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The subfamily Gobioninae is one of the most diverse fish groups within Cyprinidae. Their taxonomy and phylogenetic relationships are not completely resolved. In this study, the complete mitochondrial genomes (mitogenome) of four Gobioninae species (Microphysogobio elongatus, Microphysogobio chinssuensis, Gobio rivuloides and Rhinogobio nasutus) were sequenced and compared. The mitogenomes of four species ranges from 16603 bp to 16609 bp in length, consisting of 13 protein-coding genes (PCGs), 22 tRNA genes, two rRNA genes, and a control region. Most PCGs had significant codon usage bias. Except for the tRNASer (GCT), all the nucleotide substitutions of tRNA loops higher than the stems could fold into a stable secondary structure. The nucleotide compositions of Gobioninae mitogenome were biased toward A/T, and NAD4 was subjected to low purification selection and had a faster evolution rate among 13 PCGs. Bayesian inference and maximum likelihood phylogenetic analyses showed the consistent results. The four sequenced species clustered together with their congener species. However, more samples and mitogenome data are needed to untangle the phylogenetic relationships among genera Microphysogobio, Romanogobio, Hugobio, Biwia and Platysmacheilus.

Understanding historical processes underlying lineage distribution patterns is a primary goal of phylogeography. We selected Gobio rivuloides (Cypriniformes: Gobionidae) as a model to improve our knowledge about how intraspecific genetic divergence of freshwater fishes arises in coastal drainages of northern China via statistical analysis using cytochrome b gene. The time-calibrated phylogeny of G. rivuloides showed the divergence of two major lineages (I and II) at ~0.98 Ma (million years ago). Lineage I can be divided into two sub-lineages (I-A and I-B) with a divergence time of ~0.83 Ma. Sub-lineage I-A inhabits the Amur River, and sub-lineage I-B lives in the Luan River and Liao River. Lineage II is distributed in the Yellow River and Hai River, with close genetic relationships between the two drainages, and can be split into two sub-lineages (II-C and II-D) with a divergence time of ~0.60 Ma. Our findings indicate that the splitting of lineages and sub-lineages could be attributed to geographic isolation caused by the formation of the Bohai Sea, river capture, and the episodic hydrologic closing of a paleolake during the late Lower–Middle Pleistocene. It is also the first report we know of displaying a clear phylogeographic break for freshwater fishes across coastal drainages in northern China. [ABSTRACT FROM AUTHOR]

We newly sequenced complete mitochondrial genomes (mitogenome) of two gudgeon species Saurogobio dabryi and S. punctatus, and we downloaded 49 gudgeon mitogenomes from GenBank to investigate the phylogeny of the Pseudogobionini group and analyze selection pressure of the genes. With genera Gobio, Acanthogobio, and Romanogobio as outgroups, the phylogeny of the Pseudogobionini group was revealed as ((Xenophysogobio + Gobiobotia) + (Saurogobio + (Abbottina + (Pseudogobio + Biwia complex)))) based on the concatenated nucleotide sequences of 13 protein-coding genes (PCGs). Based on the molecular phylogeny and morphological or osteological characters, we proposed a classification system of the Pseudogobionini group. Moreover, five pairs of sister taxa were selected for gene selection pressure analyses to explore the link of mitochondrial gene evolution to group differentiation and adaptations. We detected significantly different dN/dS values in 11 out of 13 (excluding ND3 and ND4L) PCGs in five pairs of clades, significantly different mean dN/dS, dN, and/or dS values in 8 out of 13 PCGs (excluding ND2, ATP8, ND3, ND4L, and ND6) in three pairs of sub-clades and seven positively selected sites in another three pairs of sub-clades. These results indicated that mitochondrial gene evolution might have contributed to group differentiation and adaptations especially for river or lake environments. [ABSTRACT FROM AUTHOR]

