Comprehensive Description

provided by Smithsonian Contributions to Zoology
Monoasterope bex

Parasterope sp. Kornicker, 1987b:217.

ETYMOLOGY.—From the Greek bex (cough).

HOLOTYPE.—USNM 158623, 1 ovigerous female on slide and in alcohol.

TYPE LOCALITY.—Enewetak lagoon (from composite sample).

PARATYPE.—Enewetak lagoon: Composite sample: USNM 193615, 1 A-1 female in alcohol.

DISTRIBUTION.—Enewetak Atoll.

DESCRIPTION OF ADULT FEMALE (Figures 68, 69).—Dorsal and ventral margins convex; lateral outline slightly tumid; incisur just below valve midheight (Figure 68a).

Infold: Infold behind rostrum with 6 bristles forming row just above and parallel to incisur, and 11 bristles forming 1 or 2 rows parallel to anterior margin of rostrum (Figure 68b); anteroventral infold with 1 small bristle at inner end of incisur followed by short space and 12-14 bristles forming row parallel to valve margin (Figure 68c); 1 bristle on ventral infold anterior to valve midlength; 4–6 bristles on ventral infold between valve midlength and lowermost hyaline flap-like bristle on posterior list. List beginning near inner margin of incisur, extending along ventral infold and continuing on posterior infold where it broadens; posterior list with about 17 broad transparent flap-like bristles and 7–10 small bristles (not more than 2 bristles between adjacent flap-like bristles) (Figure 68d); 1 bristle between ventral end of broad list and posterior margin of valve (Figure 68d); numerous pore canals (about 40) along posterior edge of valve (not shown).

Selvage: No lamellar prolongation observed.

Carapace Size: USNM 158623, length 0.80 mm, height 0.59 mm.

First Antenna (Figure 69a): 1st joint lateral surface with long spines on dorsal half; medial surface with long indistinct hairs, and short spines forming rows at distoventral comer. 2nd joint: lateral surface with 1 short spinous distal bristle, and spines along dorsal margin and forming row near distal margin; medial surface with few minute spines forming, rows; dorsal margin with spinous bristle. 3rd joint short, triangular, delimited by well-defined sutures; ventral margin with minute bristle; dorsal margin with 6 spinous bristles; 3rd and 4th joints together wider than long. 4th joint: distal margin deeply concave on both medial and lateral surfaces; ventral margin with 2 bare terminal bristles just reaching distal end of 6th joint; dorsal margin with long spinous bristle. Sensory bristle of 5th joint with 6 terminal filaments including stem (base of proximal filament just past distal end of 8th joint). 6th joint with spinous medial bristle about same length as a-claw of 7th joint. 7th joint: a-claw with short marginal spines; b-bristle longer than a-claw, with 2 short filaments followed by 3 longer terminal filaments including stem; c-bristle about twice length of a-claw, with 4 short filaments near midlength and 1 near tip; 7th and 8th joints fused. 8th joint: d-bristle absent or represented by indistinct minute spine (not shown); e-bristle about same length as b-bristle, bare with blunt tip; f-bristle bent dorsally, slightly longer than b-bristle, with 4 short filaments near midlength and 1 short filament near tip; g-bristle about same length as c-bristle, with 4 short filaments near midlength and 1 near tip.

Second Antenna (Figure 69b): Protopodite with small distal medial bristle, and spines forming row in distal dorsal corner (Figure 69b). Endopodite weakly 2-jointed: 2nd joint separated from 1st by suture, and with long terminal filament. Exopodite: 1st joint with few long distal hairs on dorsal margin, without terminal medial bristle; bristle of 2nd joint reaching 9th joint, with spines along ventral margin; bristles of joints 2-8 with slender ventral spines and natatory hairs; 9th joint with 3 bristles (1 long with ventral spines and lateral hairs, 1 medium with natatory hairs, 1 short (obscured, but probably bare)) and without lateral spine; joints 2-8 with minute spines forming row along distal margins, but without basal spine.

