Cypretta spinosa, Cohuo-Durán, Sergio, Elías-Gutiérrez, Manuel & Karanovic, Ivana, 2013

Cohuo-Durán, Sergio, Elías-Gutiérrez, Manuel & Karanovic, Ivana, 2013, On three new species of Cypretta Vávra, 1895 (Crustacea: Ostracoda) from the Yucatan Peninsula, Mexico, Zootaxa 3636 (4), pp. 501-524 : 510-514

Cypretta spinosa n. sp.

Figs 5–7 , 11 E–H.

Material examined. Holotype: Female dissected on one slide (ECO-CH-Z-07519) from Yucatan Peninsula, Silvituc Lake (N18.64054, E-90.29552). Collected by Manuel Elías-Gutiérrez, February 28, 2005.

Paratypes: One female dissected on one slide (ECO-CH-Z-07520) from type locality. Four females preserved in 70% ethanol (ECO-CH-Z-07535) from the type locality.

Etymology. The name is a Latin adjective, spinosa , meaning spiny, thus highlighting the appearance of valve surface in this species.

Diagnosis. Small animals with several setae and spine–like setae on surface of valves and along margins. Setae En6a and En6b on A1 reduced. A2 with G2 strong and toothed. Mdp with γ-seta, strong and smooth, reaching the half length of terminal setae. On T2, f-seta reaching proximal third of terminal claw and on penultimate segment presence of two anterior setae. Posterior claw on UR reaching 3/4 of anterior claw and posterior seta exceeding half the length of posterior claw. Attachment of UR not bifurcated terminally.

Description of the female. Carapace tumid, in lateral view subovate. Greatest height around middle, slightly toward posterior half. Surface of valves pitted and covered with short, spine-like setae and thin setae ( Fig. 11 F, H). On postero-dorsal and postero-ventral side dark patches ( Fig. 5 A, B). Valves slightly asymmetrical, RV overlapping LV on ventral ( Fig. 11 E), anterior, and posterior side ( Fig. 5 C, D). Length of LV ( Fig. 5 B) ranging from 0.521–0.581 mm, height 0.393– 0.387 mm. Dorsal margin convex, sloping more softly towards anterior than towards posterior end. Ventral margin slightly concave around middle. Posterior end rounded with 12 marginal calcified projections on postero-ventral region, while 15 calcified projections are present on anterior end. Four adductor muscular and two mandible muscular imprints present. Calcified inner lamella of LV 10.3–11.96 % of length anteriorly, and 4.35–5.98 % posteriorly. From 13 to 15 anterior radial pore canals ( Fig. 5 E). Length of RV ( Fig. 5 A) ranging from 0.539–0.600 mm, height 0.418–0.424 mm. Dorsal and ventral margins similar to left valve. Posterior end broadly rounded. Anterior end with 12–14 radial pore canals ( Fig. 5 F). Calcified inner lamella 13.87–15.17 % of length anteriorly and 7.54–8.3 % posteriorly.

A1 ( Fig. 6 A). 7-segmented. First segment (CB) with three setae. Ex1 and Ex2 long and pappose, CB2 reaching distal end of following segment, CB1 missing. Second segment (En1), anteriorly with short and smooth En1a; Rome organ present. Third segment (En2) with En2a exceeding slightly penultimate segment and En2c exceeding distal end of following segment. Fourth segment (En3) with En3a and En3b smooth, subequally long, reaching distal end of terminal segment. Fifth segment (En4) with four unequal setae. Anteriorly, En4a and En4b long and pappose, 24.7 times as long as terminal segment. Posteriorly, En4c and En4d short setae. Sixth segment (En5) with four setae, En5a and En5b pappose, 27.3 times length of terminal segment. Seventh segment (En6) with four setae, En6a and En6b pappose 19.3 times length of sixth segment. En6c short, 3.6 times length of this segment and aesthetasc y a about 14 times length of last segment. Length ratios of last five segments 3.5: 1.3: 1.1: 0.6: 1.

A2 ( Fig. 6 B). 5-segmented. Protopodite two segmented, first segment with two setae equally long and pappose. Second segment with one long and pappose seta exceeding distal end of terminal segment. Exopodite with two short and one long setae. First endopodal segment (En1) with six swimming setae, five of them featherlike and just reaching tips of terminal claws, while sixth one also feather-like but less than half length of long setae. Aesthetasc Y on antero-medial side of first endopodal segment, and one smooth apical seta on anterior end, just exceeding distal end of terminal segment. Second endopodal segment (En2), with three unequally long anterior setae and two posterior smooth setae, 2.9 times length of terminal segment. Three z-seta present. Five strong terminal claws, G1, G2, G3 and GM approximately subequal, 6.4 times length of terminal segment. Gm reduced, 3/ 4 of length of other claws. G1 strongly serrated on distal end. Third endopodal segment (En3) with one short seta and one aesthetasc (y3) along with GM and Gm claws. Length ratio of endopodal segments 4.4: 2.25: 1.

Md ( Fig. 6 C). Mandibular coxa armed with seven teeth and three tooth-like setae. Basis of posterior-most tooth with three setae, longer one pappose. One strong and pappose seta present on proximal side of coxa, with less than 1/3 the length of anterior-most tooth.

