биота российских вод японского моря - Materials of Alexey Shipunov

Originally, Losina-Losinsky (1933) gave this genus name Pycnosoma, butreplaced it for Pycnosomia in his work of 1961, because the name Pycnosoma turnedout to have been preoccupied (Insecta).One species of the genus is found in the Sea of Japan.1. Pycnosomia strongylocentroti (Losina-Losinsky, 1933)(Pl. XVIII, figs. 7–11)Losina-Losinsky, 1933: 43–47, fig. 1 (Pycnosoma strongylocentroti); Hilton, 1942b: 40(Pigrogromitus robustus); Losina-Losinsky, 1961: 86; Turpaeva, 1994: 133–134 (Pycnosomiastrongylocentroti).Description. Trunk robust, elongated, with firm integument. Segments of trunkfused completely or partially on dorsal side, but separated by articulation lines onlateral and ventral sides. Lateral processes about as long as broad, separated by 0.2 to0.5 their own diameters. Ocular tubercle almost not rising over surface, situated nearerto anterior margin of cephalic segment; eyes well developed, entirely or partiallypigmented. Proboscis slender, cylindrical, much longer than half of trunk, directedobliquely downward. Abdomen thick, short, protruded horizontally. Chelifore almosttwice shorter than proboscis, smooth; scape cylindrical; chela smaller than scape;fingers without teeth. Oviger 6-segmented, devoid of setae; segment 6 longest;segment 3 shortest, others equal to one another; segment 6 smooth, swollen distally.Legs less than 1.5 times as long as whole body (with proboscis and abdomen), robust,unarmed; femur longest; tibia 1 slightly shorter than femur; tibia 2 shorter than tibia 1;tarsus short, caliciform; propodus as long as tibia 2, robust, curved, with welldevelopedheel, which bears up to 8 strong, but short spines. Main claw as long as halfof propodus, strong, curved. No auxiliary claws. Coxae 2 in both sexes ventrally beartall tubercles, which are broader in females. Measurements of holotype: trunk1.75 mm, proboscis 1.65 mm, abdomen 0.6 mm, chelifore 1.25 mm, oviger 2.95 mm,leg 5.47 mm.Remarks. Recent investigations of supplementary material allows someadditions to the foregoing description to be made. Usually the palps are vestigial, inshape of oval tubercles on both sides of the proboscis. The ocular tubercle in the Seaof Japan individuals is relatively tall, up to as tall as half of the diameter of thetubercle at the base. The genital gland is unusual for the pycnogonids. All longsegments of the legs are robust and swollen in the middle, especially in females, likeat the figure from the Losina-Losinsky’s book (1933). In females collected near IturupIsland (Kurils) and in the Sea of Japan maturing egg masses were visible even in tibiae2 of the legsGeographical distribution. This species was originally found on the sea urchinsStrongylocentrotus sp., collected in the northern part of the Sea of Japan (the TatarStrait) at a depth of 70 m. Later it was recorded in the Bering Sea, near the AleutianIslands and in the Gulf of California, on the rim of the hydrothermal area Guaymas(Losina-Losinsky, 1961; Turpaeva, 1994). It was found also in Peter the Great Bay onthe sea urchin Strongylocentrotus cf. pallidus at a depth of 155 m.Vertical distribution. P. strongylocentroti occurs in depths from 2 to 2000 m.123