Discovery of fossil Ayu (<Emphasis Type="Italic">Plecoglossus altivelis</Emphasis>) from the Upper Miocene of Shimane Prefecture,Japan

The Ayu, Plecoglossus altivelis, comprising three subspecies, is the only species in the genus Plecoglossus in the family Osmeridae. Here, we describe for the first time the discovery of fossil specimens of P. altivelis from the Upper Miocene sediment of Matsue, Shimane Prefecture, Japan. The fossil individuals are subadult and have comb teeth in the second and third generations. These fossil specimens are clearly similar to the recent P. altivelis, the former’s meristic characters being included in the three recent subspecies. In terms of numbers of pectoral fin rays and vertebrae, the fossil specimens are more similar to the subspecies Plecoglossus altivelis ryukyuensis than the other subspecies, but they also show different dorsal fin shapes and anal fin ray counts. This discovery of fossil P. altivelis indicates the persistence of the species for at least 10 million years, from the Late Miocene to the present.     

Dental variability inSaimiri and the taxonomic status ofNeosaimiri fieldsi,an early squirrel monkey from La Venta,Colombia

Neosaimiri fieldsi, from the South American middle Miocene locality of La Venta, is represented by a relatively complete mandible and dentition that strongly resembles that of extantSaimiri. Comparison with a large sample of mandibles ofSaimiri indicates that this specimen cannot be distinguished from modern populations on the basis of any reportedly diagnostic feature, such as cingulid development, molar length ratio, trigonic/talonid ratio, or mandibular depth. The fossil is best considered an extinct species of the modern genusSaimiri until further material indicates otherwise.     

A new gobiid fish of the genusClariger from Mutsu Bay,northern Japan

A new species of the genusClariger was described on the basis of thirty-two specimens collected from the subtidal zone of Mutsu Bay, Aomori Pref. This species is distinguishable from other congeners in the following: body naked; a series of large white patches on the back, one on the nape passing through the pectoral fin base and axil part; fin rays of both the second dorsal and anal fins, I, 12–14; vertebrae, 34–35; a single free filamentous ray on the upper lobe of pectoral fin. A new key to all the known species of the genusClariger is prepared.     

A new loach, Cobitis shikokuensis (Teleostei: Cobitidae), from Shikoku Island, Japan

A new species of spinous loach, Cobitis shikokuensis, is described based on 297 specimens from Shikoku Island, Japan. The new species was formerly known as the Shikoku group of Cobitis takatsuensis. It can be distinguished from other species of Cobitis and closely related genera by a combination of the following characters: dorsal fin with 6 branched soft rays; anal fin with 5 branched soft rays; one brownish streak across eye from the tip of nose, no streak on cheek; a black spot smaller than eye diameter near the dorsal corner of the caudal fin base; 3–5 small brownish speckles on ventral side of caudal peduncle; high caudal peduncle with well-developed fleshy keels on dorsal and ventral side; a lamina circularis at base of dorsal part of pectoral fin absent; first branched soft ray of pectoral fin broad in males; pectoral soft rays widely branched from the approximate midpoint; last anal fin ray with 2 elements; interorbital width 11.2–17.1% of head length.     

Parsimony analysis of the distribution pattern of Japanese primary freshwater fishes, and its application to the distribution of the bagrid catfishes

The geographic distribution of Japanese primary and some secondary freshwater fishes was analyzed using parsimony analysis of endemicity (PAE). Analysis of 73 taxa (species and intraspecific forms) on the four main islands of Japan (divided into 25 geographic areas), produced 44 most parsimonious cladograms. In all of the latter, a total of eight single and compound areas were recognized as endemic areas in nested relationships. The area cladograms showed Japan as comprising a middle-eastern Hokkaido area plus southern areas, the latter containing mainly a northeastern-Honshu endemic area and more heterogeneous southwestern areas, including four endemic areas (western Kyushu, southeastern Chugoku, middle Kinki and Tokai around Ise Bay) and several peripheral areas. Some patterns, e.g., the distinction in fauna across Fossa Magna, noted by previous studies, were supported by these results. Even though the analysis had some problems (e.g., not all geographic ranges of taxa could be included), it provided evidence for the detection of general distribution patterns, because the relationships or similarities among areas were clearly defined by shared taxa. To demonstrate the historical implications of the analysis, the allopatric distribution of, four bagrid catfishes was reconsidered in the area cladogram. The general pattern implied secondary extinction ofPseudobagrus nudiceps around lse Bay, which was in keeping with the fossil record.     