We newly sequenced complete mitochondrial genomes (mitogenome) of two gudgeon species Saurogobio dabryi and S. punctatus, and we downloaded 49 gudgeon mitogenomes from GenBank to investigate the phylogeny of the Pseudogobionini group and analyze selection pressure of the genes. With genera Gobio, Acanthogobio, and Romanogobio as outgroups, the phylogeny of the Pseudogobionini group was revealed as ((Xenophysogobio + Gobiobotia) + (Saurogobio + (Abbottina + (Pseudogobio + Biwia complex)))) based on the concatenated nucleotide sequences of 13 protein-coding genes (PCGs). Based on the molecular phylogeny and morphological or osteological characters, we proposed a classification system of the Pseudogobionini group. Moreover, five pairs of sister taxa were selected for gene selection pressure analyses to explore the link of mitochondrial gene evolution to group differentiation and adaptations. We detected significantly different dN/dS values in 11 out of 13 (excluding ND3 and ND4L) PCGs in five pairs of clades, significantly different mean dN/dS, dN, and/or dS values in 8 out of 13 PCGs (excluding ND2, ATP8, ND3, ND4L, and ND6) in three pairs of sub-clades and seven positively selected sites in another three pairs of sub-clades. These results indicated that mitochondrial gene evolution might have contributed to group differentiation and adaptations especially for river or lake environments.

Mitochondria are important organelles with independent genetic material of eukaryotic organisms. In this study, we sequenced and analyzed the complete mitogenome of a small cyprinid fish, Microphysogobio elongatus (Yao & Yang, 1977). The mitogenome of M. elongatus is a typical circular molecule of 16,612 bp in length containing 13 protein-coding genes (PCGs), 22 transfer RNA genes, two ribosomal RNA genes, and a 930 bp control region. The base composition of the M. elongatus mitogenome is 30.8% A, 26.1% T, 16.7% G, and 26.4% C. All PCGs used the standard ATG start codon with the exception of COI. Six PCGs terminate with complete stop codons, whereas seven PCGs (ND2, COII, ATPase 6, COIII, ND3, ND4, and Cyt b) terminate with incomplete (T or TA) stop codons. All tRNA genes exhibited typical cloverleaf secondary structures with the exception of tRNASer(AGY), for which the dihydrouridine arm forms a simple loop. The phylogenetic analysis divided the subfamily Gobioninae in three clades with relatively robust support, and that Microphysogobio is not a monophyletic group. The complete mitogenome of M. elongatus provides a valuable resource for future studies about molecular phylogeny and/or population genetics of Microphysogobio. [ABSTRACT FROM AUTHOR]

Abstract Knowledge of food resource partitioning among sympatric fish species is crucial for understanding the potential mechanisms of species coexistence. Gudgeons (Teleostei: Cyprinidae: Gobioninae) often dominate fish assemblages in the upper Yangtze River. However, little research has been conducted on their trophic interactions. In this paper, seasonal diet and feeding strategy variations of four sympatric gudgeon species, Coreius guichenoti, Coreius heterodon, Rhinogobio ventralis, and Rhinogobio cylindricus, were investigated by analysis of intestinal tract contents, aiming to explore whether food resource partitioning occurred among them. Fish specimens were collected during spring (April–May) and autumn (August–October) in 2010 in Hejiang, a free‐flowing stretch of the upper Yangtze River. Coreius guichenoti, C. heterodon, and R. cylindricus showed omnivorous feeding habits, while R. ventralis exhibited an obligate carnivore feeding habit. Diet overlap among the four studied species was high, especially in spring. However, changes in feeding strategies were observed in autumn. Specifically, C. guichenoti and R. cylindricus expanded their dietary niche breadth and consumed detritus, Sinopotamidae or Hydropsychidae as important complementary food resources. In contrast, C. heterodon and R. ventralis reduced their dietary niche breadth and became more specialized on mussels (Limnoperna lacustris). These results confirmed that sympatric fish species can coexist with high diet overlap, and food resource partitioning among these species may also fluctuate with the seasons.

Mitochondrial genomes of two individuals of Tachanovsky’s gudgeon Ladislavia taczanowskii have been determined on the basis of Sanger dideoxy sequencing. The gene compositions of two genomes contain 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and 1 control region with the same length 16,614 bp. The phylogenetic tree reveals that the monotypic genus Ladislavia is a sister group of the subfamily Gobioninae within the family Gobionidae.

