 bristles: 4 weakly developed proximal bristles (2 on each side, without bells), and 6 terminal bristles (3 on each side: 2 weakly developed without bells, and 1 with rings and 1 or 2 bells). Terminus elongate with small peg at base and 5 terminal teeth.

Furca (Figure 14k): With 7 claws on left lamella and 8 on right Limb otherwise similar to that of A-1 male.

Bellonci Organ (Figure 14m), Upper Lip, Posterior of Body (Figure 14n), Y-Sclerite (Figure 14n), and Pigmentation: Similar to those of A-1 male.

Eyes: Medial eye similar to that of A-1 male (Figure 14m). Lateral eye with 15 amber-colored ommatidia (13 on surface and 2 beneath the surface ommatidia at dorsal end of eye) otherwise similar to eye of A-1 male (Figure 14l).

Eggs: USNM 193655B with 2 rosettes of unextruded eggs inside of body, about 14 eggs in each rosette (Figure 14n).

Gut Content: Fragments of copepods in gut (identified by Thomas E. Bowman).
bibliographic citation
Kornicker, Louis S. 1991. "Myodocopid Ostracoda of Enewetak and Bikini Atolls." Smithsonian Contributions to Zoology. 1-140. https://doi.org/10.5479/si.00810282.505