Nematops nanosquama, a new species of righteye flounder (Pleuronectiformes: Poecilopsettidae) from off the Marquesas Islands

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.     

Genetic population structure of Japanese bagrid catfishes

 The genetic population structures of four bagrid catfishes, allopatrically distributed in Japan, were investigated based on nucleotide sequence data from the mitochondrial control region (ca. 420 bp) of 296 specimens from 29 river systems. Almost no sequence variations were found within riverine populations of each species, especially Pseudobagrus ichikawai, in which no individual variations were found in any specimens from eight river systems throughout its range. In contrast, the P. nudiceps population in the Lake Biwa–Yodo River system showed relatively high polymorphism. These results imply that the riverine populations have undergone a bottleneck situation at some time. Most of the riverine populations of P. nudiceps and P. ichikawai, which are mainly distributed in areas around an inland sea or bay, were fixed into a single haplotype for each species. On the other hand, in P. tokiensis and P. aurantiacus, which are distributed in areas surrounding extensive mountainous regions, the haplotype compositions clearly differed among conspecific populations. These results suggest that some degree of gene flow existed among populations of each of the former two species during glacial regression periods. Based on the genetic variability of P. fulvidraco, widely distributed in continental East Asia, and the degree of genetic divergence between P. aurantiacus and its possible sister species, P. taeniatus, in China, the evolutionary rate of East Asian bagrids appears to be relatively low, estimated at a few percent per million years or less. Received: June 5, 2002 / Revised: December 6, 2002 / Accepted: December 26, 2002     

Lycodes nishimurai, a new deep-sea eelpout (Teleostei: Zoarcidae) from the Sea of Japan

A new zoarcid fish, Lycodes nishimuari, is described on the basis of four specimens from the Yamato Bank, the Sea of Japan, at depths of 642–669 m. Although this species resembles Lycodes diapterus, L. hubbsi, L. pectoralis, L. macrochir, and L. nakamurae in having a deep notch in the pectoral fin and a single lateral line on the body, it is distinguished from them by the following combination of characters: no scales on pectoral fin base; scales on dorsum before dorsal fin origin; suborbital, preopercular, and last postorbital pores with risen rim; whitish lips; no whitish transverse bars on body; pectoral fin membrane and anterior part of dorsal fin membrane without black spots; basal color of vertical fins black. Supplementary material to this paper is available in electronic format at .     

Redescription of <Emphasis Type="Italic">Bregmaceros mcclellandi</Emphasis> Thompson, 1840 (Gadiformes: Bregmacerotidae)

 This study redescribes Bregmaceros mcclellandi Thompson, 1840, based on one specimen (74.4 mm SL) from the Bay of Bengal and 66 specimens (30.0–84.7 mm SL) from Mumbai (Bombay), India, because the type specimens have apparently been lost. The present specimens are characterized by having black dorsal, pectoral, and caudal fins and show the following morphology: caudal fin slightly forked; body chromatophores present mainly at the dorsal part; no scales on cheek; vertebrae 52–55 (13–15 + 38–41); dorsal rays 52–59; anal rays 54–60; pectoral rays 18–20; caudal rays 27–31 (principal rays 14); transverse scales 14–15. In the 66 Mumbai specimens, it was confirmed that the distinctive black fin pigmentation developed sequentially with growth, with complete pigmentation first on the anterior lobe of the dorsal fin, then simultaneously on the posterior lobe of the dorsal fin, the caudal fin, and the pectoral fin, and last, on the anal fin. This species is known only from the Arabian Sea, Bay of Bengal, and Gulf of Thailand. A review of 16 nominal Bregmaceros species indicates that, besides B. mcclellandi, the distinctive dark fin pigmentation is found in B. atripinnis (Tickell), B. atlanticus Goode and Bean, B. japonicus Tanaka, and B. lanceolatus Shen. B. atripinnis is considered a junior synonym of B. mcclellandi, and the others are clearly distinct from B. mcclellandi. Comments are made on some of the characters to more fully characterize the species and for reference in future revisionary and phylogenetic studies. Received: June 17, 2002 / Revised: December 2, 2002 / Accepted: December 24, 2002     

A new righteye flounder, Poecilopsetta pectoralis (Pleuronectiformes: Poecilopsettidae), from New Caledonia

A new righteye flounder, Poecilopsetta pectoralis, is described from 4 specimens (2 males, 2 females) collected from deep waters (510–580 m) around New Caledonia. The species is easily distinguished from 13 congeners by having 99–105 lateral line scales, a narrow interorbit [male: 37.00–40.25 in head length (HL); female: 47.33–50.71], long pectoral fin on ocular side (male: 0.89–0.91 in HL; female: 1.04–1.20), no scales from snout to anterior interorbital region, and 4 spots on caudal fin. Sexual dimorphism is evident in this species, showing males bearing the ocular-side pectoral fin longer than females, and it is the first example in Poecilopsetta.     

