Pseudione clevai, Boyko, 2004

Boyko, Christopher B., 2004, The Bopyridae (Crustacea, Isopoda) parasites of the Stylodactylidae (Crustacea, Decapoda, Caridea), Zoosystema 26 (2), pp. 199-210 : 205-209

Pseudione clevai n. sp.

( Figs 5-8 )

?“un isopode bopyre” Cleva 1990a: 119.

“bopyre” Cleva 1997: 402.

TYPE MATERIAL. — New Caledonia. BATHUS 2, stn CP 738, 23°02.09’S, 166°56.61’E, 558-647 m, 13.III.1993, in right branchial chamber of Parastylodactylus tranterae Cleva, 1990 , 8.9 mm (MNHN- Na 14628), holotype brooding dextral 7.2 mm ; allotype 2.3 mm (MNHN-Ep 907).

MATERIAL EXAMINED. — New Caledonia. MUSOR- STOM 6, stn CP 465, Îles Loyauté, 21°03.55’S, 167°32.25’E, 480 m, 2.II.1989, in right branchial chamber of? P. tranterae , 7 mm (MNHN-Na 11367), branchial swelling but no parasites present. — BATHUS 1, stn CP 657, 21°14.45’S, 165°54.93’E, 490-530 m, 12. III.1993, in left branchial chamber of P. tranterae , 7 mm (MNHN-Na 14622), paratypes, 1 brooding sinistral 8.3 mm; 1 2.4 mm (MNHN-Ep 909). — BATHUS 3, stn CP 833, Norfolk Ridge, 23°03’S, 166°58’E, 441-444 m, 30.XI.1993, in right branchial chambers of two P. tranterae, 7.5, 8.5 mm (MNHN-Na 12161), branchial swellings but no parasites present; stn CP 846, 23°02.9’S, 166°57.97’E, 500-514 m, 1.XII.1993, in right branchial chamber of P. tranterae , 10.5 mm (MNHN-Na 14477), paratypes, 1 brooding dextral 9.8 mm; 1 2.0 mm (MNHN- Ep 908).

ETYMOLOGY. — The species is named for Régis Cleva (MNHN) in honor of his exceptional work in identifying species diversity within the Stylodactylidae , and for his careful documentation of their parasites.

DISTRIBUTION. — Known only from Parastylodactylus tranterae from New Caledonia. Depth: with certainty between 490 and 647 m, possibly as shallow as 441 m.

DESCRIPTION

Female ( Figs 5 ; 6 )

Based on holotype. Body length 7.2 mm, maximal width 3.9 mm, head length 1.3 mm, head width 1.6 mm. Pereon with right side slightly longer than left (slightly dextral). All body regions and pereomeres distinctly separated.

Head broader than long, moderately produced with anterior lamina equal to approximately onetenth length of head ( Fig. 5A ). Eyes lacking. Antenna of six articles (right side) or three articles (left side), antennule of three articles ( Fig. 6A, B ). Maxilliped ( Fig. 6C ) with moderately broad distally rounded spur; upper margin subquadrate with broad, subtriangular, distally rounded, nonarticulating palp; palp with 12 thick setae, evenly spaced, each seta with median ring of very short fine setae.

Pereon of seven pereomeres, broadest across pereomere III, tapering anteriorly and posteriorly; pereomere I with convex posterior margin, II-VII with concave posterior margins; approximately one-half of pereomere I median obscured by head. First oostegite proximal lobe ovate-triangular, distal lobe subtriangular, distally tapering and rounded, median of distal margin shallowly concave, internal ridge smooth ( Fig. 6D, E ). Coxal plates as small lobes on pereomeres I-V, clearly separated from pereomeres and larger on longer side. Dorsolateral bosses clearly demarcat- ed with left and right sides subequal. Pereomeres II-VII with distinctly demarcated tergal area, not projecting, larger on longer side. Oostegites only enclosing approximately half of marsupium. Pereopods V-VII longer than I-IV ( Fig. 6F, G ). Ventral margin of merus and ischium with rows of short, thin setae; distoventral area of carpus with numerous subquadrate, platelike setae and few long thin setae; distoventral area of propodus with low setae at insertion of tip of dactylus. Bases of pereopods lacking bosses. First pair of pereopods surrounding head region; I-IV evenly spaced, V-VII closely approximated.

Pleon with five distinct pleomeres plus pleotelson; posterior margins of pleomeres I-III smoothly and moderately concave, those of IV and V sharply concave ( Fig. 5A ); pleotelson subquadrate with median ridge and shallowly concave posterior margin. Pleomeres I-V with biramous pleopods and uniramous lateral plates; pleomeres I-IV with lamellar exopodites and endopodites, exopodites slightly smaller, pleomere V with endopodite subequal to those of I-IV but with exopodite twice as long as those of I-IV; lateral plates on left and right sides subequal, I-III distally subquadrate and laterally directed, IV and V distally tapered and posteriorly directed; edges and surfaces of all lateral plates smooth; uropods uniramous, elongate (twice as long as lateral plates of pleomere V) and subquadrate.

Male ( Figs 7 ; 8 )

Based on allotype. Length 2.3 mm, maximal width 0.7 mm, head length 0.2 mm, head width 0.5 mm, pleon length 0.7 mm.