In this study, the complete mitochondrial genome of Sarcocheilichthys variegatus wakiyae was sequenced using samples collected from the Tamjin River (type locality), located in Jangheung-gun, Jeollanam-do, Republic of Korea. The complete mitochondrial genome of S. variegatus wakiyae includes 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, 2 ribosomal RNA (rRNA) genes, and a control region (D-loop), with a total length of 16,675 bp. The overall base nucleotide compositions encoded are 30.15% A, 26.71% C, 16.81% G, and 26.33% T with 56.48% A + T. The phylogenetic tree constructed using a neighbor-joining (NJ) method showed that S. variegatus wakiyae and S. variegatus microoculus are not sister groups, despite being subspecies of the same taxonomic species. Rather, S. variegatus wakiyae forms a sister group with S. hainanensis.

In this study, we determined the complete mitochondrial genome sequences of cyprinid freshwater fish, Microphysogobio jeoni, belonging to the subfamily Gobioninae in the order Cypriniformes. The complete mitogenome of M. jeoni was 16,602 bp in length and consisted of 13 protein-coding genes (PCGs), 22 tRNAs, and two rRNAs. The gene order was identical with other Microphysogobio species. The overall nucleotide composition of M. jeoni was A + T: 56.1% and G + C: 43.9%, with slightly AT bias. In the phylogenetic tree, M. jeoni and other congeneric species clearly formed a monophyletic clade, and each species distinguished against each other well.

The subfamily Gobioninae is one of the most diverse fish groups within Cyprinidae. Their taxonomy and phylogenetic relationships are not completely resolved. In this study, the complete mitochondrial genomes (mitogenome) of four Gobioninae species ( Microphysogobio elongatus , Microphysogobio chinssuensis , Gobio rivuloides and Rhinogobio nasutus ) were sequenced and compared. The mitogenomes of four species ranges from 16603 bp to 16609 bp in length, consisting of 13 protein-coding genes (PCGs), 22 tRNA genes, two rRNA genes, and a control region. Most PCGs had significant codon usage bias. Except for the tRNA Ser (GCT), all the nucleotide substitutions of tRNA loops higher than the stems could fold into a stable secondary structure. The nucleotide compositions of Gobioninae mitogenome were biased toward A/T, and NAD4 was subjected to low purification selection and had a faster evolution rate among 13 PCGs. Bayesian inference and maximum likelihood phylogenetic analyses showed the consistent results. The four sequenced species clustered together with their congener species. However, more samples and mitogenome data are needed to untangle the phylogenetic relationships among genera Microphysogobio , Romanogobio , Hugobio , Biwia and Platysmacheilus., Competing Interests: The authors declare there are no competing interests., (©2024 Tang et al.)

Knowledge of food resource partitioning among sympatric fish species is crucial for understanding the potential mechanisms of species coexistence. Gudgeons (Teleostei: Cyprinidae: Gobioninae) often dominate fish assemblages in the upper Yangtze River. However, little research has been conducted on their trophic interactions. In this paper, seasonal diet and feeding strategy variations of four sympatric gudgeon species, Coreius guichenoti, Coreius heterodon, Rhinogobio ventralis, and Rhinogobio cylindricus, were investigated by analysis of intestinal tract contents, aiming to explore whether food resource partitioning occurred among them. Fish specimens were collected during spring (April–May) and autumn (August–October) in 2010 in Hejiang, a free‐flowing stretch of the upper Yangtze River. Coreius guichenoti, C. heterodon, and R. cylindricus showed omnivorous feeding habits, while R. ventralis exhibited an obligate carnivore feeding habit. Diet overlap among the four studied species was high, especially in spring. However, changes in feeding strategies were observed in autumn. Specifically, C. guichenoti and R. cylindricus expanded their dietary niche breadth and consumed detritus, Sinopotamidae or Hydropsychidae as important complementary food resources. In contrast, C. heterodon and R. ventralis reduced their dietary niche breadth and became more specialized on mussels (Limnoperna lacustris). These results confirmed that sympatric fish species can coexist with high diet overlap, and food resource partitioning among these species may also fluctuate with the seasons. [ABSTRACT FROM AUTHOR]

