Ancohenia robusta (Brady 1890)

Ancohenia robusta (Brady, 1890)

Pleoschisma robusta Brady, 1890:513 [probably only part], pl. 4: figs. 13, 14(?).

Sarsiella robusta.—Brady, 1897:94, pl. 17: figs. 14, 15.—Müller, 1912:42.

Eusarsiella robusta.—Poulsen, 1965:83.

Ancohenia robusta.—Kornicker, 1981a:12, figs. 4, 5.

Ancohenia sp. Kornicker, 1987b:217, 218, fig. 1f.

HOLOTYPE.—None selected. Syntypes at the Hancock Museum, Newcastle upon Tyne, England.

SYNTYPE LOCALITY.—Vuna Point, Taveuni, Fiji, in tide pools.

MATERIAL.—Enewetak lagoon: Midwater trawl off Bokandretok Island: USNM 193623, instar III female on slide and in alcohol. Sta A, plankton trap 6, night, coral substrate: USNM 193649, 1 adult male in alcohol. Sta B, plankton trap 7, night, coral rubble substrate: USNM 193661, 1 adult male: Composite sample: USNM 158311, adult male on slide and in alcohol; USNM 158312, adult male in alcohol.

DISTRIBUTION.—Fiji; Enewetak Atoll.

SUPPLEMENTARY DESCRIPTION OF ADULT MALE (Figures 43–45).—Carapace with shallow incisur and truncate posterior (Figure 43).

Ornamentation: Surface with abundant shallow fossae each with peripheral minute spines (Figure 43); surface between fossae with scattered short bristles, most with small bulbous tips (not all shown on Figure 43); numerous bristles and small spines along anterior and ventral margins, some bristles with broad basal part. Posterior half of dorsal margin with low nodes forming row (Figure 43).

Infold: Anterior infold with small bristle near inner margin ventral to incipient rostrum (Figure 44a). Infold anterior to low caudal process with 4 bristles near midwidth, and 3 or 4 smaller bristles near inner margin (not all shown in Figure 44b). Posterior infold with 2 setal bristles (Figure 44b).

Selvage: Wide lamellar prolongation with marginal fringe along anterior, ventral, and posterior margins.

Central Adductor Muscle Attachments (Figure 45e): Consisting of numerous ovoid individual attachments.

Carapace Size: USNM 158311, length 1.00 mm, height 0.80 mm; USNM 158312, length 1.01 mm, height 0.77 mm; USNM 193649, length 0.99 mm, height 0.80 mm; USNM 193661, length 1.01 mm, height 0.76 mm.

First Antenna (Figure 44c): 1st joint bare. 2nd joint with 1 spinous dorsal bristle. 3rd and 4th joints fused; 3rd joint with 1 spinous dorsal bristle; 4th joint with 2 bristles (1 ventral, 1 spinous dorsal). 5th joint wedged ventrally between 4th and 6th joints; sensory bristle with bare stem and proximal cup with abundant slender filaments with proximal rings. 6th joint elongate with small spinous medial bristle. 7th joint: a-bristle spinous, about same length as bristle of 6th joint; b-bristle slightly longer than a-bristle, bare except for minute terminal spine; c-bristle bristle-like, longer than e-bristle, with 2 marginal filaments (on left limb of holotype filaments together, on right limb filaments widely separated) (distal part of bristle broken off illustrated limb). 8th joint d- and e-bristles long with blunt tips, d-bristle shorter than e-bristle; f- and g-bristles claw-like, unringed in proximal part, ringed in distal part, both bristles about same length as e-bristle; f-bristle with short filament proximal to midlength; g-bristle with 2 filaments.

Second Antenna: Protopodite bare. Endopodite 3-jointed (Figure 44d): 1st joint elongate, with 2 small anterior bristles (illustrated right limb with hair-like foreign growth on 1st joint absent from left limb); 2nd joint long, narrow, with 2 long bristles with marginal spines; 3rd joint elongate, reflexed, with 2 minute subterminal bristles and several minute ridges. Exopodite: 1st joint with minute terminal medial process (Figure 44d); bristle of 2nd joint long, with about 15 proximal ventral spines, and distal natatory hairs; bristle of 3rd joint with long proximal ventral hairs followed by about 8 ventral spines, then natatory hairs; bristles of joints 4–8 with natatory hairs, no spines; 9th joint with 2 bristles (1 long with natatory hairs, 1 short bare).

