Cypretta maya, 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 : 514-521

Cypretta maya n. sp.

Figs 8–10 , 12 A–E .

Material examined. Holotype: Female dissected on one slide (ECO– CH –Z–07529) from Ramonal Pond (N19.392111, E-88.623861). Collected by Manuel Elías-Gutiérrez, February 28, 2005.

Paratypes: A female dissected on one slide (ECO-CH-Z-07530) from type locality. Two females preserved in 70% ethanol (ECO-CH-Z-07536) from type locality. Other material: Six females from Charco near Carrillo Puerto Town (N19.6425, E-87.998), three of them dissected on separated slides (ECO-CH-Z-07521, ECO-CH-Z-07522, ECO-CH-Z-07523), remaining three preserved in 70% ethanol (ECO-CH-Z-07537).

Etymology. The name is chosen in honour of the Mayan culture, which is still alive in the area of distribution of this species.

Diagnosis. Small animals with the surface of its valves pitted and covered by abundant setae mainly along margins. Septa on RV not reaching the margins. LV with calcified projections on anterior and posterior internal margins. On A2, aesthetasc Y three-segmented. Smooth teeth of third masticatory process of maxilla. Last segment of Mx1p 1.4 times longer than wide. On Mdp α-seta smooth, reaching the distal end of following segment. Short setae d1, d2 on T2. On UR, posterior claw more than half length of anterior claw and posterior seta very short just reaching 1/5 length of posterior claw; anterior setae tiny with 1/11 length of anterior claw. Curved main branch on UR attachment.

Description of the female. Carapace tumid, in lateral view subovate. Greatest height approximately on middle of valves. Surface of valves pitted, covered with thin and short setae ( Fig. 12B ). Valves asymmetrical with RV overlapping LV at ventral ( Fig. 12A ), anterior ( Fig. 12D ) and posterior side ( Fig. 8 C, D). Length of LV ( Fig. 8 B) ranging from 0.630 to 0.670 mm, height from 0.430 to 0.448 mm. Dorsal margin convex, sloping more softly to the posterior side. Ventral margin slightly concave on medial region. Posterior side rounded, internally along posteroventral margin 10–12 prominent calcified projections ( Fig. 8 E). Anterior side slightly ovate, along internal margin 10–13 prominent calcified projections uniformly distributed and 12 long radial pore canals ( Fig. 8 E). Four adductor muscular and two mandible muscular scars present. Calcified inner lamella of LV covering 7.46–8.94 % on anterior side and 6.45–7.31 % on posterior side. Length of RV ( Fig. 8 A) from 0.660 to 0.703 mm, height 0.436 to 0.449 mm, dorsal and ventral side similar to left valve. Posterior side rounded and on inner calcified lamella 9 nodes ( Figs. 8 F, 12E). Anterior side with 15 radial pore canals not reaching the margin. Calcified inner lamella covering 8.80–9.75 % on anterior side and 5.8–6.5 % on posterior side ( Fig. 8 F).

A1 ( Fig. 9 A). 7-segmented. CB with three setae. Ex1 and Ex2 long and pappose. CB2 short, not reaching distal end of following segment; CB 1 missing. Second segment (En1), with En1a short and with Rome organ. Third segment (En2) with En2a not reaching distal end of penultimate segment and En2c short, reaching about half length of following segment. Fourth segment (En3) with En3a and En3b long and smooth, En3c and En3d short and unequal. Fifth segment (En4) with four unequal setae. Anteriorly, En4a and En4b long and smooth, slightly unequal, the longer one (En b) 30.6 times length of terminal segment. Posteriorly, En4c and En4d short and unequal. Sixth segment (En5) with four setae, En5a, En5b and En5c, smooth and 32.4 times length of last segment. En5d, short, 18 times length of terminal segment. Seventh segment (En6) with four setae, En6a and En6b long and smooth, 33.2 times length of last segment. En6c short, 4.9 times length of last segment and aesthetasc y a, 14.1 times length of last segment. Length ratios of terminal five segments 2.9: 1.8: 1.3: 1.1: 1.

A2 ( Fig. 9 B). 5-segmented. First segment of the protopodite with two setae long and pappose. Second segment of the protopodite with a long anterior seta extending beyond distal end of terminal segment and remains of exopodite (Ex) composed of two short and a long seta. First endopodal segment (En1) with six swimming setae, five of them reaching the tips of terminal claw while the sixth one short with about one third length of adjacent setae. On anterior side of this segment, an apical seta is exceeding distal end of terminal segment and on medially region one aesthetasc Y, three-segmented. Second endopodal segment (En2) with two posterior seta slightly unequal and two anterior setae. Three z-seta present. On distal end, claws G1, G2 and G3 approximately subequal, 8.4 times length of last segment. Third endopodal segment (En3) carrying GM approximately subequal in length with G3, Gm reduced, 5/6 length of GM and one aesthetasc y3, with more than half the length of GM. Length ratios of endopodal segments 5.8: 3.1: 1.

Md ( Fig. 10 A). Mandibular coxa armed with nine teeth and two teeth-like setae. The basis of posterior-most tooth with two unequal setae. The basis of anterior tooth with a strong and smooth seta.