Mdp ( Fig. 6 D). 4-segmented. First segment with two long S-setae, one long seta, and α-seta smooth just reaching distal end of segment. Second segment with setal group composed of three pappose setae extended beyond last segment, and β-seta swollen and pappose. On posterior side three setae present, one of them short and pappose, other two long and smooth. Third segment with nine setae, one of them smooth, modified into a claw (γseta). Terminal segment with four claw-like setae, longer one approximately 5 times length of terminal segment. Mx1p ( Fig. 6 E). 2-segmented. First segment with six setae, longer one three times length of terminal segment. Second segment cylindrical, two times longer than wide. Distally five claw-like, subequally long setae, three times length of segment. Teeth on third masticatory process of maxilla smooth.

Rake-like organ ( Fig. 6 F) T-shaped with eight teeth on each side.

T1 ( Fig. 7 A) with protopodite armed distally with eight similar pappose setae and three subterminal pappose seta. Two a–setae and one d-setae present, far exceeding distal end of protopodite.

T2 ( Fig. 7 B). 5-segmented. Protopodite with relatively long d1 and d2 setae. First endopodal segment with eseta exceeding distal end of following segment. Second endopodal segment with f-seta, 6.8 times length of terminal segment. Third segment with two short, unequal, anterior setae. Terminal segment with strong h2 seta, distally serrated, 12.4 times length of segment. Seta h1 twice as long as h3.

T3 ( Fig. 7 C). 4-segmented. Protopodite with d1, d2 and dp setae long and pappose. First endopodal segment with smooth e-seta. Second endopodal segment with short f-seta. Third endopodal segment transformed into pincer organ with long h2 seta, distally serrated. Seta h3 smooth, slightly longer than half length of segment.

UR ( Fig. 7 D) long and thin, ventral margin smooth, 1.2 times longer than anterior claw. Anterior claw distally serrated. Anterior seta short and smooth, approximately 1/7 length of anterior claw. Posterior claw smooth, 3/4 length of anterior claw. Posterior seta smooth, slightly longer than half length of posterior claw. Attachment of UR long and narrow, not distally bifurcated ( Fig. 7 E).

Male unknown.

Distribution. Only found at the type locality ( Fig. 13 ).

Remarks and affinities. Cypretta spinosa n. sp. belongs to the group of Cypretta species with RV overlap. Within this group, C. spinosa n. sp. is closely related to C. obfuscata Victor & Fernando, 1981 ; C. raciborskii (Grochmalicki, 1915) ; C. intonsa Furtos, 1936 and C. vivacis Würdig & Pinto, 1993 . They all share the following characters: posterior seta on the UR equals more than half length of the posterior claw, and the seta on the antepenultimate segment of the T2 by far exceeds distal end of the terminal segment. Cypretta obfuscata and C.

raciborskii are known from Malaysia and Indonesia (Victor & Fernando 1981). Cypretta intonsa and C. vivacis are American species, the former being known from the north (Furtos 1936) and the latter from the south of the continent (Würdig & Pinto 1993).

Cypretta spinosa n. sp. differs clearly from the South East Asian Cypretta species by the appearance of the shell surface: in the Mexican species the surface is pitted and covered with several soft and spiny setae; in C. obfuscate , the valve surface is reticulated and sparsely hirsute; in C. raciborskii , the surface is punctuate with few and sparsely distributed soft setae. The three species also differ in the appearance of the aesthetasc Y on A2: in C. spinosa n. sp. it is long and 2-segmented, in C. obfuscata and C. raciborskii it is short and 3-segmented. The Mexican species differ from C. raciborskii in the length of the posterior claw on UR, which in C. spinosa n. sp. exceeds half-length of the anterior claw, while in C. raciborskii it is less than half as long as the anterior one. In comparison to the American species, C. spinosa n. sp. differs from C. intonsa by its length: width ratio of the terminal segment of the Mx1p (it is two times longer than wide in the Mexican species, three times in C. intonsa ). Both American species differ from C. spinosa n. sp. in the length of the posterior seta on the UR, which is slightly longer than half the length of the posterior claw in C. spinosa n. sp., while in C. intonsa and C. vivacis it is as long as the posterior claw. Cypretta spinosa n. sp. and C. vivacis additionally differ in the appearance of the valve surface: in C. vivacis the surface is hirsute and sculptured, but not pitted.

Figures

FIGURE 5. Cypretta spinosa n. sp. A – F, Holotype female. A, right valve external view; B, left valve external view; C, valves ventral view; D, valves dorsal view; E, left valve internal view; F, right valve internal view.

FIGURE 6. Cypretta spinosa n. sp. A – F, Holotype female. A, A 1; B, A 2; C Md; D, Mdp; E, Mx 1 p; F, rake – like organ and upper lip.

FIGURE 7. Cypretta spinosa n. sp. A – E Holotype female. A, T 1; B, T 2; C, T 3; D, UR; E, Attachment of UR.

FIGURE 13. Distribution map of the Mexican Cypretta species.

FIGURE 11. A – D, Cypretta campechensis n. sp. SEM. Female. A, ventral view; B, RV external view; C, LV internal view. D, detail of nodes on postero-ventral inner calcified lamella. E – H, Cypretta spinosa n. sp. Female. E, Ventral view; F, LV External view; G, RV internal view; H, Detail of hinge.