Head subovate, widest posteriorly, fused with first segment of pereon ( Fig. 7A ). Eyes lacking. Antenna of eight articles, last five distally setose; extending beyond margin of head; antennule of three articles, distally setose ( Fig. 8A ).

Pereomeres IV broadest, tapering anteriorly and posteriorly. Pereomeres I-V directed laterally, VI and VII directed slightly posterolaterally, distolateral margins of all pereomeres rounded. No detectable pigmentation. Pereopods ( Fig. 8B, C ) all nearly alike in size and structure; in each pereopod, all articles distinctly separated, areas of subquadrate, plate-like setae on palm of propodus, distoventral region of carpus, and distoventral tip of merus; distoventral region of carpus with few long, thin setae.

Pleon of six pleomeres. Pleomeres I-V all directed slightly posterolaterally, with distolateral margins rounded. Pleomere VI (pleotelson) subtriangular with posterolateral lobes of approximately threefourths its length; medial ventrodistal area with small anal cone, posterolateral lobes with tuft of short setae at distal tips and irregular crenulations on surface ( Fig. 8D ). Pleopods as low, ovate swellings on pleomeres I-V ( Fig. 7B ). No midventral tubercles or uropods.

Variations

Specimens occur in both dextral and sinistral forms. The numbers of segments in the antennae of the holotype are asymmetrical and not typical of the species, as all other specimens have five segments on each side. The width of the females’ pleomere V lateral plates is somewhat variable, from half the width of the pleomere IV lateral plate (as in the holotype) to subequal in width to the pleomere IV lateral plate. The lateral plates and uropods in one female specimen (MNHN- Ep 908) are dorsoventrally inflated, but this is clearly an artifact of preservation.

REMARKS

The two lots of hosts lacking parasites (MNHN- Na 11367, 12161) probably contained specimens of P. clevai n. sp. based on the identity of the hosts and locality information, but they are included only provisionally as records of this species.

The affinities of P. clevai n. sp. to the other caridean-infesting species of the genus are obscure as it does not appear particularly closely related to any of the other described taxa. The female pleotelson is vaguely similar to that of P. affinis , but the two species differ in all other critical characters. Perhaps the closest taxon in overall shape and appearance is the nominal subspecies of P. elongata , but females of the two taxa differ in numerous characters such as the development of the tergal projections (much smaller in P. e. elongata ), the shape of the oostegites, the shape of the pleomere lateral plates (more concave, laterally directed, and with irregular margins in P. e. elongata ), and the shape of the uropods (shorter and not truncate distally in P. e. elongata ). Males of P. e. elongata have a narrower pleotelson than those of P. clevai n. sp., and possess midventral tubercles that are lacking in P. clevai n. sp.

INDETERMINATE RECORDS

Bopyrid(s) of Stylodactylus licinus Chace, 1983 “bopyre” Cleva 1997: 390.

HOST EXAMINED. — Indonesia. KARUBAR, stn CP 20, 05°16.30’S, 132°58.20’E, 768-810 m, 25.X.1991, in left branchial chamber of Stylodactylus licinus , 10.5 mm CL (MNHN-Na 12134), branchial swelling but no parasites present.

LITERATURE RECORDS. — Indonesia. KARUBAR, stn CC 57 , 08°15.48’S, 131°56.38’E, 603-622 m, 31.X.1991, in unknown branchial chamber of Stylodactylus licinus , 16 mm CL (MNHN-Na 12151), host and parasite not in MNHN ; stn CP 19, 05°15.52’S, 133°00.01’E, 576-604 m, 25.X.1991, in unknown branchial chamber of Stylodactylus licinus , size unknown (MNHN-Na 12150), host and parasite not in MNHN .

REMARKS

None of the above cited specimens is present in MNHN; all were lent out several years ago and were never returned. Because no specimens are available for examination, and no other parasites of S. licinus have been examined, it cannot be determined whether these records refer to either of the new species described herein, to other described or undescribed bopyrid species of indeterminate genus, or to a combination of both. They are cited here for completeness and to bring attention to their occurrence in the event that the missing specimens eventually are returned to MNHN.

Bopyrid of Parastylodactylus bimaxillaris

Figures

FIG. 5. — Pseudione clevai n. sp., holotype, 7.2 mm (MNHN-Ep 907); A, dorsal view; B, ventral view. Scale bar: 0.75 mm.

FIG. 6. — Pseudione clevai n. sp., holotype 7.2 mm (MNHN-Ep 907); A, right antenna and antennule; B, left antenna and antennule; C, left maxilliped; D, left oostegite 1, external; E, left oostegite 1, internal; F, left pereopod 1; G, left pereopod 7; H, pleon, ventral view. Abbreviations: L, lateral plate; U, uropod; numbers indicate pleon segment. Scale bars: A-G, 0.1 mm; H, 0.375 mm.

FIG. 7. — Pseudione clevai n. sp., allotype 2.3 mm (MNHN-Ep 907); A, dorsal view; B, ventral view. Scale bar: 0.1 mm.

FIG. 8. — Pseudione clevai n. sp., allotype 2.3 mm (MNHN-Ep 907); A, right antenna and antennule; B, left pereopod 1; C, left pereopod 7; D, pleotelson, ventral view. Scale bars: 0.1 mm.