Mandible (Figure 69c,d): Coxale endite: dorsal branch broken off on USNM 158623 but tip illustrated in Figure 69c; tip of ventral branch obscured; ventral branch with spines forming 4 rows; small bristle near base of branch (Figure 69d). Basale endite with 4 pectinate end bristles (teeth slightly decreasing in size distally along bristle), 2 triaenid bristles with 3 or 4 pairs of marginal spines excluding terminal pair, 1 fairly long dwarf bristle (about ¾ length of triaenid bristle), and glandular peg; dorsal margin of basale with 2 long spinous terminal bristles; ventral margin bare; medial surface with few spines in rows. Exopodite about 2/3 length of dorsal margin of 1st endopodial joint, hirsute, with 2 short subterminal bristles. Endopodite: 1st joint with 3 ventral bristles (2 with long spines and 1 with short spines). 2nd joint: ventral margin with 3 terminal bristles with short spines; dorsal margin with stout a-, b-, c-, and d-bristles (b-, c-, and d-bristles with ventral spines along midlength); c-bristle stouter than others; 1 fairly long bare bristle proximal to a-bristle; 1 long slender lateral bristle between b- and c-bristles (almost as long as c-bristle); 1 long slender lateral bristle (with short spines) between c- and d-bristles (as long as d-bristle); medial side with 1 cleaning bristle between b- and c-bristles, 3 cleaning bristles forming oblique row between c- and d-bristles, and 1 long bristle with short marginal spines just distal to d-bristle (almost as long as d-bristle). 3rd joint with stout dorsal claw with stout spines along ventral margin, and 4 long bristles and 1 short bristle, all with short marginal spines.

Maxilla (Figure 69e,f): Epipodite slender, pointed, reaching to about midlength of basale, hirsute near tip (epipodite not shown). Endite I with 4 bristles (3 long, 1 short); endite II with 3 long bristles. Basale: medial surface near dorsal margin with 2 short bristles (1 proximal, 1 terminal); dorsal margin and medial surface hirsute (not all hairs shown); ventral margin with short proximal bristle (oriented posteriad), minute distal bristle, and long plumose terminal bristle; lateral surface with short proximal bristle. Endopodite: 1st and 2nd joints fused, with bare terminal bristle slighdy longer than endopodite.

Fifth Limb (Figure 69g): Lateral surface of comb with stout spinous bristle reaching past end of comb, 2 short slender bristles just ventral to base of spinous bristle, 4 bristles near ventral margin at midlength, and 1 proximal and 2 distal bristles almost on ventral margin.

Sixth Limb (Figure 69h,i): Medial surface with 1 short spine in proximal anterior corner, and 2 short endite bristles near anterior margin; anteroventral corner of skirt with 1 long hirsute bristle; lateral flap with hairs along distal edge; posteroventral margin with 12 hirsute bristles.

Seventh Limb (Figure 69j): Proximal group with 4 bristles (2 on each side), each with 3 or 4 bells. Distal group with 6 bristles, 3 on each side (2 on next to last ring, each with 3 bells; 4 on terminus, each with 3 or 4 bells). Terminus with opposing combs, each with 4 or 5 spinous teeth.

Furca (Figure 68e,f): Each lamella with 9 claws of which 2 posterior claws curve posteriorly and have slender tips, last claw with indistinct distal rings; claws 1–6, possibly others, with teeth along posterior margins (teeth along each claw similar in size); claws 1 and 2 with distal spines along anterior margins; tips of claws 2-4 bending posteriorly, almost hook-like; right lamella slightly anterior to left.

Bellonci Organ (Figure 69m): Elongate, crinkled in proximal fourth, broader near midlength, with rounded tip.

Eyes: Medial eye bare, unpigmented (Figure 69m). Lateral eye slightly smaller man medial eye, unpigmented, with about 16 amber-colored ommatidia (Figures 68a, 69l).

Upper Lip (Figure 69k): with a pair of hirsute anterior lobes, each lobe with 2 anterior spines (1 much stouter than other); saddle between lobes with 2 small anterior spines. Hirsute lateral flap on each side of mouth.

Posterior of Body (Figure 68e–h): Part between apex of internal muscles and posterior end of girdle with long hairs at midheight and shorter suffer hairs near apex. Dorsum evenly rounded with long hairs forming row on each side.

Y-Sclerite (Figure 68f): Normal for subfamily.

Gills (Figure 68g,h): Rudimentary, represented by 2–4 small processes on each side of posterodorsal part of body; tips colorless in contrast to amber-colored body.

Eggs (Figure 68a): USNM 158623 with 1 well-developed embryo (with valves formed) in marsupium.

