Kunio Amaoka’s research while affiliated with Hokkaido University and other places

Specimens of the largescale dwarf flounder, Engyprosopon macrolepis (Regan, 1908) (Pleuronectiformes: Bothidae), were collected from the fishery landing of Chi-kan, Peng-hu Islands, western Taiwan. Although this species has been recorded from western Pacific Ocean including the Philippines and Japan, it has never been recorded from Taiwanese waters. Therefore, our specimens represent the first record for Taiwanese waters and fill a gap in the distribution of this species between the two countries. A detailed description of the specimens, including coloration of the fresh condition is provided and compared to the data of specimens collected in other regions. With the addition of E. macrolepis, a total of 11 species of Engyprosopon are recorded from Taiwanese waters, and we suggest that more species are expected to occur off Taiwan.

A new bothid flounder, Engyprosopon keliaoense sp. nov., is described on the basis of 4 specimens collected from off southwestern Taiwan. The new species belongs to these congeners with a pair of black botches on the caudal fin and is most similar to E. grandisquama (Temminck & Schlegel). It can be separated from the latter by having smaller upper and lower eyes, narrower interorbital width, shorter pectoral fin on the ocular side, and more scales in the lateral line. Investigation on Rhombus grandisquama and its junior synonyms revealed that Rhombodoichthys spilurus Günther and Rhombus poecilurus Bleeker are retained as junior synonyms of E. grandisquama, whereas Rhombodoichthys spiniceps Macleay and Scaeops orbicularis Jordan & Seale are now excluded from the synonymy of E. grandisquama.

The family Bothidae in Taiwan is reviewed. A total of 15 genera and 42 species are recognized. Historical records are re-evaluated and five species are recorded in Taiwan for the first time: Arnoglossus yamanakai Fukui & Ozawa, 1988, Crossorhombus valderostratus (Alcock, 1890), Parabothus polylepis (Alcock, 1889), Parabothus coarctatus (Gilbert, 1905), and Psettina variegata (Fowler, 1933). Laeops tongkongensis Chen & Weng, 1965 is recognized as a junior synonym of Laeops kitaharae Smith & Pope, 1906. Keys to genera and species, diagnostic characters, distribution and photographs are provided.

Species of the bothid genus Engyprosopon Günther, 1862 from the waters off Taiwan are reviewed. Nine species are recognized and described. Of the nine species, E. grandisquama (Temminck & Schlegel, 1846), E. multisquama Amaoka, 1963 and E. maldivense (Regan, 1908) previously known from Taiwan are confirmed, whereas E. xystrias Hubbs, 1915, E. mogkii (Bleeker, 1854), E. longipelvis Amaoka, 1969 and E. mozambiquense Hensley, 2003 represent new records for Taiwan. Moreover, two further species are described new to science. Engyprosopon brevifrontale sp. nov. is characterized by a deep and short body, large eyes situated close to the head margin, 0 + 9–10 smooth gill rakers, strong rostral and upper orbital spines on the ocular side, small rostral spine on the blind side, and a dark blue peritoneum. Engyprosopon parvipectorale sp. nov. is characterized by the combination of serrate gill rakers, large head (3.1–3.4 in SL); extremely narrow or almost ridge-like interorbital in both sexes; ocular-side pectoral fin distinctly short (1.4–1.6 in HL) in both sexes; and no rostral or orbital spines in either sex. Detailed descriptions and a key to all of the species of Engyprosopon recorded from the waters off Taiwan are provided.

Nine specimens of a flatfish collected from Western Australia were tentatively identified as Arnoglossus aspilos praeteritus Whitley, 1950. The original description of this subspecies is brief and the validity of the taxon had not been investigated, despite its inclusion in subsequent short notes and lists. Our examination of the new material and the type series of A. aspilos praeteritus reveals that this taxon clearly differs from the members of the genus Arnoglossus in having a well-defined interorbital space and split hypurals. It differs subtly from A. aspilos (Bleeker, 1851) in appearance, although both taxa closely resemble each other in most counts and proportional measurements. Arnoglossus aspilos praeteritus is herein redescribed and reassigned as a valid species of the genus Engyprosopon, viz., E. praeteritus. This species differs from other species of Engyrposopon in having a series of dark blotches on the dorsal and anal fins and a pair of small black blotches on the caudal fin, and by lacking sexual differences in morphology and coloration.

A new righteye flounder, Samariscus neocaledonia sp. nov., is described on the basis of two specimens collected in deep waters (244-278 m) around New Caledonia. The new species is easily distinguished from its 18 congeners in having a combination of 78-81 dorsal fin rays, 62-65 anal fin rays, five pectoral fin rays, ca. 55-62 lateral line scales, and 10 abdominal and 31-32 caudal vertebrae.

A new righteye flounder, Poecilopsetta multiradiata, is described from eight specimens (two males and six females) collected from deep waters (336–408m) around New Zealand and New Caledonia (South-West Pacific). This new species is distinguished from its 14 congeners by the following combination of characters: high numbers of dorsal (70–73) and anal (58–62) fin rays, ca. 85–99 lateral-line scales, 31–32 caudal vertebrae, and a relatively shallow body depth of 36.9–41.9% SL. Keywords Poecilopsetta multiradiata sp. nov.-Poecilopsettidae-Pleuronectiformes-New Zealand-New Caledonia-SW Pacific

A new dextral flounder, Samariscus multiradiatus, is described from six specimens (four males and two females) collected in deep waters (296–430m) around New Caledonia. The species is easily distinguished from its 16 congeners in having a combination of 85–91 dorsal fin rays, 67–72 anal fin rays, 5 pectoral fin rays, and 9 abdominal and 34–35 caudal vertebrae.

A new poecilopsettid flounder, Nematops nanosquama, is described from 10 specimens (4 males, 6 females) collected from deep waters (96–650 m) off Hiva Oa, Marquesas Islands. This species is easily separated from the three recognized species of the genus Nematops by having large numbers of dorsal fin rays, anal fin rays, lateral line scales, and vertebrae, five dark transverse broad bands on the body, and a black blotch on the distal area of the pectoral fin. N.nanosquama shows the easternmost record of this genus from the Pacific Ocean.