The infection status with Clonorchis sinensis metacercariae (CsMc) was examined in freshwater fishes from Yangcheon (a branch of Gyeongho-gang), which is located in Sancheong-gun, Gyeongsangnam-do, the Republic of Korea. Total 2,201 fishes in 26 species were examined by the artificial digestion method through 7 years. CsMc were detected in 1,171 (53.2%) fishes in 21 spp. (80.8%) and their density was 85 per fish infected. Total 532 (99.6%) out of 534 Pungtungia herzi (index fish) examined were infected with 147 CsMc per fish infected. Metacercarial densities in this fish were highest in 2015 (179 CsMc), followed by 2012 (168), 2013 (152), 2016 (145), 2014 (114), and 2017 (89) respectively. In the gobioninid fish group, i.e., P. herzi, Sarcocheilichthys spp., Squalidus spp., Pseudogobio esocinus, Hemibarbus longirostris, and Hemibarbus labeo, 841 (92.7%) fishes were infected with 117 CsMc per fish infected. Total 250 (54.7%) acheilognathinid fish (bitterlings), Acheilognathus spp. and Acanthorhodeus spp. were infected with 5.8 CsMc. In the rasborinid fish (chubs) group, i.e., Zacco platypus, Zacco temminckii, and Zacco koreanus, 77 (13.7%) out of 563 fish examined were infected with 2.4 CsMc in average. The susceptibility indices of CsMc were 49.09 in the overall positive fish group, 104.15 in the gobioninid group, 3.17 in the acheilognathinid group and 0.35 in the rasborinid fish group respectively. Only 1 CsMc was detected in 3 fish species, Coreoperca herzi, Channa argus, and Lepomis macrochirus, respectively. Conclusively, it was confirmed that CsMc are moderately prevalent in fishes from Yangcheon in Sancheon-gun, Gyeongsangnam-do, Korea. [ABSTRACT FROM AUTHOR]

We sequenced the mitochondrial genome of Pseudorasbora interrupta using Illumina technology and additional Sanger sequencing. The assembled 16601 bp mitogenome had a GC content of 40.98% and consisted of 13 protein-coding genes, 22 tRNA genes, two rRNA genes, and one non-coding control region (CR), with a gene order identical to the fishes. In addition, we downloaded the mitogenome of the closely related species Topmouth Gudgeon P. parva. The mitogenomes of P. interrupta and P. parva showed a sequence identity of 99.2% with the previously published P. parva mitogenome. The phylogenetic reconstruction based on 14 Gobioninae mitogenomes supported P. interrupta and its sister species P. parva as a monophyletic group. However, Pseudorasbora was proved to be a polyphyletic group which means amendments will be needed for the taxonomy of this genus.

Abbottina binhi has been misidentified as Abbottina rivularis in China for a long time. In this study, we determined three mitochondrial genomes of A. rivularis and A. binhi such that these data should contribute to molecular identifications of the two species. The size of new mitochondrial genomes was 16,609 or 16,599 bp with A + T bias of 55.7–56.5% in the base compositions. Our reconstructed phylogeny showed that A. rivularis and A. binhi formed a sister taxon relationship, and they together were a monophyletic group.

The infection status of Clonorchis sinensis metacercariae (CsMc) was examined in freshwater fish from a highly prevalent site, Wicheon (a branch of Nakdong-gang), which is located in Gunwi-gun, Gyeongsangbuk-do, the Republic of Korea. Total 1,162 fish in 32 species were examined by the artificial digestion method through 6 years. CsMc were detected in 720 (67.5%) out of 1,067 fish (26 spp.) and their density was 610 per fish infected. In the susceptible gobioninid fish group, i.e., Pungtungia herzi, Squalidus gracilis majimae, Squalidus japonicus coreanus, Sarcocheilichthys variegatus wakiyae and Pseudorasbora parva, all of 323 fish were infected with an average of 1,310 CsMc. Total 23 (95.8%) gobioninid fish, i.e., Pseudogobio esocinus, Abbottina springeri, Hemibarbus longirostris, Microphysogobio koreensis, and Microphysogobio jeoni, were infected with 127 CsMc in average. In the acheilognathinid fish (bitterlings) group, the prevalence was 77.0%, and the density was 50 CsMc per fish infected. In the rasborinid fish (chubs) group, i.e., Zacco platypus, Zacco temminckii, Zacco koreanus, and Opsariichthys uncirostris amurensis, 147 (36.5%) out of 403 fish examined were infected with 15 CsMc in average. The susceptibility indices of CsMc were 412 in the overall positive fish group, 1,310 in the gobioninid group-1, 122 in the gobioninid group-2, 38.5 in the acheilognathinid group, and 5.5 in the rasborinid fish group. Conclusively, it was confirmed that CsMc are highly prevalent in fish from Wicheon, and their infection tendency varied according to the subfamily groups in Cyprinidae fish hosts. [ABSTRACT FROM AUTHOR]

