First record of Bathynellacea (Crustacea, Syncarida, Parabathynellidae) in China: a new genus Author Camacho, Ana Isabel Author Trontelj, Peter Author Zagmajster, Maja text Journal of Natural History 2006 2006-12-01 40 29 - 31 1747 1760 http://dx.doi.org/10.1080/00222930600969356 journal article 10.1080/00222930600969356 1464-5262 10092243 Sinobathynella decamera n. g. n. sp. ( Figures 1–4 ) Material examined Type locality: ‘‘ Si Haizi Dong’ ’ cave ( Four Children’s Cave ), Changjiang County , Hainan Island , China , 1 February 2005 , one male and one female collected. The details of the new description are based on the two specimens . The holotype is a male and the paratype is a female ( holotype MNCN 20.04 /7047; paratype MNCN 20.04 /7048) . Description Body. Total length of holotype (male) 3.7 mm ( Figure 1 ) and paratype (female) 3.5 mm . Body elongated. Length of head greater than width. All drawings are of the holotype (male), except the antennule ( Figure 3A ) and Th 8 female ( Figure 4C ), which are of the paratype . Antennule (A.I) ( Figure 2A ). Ten segments; no sexual dimorphism; the total length of first four segments similar to that of last six segments; first segment with four smooth setae and three plumose setae; second segment with three smooth and four plumose setae; third segment with nine smooth setae; setation in other segments as in Figure 2A (segments 5–9 with two terminal dorsolateral aesthetascs; segment 10 with three subterminal aesthetascs). Figure 1. Photograph of Sinobathynella decamera n. g. n. sp., male. Optical microscope 10×. Figure 2. Sinobathynella decamera n. g. n. sp., male holotype. (A) A.I (female); (B) A.II; (C) labrum; (D) mandible (ventral view); (E) maxillule (dorsal view); (F) maxilla (dorsal view). Scale bar in mm. Antenna (A.II) ( Figure 2B ). Six segments, last four segments similar in size, longer than the first two segments; last segment with three smooth and one plumose terminal setae; segments 1 and 4 without setae; setation in the other segments as in Figure 2B . Figure 3. Sinobathynella decamera n. g. n. sp., male holotype. (A) Th 1; (B) Th 2; (C) Th 3; (D) Th 4; (E) Th 5; (F) Th 6; (G) Th 7; (H) exopod of Th 3. Scale bar in mm. Labrum (Lb) ( Figure 2C ). Concave, with eight main teeth, and six lateral teeth at either end. Mandible (Md) ( Figure 2D ). Pars incisiva with three well-developed teeth as in Figure 2D ; proximal tooth of the pars incisiva long with denticles; pars molaris with 14 claws, the nine distal ones being strong and with small teeth, and five proximal small claws joined and with a large number of fine hairs; mandibular palp does not exceed pars incisiva in length. Figure 4. Sinobathynella decamera n. g. n. sp. (A) Th 8 male (holotype) (lateral external view); (B) Th 8 male (holotype) (caudal view); (C) Th 8 female (paratype) (frontal view); (D) pleotelson and furca (dorsal view); (E) uropod (lateral external view). Scale bar in mm. Maxillule (Mx.I) ( Figure 2E ). Proximal endite with four teeth (like setae of different sizes); distal endite with seven claws, two smooth and apical, the other five with strong small teeth and three subterminal smooth setae on outer distal margin. Maxilla (Mx.II) ( Figure 2F ). Four segments, with two setae on basal segment; segment 2 with three long setae; segment 3 elongated with 16 setae and last segment with one strong terminal seta and two lateral setae. Thoracopod 1–7 (Th 1–7) ( Figures 3A–H ). Length gradually increasing from first to fifth, last three similar in size; well-developed epipodite on 3–7, measuring near half-length of basipod; basipod with one terminal and two inner barbed setae on Th 1, 2, 3, 5, and 6, four (one terminal and three lateral) on Th 4 (three in the female) and only two barbed setae on Th 7 male (three in the female); exopod of Th 1, with seven segments, shorter than endopod; exopod of Th 2 with nine segments and similar in length to endopod; exopods of Th 3–7, with 10 segments, longer than endopods; all the segments of the exopod of Th 1–7 with two barbed setae (with one group of ctenidia at the base of setae), except the first segment in Th 2–4 and 6, which has three barbed setae and in Th 5 which has four barbed setae; endopods of Th 1–7 with four segments, the first segment is small, the second and the third long, and the fourth is very small (with two smooth similar strong claws and one barbed seta), all inner setae on the segments are barbed and the outer seta of the first and second segments of Th 1–7 are plumose, setal formula: Th 1 4+1/4+1/4+1/3(1) Th 2 2+1/7+1/4+1/3(1) Th 3 2+1/6+1/5+1/3(1) Th 4 2+1/5+1/5+1/3(1) Th 5–6 2+1/5+1/4+1/3(1) Th 7 2+1/4+1/3+1/3(1) Paratype (female) setal formula of the endopods of thoracopods: Th 1 4–5+1/5–6+1/4+1/3(1) Th 2 2+1/6+1/4–5+1/3(1) Th 3 3+1/5–6+1/4+1/3(1) Th 4–5 2+1/6+1/4+1/3(1) Th 6 1+1/6+1/4+1/3(1) Th 7 1+1/6+1/3+1/3(1) Thoracopod 8 male (Th 8) ( Figure 4A, B ). Large, massive, almost square; basal region massive; inner lobe not completely integrated into the basal region; basipod (Bsp.) with one very marked distal protuberance on the internal lateral edge which exceeds the end of the inner lobe (I. Lob.); endopod (Endp.) almost square, with two long barbed setae; large exopod (Exp.), longer than wide and overhanging the basipod and the outer lobe (O. Lob.); outer lobe is not fused with basipod and does not exceed the end of the external side of the basipod; dentate lobe (D. Lob.) without very marked teeth. Thoracopod 8 (Th 8), female paratype ( Figure 4C ). Large with smooth cuticle, almost square, has two small teeth and two long smooth setae. Dorsal margin of pleotelson ( Figure 4D ). With a small rounded anal operculum; one ventral seta (broken on the holotype ). Uropod (Urp.) ( Figure 4D, E ). Sympod (Symp.) twice as long as the endopod (Endp.) and five times longer than wide; with 20 barbed spines of similar size; endopod similar in length to exopod (Exp.), with four strong barbed spines ( Figure 4D, E ) (three on the female) and one claw ( Figure 4C ) on the distal end, two plumose setae on the external part, the most basal does not exceed the distal end of the endopod, and two strong barbed terminal and subterminal setae, several groups of ctenidia on dorsal face; exopod has two barbed terminal setae, the outer longer than the inner, and six barbed setae on external face (one of these basal). Furca (Frc.) ( Figure 4D ). Nine barbed spines ( 10 in the female) (the two terminal ones being longer and thicker); two dorsal plumose setae of similar size that do not exceed the distal spines. Etymology The generic name is dedicated to China . The species name, decamera , refers to the characteristic found for the first time within the Bathynellacea , that of 10 segments in the A.I and in the exopod of the Th 3–7.