Cyclocypris anacola n., Smith & Lee & Chang, 2014
Smith, Robin James, Lee, Jimin & Chang, Cheon Young, 2014, Nonmarine Ostracoda (Crustacea) from Jeju Island, South Korea, including descriptions of two new species, Journal of Natural History 49 (1), pp. 37-76: 48-52
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|Cyclocypris anacola n.|
Seeps and crevices of the walls in the entrance of a natural cave in volcaniclastic deposits at the coast of Suwolbong , Gosan-ri , Hangyeong-myeon , Jeju-si, Jeju Island, South Korea (33° 17 ′ 55.9 ′′ N, 126° 10 ′ 4.1 ′′ E) (locality 1 on Figure 1 View Figure 1 ) GoogleMaps .
Holotype – dissected male ( NIBRIV0000297033) . Allotype – dissected female ( NIBRIV0000297034) . Paratypes – dissected female ( DB40034), and whole, dried female ( DB40035) .
One male from the type locality, 6 September 2013. Three females from seeps and crevices of the walls in the entrance of a nearby man-made cave (33° 17 ′ 55.9 ′′ N, 126° 10 ′ 4 ′′ E) (locality 1 on Figure 1 View Figure 1 ), 6 September 2013.
Derivation of name
From the Greek, anakolos, meaning shortened or stunted, referring to the strongly reduced natatory setae of the antennae.
Right valve overlaps left, greatest height anterior of adductor muscle scars, apex of curvature of anterior and posterior margins below mid-height, dorsal view ovoid, but relatively narrow, with anterior more pointed than posterior. Antenna with very reduced natatory setae, not reaching to end of next segment. Claw G2 of female antenna relatively short, approximately 80% length of claw G1. Seventh limb with relatively long g seta, approximately as long as final segment, and with relatively long, straight h2 seta. Claw Gp of caudal ramus slightly shorter than claw Ga, setae sa and sp approximately equal in length. Lobe b of hemipenes triangular in shape with narrowly rounded apex, lobe a with quadrate end, projecting beyond lobe b.
Carapace ( Figures 2C–F View Figure 2 , 3A View Figure 3 ) length 524–536 µm, height 304–320 µm. Right valve overlaps left along all margins. Ventral margin almost straight. Dorsal margin straight, slightly sloping towards posterior. Greatest height anterior of adductor muscle scars. Inner calcified lamella wider anteriorly than posteriorly. Right valve with list on anterior calcified lamella. Dorsal view ovoid, greatest width behind midlength. Anterior more pointed than posterior. Carapace colour chestnut brown. Surface generally smooth, but with small area of very shallow, ill-defined pits in central-ventral area (only observable with SEM).
Antennule ( Figure 3B View Figure 3 ) with seven articulated segments. First segment with one dorsal seta and two long ventral setae. Second segment with tiny Rome organ and one short dorsoapical seta. Third segment with one medium-length dorsoapical seta. Fourth segment with two long dorsoapical setae and two short ventroapical setae. Fifth segment with two long dorsoapical setae, and one short and one long ventroapical seta. Sixth segment with four long apical setae. Seventh segment with three long setae and aesthetasc ya.
Antennal ( Figure 3C View Figure 3 ) natatory setae on third segment strongly reduced, not reaching to fifth segment. Male antenna with sub-divided fourth segment. Seta z3 very short, claw z2 well-developed, seta z1 medium-length. Claw G1 short, similar in length to z1. Seta G3 very small. Claw Gm short, less than half length of claw GM.
Female antenna ( Figure 3D View Figure 3 ) with claw G2 approximately 80% length of claw G1. Setae z2 and z3 short to medium-length, seta z1 long, approximately reaching to end of claw G2. Claw Gm longer than in male, approximately 70% length of GM.
Mandible palp ( Figure 4A, B View Figure 4 ) large with four segments. Alpha seta very short and slender. Beta seta very short and stout, with stiff setules. Final segment supporting three claws and two setae.
Maxillula ( Figure 3E View Figure 3 ) with two-segmented palp. First segment with three setae on outer apical edge and one seta in sub-apical position near outer edge. Final segment quadrate with three robust setae and three shorter and more slender setae.
Fifth limb male palps ( Figure 3F View Figure 3 ) asymmetrical. Left palp slightly widens distally with wide, bluntly rounded terminal hook. Right palp with tightly curved, finger-like terminal hook.
Sixth limb ( Figure 4C View Figure 4 ) five-segmented, first segment with d1 seta. Second segment with long e seta, extending beyond end of third segment. Third segment with f seta reaching to about end of fourth segment. Fourth segment with two g setae, both extending just beyond fifth segment. Fifth segment with h1 and h3 setae of similar length, and with well-developed, robust, long claw h2.
Seventh limb with four segments ( Figure 4D View Figure 4 ), first segment with d1, d2 and dp setae present. Second segment with e seta reaching beyond mid point of next segment. Third segment with long f seta, extending beyond end of third segment and g seta extending to end of fourth segment. Fifth segment with long, reflexed h3 setae, relatively long h1 and h2 setae.
Caudal ramus ( Figure 4E View Figure 4 ) relatively robust, claw Gp slightly shorter than Ga. Seta sp almost reaching to base of claw Gp. Seta sa approximately one-third the length of claw Ga.
Hemipenes ( Figure 4F View Figure 4 ) with strongly rounded outer margin and slightly curved inner margin, lobe a with quadrate shape distally. Lobe b triangular, with rounded apex, not reaching to end of lobe a.
Three previously described Cyclocypris species have natatory setae not reaching beyond the claws of the antennae: Cyclocypris breviseptosa ( Bronshtein, 1925) , C. mediosetosa Meisch, 1987 , and C. diebeli Absolon, 1973 . Cyclocypris breviseptosa is known from only one site in north-east Russia, near the Arctic Circle ( Bronshtein 1988). Compared with C. anacola n. sp., C. breviseptosa has longer natatory setae on the antennae, a wider a-lobe on the hemipenis, and is much more inflated in dorsal view (width/length = 0.71, compared with 0.55 for C. anacola n. sp.). Cyclocypris mediosetosa is known from France and Italy ( Meisch 1987; Pieri et al. 2009). The overall carapace shape of C. mediosetosa is similar to that of C. anacola n. sp., although in dorsal view C. mediosetosa is slightly wider (width/length = 0.6), and the carapace has a vertical band of shallow pits mid-length. Additionally, C. mediosetosa has longer natatory setae, a S-shaped h2 seta on the seventh limb (straight with a small hook distally in C. anacola n. sp.) and considerably differently shaped hemipenes. Extant C. diebeli are only known from Hokkaido, Japan, although fossils are known from Europe ( Matzke-Karasz et al. 2004). The carapace of C. diebeli is much more globular than that of C. anacola n. sp., has a series of small platelets along the anterior margin of the right valve, and opposite valve overlap (left valve overlaps right). The natatory setae of the antennae are much longer than those of C. anacola n. sp., reaching to almost the ends of the claws, and the hemipenes are shaped differently, especially the outer margins.
The strongly reduced natatory setae on the antennae indicate that this species cannot swim. The presence of an eye and dark coloration of the carapace suggest that this species may not be restricted to subterranean habitats.
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