Mandible (Figure 44e): Coxale endite consisting of small medial spine near ventral margin. Basale: medial side with 3 short proximal bristles near ventral margin; ventral margin proximal to midlength with 3 short bristles; dorsal margin with 2 short bristles. Exopodite consisting of well-developed hirsute process. Endopodite: ventral margin of 1st joint with 1 stout claw and 2 small bristles, stout claw with small marginal spines projecting vertically; ventral margin of 2nd joint with stout terminal claw with short marginal spines projecting vertically, tip of claw blunt, nozzle-like, a minute medial spine-like bristle may be present distal to base of claw but difficult to resolve; dorsal margin of 2nd joint with long bristle at midlength; 3rd joint with long bare curved terminal claw with pointed tip, short ventral bristle, and minute dorsal bristle.

Maxilla (Figure 45a): Limb reduced. 3 endites with total of about 13 weak bristles, some with spines (endites not shown). Coxale with 1 bristle. Exopodite with 3 bristles. 1st endopodial joint with 1 weak alpha-bristle and 1 weak beta-bristle; 2nd endopodial joint with about 7 weakly developed bristles.

Fifth Limb (Figure 45b): Epipodite with 35 hirsute bristles. Exopodite reduced: 1st joint with 2 bristles; remaining joints with total of 8 bristles. Endite without bristle (? always).

Sixth Limb (Figure 45c): Endite I with 2 or 3 small bristles. Endite II (this endite could be interpreted to be part of end joint but is separated from it by small indentation in margin) with 5 long spinous and hirsute bristles. End joint with 12 spinous and hirsute bristles.

Seventh Limb (Figure 45d): Limb of USNM 158312 long with 2 terminal paired bristles (each pair on small mound, each bristle with 6 bells but no marginal spines) and 2 proximal bristles, 1 on each side, each bristle with 3 bells but no spines; terminus without comb teeth. USNM 158311 without 7th limbs (absence interpreted to be aberrancy, but more specimens needed to affirm interpretation).

Furca (Figure 45f): Each lamella with 6 claws; claws 1, 2, 4 stout and fused to lamella; claws 3, 5, 6 small, articulated; 1 or 2 small spines and long hairs on lamellae following claws; claws 1–5 with teeth along posterior margins. (Furca missing from USNM 158312.)

Bellonci Organ (Figure 44f,g): Elongate, broadening distally, with round tip.

Eyes: Medial eye without pigment, bare (Figure 44f,g). Lateral eye smaller than medial eye, unpigmented, with 8 or 9 light amber-colored ommatidia (Figure 44f).

Genitalia (Figure 45f): Small copulatory organ on each side of body but not examined in detail.

Posterior of Body: Evenly rounded, bare.

Y-Sclerite (Figure 45g): Typical for family.

DESCRIPTION OF FEMALE INSTAR III (Figures 46, 47).—Carapace oval in lateral view; posterior margin truncate; posteroventral corner less rounded than posterodorsal margin but caudal process not evident in lateral view (Figure 46a).

Ornamentation (Figure 46a–f): Surface with small indistinct fossae visible only where concretions present in shell (Figure 46b), and with minute indistinct spines (Figure 46d–f). Bristles with pointed tips (some with broad basal part) present along anterior, ventral, and posterior edges of valve and on lateral surface close to anterior and ventral margins, sparse elsewhere (Figure 46a–c, e); bristles with bulbous tips widely distributed on valves except close to free margins (some bulbous tips collapsed, appearing cup-like) (Figure 46a,b). With transmitted light numerous small pores evident, but these may be internal and not on valve surface (Figure 46a).

Infold: Ventral infold with minute bristle near inner edge ventral to valve midheight (Figure 46c). Infold in posteroventral corner with 3 small bristles near inner margin and 2 sets of minute paired bristles closer to inner margin (not all bristles shown in Figure 46d,f). Posterior infold with 2 setal bristles and with minute bristle close to inner margin (Figure 46d,f).

Selvage: Wide lamellar prolongation along anterior, ventral, and posterior margins, with marginal fringe in vicinity of caudal process, with individual widely separated marginal hairs along ventral margin.

Central Adductor Muscle Attachments (Figure 46a): Consisting of numerous ovoid individual attachments.

Carapace Size: USNM 193623, length 0.88 mm, height 0.69 mm.

