Macrocyprina coimbrai, Brandão, 2005

Brandão, Simone N., 2005, Three new species of Macrocyprina Triebel, 1960 (Crustacea, Ostracoda, Macrocyprididae) from Brazilian shallow marine waters, Zoosystema 27 (2), pp. 219-243 : 235-241

Macrocyprina coimbrai n. sp.

( Figs 11-14 )

MATERIAL EXAMINED. — Holotype: Abrolhos, BA, 17°59.646’S, 38°45.147’W, between 10 and 20 m, 20. III.1995, P. S. Young, CBC, CAE, RJTS coll., 1 dissected, appendages in slide with CMC medium, valves in micropalaeontological slide ( MNRJ 15706 ). Paratypes: same locality, 1, 1, 2 spms ( MNRJ 15714 ) ; Abrolhos, BA, 17°58.853’S, 38°39.629’W, on carbonate sediment, 25 m, 24. II.2000, 3 adult with damaged appendages, 1 adult of indeterminate sex, 2, 40 RLV, 1 RV, 1 LV ( MNRJ 15713 ) ; same locality, 1 RLV (MNHN-Os 594) ; 17°59.646’S, 38°45.147’W, between 10 and 20 m, on sponges, 20. III.1995, P. S. Young, CBC, CAE, RJTS coll., 1 adult, 2 juvs, 1 LV ( MNRJ 15715 ) ; 17°59.646’S, 38°45.147’W, between 10 and 20 m, on corals, 20. III.1995, P. S. Young, CBC, CAE, RJTS coll., 2 ( MNRJ 15716 ) ; Abrolhos, BA, Paredes Reef, 17°46.029’S, 39°02.655’W, between 10 and 20 m, 19. III.1995, P. S. Young, CBC, CAE, RJTS coll., 2 adults ( MNRJ 15711 ) ; 17°46.029’S, 39°02.655’W, on corals, 19. III.1995, P. S. Young, CBC, CAE, RJTS coll., 2, 1, 1 juv. ( MNRJ 15712 ) ; same locality, 1 (MNHN-Os 595) ; on sponges, 3. III.1994, P. S. Young, C. S. Serejo coll., 1 adult ( MNRJ 15708 ) ; Abrolhos, BA, Coroa Vermelha , Nova Viçosa, on corals and sponges, 25.I.1995, P. S. Young, C. S. Serejo coll., 1, 6 juvs ( MNRJ 15718 ) ; same locality, 1 juv. (MNHN-Os 596) ; Abrolhos, BA, Viçosa Reef , 28. II.1994, P. S. Young, A. L. Leta, C. B. Castro coll., on corals, 1, 2 juvs ( MNRJ 15710 ) ; 17°58.30’S, 39°15.40’W, on algae, 18. III.1995, P. S. Young, CBC, CAE, RJTS coll. ( MNRJ 18629 ) .

DIMENSIONS. — Holotype (MNRJ 15706): LV, h 0.58 mm, l 1.40 mm; RV, h 0.60 mm, l 1.43 mm. Paratypes (MNRJ 15713) spm 1,: LV, h 0.55 mm, l 1.44 mm; RV, h 0.59 mm, l 1.45 mm; spm 2,: LV, h 0.55 mm, l 1.43 mm; RV, h 0.58 mm, l 1.44 mm; spm 5,: LV, h 0.60 mm, l 1.51 mm; RV, h 0.63 mm, l 1.53 mm; spm 7 (MNRJ 15715),: LV, h 0.55 mm, l 1.38 mm; RV, h 0.58 mm, l 1.40 mm.

ETYMOLOGY. — Named in honor of Dr João C. Coimbra (Universidade Federal do Rio Grande do Sul), who has published important studies on Brazilian ostracods, and who helped me in my first steps studying ostracods.

DISTRIBUTION. — Recent. Brazil, south Bahia, between 10 and 25 m.

DIAGNOSIS. — Carapace large, elongate-ovate in lateral outline, with conspicuous posterodorsal concavity, lateral surface with three large central patches, other irregular patches at dorsal and ventral margins. Male appendages V very asymmetrical, right appendage larger than left; left appendage bell-shaped, with base and two podomeres, most ventral peg of podomere I elongated; podomere II not recurved, profusely setose. Zenker’s organ with small terminal bulb; hemipenis with bilobated posterior lamella.

