Comparative histology of the testes of the spined loach Cobitis taenia L. and natural allotetraploids of Cobitis (Pisces, Cobitidae)

The spined loach Cobitis taenia L. creates exclusively diploid and mixed diploid–polyploid populations. Allotriploid females, which co-exist with C. taenia or C. elongatoides and a few tetraploid males and females dominate in most Cobitis mixed populations. They reproduce gynogenetically and produce triploid eggs that are stimulated to development by sperm from Cobitis males. Some of these eggs are fertilized, which leads to the production of bisexual tetraploids. Males of C. taenia (2n = 48) from a diploid population in Lake Klawój, Northern Poland (46 individuals) and from a mixed Cobitis population in the Bug River, Eastern Poland (7 individuals), and three tetraploid males (4n = 98) from the same mixed population were examined. All the fish were analyzed karyologically and histologically. Tubules with cysts of the testes of C. taenia from both populations were filled with germ cells at various developmental stages. Among fishes from Lake Klawój sperm maturation in batches simultaneous with the batch spawning of C. taenia females was found. The testes of the loach C. taenia, from a mixed population in the Bug River, were filled with spermatozoa over the entire reproductive season. Sperm maturation in batches was not observed. Sperm maturation in batches seems to be only connected with a few diploid males in this population. So, a continuous process of spermatogenesis in their testes is required. Only in the testes of all tetraploid Cobitis males were cells characteristic of the early stages of spermatogenesis observed, i.e. without spermatids and spermatozoa. Furthermore, the histological sections of the testis of a male captured in August, revealed fragments with connective tissue between the germ cells. However the participation of tetraploid, infertile Cobitis males in the process of reproduction in the investigated mixed population remains controversial. The results obtained so far, reveal that even the infertile sperm of tetraploid males may induce gynogenesis in Cobitis triploid females.     

Replication banding patterns in the spined loach,Cobitis taenia L. (Pisces,Cobitidae)

The chromosomal complement of Cobitis taenia was analysed by replication banding techniques to determine whether there were specific patterns that could allow distinction of the different chromosomes. The diploid chromosome number of 2n = 48 is diagnostic of this species. In vivo 5-bromodeoxyuridine (5-BrdU) incorporation induced highly reproducible replication bands. Most of the chromosome pairs were distinguishable on the base of their banding patterns. The karyotype, consisting of five pairs of metacentrics, nine pairs of submetacentrics and 10 pairs of subtelocentrics and acrocentrics, was confirmed. C-banding and replication banding patterns were compared, and heterochromatin was both early and later replicating. C-positive heterochromatin in centromeric regions was mainly early replicating, but that located in pericentromeric regions was late replicating. Most of the late-replicating regions found interstitially were C-band negative. The results obtained so far for combined chromosomal staining methods of C. taenia and other Cobitis fish species are discussed.     

Genetic relationships among the Japanese and Korean striated spined loach complex (Cobitidae: Cobitis) and their phylogenetic positions

The striata complex, a group of spined loaches included in the genus Cobitis and characterized by a striped coloration pattern on the lateral midline, is distributed in rivers in northeastern Asia to western Japan. The complex comprises 2 continental species (Cobitis tetralineata and Cobitis lutheri) and 3 Japanese races of species rank (large race, middle race, and small race), the small race further comprising 6 local forms of subspecific rank (Tokai form, Biwa form, Yodo form, Sanyo form, San-in form, and Kyushu form). Previous karyological studies have revealed that the large race is an allotetraploid, the others being diploid. In this study, mitochondrial (mt) DNA analyses were conducted for 30 diploid populations of the Cobitis striata complex from Japan and Korea to examine: (1) their phylogenetic relationships and the position of the complex among the major lineages of Cobitis; and (2) the genetic relationships among the Japanese and Korean populations. The results, based on cytochrome b sequences (724 base pairs) analyzed with those of the main lineage of European and Japanese Cobitis, indicated that the striata complex should be considered as a monophyletic group, which evolved in northeastern Asia. Initially considered as a subspecies of Cobitis taenia, widely distributed from Europe to Asia, the striata complex does not have a sister-relationship with the former. Although the Korean species C. tetralineata was formerly believed to be closely related to the middle race in Japan, and a second continental species, C. lutheri, closely related to the Kyushu or San-in forms of the small race in Japan, the trees resulting from the present study revealed that the two Korean species were clustered with each other and separated from all Japanese races.     