Gut Content (Figure 68e,f): Unidentified minute particles.

DESCRIPTION OF A-1 FEMALE (Figure 70).—Carapace similar to that of adult female but with straighter ventral margin, and less tumid in lateral view (Figure 70a).

Infold: Not examined in detail but, in general, similar to that of adult female.

Carapace Size: USNM 193615, length 0.70 mm, height 0.48 mm.

First Antenna: Missing from USNM 193615.

Second Antenna (Figure 70b): Right limb missing on USNM 193615. Protopodite of left limb with small medial bristle similar to that of adult female. Endopodite weakly 2-jointed, with terminal filament offset from midwidth. Exopodite similar to that of adult female, 9th joint with 3 bristles.

Mandible: Right limb missing from USNM 193615. Left limb similar to that of adult female.

Maxilla (Figure 70c,d): Similar to that of adult female.

Fifth Limb: Epipodite with 46 hirsute bristles. Comb not examined in detail but, in general, similar to that of adult female.

Sixth Limb: Similar to that of adult female except skirt with only 9 posteroventral bristles.

Seventh Limb: 4 strongly tapered bristles in proximal group (2 on each side), each with 2 or 3 bells. Terminal group with 6 bristles (2 on ring proximal to terminus, 1 on each side; 4 on terminal segment, 2 on each side), each with 2 or 3 bells. Terminus with opposing minute combs, each with 2 or 3 teeth.

Furca (Figure 70e): Each lamella with 8 claws; posterior 2 claws oriented posteriad, appearing flexible, bristle-like, but unringed; claws 1 and 2 with distal spines on anterior margins; claws 1-5, possibly others, with teeth along posterior margins; teeth on each claw about same size; right lamella slightly anterior to left lamella by about width of claw 1 at base.

Bellonci Organ (Figure 70f): Broadening at midlength, with rounded tip.

Eyes: Medial eye bare unpigmented (Figure 70f). Lateral eye with 13–15 amber-colored ommatidia, without pigment between ommatidia (Figure 70a,f).

Posterior of Body (Figure 70e,g) and Y-Sclerite (Figure 70e): Similar to those of adult female.

Gills (Figure 70e,g): With 4 or 5 rudimentary structures projecting from posterior of body on each side. Structures colorless in contrast to amber-colored body.

Eggs: USNM 193615 with 3 small unextruded eggs (Figure 70e).

Gut Content: Unidentified minute particles.


COMPOSITION.—The Cyclasteropinae include 3 tribes: Cycloleberidini Hartmann, 1974, Cyclasteropini Poulsen, 1965, and Tetraleberidini Kornicker, 1981c. Only the first is represented in the present collections.

DISTRIBUTION.—Widespread in shelf waters from about 46°S in the vicinity of New Zealand to about 42°N in the Mediterranean, but with 1 questionable locality in the vicinity of Alaska. Except for 1 sample at 1100 m off Mauritanea, members of the subfamily have not been collected deeper than about 290 m (Kornicker, 1981c:72).


COMPOSITION.—The Cycloleberidini comprise 3 genera: Cycloleberis Skogsberg, 1920, Alphaleberis Kornicker, 1981c, and Leuroleberis Kornicker, 1981c. Only Leuroleberis is in the collections from Enewetak.

DISTRIBUTION.—Mediterranean Sea, Atlantic Ocean; western Indian Ocean, Pacific Ocean, and in the vicinity of Australia and New Zealand; absent from the Arctic and Antarctic. Depth range intertidal to 96 m, but also collected in a surface tow; a record of 1100 m off Mauritania is considered atypical or questionable (Kornicker, 1981c:78).

Leuroleberis Kornicker, 1981

Leuroleberis Kornicker, 1981c:91.

TYPE SPECIES.—Leuroleberis sharpei, Kornicker, 1981c:97.

COMPOSITION.—Six species are referred to this genus: Leuroleberis zealandica (Baird, 1850), L. orbicularis (Brady, 1897), L. poulseni (Moguilevsky and Ramírez, 1970), L. mackenziei Kornicker, 1981c, L. sharpei Kornicker, 1981c, and L. surugaensis Hiruta, 1982. Only 1 specimen of this species, a juvenile male, was collected at Enewetak, and it is left in open nomenclature as Leuroleberis species A.