Mdp ( Fig. 10 B). 4-segmented. First segment with S-setae long and α-seta smooth, reaching the distal end of following segment. Second segment anteriorly with setal group pappose and smooth, 5.6 times length of last segment. Seta β swollen and pappose reaching the distal end of third segment. On posterior side three unequal seta, longer one 9.2 times length of last segment. Third segment with five setae on postero-medial region. On distal end six setae, γ-seta modified into a strong claw and covered with short setules. Terminal segment with five unequal claw-like setae, all of them smooth.

Mx1p ( Fig. 9 C). 2-segmented. First segment with two subterminal setae, one of them long and pappose, with 4.6 times length of terminal segment. Five unequal setae on distal end of segment, the long one pappose, 5.2 times length of last segment. Second segment cylindrical, 1.4 times longer than wide. Distally five claw-like setae, slightly unequal, the longer one 3.1 times length of the segment. Teeth of third masticatory process of maxilla smooth.

Rake-like organ ( Fig. 9 D) T-shaped with eight teeth on each side.

T1 ( Fig. 10 B) with protopodite, armed on distal end by nine pappose setae, seven of them approximately similar in length. Two subterminal pappose setae and one c–seta next to d-seta, exceeding distal end of protopodite.

T2 ( Fig. 10 C). 5-segmented. Protopodite bearing short and pappose d1 and d2 setae. First endopodal segment with e-seta, short and strong, reaching distal end of following segment. Second endopodal segment with f-seta, long and strong, 8.1 times length of terminal segment. Third segment with g-seta just reaching distal end of following segment. Terminal segment with a strong claw, distally serrated (h2), with length of four previous segments combined. Seta h1 short. Seta h3 missing.

T3 ( Fig. 10 D). 4-segmented. Protopodite with d1 short just reaching the distal end of protopodite; d2 and dp long and pappose. First endopodal segment with a short and strong apical seta, reaching 1/4 length of following segment. Second endopodal segment with f-seta short and smooth. Third endopodal segment, transformed into pincer organ, with a long h2, distally serrated. Seta h3 pappose, reaching more than half length of second endopodal segment.

UR ( Fig. 10 E). Ramus long and thin, ventral margin smooth, 1.2 times longer than anterior claw. Anterior claw long and smooth. Anterior seta short with 1/11 the length of anterior claw. Posterior claw smooth, exceeding half length of anterior claw. Posterior seta short and smooth, approximately 1/5 length of posterior claw. Attachment of UR long and narrow, distally bifurcated ( Fig. 10 F).

Male unknown

Distribution. Recorded from Ramonal pond and Charco near the town of Carrillo Puerto, in the Mayan zone of the state of Quintana Roo, central Yucatan Peninsula ( Fig. 13 ).

Remarks and affinities. Cypretta maya n. sp., belongs to the group of Cypretta species with RV overlap, and it is most closely related to C. hirsuta Henry, 1923 , C. longidactyla Victor & Fernando, 1981 , and C. patialensis Battish, 1982 . They all have the posterior claw on the UR shorter than the anterior one, and the posterior seta reaching only the distal end of the ramus. Their valves are globular with both margins approximately equally wide, and the greatest height lying around the middle. These three species are distributed in the South and Southeast Asia and Oceania: C. hirsuta was described from Australia (Henry 1923); C. patialensis from India (Battish 1982) and C. longidactila from the Philippines (Victor & Fernando 1981).

Cypretta maya n. sp. can be easily distinguished from C. patialensis based on the morphology of the third masticatory process of the maxilla (teeth are present on the claws of this appendage in C. maya n. sp. and absent in C. patialensis ), the length of the ramus (in C. maya n. sp. it is 1.2 times longer than the anterior claw, in the Indian species the claw is longer than the ramus) and the length of the posterior claw (in C. maya n. sp., it is more than half the length of the anterior claw, in C. patialensis this claw is shorter than half the length of the anterior one).

C. maya n. sp. and C. longidactila clearly differ in the morphology of the ventral margin of the valves. Namely, C. longidactila has a prominent bulge on the interior margin of the LV, while in C. maya n. sp. the internal margins are normally developed, i.e. they do not possess a bulge. In C. longidactila the anterior claw on the UR is extremely long, overpassing the length of the ramus.

Cypretta maya n. sp. and C. hirsuta clearly differ in the valve appearance: the Mexican species is more elongated, being about two times longer than wide, while C. hirsuta is more globular being almost equal in length and width. Cypretta hirsuta is also slightly longer than C. maya n. sp.

Figures

FIGURE 8. Cypretta maya n. sp. A – F, Holotype female. A, right valve external view; B, left valve external view; C, carapace ventral view; D, carapace dorsal view; E, left valve internal view; F, right valve internal view.

FIGURE 9. Cypretta maya n. sp. A – D, Holotype female. A, A 1; B, A 2; C, Mx 1 p; D, rake like organ and upper lip.

FIGURE 10. Cypretta maya n. sp. A – F, Holotype female. A, mandible and mandibular palp; B, T 1; C, T 2; D, T 3; E, UR; F, attachment of UR.

FIGURE 13. Distribution map of the Mexican Cypretta species.

FIGURE 12. A – E, Cypretta maya n. sp. Female SEM. A, ventral view; B, LV external view; C, RV internal view; D, detail of anterior region on valves; E, detail of nodes on postero-ventral inner calcified lamella. Valves seem to be quite delicate, in all specimens reviewed some damage was observed.