Biochemical genetic evidence for a hybrid origin of spined loach, Cobitis taenia taenia, in Japan

Starch gel electrophoresis and isoelectric focusing were performed on sarcoplasmic proteins from three taxa of cobitid fish in Japan, Cobitis biwae , C. taenia striata and C. l. taenia . These taxa are hardly distinguishable from each other by external appearance or morphological characters. Electrophoretic patterns of sarcoplasmic proteins from white muscle suggested fixed allelic differences between C. biwae and C. t. striata at two protein-coding loci (parvalbumin and creatine kinase). The third taxon, C. t. taenia , showed composite banding patterns with respect to the above two proteins, suggesting C. t, taenia originated from hybridization between C. biwae and C, t. striata . Previously, C. t, taenia and C. t. striata were believed to have shared a common ancestor subsequent to their divergence from C. biwae .     

Iksookimia yongdokensis, a new cobitid fish (Pisces: Cobitidae) from Korea with a key to the species ofIksookimia

A new cobitid fish,Iksookimia yongdokensis, is described from rivers flowing to the southeastern coast of Korea. The species is distinguishable from its congeners by the following characteristics: reduced laminar circularis at the base of the pectoral fins in males; color pattern including 9–13 vertical bars on the body; 13–14 gill rakers; 17–20 caudal vertebrae; and small scales with a large focal area. Its unique discontinuous distribution on the Korean Peninsula is discussed and the biogeographic implications considered.     

Antennatus flagellatus (Teleostei: Antennariidae), a new species of frogfish from southern Japan

A new species of frogfish,Antennatus flagellatus, is described on the basis of two specimens from Kashiwajima Island, Kochi Pref., southern Japan. It is distinguished from congeneric species as follows: illicium long, more than 40% SL and about 3.6 times length of second dorsal spine; caudal peduncle present.     

Spawning habitat in the spined loach, <Emphasis Type="Italic">Cobitis taenia</Emphasis> (Cypriniformes: Cobitidae)

Spawning habitat of the endangered spined loach Cobitis taenia was studied in northwestern Germany. The distribution of eggs of the loach in the field was best correlated with the density of vegetation but had little correlation with current velocity, water depth, or bottom substrate. In the aquarium, the loach chose dense vegetation for an oviposition site, as inferred by the direct observations of spawning and the location of spawned eggs. It is concluded that such habitat specialization is an important element in the autecology of the endangered fish and a critical stage in the habitat requirements of its populations.     

A new cottid species, Icelus sekii (Perciformes: Cottoidei), from Hokkaido, Japan

A new cottid species, Icelus sekii, is described on the basis of six specimens collected from off Rausu and Urakawa, Hokkaido Island, Japan. This species is distinguished from its congeners by the following combination of characters: supraocular and parietal spines absent; nuchal spine obscure; uppermost preopercular spine unbranched; no scales between dorsal scale row and lateral line scale row, and no scales below lateral line scale row; supraocular, parietal, and nuchal cirri present; five dark brown saddles dorsolaterally; anal fin rays 13; pectoral fin rays 15; vertebrae 12 + 24–25 = 36–37. Icelus sekii can be mature at the smallest size among the species of Icelus. As a secondary sexual character, the male holotype has unique ensiform flaps on the distal tips of the first dorsal fin.     

A new species of scabbardfish, Evoxymetopon macrophthalmus (Scombroidei: Trichiuridae), from Okinawa, Japan

Evoxymetopon macrophthalmus sp. nov. is described on the basis of a single specimen collected off Okinawa Island, Ryukyu Islands, Japan. Among the two valid species of Evoxymetopon, the new species is more similar to E. poeyi in having the first dorsal-fin spine enormously large, compressed, and sword shaped. It differs from E. poeyi in having the upper profile of head uniformly convex without a prominent sagittal crest (vs. with a prominent sagittal crest), tip of first anal pterygiophore connected to the last rib in the anterior part, while the first hemal spine is long and connected to the posterior margin of pterygiophore bone plate (vs. connected to the first hemal spine only), a larger eye, 4.5 times in head length (vs. 5.5–5.9 times), 15 externally visible anal-fin soft rays (vs. 20), 9 upper gill rakers of the first arch (vs. 4–6), and 60 caudal vertebrae (vs. 64).     