DISTRIBUTION.—Eastern and Western Pacific Ocean, Western South Atlantic, and in the vicinity of Australia and New Zealand. Known depth range intertidal to 146.3 m (Kornicker, 1981c:91).

Leuroleberis species A

MATERIAL.—Enewetak lagoon: Midwater trawl off Bokandretok Island, USNM 193618, 1 juvenile male instar ?IV.

DISTRIBUTION.—Enewetak Atoll.

DESCRIPTION OF JUVENILE MALE (INSTAR ?IV) (Figure 71).—Carapace oval in lateral view with short incisur (Figure 71a).

Ornamentation (Figure 71b, d–g): Anterior edge of rostrum and anteroventral margin with smooth narrow ridge having undulating but not scalloped inner edge (Figure 71g). Each valve with short lumen near lower end of incisur (Figure 71b,d). In lateral view valve extending past valve edge along anteroventral and ventral margins (Figure 71d). Anteroventral edge scalloped on right valve (Figure 71b,d), smooth or slightly uneven on left valve. Anteroventral and ventral edges of valve with long bristles forming row (Figure 71b,d); 2 or 3 shorter bristles along valve edge anterior to lumen (Figure 71b). In transmitted light at magnification × 300 each valve with abundant minute pores. Surface of valve with short ridges (Figure 71e); short bristle emerging from closed pore posterior to most ridges (Figure 71e). Valve surface with sparsely distributed bristles emerging from open pores with a single rim centered within a stellate pattern of ridges (Figure 71f). Neither fossae, nor bristles emerging from pores with concentric rims observed.

Infold: Rostral and anterodorsal infold with numerous bristles, mostly in 2 rows paralleling outer edge of valve. List with anterior end just ventral to lumen continues along ventral margin and broadens along posteroventral and posterior infold; anteroventral list with lamellar prolongation; anteroventral and ventral list with about 50 slender bristles forming row along list edge; posteroventral and posterior list with numerous long and short bristles with bases inward from outer list edge. Anteroventral infold with about 12 bristles forming row between list and valve edge.

Selvage: Broad lamellar prolongation with fringed edge along lower edge of incisur; prolongation narrow with smooth outer edge along anterior and ventral margins of valve; lamellar prolongation along dorsal margin anterior to anterior juncture with long marginal fringe.

Central Adductor Muscle Attachments: Typical for genus.

Dentition (Figure 71c): Right valve only with minute teeth forming row along dorsal edge anterior to anterior juncture.

Carapace Size: USNM 193618, length 2.50 mm, height 2.17 mm.

First Antenna: 1st joint with long and short hairs on medial surface. 2nd joint with hairs along ventral margin, proximally on dorsal margin, and near terminal edge of medial surface; dorsal margin with 2 proximal and 1 terminal bristles; lateral side with 2 or 3 distal bristles. 3rd joint with 4 bristles along long dorsal margin and 0 or 1 bristle on shorter ventral margin. 4th joint with 1 terminal bristle on short dorsal margin and 2 terminal bristles on longer ventral margin. Sensory bristle on long 5th joint with 2 short proximal and 7 long terminal filaments. Short 6th joint with long bare medial bristle. 7th joint: a-bristle bare, claw-like; b-bristle reaching just past tip of sensory bristle of 5th joint, with 5 or 6 marginal filaments with terminal papilla; c-bristle longer than b-bristle, with many marginal filaments. 8th joint: d- and e-bristles about same length as sensory bristle, bare with blunt tips; f-bristle bent dorsally, shorter than sensory bristle, with 5 marginal filaments with terminal papilla; g-bristle about same length as c-bristle, with 7 marginal filaments with terminal papilla.

Second Antenna: Protopodite with few long hairs along ventral margin and 1 small distal medial bristle. Endopodite 3-jointed (Figure 71h,i): 1st joint with 0–2 short proximal bristles and 1 or 2 small distal bristles; 2nd joint with 0 or 1 small bristle; 3rd joint with minute terminal spine-like process and long subterminal bristle. Exopodite: 1st joint with small straight distal medial bristle; bristle of 2nd joint reaching past 9th joint, with 11 minute ventral spines and without natatory hairs; bristles of joints 3–8 with stout ventral spines and natatory hairs; 9th joint with 4 bristles (1 short, dorsal, and with short marginal hairs, 1 medial with natatory hairs, 2 long with ventral spines and natatory hairs); joints 2–8 with basal spines increasing in length on distal joints; basal spine of 8th joint about 2/3 length of 9th joint; 9th joint with 3 lateral spines (dorsal and ventral spines about same length as basal spine of 8th joint, middle spine shorter); joints 2–8 with few minute spines forming short distal medial row.