DESCRIPTION

Carapace large ( Fig. 11 A-D), elongate-ovate in lateral outline, inequilateral, with slightly ramified radial pore canals. Greatest height at midlength, slightly posterior to muscle scars. Length approximately 2.6 times maximum height. Lateral surface with three large patches. Anterior patch subcircular; central patch elongated tending to fuse with the small, elongated mid-dorsal patch; posterior patch subcircular to subquadrate, also tending to fuse with the small, elongated, posterodorsal patch. One anterior patch sometimes present in dorsal margin. Two mediumsized, irregular patches anteriorly and posteriorly at ventral margin, one small patch sometimes present at mid-ventral margin. Dark brown cuticle covering small areas around adductor muscle scars, and at anterodorsal and posterior regions of valve surface. Anterior margin narrowly rounded. Ventral margin rounded anteriorly, with conspicuous, broad indentation, upswung posteriorly. Posterior angle truncate, dorsal and ventral margins forming an angle of about 50°. Posterodorsal margin concave. Dorsal margin evenly arched, with indistinct dorsal angle, with slight anterodorsal concavity. Irregular zone of concrescence broad, especially anterodorsally. Adductor muscle scar pattern ( Fig. 11E ) with three large, dorsal scars and seven or eight scars of variable size situated below. Carapace elongate in dorsal and ventral views ( Fig. 11F, G ).

Antenna I ( Fig. 12A ) with seven slender, elongate podomeres, with long, thin, flexible setae. Podomeres II and III fused with very slight, incomplete suture. Podomere VII with four setae. Antenna II ( Fig. 12 B-F) robust, with six podomeres. Podomere III, medially, with seven subequal setae located ventrally at proximal margin; laterally, dorsoproximal scale with three setae; v e n t r a l l y a t d i s t a l m a r g i n w i t h f o u r s e t a e. Podomere IV with two thin setae proximally at dorsal margin; with one thin seta near ventrodistal edge; medially, dorsodistal angle with three setae, two of them median-sized, sexually dimorphic setae (simple in female and candle-shaped in male) ( Fig. 12C, D ); sexually dimorphic setae subequal in length in male, but in female more ventral seta about two thirds length of more dorsal seta. Male also with one thin seta dorsal to sexually dimorphic setae. Podomere V subtriangular ( Fig. 12E ); distal angle with four claws and one seta; dorsoproximal angle with one claw and one setae.

Mandible ( Fig. 12G ) with a broad masticatory jaw armed with one dorsal, conical tooth followed by six tricuspidate teeth and several setae and pegs. Podomere I with exopodite with a dorsoproximal peg on medial surface, and five distal setae. Podomere I with three setae at ventrodistal angle. Podomere II with eight ventrodistal setae. Podomere III with three mid-dorsal setae; and six ventrodistal setae. Podomere IV with about five thick distal claws.

Maxilla I ( Fig. 12H ) with three slender endites, each armed distally with a dense fringe of subequal claws. Endite I with two ventral setae. Dorsal vibratory plate with two proximal setae; and with a series of long setae along posterior and ventral margins. Palp slender, flexible with three podomeres. Podomere II with four dorsodistal setae. Podomere III with five distal setae.

Anterior lobe of appendage V similar in males and females ( Fig. 13A, B ), with 10 to 12 setae. Female left and right appendages V symmetrical, slender, with thick distal claws ( Fig. 13A ). Podomere IV with three distal claws (middistal one longest). Male appendages V very asymmetrical ( Fig. 13B, C ). Right appendage ( Fig. 13B ) robust, highly sclerotized, considerably larger, about 1.5 times length of left appendage. Palp hook-shaped, ventrodistal angle of podomere I with two thick pegs; and one short, thin seta. Dorsodistal angle with one seta. Podomere II recurved at approximately 110°; with one robust, distal aesthetasc; without thin aesthetascs (also without visible gaps in dorsal and ventral cuticle). Left appendage ( Fig. 13C ) slightly sclerotized, highly modified. Podomere I with convex ventral margin; distal seta at dorsodistal angle; ventrodistal angle with one short, thin seta; and two pegs, one of them thick basally and elongated distally. Podomere II short, but conspicuous, not recurved, lateral surface covered with numerous short setulae; with well developed aesthetasc on dorsodistal angle; without thin, ventral aesthetascs (also without visible gaps in dorsal and ventral cuticle). Suture between podomeres I and II conspicuous, but not complete.

Podomeres I and II of appendage VI ( Fig. 13D ) fused, with an incomplete suture, recurved, forming a knee; with one seta at posterodistal angle

A

B

(inside the knee); anterior margin (outside the knee) with two setae proximal to incomplete suture, and three setae distal to suture. Distal margin of podomere III with a fanlike tuft of setulae. Podomeres III, IV and V with tufts of very short, fine setulae at dorsal margin. Podomere VI with two thick claws and one seta; dorsodistal claw slightly smaller than middistal claw; length of short seta about one third length of middistal claw.

Appendage VII ( Fig. 13E ) with basal segment recurved, forming a knee; and apparently composed of two podomeres (I + II), separated by a weak, incomplete suture; posterodistal angle (inside the knee) with one seta. Dorsal margin with one seta proximal to suture; and three setae distal to suture, two of them modified. Podomere III with one ventrodistal seta. Podomere IV with one ventrodistal seta. Podomere V with two ventrodistal setae. Podomere VI with two ventrodistal setae, the most ventral longest; and one reflexed seta, same length of podomeres III to VI together.