MtDNA phylogeny provides evidence of generic polyphyleticism for East Asian bagrid catfishes

We explore the intrafamilial relationships of East Asian bagrid catfishes (Hemibagrus, Pseudobagrus, Pelteobagrus, and Leiocassis) based on 245 sequences of 1092 bp mitochondrial cytochrome b fragments. Four haplotypes were found to be shared by Pseudobagrus ussuriensis, Pelteobagrus vachelli and Pelteobagrus nitidus. Phylogenetic trees were performed using the neighbor joining, maximum parsimony, maximum likelihood, and Bayesian likelihood methods. The phylogenetic trees based on NJ, MP, ML and BL inferences strongly support polyphyleticism for the currently recognized genera Pseudobagrus, Pelteobagrus and Leiocassis. However, the species currently assigned to these three genera form a robustly monophyletic group with relatively low genetic divergence. The structure of maxillary barbels and serrations on the anterior edge of the pectoral spines seem to be indicatory of appropriate phylogenetic traits. We propose that only Hemibagrus and Pseudobagrus are the only valid genera of East Asian bagrids. Handling editor: K. Martens     

<Emphasis Type="Italic">Samariscus multiradiatus</Emphasis>, a new dextral flounder (Pleuronectiformes: Samaridae) from New Caledonia

A new dextral flounder, Samariscus multiradiatus, is described from six specimens (four males and two females) collected in deep waters (296–430 m) 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.     

Fossil record of a silurid catfish from the Middle Miocene Sanuki Group of Ohkawa, Kagawa Prefecture, Japan

A fossil specimen identified as a silurid catfish (92.5 mm SL) was collected from the Middle Miocene Sanuki Group (15.8±0.9 Ma) of Ohkawa, Kagawa Prefecture, Japan. This is the oldest certain record of a silurid catfish. Morphological characteristics of the specimen are as follows: 52 or 53 vertebrae, 61 or 62 anal fin rays, a stout, short spine (11%SL) and 10 or more soft rays of the pectoral fin, 8 or more pelvic fin rays, 8 or more branchiostegal rays, head length of ca. 24%SL, and most probably not forked caudal fin. The fossil specimen is clearly distinct from three extant silurids in Japan, and probably belongs to an undescribed form considering its geological age.     

Hemimyzon nanensis, a new balitorid fish from the chao phraya basin, thailand

A new balitorid fish,Hemimyzon nanensis, is described from the Mae Nam Nan River basin, a tributary of the Chao Phraya River, in northern Thailand. This species is distinguishable from its congeners by the following unique combination of characters: pectoral fin with 9–11 simple and 10–12 branched, rays; pelvic fin with 3–4 (usually 3) simple and 8–9 (usually 9) branched rays; 59–63 total lateral line scales; distance between pelvic fin bases 8.1–9,6% SL.H. nanensis is the first species of the genus recorded outside China and Taiwan.     

Sinocyclocheilus donglanensis, a new cavefish (Teleostei: Cypriniformes) from Guangxi, China

Sinocyclocheilus donglanensis, a new cyprinid species from a subterranean river in Donglan County in the Guangxi Zhuang Autonomous Region of southern China, is described. It is distinguished from all congeners by the following combination of characteristics: a completely scaled body with well-developed eyes; a curved lateral line possessing 57–64 scales; pectoral fin not reaching pelvic fin origin and last unbranched ray of the dorsal fin clearly serrated along its posterior edge; 8–9 predorsal vertebrae; 8–9 gill rakers; joints of dentary-angulars not close to each other at the isthmus; and a slightly inferior mouth with the upper jaw (6.2–7.4% in standard length: SL) protruding slightly beyond the lower one (5.7–6.7% SL). Sinocyclocheilus donglanensis is sympatric with the peculiarly shaped, hunchbacked S. altishoulderus.     