First Antenna (Figure 41a,b): 1st joint broad, bare. 2nd joint with distal dorsal bristle. 3rd and 4th joints fused; 3rd joint short with 2 bristles (1 ventral, 1 dorsal); 4th joint long with 2 bristles (1 ventral, 1 dorsal). Sensory bristle of long 5th joint slender, with terminal papilla (Figure 47b). Medial bristle of 6th joint small. 7th joint: with small lateral pore near b-bristle (Figure 41b); a-bristle about 1/3 longer than bristle of 6th joint and stouter, ringed, spinous; b-bristle shorter than a-bristle, bare; c-bristle about 1/3 longer than sensory bristle of 5th joint, with terminal papilla. 8th joint: d-bristle slightly shorter than sensory bristle, bare with blunt tip; e-bristle almost twice length of d-bristle and slightly shorter than c-bristle, bare with blunt tip; f-bristle claw-like, slightly shorter than d-bristle; g-bristle claw-like, slightly longer than d-bristle.

Second Antenna (Figure 47c): Protopodite bare. Endopodite with small terminal thumb-like process and 2 short proximal bristles. Exopodite 9-jointed: 1st joint with small straight medial terminal spine; 2nd joint about twice length of 3rd joint; joints 3–8 decreasing is size gradually; joint 9 minute, less than ½ length and width of joint 8; bristle of 2nd joint with hair-like proximal ventral spines and distal natatory hairs; bristles of joints 3–8 with natatory hairs, no spines; 9th joint with small bare dorsal bristle and long bristle with few proximal ventral spines and distal natatory hairs.

Mandible (Figure 41d,e): Coxale with long hairs along ventral margin; endite consisting of small proximal medial spine near ventral margin (Figure 47d). Basale: ventral margin with 3 small bristles (2 proximal with bases on medial surface); dorsal margin with 2 small distal spines. Exopodite absent Endopodite: 1st joint with medial spines, 1 minute ventral spine proximal to main claw, and sinuate dorsal margin (Figure 47e); 2nd joint with small subterminal dorsal spine and main ventral claw; 3rd joint minute, with small dorsal spine and longer ventral spine, both at base of main claw.

Maxilla (Figure 47f,g): Endite I with 6 bristles, endite II with 4 bristles, endite III with 5 bristles (Figure 47f). Coxale with short anterior bristle. Basale with 1 lateral bristle near exopodite. Exopodite with 3 bristles (1 long, 2 short). 1st endopodial joint with pectinate alpha-bristle and spinous beta-bristle; 2nd endopodial joint with 2 lateral a-bristles, 1 medial c-bristle, and 5 pectinate terminal bristles (middle bristle shorter than others).

Fifth Limb (Figure 47h): Epipodial appendage with 35–37 bristles (3 proximal bristles shown in Figure 46i); single endite with 1 short bristle. Exopodial joints fused: 1st joint with 2 long bristles; 2nd joint with 1 minute proximal bristle and 3 long terminal bristles; joints 3–5 with total of 7 bristles (interpretation: 2 proximal on outer lobe of 3rd joint, 1 minute and 2 long on inner lobe of 3rd joint, and 2 long on 4th plus 5th joints).

Sixth Limb (Figure 47i): With 2 endites; endite I with 2 bristles (1 short stout and 1 long slender on right limb; 2 short stout subequal on left limb); endite II with 4 bristles (1 long, 3 short). End joint with 4 bristles (2 long, 2 short) on anterior part and separated by space from 3 long bristles on posterior part (anterior part could be considered 3rd endite); posterior edge of limb hirsute.

Seventh Limb (Figure 46i): Elongate, bare. (7th limb of instar IV present inside limb of USNM 193623, 4 bristles visible, each with 2 or 3 bells).

Furca (Figure 47j): Each lamella with 6 claws; claws 1, 2, 4 nonarticulated; claws 3 and 5 articulated; claw 6 weakly articulated or nonarticulated; claw 3 much smaller and more slender than claw 4; tips of long claws blunter than ups of short claws; claws 1–5 with teeth along posterior margin and spines along anterior margin; posterior margin of claw 6 bare or with few teeth; claw 1 of both lamellae with long hairs forming row near base; ventral edge of left lamella with long spines following claw 6; anterior margin of right lamella anterior to left lamella by width of base of claw 1, and with few spines.

Bellonci Organ (Figure 47k): Elongate, broadening distally, with round lip.

Eyes: Medial eye obscured but not pigmented (Figure 47k). Lateral eye not pigmented (ommatidia colored light amber, and between ommatidia lighter amber), each eye with 4 ommatidia (Figures 46j, 47a).

