Heteronarce rierai sp.nov. is described on the basis of six specimens, one male and five females, caught in the waters off Mozambique (western Indian Ocean). Total lengths range from 257 to 296mm . The new species is distinguished from the three other species of the genus Heteronarce by its narrower disc width (29.6% of TL in male, and 33.0 to 39.2% of TL in females), shorter disc length (32.7% of TL in male, and 34.4 to 40.6% of TL in females), and its longer interdorsal distance (10.1 to 11.7% of TL).
Hypergastromyzon eubranchus sp.nov. is described from the Lupar basin of Sarawak, Malaysian Borneo. It differs from the only other known species of Hypergastromyzon, H. humilis, from the Kapuas basin of western Borneo, in having a very large gill opening instead of a greatly reduced one, 23-25 instead of 28-30 branched pectoral fin rays, and pelvic fins incompletely rather than completely united to each other posteriorly.
A new species of tripterygiid fish, belonging to the recently described genus Ceratobregma Holleman, 1987, is characterized by a total of 17 spines in the second dorsal fin, 8 rays in the third dorsal fin, 20 anal fin rays (spines+rays=22), 14+21 lateral line scales, a total of 35-37 lateral scale series, small spiny scales on the sides of the head behind the eye and on the upper cheeks, 14 vertical dark stripes along the upper sides of the body, and 8 basal blotches on the second dorsal fin. A key to the species of Ceratobregma is presented. Norfolkia brachylepis is described and recorded from northwestern Australia. Norfolkia springeri is synonymized with N. brachylepis.
Examination of the holotype and only known specimen of Paroxyurichthys typus Bleeker, 1876, from Indonesia revealed it to have distinctions of the cephalic lateralis, post-cranial axial osteology and pigmentation diagnostic of Gobionellus oceanicus (Pallas, 1770) of the western Atlantic. Paroxyurichthys Bleeker, 1876, is a junior synonym of Gobionellus Girard, 1859. The only other species commonly referred to Paroxyurichthys, Oxyurichthys laterisquamatus Weber, 1908, from New Guinea, has anterior nares medial to the oculoscapular canals of the spout, This feature is a synapomorphy of the genus Stenogobius Bleeker, 1874. The new combination, Stenogobius laterisquamatus is proposed.
The karyotype of the dolly varden Salvelinus malma from Alaska was analysed. A pair of huge acrocentrics, which could have resulted from either tandem fusion or centric fusion followed by pericentric inversion, was observed. Ag-NORs were observed at the terminal regions of the second largest chromosome pair, and individual size-differences in Ag-NORs and in chromosomes with Ag-bands were found. From a comparison of the karyotypes of the dolly varden from Alaska and Hokkaido (Japan), karyotype differentiation by pericentric inversion and translocation was discussed.
Karyotypes and cellular DNA contents of three species of the family Cottidae viz. Icelus cataphractus, Gymnocanthus intermedius and Alcichthys alcicornis were analyzed. Structural modifications within the family were supposedly by Robertsonian translocations. The diploid chromosome numbers were determined to be 48 in Alcichthys alcicornis, 44 in Gymnocanthus intermedius and 40 in Icelus cataphractus. The DNA contents ranged from 1.46 to 1.50pg/cell in the three species. The karyotype of Icelus cataphractus is unique in having the smallest chromosome number (2n=40) and 14 large-sized chromosomes. From the chromosome number and the existence of some large chromosome pairs, Robertsonian translocations seem to have occurred frequently in Icelus cataphractus and Gymnocanthus intermedius.
Coloration and sex change were studied in a temperate wrasse Halichoeres poecilopterus in the central part of the Seto Inland Sea, Japan. 1, 270 examples, 45-179mm SL, were collected from May to December both in 1983 and 1984. The species is a diandric, protogynous hermaphrodite, and has three color patterns: pale color type (A), brilliant color type (B) and intermediate color type (AB). A-fish were less than 142mm SL and consisted of primary males (42.6%), females (55.4%), secondary males (0.3%) and fish with transitional gonads (1.7%). A-females changed their color to B, through AB, in the size range 101-131mm SL. A-primary males changed their color to B, through AB, in the size range 103-134mm SL. B-fish consisted of primary males (38.6%), secondary males (54.6%) and fish with transitional gonads (6.8%). The majority of females changed their sex to male in the size range 98-131mm SL.
The wrasse, Suezichthys gracilis, is a diurnal fish which buries itself in sand during the night-time. The present paper deals with the locomotor activity rhythms of S. gracilis, examined by using an actograph with infra-red photo-electric switches in a dark room. The fish were kept in eight experimental tanks (each 30l in capacity), with three different bottom conditions: sand (grain size about 1mm in diameter and 5 cm deep); 1 or 2 stones (about 10cm in diameter) without sand; and transparent acrylic pellets (2×2×3mm in size, 5cm deep). The light intensities were 550-700 lux just above the water surface, decreasing to 21.3% under the acrylic pellets at a water depth of 20cm. The water temperatures were kept at 22.0-25.0°C during the experiments for 7 to 14 days. In the aquarium with bottom sand, diel activity rhythms of S. gracilis were mostly synchronized to LD (LD12: 12; 06: 00-18: 00 light, 18: 00-06: 00 dark), free-running activity rhythms continued distinctly under LL (constant illumination), and locomotor activity was greatly suppressed, with disappearance of the activity rhythm, under DD (constant darkness). In the aquarium without sand, locomotor activity of S. gracilis could be summarized as follows. The fish moved throughout almost the entire period under LD, though more frequent movements were observed in light conditions than in dark ones. Under LL they showed continuous locomotor activity during the experiment, with no obvious periodicity. Under DD the activity of the species was somewhat suppressed, but irregular movement or indistinct periodicity was observed. In the aquarium with transparent acrylic pellets, locomotor activity under LD and DD, respectively, bore a close resemblance to activity patterns under the same light conditions with sand, whilst activity under LL was identical to that under LL without sand. Accordingly, it seems that maintenance of normal activity rhythms in the wrasse was due not only to the darkness, but also to the presence of bottom sand. It therefore seems that the biological clock in S. gracilis is not related to locomotor activity, but to burying behavior.