Pseudopolycope helix, Kornicker & Iliffe & Harrison-Nelson, 2007

Kornicker, Louis S., Iliffe, Thomas M. & Harrison-Nelson, Elizabeth, 2007, Ostracoda (Myodocopa) from Anchialine Caves and Ocean Blue Holes, Zootaxa 1565 (1), pp. 1-151 : 81-84

Pseudopolycope helix , new species

Figs. 43 , 44

Etymology. The specific name from the Latin helix (coil, spiral, turn) in reference to the coil visible within furcal lamellae of the species.

Holotype. USNM 1021452 , undissected adult female in alcohol.

Type locality. Double Drop Blue Hole, South Andros, Great Bahama Bank, Sta 99-055.

Paratype. USNM 1021453 , adult female on slide .

Distribution. Type locality and Cenote Aerolito, Isla Cozumel, Quintana Roo, Mexico, Sta 01-011.

Description of adult female ( Figs. 43 , 44 ). Carapace oval in lateral view with slight anterior concavity just ventral to rostral bulge ( Fig. 43 a,b,e ). Outer surface of valves appearing smooth, but with faint lines parallel to ventral margin (observed on holotype when immersed in glycerin). Anteroventral edge of valve with minute serrations. Carapace transparent and extremely fragile. Lamellar prolongation of the selvage along the ventral margin serrate ( Fig. 43 a,b,e ).

Central adductor muscle attachments ( Fig. 43 a,b,e–g ): Indistinct but with closely spaced scars forming oval.

Carapace size (length, height in mm): USNM 1021452 , holotype , 0.37, 0.31. USNM 1021453 , 0.32, 0.28.

First antenna ( Fig. 43 c,h,i ): 1st and 2nd segments fused, with dorsal hairs; 2nd segment with long, terminal, dorsal bristle. 3rd to 5th segments fused, without bristles. 6 to 8th segments fused, with 5 long terminal bristles.

Second antenna: Protopod bare ( Fig. 43 j ). Endopod ( Fig. 43 j ): 1st segment bare; 2nd segment with 1 dorsal bristle and 3 terminal bristles; 3rd segment with 6 bristles; some long bristles with proximal rings and long spines. Exopod with 9 segments ( Fig. 43 k ); segments 1 to 8 each with single long bristle; 9th segment with 2 bristles (1 long, 1 medium length).

Mandible ( Fig. 44 a ): Coxa endite well developed with tapered tip (details not resolved). Basis with 4 ven- tral bristles and 1 dorsal bristle. Exopod with broad segment with 1 terminal bristle and indistinct broad 2nd segment or bristle. Endopod: 1st and 2nd segments fused; 1st segment with 3 bristles on or near ventral margin; 2nd segment with 2 long bristles; 3rd segment with 2 long bristles.

Maxilla ( Fig. 44 b,c ): Precoxa with about 7 bristles ( Fig. 44 c ). Coxa with about 7 bristles. Basis with dorsal hairs and 2 bristles on or near ventral margin ( Fig. 44 b ). Exopod with dorsal hairs and 8 terminal bristles. Endopod: 1st segment with 1 ventral bristle. 2nd segment with 2 ventral and 1 dorsal bristle. 3rd segment with 4 terminal bristles.

Fifth limb ( Figs. 44 d,f ): Epipod with 9 plumose bristles. Precoxa hirsute, with 1 dorsal bristle. Coxa with 3 bristles. Exopod broad with 4 terminal bristles. Endopod with 2 segments: segment 1 with 1 terminal bristle ventral to base of 2nd segment; 2nd segment hirsute, with 1 spinous terminal bristle. Most bristles faint.

Furca ( Figs. 43 d , 44 e,f ): Each lamella with 7 articulated claws; slender spines visible along posterior edge of some claws. Small nonarticulated process between adjacent claws, some with slender protracted tip. Stout pointed unpaired process on body proximal to posterior claw. Indistinct coiled process visible within anterior part of lamellae.

Bellonci Organ ( Figs. 43 c,h,i ): 2 spinous bristles joined near base.

Upper lip ( Fig. 43 l ): Anteroventral margin broadly rounded in lateral view (esophagus dashed in Fig. 43 l ).

Posterior of body ( Fig. 43 d ): With rows of spines dorsal to furca.

Remarks. A round amber-colored sphere filled with minute cells is present within the carapace just anterior to the furca of USNM 1021453 ( Fig. 44 f ). No limbs or structures are visible within sphere, so it is unlikely to be an extruded egg, unless it was aborted. It has no exterior appendages usually present on crustacean parasites.

Comparisons. The new species, P. helix is smaller and has a more fragile and transparent carapace than species previously referred to the genus. The carapace of the new species differs from that of Eupolycope bahamensis in not having two small projections along the posteroventral edge of the right valve. The partly coiled structure within the lamellae of the furca of P. helix has not been described previously in members of the genus and could be characteristic of the species, although it may have been overlooked on previously described species. The transparency of the valves of the holotype permitted comparison of pertinent appendages with those of the dissected paratype. The undissected holotype is preserved in alcohol because it is a more permanent method than slides.

Figures

FIGURE 43. Pseudopolycope helix, new species, holotype USNM 1021452, adult female: a, complete specimen from left side (slightly tilted), length 0.37 mm; b, complete specimen from right side and detail of central adductor muscle scars; c, Bellonci Organ and left first antenna as seen through left valve (nabs); d, left lamella of furca. Paratype USNM 1021453, adult female: e, complete specimen from left side, length 0.32 m; f, g, detail of central adductor muscles of left and right valves; h, Bellonci Organ and left first antenna as seen through valve (nabs); i, Bellonci Organ and left and right first antenna (under cover slip); j, protopod and endopod left second antenna, lv; k, exopod left second antenna (only proximal part of each bristle shown), lv; l, anterior of body from right side showing mouth and esophagus (dashed), upper lip, protopod right second antenna, and segment of left mandible. Scale equals 0.05 mm (b (detail)–d, f–h,l) and 0.02 mm (i–k).

FIGURE 44. Pseudopolycope helix, new species, paratype USNM 1021453, adult female: a, right mandible, lv; b, left maxilla, lv; c, precoxa of right maxilla, lv; d, right fifth limb, lv; e, posterior of body and right lamella of furca, lv; f, part ventral edge of complete specimen slightly open, from left side showing location of left fifth limb and furca (round object unidentified). Scale equals 0.02 mm (a–d) and 0.05 mm (e,f).