Upper Lip (Figure 46k): Evenly rounded.

Anterior of Body (Figure 46k): Triangular projection on each side just dorsal to socket at base of mandible.

Posterior of Body (Figure 47l): Evenly rounded, bare.

Y-Sclerite (Figure 47l): Typical for subfamily.

Epizoa or Epiphyte: USNM 193623 with long closely segmented filament attached near dorsal margin of right valve (Figure 46h). A 2nd filament with internal structures attached near anterior of left valve of same specimen (Figure 46g).

DISTRIBUTION.—World-wide between latitudes of about 63°N and 37°S, generally found in bays, lagoons, and on the continental shelf and upper slope, but recently collected in an anchialine cave in Bermuda (Kornicker and Iliffe, 1989b:32). Usually collected in waters of normal marine salinity, but also found in waters of lower and higher salinity (18–40.5%). Known depth range intertidal to 1120 m (Kornicker, 1986b:41).

Ancohenia robusta (Brady, 1890)

Pleoschisma robusta Brady, 1890:513 [probably only part], pl. IV: figs. 13, 14 (?).

Sarsiella robusta.—Brady, 1897:94, pl. XVII: figs. 14,15.—Müller, 1912:42.

Eusarsiella robusta.—Poulsen, 1965:83.

HOLOTYPE.—None selected. Syntypes at the Hancock Museum, Newcastle upon Tyne. Syntype-locality: Vuna Point, Taveuni, Fiji; low-tide pools.

MATERIAL.—At my request, Mr. Albert G. Long, the Hancock Museum, Newcastle-upon-Tyne, sent me three glass slides of Pleoschisma robusta Brady from the Brady Collection. For reference purposes I have numbered these slides 1–3. The slides have partly dried out, and structures are generally obscure.

Slide 1: This slide contains most of the appendages of an adult male and 2 fragments of a valve. The slide bears 2 labels: 1, a small label on which is printed “Hancock Museum, Newcastle-on-Tyne” 2, a label on the left side containing the handwritten information, “Sarsiella , Cypridina (with 3 lines through it crossing out the name), Pleoschisma robusta n. sp. Vuna Point, Fiji.” The handwriting appears to be the same, but the words “Sarsiella” and “Fiji” are darker than the other words on the label.

Slide 2: This contains a few appendages of an adult male and some appendages of 2 females (developmental stage uncertain). The appendages on this slide are in much poorer condition than those on slide 1, but all are from specimens in the subfamily Sarsiellinae. In addition to the printed label “Hancock Museum, Newcastle-on-Tyne,” this slide bears 2 handwritten labels: (1) label on right states “Vuna Point, Fiji” and contains a pink paper disc glued to the label; (2) label on left states “ & , Sarsiella, Pleoschisma robusta, G.S.B., types.” The handwriting appears to be the same but the word “Sarsiella” is darker than the other words on the labels.

Slide 3: This slide, which has a only part of the cover slip remaining, bears the fragments of valves in very poor condition. The labels have the same information as on slide 2, including the pink disc, with the following exceptions: (1) the word “Sarsiella” is not present, and (2) the words “shell only” appear on the left label.

In addition to the above glass slides, I had received from Dr. K. G. McKenzie in 1976 two cardboard slides he had prepared from Brady's material at the Hancock Museum. Each slide contains one closed dry carapace (although they may contain appendages, they are not evident). Each slide is labeled “Pleoschisma robusta Brady, 1890. Loc: Vuna Point, Taviuni, Fiji, K.G.M. July 1967.” One of the slides also contains the number “B473” and the word “syntype.” The other slide contains within brackets the words “non robusta.” In my opinion, the “syntype” is a male in the subfamily Sarsiellinae, whereas the specimen marked “non robusta” belongs in the subfamily Philomedinae and probably in the genus Pleoschisma.

METHODS.—The appendages on slide 1 are in much better condition than those on slide 2, and all appear to belong to the same specimen, an adult male. Therefore, the appendages on slide 1 were used herein to describe the species. The label on slide 1 does not state that the specimen is part of the type-series, but it is from the type-locality. The appendages of the adult male on slide 2, which is labeled “type,” are mostly in poor condition, but the mandible and 1st and 2nd antenna are sufficiently similar to those on slide 1 to conclude that the adult males on each slide are conspecific. Endopodites of female 2nd antennae on slide 2 are obscure but appear to be similar to those of the female Ancohenia hawaiiensis (Kornicker, 1976: fig. 8d). This suggests that male and females on slide 2 are probably conspecific.