A new species of armored sea robin, Paraheminodus kamoharai (Teleostei: Peristediidae), from the Philippines

A new peristediid, Paraheminodus kamoharai, is described from three specimens (106.9–114.8mm SL) collected from the Sulu Sea, the Philippines. The new species is easily distinguished from its congeners (Paraheminodus laticephalus and P. murrayi) in having 33 bony plates in the upper lateral row, the 24–25th to 30th bony plate each in the upper lateral row with a forwardly directed spine, 17–19 gill rakers on the lower limb, a long slender rostral projection (43.4–47.0% of head length), and short upper (41.1–42.3%) and lower jaws (36.5–37.2%).     

Cryptic clonal lineages and genetic diversity in the loach Misgurnus anguillicaudatus (Teleostei: Cobitidae) inferred from nuclear and mitochondrial DNA analyses

In the loach Misgurnus anguillicaudatue, the asexual lineage, which produces unreduced clonal diploid eggs, has been identified. Among 833 specimens collected from 54 localities in Japan and two localities in China, 82 candidates of other lineage(s) of cryptic clones were screened by examining RFLP (restriction fragment length polymorphism)-PCR haplotypes in the control region of mtDNA. This analysis was performed because triploid loaches arise from the accidental incorporation of the sperm nucleus into unreduced diploid eggs of a clone. The categorization of members belonging to three newly identified lineages (clones 2–4) and the previously identified clonal lineage (clone 1) was verified by evaluating the genetic identity between two or more individuals from each clonal lineage based on RAPD (random amplified polymorphic DNA)-PCR and multilocus DNA fingerprints. We detected 75 haplotypes by observing the nucleotide status at variable sites from the control region of mtDNA. Phylogenic trees constructed from such sequences showed two highly diversified clades, A and B, that were beyond the level common for interspecific genetic differentiation. That result suggests that M. anguillicaudatus in Japan is not a single species entity. Two clone-specific mtDNA sequences were included in clade A, and the loaches with such sequences may be the maternal origin of the clones. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

中国广西盲鳅一新种——环江高原鳅(英文)

2007年4月,在广西壮族自治区环江县川山镇乐衣村附近一洞穴采集到一批盲鳅类标本。经鉴定,为高原鳅属(Triplophysa)鱼类一新种,被命名为环江高原鳅(Triplophysa huangjiangensis)。该新种以以下组合特征与高原鳅属的其他已知种类相区别:无眼;通体无鳞;尾鳍分叉;尾柄上、下叶具发达的软鳍褶;背鳍后缘平截;背鳍起点距尾鳍基的距离短于距吻端的距离;背鳍分枝鳍条数为8~9;胸鳍分枝鳍条数为10~11;腹鳍分枝鳍条数为6~7;臀鳍分枝鳍条数为6;尾鳍分枝数为13~14;胸鳍长为胸鳍起点至腹鳍起点间距的52.3%~70.7%;腹鳍起点位于背鳍起点之前下方;外侧吻须最长,为侧面头长的47.0%~73.8%;前鼻孔位于一短管中,末端延长呈须状;鳔后室发达,末端可伸达腹鳍起点。     

Phylogeography and the maternal origin of the tetraploid form of the Japanese spined loach, <Emphasis Type="Italic">Cobitis biwae</Emphasis>, revealed by mitochondrial DNA analysis

The Japanese spined loach Cobitis biwae includes the tetraploid form, which has 96 chromosomes, as well as the diploid form, which has 48 chromosomes. In the present study, we analyzed the mitochondrial DNA (mtDNA) to examine the genetic relationships among 82 populations of diploid–tetraploid complexes of C. biwae. Restriction fragment length polymorphism (RFLP) analysis of the ND1 region on 202 individuals revealed that C. biwae contains three genetically divergent major groups corresponding to geographical proximities (the Eastern, Western, and Kochi groups). Phylogenetic analyses (neighbor-joining, NJ and maximum-parsimony, MP) of a part of the cytochrome b gene sequence (748bp) in 31 individuals supported the three major groups recognized by RFLP, and indicated considerable genetic differentiation between the Western group and the other two groups (average, 15.2%). The genetic relationship and distribution pattern of the three major groups hypothesized two major dispersions of C. biwae during the middle Miocene: first, the ancestor of the Eastern and Kochi groups had spread from the West through wide regions of present-day Honshu and Shikoku Islands, and following that period, the ancestor of the Western group with a different mtDNA composition, probably resulting from the mtDNA introgression from C. takatsuensis, moved into western Japan and pushed the former north eastward. All tetraploid form populations were included in the Western group and treated as a monophyletic cluster with low genetic divergence. It is notable that two diploid populations geographically adjacent to the tetraploid range were genetically closely related to the tetraploid forms. This result suggests that these diploid populations were directly related to the maternal origin of the tetraploid form.     