Freshwater fishes of the subfamily Gobioninae (Cypriniformes: Cyprinidae) are composed of three major clades, the tribes Gobionini and Sarcocheilichthyini, and a Hemibarbus–Squalidus group. In this study, we determined ten complete fish mitogenomes from eight of all twelve genera in the tribe Gobionini. The ten mitogenomes displayed similar patterns in gene arrangements, codon use and gene overlaps with the length of 16,605–16,617 bp and base compositions slightly A + T bias of 56.1–58.0%. Our phylogeny of the tribe Gobionini revealed that the genera Gobio, Xenophysogobio, Gobiobotia, Saurogobio and Pseudogobio were monophyletic, and other genera Abbottina, Biwia, Microphysogobio and Platysmacheilus were paraphyletic or polyphyletic. The findings indicate that the genera classifications of Gobionini are needed to be further confirmed.

A new species of gudgeon, Microphysogobio xianyouensis, is described from Mulan River in Fujian Province, southeastern China. M. xianyouensis appears to be closely related to M. brevirostris (Günther, 1868) of Taiwan. However, it can be well distinguished based on a combination of meristics, morphometric measurements, color pattern and molecular data. A molecular phylogenetic analysis of species of Microphysogobio from southeastern China and Taiwan based on concatenated mitochondrial Cyt b and D-loop genes is presented and tree topology strongly supports that M. xianyouensis as a distinct species and sister to M. brevirostris. Our molecular evidence agreed with Bănărescu's proposed taxonomic viewpoint, the tree topology reveals that the type species of the genus Huigobio, H. chenhsienensis, is nested within several valid species of Microphysogobio, and Huigobio is confirmed to be a junior synonym of the genus Microphysogobio. [ABSTRACT FROM AUTHOR]

The spawning behaviour of Pseudogobio esocinus was examined in an experimental water tank. Spawning was observed on 66 occasions in five experiments, and one female repeatedly spawned 7-18 times during one night. Four easily distinguishable behavioural phases were recognised during the spawning sequence: phase 1, male nuzzling to the female's body or face; phase 2, male pursuing a swimming female; phase 3, pair or trio trembling while swimming; and phase 4, spawning (scattering eggs and sperm) near the water surface. The spawning behaviour mainly occurred between pairs (53 times) and occasionally among a trio (13 times). A generalised linear mixed model was used to analyse the relationships between male spawning success and four fixed variables. As a result, more aggressive and larger males tended to be successful spawners. A digital video image of P. esocinus spawning behaviour is available at . [ABSTRACT FROM AUTHOR]

The variability of life history traits in Pseudogobio esocinus was investigated in a single river (Nakagawa River, Kyushu Island, Japan) by comparing two sub-populations inhabiting river reaches with different thermal characteristics. A total of 689 individuals in the upper reach (St. A) and 705 individuals in the lower reach (St. B) were collected from April 2004 to March 2006 at monthly intervals. Water temperatures of both stations were measured by a logger during the period of survey, and these dates clearly showed that St. A was colder than St. B. The sub-population of St. A consisted of six age groups, and the age at maturity was 2 or 3 years. Spawning occurred between April and July, and peaked in May. The sub-population of St. B consisted of four age groups, the age at maturity was 1 or 2 years and spawning occurred between March and July, peaking in April. The length-weight relationship and body condition were also different between the two sub-populations. In conclusion, the sub-population in the colder reach was characterised as longer lived, slower growing and later maturing, with larger body size and higher fecundity compared with the sub-population of the warmer reach. These results showed that the life history traits of P. esocinus were variable under the influence of water temperature, even in a single small river. [ABSTRACT FROM AUTHOR]

