Paranikione distorta, An & Boyko & Li, 2015

An, Jianmei, Boyko, Christopher B. & Li, Xinzheng, 2015, A Review Of Bopyrids (Crustacea: Isopoda: Bopyridae) Parasitic On Caridean Shrimps (Crustacea: Decapoda: Caridea) From China, Bulletin of the American Museum of Natural History 2015 (399), pp. 1-85 : 25-27

Paranikione distorta , n. sp.

Figure 5

Urobopyrus bicornis An, 2006: 70–71 , fig. 30 (unavailable name).

MATERIAL EXAMINED: Infesting Hayashidonus japonica (De Haan, 1844) . Holotype ♀ ( CIEPR 010801), allotype ♂ ( CIEPR 010802), eastern Yellow Sea, Stn. 0108, 122 ° 45′E, 31 ° 15′N, 94 m, 15 August 1964, coll. unknown. Paratypes: 1 ♀, 1 ♂ ( CIEPR 601201), Shantou, Guangdong Province, Stn. 6012, 117 ° 00′E, 22 ° 30′N, 47.3 m, 23 December 1959, coll. Yu.

OTHER MATERIAL: 1 ♀, 1 ♂ ( CIEPR 625401), Beibu Gulf, Stn. 6254, 107 ° 30′E, 18 ° 30′N, 63.9 m, 10 July 1960, coll. Zhengang Fan.

DESCRIPTION: Holotype female ( CIEPR 010801 ): Length 5.15 mm, maximal width 4.96 mm, head length 0.82 mm, frontal lamina 0.22 mm, head width 1.37 mm, pleon length 1.38 mm, sinistral 67 ° (fig. 5A, B).

Head triangular, frontal lamina extending beyond sides of head and produced into earlike lamellae at anterolateral corners. Eyes absent (fig. 5A). Antennule of three articles, antenna of four articles, both terminally setose (fig. 5C). Maxilliped of two segments with short stout nonarticulated palp (fig. 5D), terminal end of palp and adjacent margin fringed with setae (fig. 5E). Barbula with two pairs of smooth falcate lateral projections on each side (fig. 5F).

Pereon broadest across third pereomere (fig. 5A), boundary between pereomeres 2–4 obscure, weakly fused. All pereomeres with coxal plates, those on left side much larger than right. Dorsolateral bosses on first four pereomeres. Brood pouch widely open (fig. 5B). Oostegite 1 visible from ventral view (fig. 5B), two articles subequal in length, smooth internal ridge and nearly straight posterior edge (fig. 5G, H). Pereopods smaller posteriorly (fig. 5I, J), each with five articles, carpi and meri fused, dactyli small. Pleon of six pleomeres, medially fused and sharply distorted sinistrally. First five pleomeres with biramous pleopods and lateral plates. Lateral plates of left side larger than right. Sixth pleomere with lobate biramous uropods. Ventral surface of pleopods thickly tubercular (fig. 5B), but uropods nearly smooth and lanceolate.

DESCRIPTION: Allotype male (CIEPR010 802): Length 2.15 mm, maximal width (across pleon 4) 0.38 mm, head width 0.31 mm, pleotelson length 0.83 mm. All pereomeres distinctly segmented (fig. 5K, L). Head semicircular (fig. 2K); dark eyes in posteriolateral corners (fig. 5K). Antennule of three articles, antenna of four articles, terminal articles setose (fig. 5N). Pereomeres subequal in width, midventral projections lacking (fig. 5L). All pereopods with six articles and subequal in size (fig. 5O). Pleon of six segments, first five pleomeres with large tubercular pleopods. Sixth pleomere with minute medial anal cone and long posteriorly directed tapering uropods (fig. 5L), distal tips of uropods with setae.

VARIATION: The paratype female (CIEPR60 1201) agrees with the holotype, but the antennae can be seen in dorsal view, and the median part of the pereon bulges outward. The paratype male (CIEPR601201) has a curved posterior margin of the head and its uropods are longer than those of the allotype (fig. 2M). The other female (CIEPR625401) is much larger (total length 6.09 mm) and has a wider frontal lamina and longer pleopods than the types.

ETYMOLOGY: The specific name, distorta , refers to the sharply sinistrally distorted pleon of the female.

HOST AND LOCALTIES: Infesting Hayashidonus japonica (De Haan, 1844) (Processidae) . Yellow Sea, Beibu Gulf, and Guangdong Province, China, 47– 94 m.

REMARKS: Paranikione distorta , n. sp., has a well-developed frontal lamina, pleon of six segments, lateral plates of the pleon lamellar, and is clearly congeneric with Paranikione sibogae , n. sp. The new species differ from P. sibogae , n. sp., in having (1) median part of female pleon fused, (2), female lacking acute median projections on the barbula, (3) female with sharply distorted pleon, (4) pereopods of the female with carpi and meri fused, (5) male with large tubercular pleopods and (6) male with long posteriorly directed uropods.

Figures

Fig. 5. Paranikione distorta n. sp., holotype female (CIEPR010801) (A–J): A. Dorsal view. B. Ventral view. C. Right antenna and antennule. D. Right maxilliped, external view. E. Palp of maxilliped. F. Left side of barbula. G. Left oostegite 1, external view. H. Left oostegite 1, internal view. I. Left pereopod 4. J. Left pereopod 6. Allotype male (CIEPR010802) (K, L, N, O): K. Dorsal view. L. Ventral view. M. Male (CIEPR601201) dorsal view. N. Left antenna and antennule. O. Left pereopod 5. Scale: 2 mm (A, B); 0.5 mm (D, F–H, K–M,); 0.25 mm (C, E, I, J, N, O).