Furcal rods ( Fig. 13F ) symmetrical, long, rather thick, curved at tips, with conspicuous suture between rami and distal setae; with short proximal setae; distal two thirds of posterior margin of each ramus with thin, short barbs.

Male genitalia: hemipenis ( Fig. 14A, B ) oblongovate, with bilobated posterior lamella; hemipenis approximately half of length of body. Zenker’s organ ( Fig. 14C, D ) long, approximately two thirds of body length, with tiny terminal bulb; vas deferens arranged in three loose loops, about equal in length to Zenker’s organ and situated around it.

REMARKS

The male appendages are known for 15 species of Macrocyprina (enumerated in Remarks of M. youngi n. sp.). The male left appendages V of these species, with the exception of M. hawkae , are hookshaped, being similar to the respective right appendages. The male left appendage V of M. coimbrai n. sp. is remarkably different ( Fig. 13C ) from these species (details of these differences described to M. youngi n. sp. also apply to M. coimbrai n. sp.).

Beside the differences on the male left appendage V, the carapace outline of M. hawkae is less elongated, higher in proportion to length than that of M. coimbrai n. sp.; the lateral patches of M. hawkae are larg- er; the posterior angle of M. hawkae is more acute; the podomere I of the male left appendage V of M. hawkae presents a short ventral peg, while in M. coimbrai n. sp. this peg is elongated; and the posterior lamella of the hemipenis of M. hawkae is irregularly shaped, while in M. coimbrai n. sp. the posterior lamella is bilobated.

Macrocyprina belizensis presents the valves with the anterior margin less acutely rounded; the ventral margin more concave; and anterodorsal and posterodorsal margins less sinuous than M. coimbrai n. sp. Macrocyprina bonaducei has a more truncate anterior margin and a deeper ventral indentation. Macrocyprina caiman has a less sinuous dorsal margin and a deeper ventral indentation. Macrocyprina jamaicae and M. noharai have less sinuous outlines; less lateral patches; and narrower zones of concrescence. Macrocyprina okinawae has a more subtriangular and equilateral outline. Macrocyprina parcens has a more truncate anterior margin; a unique, large lateral patch; and narrower zone of concrescence. Macrocyprina quadrimaculata has a more straight ventral margin, and a less sinuous dorsal margin. Macrocyprina rattrayi has a less sinuous and more subtriangular outline. And M. vargata is more equilateral, with a more concave ventral margin.

Macrocyprina sp. 1 recorded by Dias-Brito et al. (1988) presents a less sinuous outline, without the posterodorsal concavity and ventral indentation present in M. coimbrai n. sp.

Macrocyprina sp. 2 recorded by Coimbra (1995) and Coimbra et al. (1999) is larger, has a more broadly rounded anterior margin,and a more straight posterodorsal margin than M. coimbrai n. sp.

Macrocyprina youngi n. sp. is smaller, and lower in relation to length, with proportionately smaller lateral patches, with less acute posterior angle than M. coimbrai n. sp. In dorsal view, M. youngi n. sp. has less acutely tapering anterior and posterior ends, and the male left appendage V presents a less elongated ventral peg.

The carapace of M. rocas n. sp. is smaller and more elongated than M. coimbrai n. sp., with a less acute posterior angle, and with a concave ventral margin, while in M. coimbrai n. sp. this margin is posteriorly upswung. In dorsal view, M. rocas n. sp. has more parallel sides, while M. coimbrai n. sp. is more lozenge-shaped. The podomere I of male left appendage V of M. rocas n. sp. has a shorter ventral peg than that of M. coimbrai n. sp.

Figures

FIG. 11. — Macrocyprina coimbrai n. sp.; A, B, E, holotype (MNRJ 15706); C, D, paratype (MNRJ 15713), spm 2; F, G, paratype (MNRJ 15714), spm 5; A, right valve; B, left valve; C, right valve; D, left valve; E, adductor muscle scars; F, dorsal view of carapace; G, ventral view of carapace. The arrows point towards the anterior of the animal. Scale bars: A-D, F, G, 1 mm; E, 0.1 mm.

FIG. 12. — Macrocyprina coimbrai n. sp.; A, B, D-H, holotype (MNRJ 15706); C, paratype (MNRJ 15714), spm 7; A, antenna I; B, antenna II; C, distal region of podomere IV of antenna II of female; D, distal region of podomere IV of antenna II of male; E, podomere V of antenna II; F, podomere VI of antenna II; G, mandible; H, maxilla I. Scale bars: 0.2 mm.

FIG. 13. — Macrocyprina coimbrai n.sp.; A, paratype (MNRJ 15714),spm 7; B-F, holotype (MNRJ 15706);A, female appendage V; B, male right appendage V; C, male left appendage V; D, appendage VI; E, appendage VII; F, furca. Scale bars: 0.2 mm.

FIG. 14. — Macrocyprina coimbrai n. sp.; A, C, holotype (MNRJ 15706); B, D, paratype (MNRJ 15714), spm 5,; A, B, hemipenis; C, D, Zenker’s organs. Scale bars: 0.5 mm.