Mitochondrial genomes of two individuals of Tachanovsky's gudgeon Ladislavia taczanowskii have been determined on the basis of Sanger dideoxy sequencing. The gene compositions of two genomes contain 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and 1 control region with the same length 16,614 bp. The phylogenetic tree reveals that the monotypic genus Ladislavia is a sister group of the subfamily Gobioninae within the family Gobionidae. [ABSTRACT FROM AUTHOR]

Rapid adaptation and speciation have not been well documented for organisms in Lake Biwa, Japan, the oldest ancient lake in East Asia. To examine these processes, we focused on the divergence of Sarcocheilichthys gudgeons and conducted phylogeographic and population genetic analyses using mitochondrial DNA sequences and microsatellite data. No remarkable genetic differentiation was found between two species, S. biwaensis and S. variegatus microoculus, both endemic to Lake Biwa, whereas this species group, including S. v. variegatus, was genetically divided into three major regional groups: the Lake Biwa, Ise Bay, and western groups. Divergent mtDNA haplotypes were included within the Lake Biwa and western groups, strongly suggesting secondary contacts among allopatrically isolated populations. Dating for mtDNA phylogeny using a geological constraint suggested the colonization of Lake Biwa by multiple Sarcocheilichthys lineages that diverged from each other in the early-middle Pleistocene. Coalescent-based population analyses indicated that the local populations colonized the rocky bottom habitat in Lake Biwa from other habitats after the Last Glacial Maximum, likely reflecting past environmental changes in the lake, including the disappearance of rocky areas during the glacial climate. Divergent morphological adaptation in Sarcocheilichthys associated with substrate type may have rapidly proceeded along with environmental changes. [ABSTRACT FROM AUTHOR]

The “whitefin” gudgeon Romanogobio cf. belingi was recorded in the Nida River, a large lowland tributary of the upper Vistula (Southeastern Poland), for the first time in 2009. Since then, it has been caught during the periodical (three times per year) monitoring only sporadically. Conversely, in October and November 2012 R. cf. belingi was recorded frequently along an ∼60-km lowermost stretch of the Nida River. The abundance of this fish gradually increased downstream. This paper provides details of that phenomenon and discusses it in the context of the currently known distribution of this species. [ABSTRACT FROM PUBLISHER]

The Korean shiner (Coreoleuciscus splendidus, Gobioninae), a small freshwater fish native to Korea Peninsula, widely inhabits in most of the major drainages in South Korea. Here we describe the development of 14 novel and polymorphic microsatellites for this species and its effective utilization in estimation of genetic diversity using 72 individuals from three sampling sites in different drainages. Loci were isolated from a microsatellite enrichment procedure using probe-labeled magnetic beads. A total of 242 alleles were detected across all loci with an average of 17.3 alleles per locus ranging 4–32. The loci varied levels of polymorphism as evident from its expected heterozygosity ranging from 0.111 to 0.957. The average pairwise F ST between two populations examined shows significant differentiation (F ST=0.215, p < 0.05). The 14 microsatellite loci developed here will also be useful to explain for the genetic structures among geographically isolated populations and gene flow dynamics within drainages in this species as well as the closely related species. [ABSTRACT FROM PUBLISHER]

Abstract: The members of the cyprinid subfamily Gobioninae, commonly called gudgeons, form one of the most well-established assemblages in the family Cyprinidae. The subfamily is a species-rich group of fishes, these fishes display diverse life histories, appearances, and behavior. The phylogenetic relationships of Gobioninae are examined using sequence data from four loci: cytochrome b, cytochrome c oxidase I, opsin, and recombination activating gene 1. This investigation produced a data matrix of 4114bp for 162 taxa that was analyzed using parsimony, maximum likelihood, and Bayesian inference methods. The phylogenies our analyses recovered corroborate recent studies on the group. The subfamily Gobioninae is monophyletic and composed of three major lineages. We find evidence for a Hemibarbus–Squalidus group, and the tribes Gobionini and Sarcocheilichthyini, with the Hemibarbus–Squalidus group sister to a clade of Gobionini–Sarcocheilichthyini. The Hemibarbus–Squalidus group includes those two genera; the tribe Sarcocheilichthyini includes Coreius, Coreoleuciscus, Gnathopogon, Gobiocypris, Ladislavia, Paracanthobrama, Pseudorasbora, Pseudopungtungia, Pungtungia, Rhinogobio, and Sarcocheilichthys; the tribe Gobionini includes Abbottina, Biwia, Gobio, Gobiobotia, Huigobio, Microphysogobio, Platysmacheilus, Pseudogobio, Romanogobio, Saurogobio, and Xenophysogobio. The monotypic Acanthogobio is placed into the synonymy of Gobio. We tentatively assign Belligobio to the Hemibarbus–Squalidus group and Mesogobio to Gobionini; Paraleucogobio and Parasqualidus remain incertae sedis. Based on the topologies presented, the evolution of swim bladder specializations, a distinctive feature among cyprinids, has occurred more than once within the subfamily. [Copyright &y& Elsevier]