Mandible: Coxale endite: ventral branch with spines forming 5 oblique rows; tip of branch with 2 ventral teeth and 1 terminal tooth with digitate tip; a fairly long slender bristle present near proximal end of branch; ventral margin of dorsal branch with 3 triangular processes (proximal with 3 teeth along posterior edge) and 3 backward curving processes (with teeth along anterior margin) proximal to short main spine; main spine with minute spines along anterior margin; up of branch usually bearing bristle broken off specimen examined and not observed; dorsal margin of branch with few minute spines opposite curving processes on ventral margin. Basale: endite with 12 long bristles with distal spines and minute triaenid tips and 1 dwarf bristle; ventral margin of basale with 6 triaenid bristles and 3 subterminal bristles (2 long spinous, 1 minute bare); 1 minute proximal medial bristle near ventral margin; dorsal half of medial surface of basale with few long hairs; dorsal margin with 2 short distal bristles (only stumps remaining on limb examined) and 2 long stout terminal bristles. Exopodite with hirsute tip reaching just past distal end of dorsal margin of 1st endopodial joint, with 2 bare ventral bristles (proximal longer). Endopodite: 1st joint with 6 ventral bristles. 2nd joint: medial surface with about 17 cleaning bristles; dorsal margin with about 9 bristles; ventral margin with 4 bristles forming 2 distal groups, with 2 bristles in each group. 3rd joint with 3 long subequal claws (dorsal claw shorter and with few, minute, ventral teeth proximally), 1 long spinous lateral bristle, and 2 short, slender, ventral bristles with short marginal spines.

Maxilla: Endites with 3 long and 1 short bristle followed by 5 long bristles. Basale: medial surface spinous, with 3 small bristles dorsal to distal endite, 1 proximal bristle near dorsal margin, 10 short bristles forming row near ventral margin, 3 long distal bristles followed by 2 short bristles (all near ventral margin), and 1 long terminal ventral bristle; distal edge of dorsal margin missing on limb examined but stump of stout bristle present. Endopodite: 1st joint with short bare distal alpha-bristle and long terminal beta-bristle; 2nd joint with 6 long bristles. Exopodite represented by short lateral lobe with 2 small terminal bristles.

Fifth Limb (Figure 71j): Dorsal margin of comb hirsute and with 2 small minute proximal bristles. Exopodial bristles: 2 long bristles, 4 minute bristles near bases of long bristles, and 5 small bristles ventral to minute bristles and near ventral margin.

Sixth Limb: 2 epipodial bristles. Limb not examined in detail but with numerous bristles, typical for genus.

Seventh Limb: Single limb examined with 36 bristles (17 on 1 side, 19 on other); segments of limb narrow, some with 1 bristle on each side but most with only 1 bristle; bristles with 2–5 bells except for 1 minute proximal bristle without bells; bristles tapered (juvenile character). Terminus with opposing combs with many spinous teeth.

Furca (Figure 71k): Each lamella with 3 stout primary claws followed by 5 bristles; bristle following claw shorter and slenderer than next bristle; left lamella with bristles close to claw 3, right lamella with bristles separated from claw 3 by space; primary claws with teeth forming lateral and medial rows along posterior edges (teeth not shown); some stouter teeth with 1 or 2 smaller teeth between them; bristles with small spines along both margins; few spines on proximal bristle stouter than those on distal bristles; right lamella anterior to left by about width of claw 1 at its base.

Bellonci Organ (Figure 71l): Elongate, with suture proximal to midlength; distal segment with short broad part separated from longer tapered part by narrow saddle; tip rounded.

Eyes (Figure 71l): Medial eye amber colored in part, bare. Lateral eye slightly larger than medial eye, with about 46 amber-colored ommatidia, without black pigment.

Upper Lip: Comprising 2 hirsute lobes without spines.

Posterior of Body (Figure 71m): Hirsute without lobate dorsal process.

Gills: Well developed.
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