Some factors influencing the microdistribution of a population of spined loach,Cobitis taenia (L.)

Monthly observations (October 1972–October 1974) of a natural population of spined loach, Cobitis taenia (L.), in the River Great Ouse at Newport Pagnell indicated a patchy microdistribution, which varied seasonally. The distribution was clearly linked to the areas of fine substrate, which altered seasonally in position.Flow rates measured at monthly intervals in areas where Cobitis taenia (L.) were present were found to be approximately half those of areas in which Cobitis taenia L. were not found (0.148 m/sec and 0.293 m/sec). Substrate samples from areas where Cobitis taenia L. were present had a fine organic component, in contrast to the remainder of the river bed, which consisted of hard-packed gravel.In the laboratory, choice chamber experiments demonstrated a positive selection for fine organic deposits.     

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 .     

A new species ofRhinogobius (Teleostei: Gobiidae) from Fujian Province, China

A new freshwater goby,Rhinogobius xianshuiensis sp. nov. was collected from the upper Mulan River basin of Xianyou County, Fujian Province, eastern China. The species is distinguished from related species in the region by 3–7 predorsal scales, 27 vertebrae, cephalic lateralis canals always always with 2 derived post-orbital pores (ε1) in adults, a reddish-brown vertical line below the anterior margin of the eye, and a red netlike pattern on the opercle. A key to species ofRhinogobius with higher vertebral numbers (27–29) from eastern China, Taiwan and Japan is provided.     

Evolutionary history of asexual hybrid loaches (Cobitis: Teleostei) inferred from phylogenetic analysis of mitochondrial DNA variation

Reconstruction of the evolutionary history of asexual lineages undermines their suitability as models for the studies of evolutionary consequences of sexual reproduction. Using molecular tools we addressed the origin, age and maternal ancestry of diploid and triploid asexual lineages arisen through the hybridization between spiny loaches Cobitis elongatoides, C. taenia and C. tanaitica. Reconstructions of the phylogenetic relationships among mitochondrial DNA (mtDNA) haplotypes, revealed by sequence analyses, suggest that both hybrid complexes (C. elongatoides-taenia and C. elongatoides-tanaitica) contained several asexual lineages of independent origin. Cobitis elongatoides was the exclusive maternal ancestor of all the C. elongatoides-tanaitica hybrids, whereas within the C. elongatoides-taenia complex, hybridization was reciprocal. In both complexes the low haplotype divergences were consistent with a recent origin of asexual lineages. Combined mtDNA and allozyme data suggest that the triploids arose through the incorporation of a haploid sperm genome into unreduced ova produced by diploid hybrids.     

A new cave-dwelling loach, Triplophysa macrocephala (Teleostei: Cypriniformes: Balitoridae), from Guangxi, China

A new cave-dwelling species, Triplophysa macrocephala sp. nov. is described based on specimens collected from a karst cave in Renguang village, Lihu Town, Nandan County, Guangxi Zhuang Autonomous Region, China. The new species can be distinguished from its congeners by possessing the following combination of characters: pectoral fin not reaching beyond pelvic-fin origin; caudal fin forked; body smooth or scaleless; dorsal-fin origin anterior to pelvic-fin origin, edge of dorsal fin truncate; dorsal fin with eight branched rays; anal fin with five branched rays; eye small and vestigial; lower jaw arched with a median notch; air-bladder wrapped in bony capsule, lateral enlarged, posterior chamber of air-bladder degenerated.     

Two new Artotrogids (Copepoda: Siphonostomatoida) from Madeira Island,Portugal

Two new artotrogids are recorded from Madeira Island. A new species of Cryptopontius, associated with algae, differs from its congeners in the number of antennular segments, setation of the antennal exopod, setation and length of the maxillule lobes, and setation of both rami of the first and fourth legs. The second new artotrogid belongs to Dyspontius.It was associated with Gerardia savagliae Lacaze-Duthiers, 1864 (Cnidaria: Zoanthidea) and differs from its congeners in cephalothorax shape, siphon length and setation of the maxillule lobes.