A new species of <Emphasis Type="Italic">Rhinogobius</Emphasis> (Teleostei: Gobiidae) from the Julongjiang Basin in Fujian Province,China

Ten specimens of a new freshwater goby, Rhinogobius longyanensis were collected from the small tributary of the Julongjiang Basin, Fujian Province, southeastern China. The new species can be distinguished from all congeneric species by following unique combination of features: second dorsal fin rays I, 8; anal fin rays I, 7–8; pectoral fin rays modally 17; longitudinal scale series 30–32; predorsal scales 6–8; vertebral count 10 + 17 = 27; three parallel, deep brown oblique stripes crossing on cheek; branchiostegal membrane with 24–28 orange red spots in male; body with 5–6 deep brown blotches; pectoral fin base with a blackish brown bar. A diagnostic key to all nominal species with high vertebral counts from mainland Southeast Asia, China, Taiwan, and Japan is also provided.     

Developmental morphology of the cottid fish Pseudoblennius marmoratus

Embryonic, larval, and juvenile development of a Japanese cottid fish Pseudoblennius marmoratus is described from laboratory-reared specimens. Eggs of P. marmoratus resembled those of two congeners, Pseudoblennius cottoides and Pseudoblennius percoides, but differed in their smaller diameter and yolk color. Although the larvae and juveniles of P. marmoratus were also similar to them in general morphology, the former differed in the lengths of newly hatched larvae, pigmentation patterns, number of pectoral fin rays, and dorsal fin spine elongation.     

Development of eggs, larvae and juveniles of laboratory-reared blue whiting,Sillago parvisquamis (Percoidei: Sillaginidae)

The embryonic, larval and juvenile development of blue whiting,Sillago parvisquamis Gill, are described from a series of laboratory-reared specimens. Mean egg diameter and mean total length (TL) of newly-hatched larvae were 0.71 mm and 1.58 mm, respectively. The eggs were non-adhesive, buoyant and spherical with an oil globule (mean diameter 0.18 mm). Hatching occurred about 20 hours after fertilization at a temperature of 24.0–25.0°C, newly-hatched larvae having 38–40 myomeres. The yolk and oil globule were completely absorbed 3 days after hatching at 2.8–3.2 (mean 3.0) mm TL. Notochord flexion was completed by 7.2–8.2 (7.7) mm TL, and pectoral and caudal fin rays fully developed by approximately 10 mm and 8.5 mm TL, respectively. Completion of fin development occurred in the following sequence: caudal, pectoral, anal and second dorsal, first dorsal and pelvic, the last-mentioned by approximately 11 mm TL. The larvae ofS. parvisquamis andS. japonica, which closely resemble each other in general morphology and pigmentation, could be distinguished as follows. Newly-hatchedS. parvisquamis larvae had more myomeres thanS. japonica (38–40 vs. 32–34) and more melanophores on the dorsal surface of the body (19–28 vs. about 40).Sillago japonica had a vertical band of melanophores on the caudal peduncle, which was lacking in postflexionS. parvisquamis larvae. In addition, juveniles ofS. parvisquamis (larger than 23 mm TL) had melanophores on the body extending anteriorly to below the lateral line to form a midlateral band, whereas no obvious band occurred on similarly-sizedS. japonica juveniles.     

A new zoarcid, Lycodes mcallisteri, from eastern Arctic Canada (Teleostei: Perciformes)

A new zoarcid fish, Lycodes mcallisteri, is described on the basis of nine specimens (230–375 mm SL) from eastern Arctic Canada, Nunavut (Hudson Strait, 298 m; Cumberland Sound and Baffin Bay, 579 m). It resembles about 15 other Lycodes spp. in having a long tail and a "ventromediolateral" type of lateral line. It is distinguished from Arctic members of this group (Lycodes marisalbi, L. palearis, and L. sagittarius) by the high number of pectoral fin rays (22–23), short pelvic fins, low submental crests, and coloration (6–10 light patches dorsally). It resembles two Pacific species (L. macrochir and L. soldatovi) by the high number of pectoral fin rays, but differs by coloration, meristics, and shape of the pectoral fin. Received: April 13, 2000 / Revised: September 7, 2000 / Accepted: January 11, 2001     

A new genus and species of prickleback (Perciformes: Stichaeidae) from Japan

A stichaeid fish, Xenolumpenus longipterus gen. et sp. nov., is described on the basis of 2 specimens (107.1–114.9 mm in standard length) collected from 167 to 300 m in the northern Sea of Japan off southern Hokkaido, Japan. Xenolumpenus is unique among all known genera of the subfamily Lumpeninae in having all pectoral, pelvic, and anal fin rays elongate and unbranched with fin membranes well-incised. Xenolumpenus longipterus can be further distinguished from all species of the subfamily in having the following combination of characters: dorsal fin XLVI–XLVIII; anal fin II, 28–29; pectoral fin 11; large black blotches on pectoral fin; and black ocellus on caudal fin.