The fragments of shell on slide 3 bear pits similar to those on the carapace on the slide prepared by K. G. McKenzie, which is labeled “syntype,” and in my opinion is a male in the Sarsiellinae. Pits are commonly present on species in diverse ostracode families, so it is not possible to conclude with certainty that the dry specimen is conspecific with the males on slides 1 and 2, but I think it likely and therefore have illustrated the dry specimen in Figure 4.

DESCRIPTION OF ADULT MALE (Figures 4, 5).—Carapace with distinct but shallow sinus (Figures 4, 5a) and truncate posterior; dorsal margin arched but fairly linear in posterior half; ventral margin evenly convex (Figure 4). (Although a small caudal process is shown in Figure 4, its presence is uncertain because this area is covered by debris on the specimen.)

Ornamentation: Surface with distinct, closely spaced, round fossae. Long bristles abundant along free margins and sparsely distributed on valve surface (Figure 5a).

Size: Dry specimen on slide B473, length 0.96 mm, height 0.76 mm.

First Antenna (Figure 5b): 1st joint without bristles. 2nd with 1 distal dorsal bristle. 3rd and 4th joints fused; short 3rd joint with single dorsal bristle; long 4th joint with 2 bristles (1 ventral, 1 dorsal). 5th joint small, wedged ventrally between 4th and 6th joints, bristle with stout cuplike proximal part with numerous filaments and stout, long, bare stem. 6th joint long, with 1 short medial bristle. 7th joint; a-bristle small; b-bristle about same length as a-bristle but with broad proximal part; c-bristle long, with 2 small proximal filaments. 8th joint: d- and e-bristles bare, with blunt tips; d-bristle shorter and narrower than e-bristle; f-bristle and g-bristle long, clawlike proximally but bristle-like with rings distally (tip of f-bristle missing on appendage illustrated), each bristle with short proximal filament.

Second Antenna (Figure 5c): Protopodite bare. Endopodite 3-jointed: 1st joint short, with 2 proximal anterior bristles; 2nd joint elongate with 2 long proximal bristles; 3rd joint elongate, reflexed on 2nd joint, with broad rounded tip with transverse ridges and 2 minute bristles. Exopodite: 1st joint elongate, remaining joints short, decreasing in size distally, 9th joint minute, with 2 bristles, 1 short, 1 fairly long with natatory hairs; joints 2–8 with long natatory bristles, some with small slender ventral spines in addition to hairs.

Mandible (Figure 5d): Coxale endite not observed. Basale: ventral margin fragmented but with 1 small proximal bristle remaining (2 long bristles like those present on the ventral margin of the basale of Ancohenia hawaiiensis illustrated in Kornicker (1976, fig. 12h) may have been present on the mandible of A. robusta illustrated herein, but are now missing); medial surface of limb with 2 small faint bristles in proximal ventral corner; dorsal margin with 2 short bristles (1 near middle, 1 subterminal). Exopodite not observed. Endopodite: 1st joint with stout terminal claw and 2 small bristles; 2nd joint with stout ventral claw and 1 dorsal midbristle; 3rd joint with long stout claw and 2 bristles (1 ventral, 1 dorsal).

Maxilla: Not observed.

Fifth Limb: Exopodite reduced with few weak bristles.

Sixth Limb (Figure 5e): Single endite with 3 small bristles. End joint with 3 very long spinous anterior bristles followed by about 7 slender spinose bristles and then 2 long, hirsute, posterior bristles.

Seventh Limb (Figure 5f): Limb with 4 terminal bristles (2 on each side) and 2 proximal bristles (1 on each side); each bristle with up to 6 bells. Terminus with central depression but without teeth.

Furca (Figure 5g): Each limb with primary claws 1, 2, and 4 fused to lamella, and secondary claws 3, 5, and 6 separated from lamella by suture. Most claws with teeth along posterior margins.

Bellonci Organ: Not observed.

Eyes: Medial eye not observed. Lateral eyes fairly large, each with 7 or 8 ommatidia (Figure 5h).

Copulatory Organ (Figure 5i): Consisting of a lobe on each side of body, each terminating in sclerotized hook. (Only 1 bristle shown on illustrated organ, but others that may be present obscure on organ examined.)