In this study, the complete mitogenome sequence of the Fujian rod gugeon,Microphysogobio fukienensis(Nichols) (Cypriniformes, Cyprinidae, Gobioninae) has been amplified. The mitogenome, consisting of 16,600 bp, had the typical vertebrate mitochondrial gene arrangement, including 13 protein-coding genes, 22 transfer RNAs, 2 ribosomal RNAs genes and a noncoding control region (CR). CR of 930 bp length is located between tRNAProand tRNAPhe. The overall base composition ofM. fukienensisis 31.0% for A, 26.0% for C, 26.6% for T and 16.4% for G, with higher AT content of 57.0%. The complete mitogenome may provide rather essential and important DNA molecular data for further phylogenetic analysis for not only congeneric species but also higher different taxa of Cyprinid fishes. [ABSTRACT FROM AUTHOR]

Twelve dinucleotide markers were successfully isolated and characterized from a microsatellite-enriched genomic library obtained for the gudgeon Squalidus chankaensis biwae. These markers were also available for the congeners S.  c. tsuchigae and S. japonicus from Japan, which had five to 46 alleles and an expected heterozygosity ranging from zero to 0.946. Linkage equilibrium was observed at all loci, and most loci did not show significant deviation from Hardy–Weinberg equilibrium. The isolated microsatellite markers will be useful for genetic diversity studies of Squalidus populations. [ABSTRACT FROM AUTHOR]

Habitat selection of the pike gudgeon Pseudogobio esocinus esocinus (Cyprinidae) was examined in the Nakagawa River in northern Kyushu, Japan. The study area was 80 m long with two meanders comprising three riffles and two pools, located 20 km upstream from the river mouth. The pike gudgeon were visually counted underwater. Larvae and juveniles were observed in the shallow and slow-flowing water near the shores. Simultaneously, young and adult individuals were observed to inhabit the river bed. Principal component analysis and cluster analysis were applied to estimate the microhabitat selections of the larvae, juveniles and other individuals by using four variables (water depth, current velocity, particle size of substrate and amount of organic matter). The larvae and juveniles inhabited the shallow (<30 cm) and slow-flowing waters (<6.5 cm/s) near the shore; habitat selection was independent of particle size of the substrate and the amount of organic matter present. Young and adult individuals inhabited the river bed independent of the four variables. [ABSTRACT FROM AUTHOR]

In this study, the complete mitochondrial genome of Sarcocheilichthys variegatus wakiyae was sequenced using samples collected from the Tamjin River (type locality), located in Jangheung-gun, Jeollanam-do, Republic of Korea. The complete mitochondrial genome of S. variegatus wakiyae includes 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, 2 ribosomal RNA (rRNA) genes, and a control region (D-loop), with a total length of 16,675 bp. The overall base nucleotide compositions encoded are 30.15% A, 26.71% C, 16.81% G, and 26.33% T with 56.48% A + T. The phylogenetic tree constructed using a neighbor-joining (NJ) method showed that S. variegatus wakiyae and S. variegatus microoculus are not sister groups, despite being subspecies of the same taxonomic species. Rather, S. variegatus wakiyae forms a sister group with S. hainanensis. [ABSTRACT FROM AUTHOR]

In this study, we determined the complete mitochondrial genome sequences of cyprinid freshwater fish, Microphysogobio jeoni, belonging to the subfamily Gobioninae in the order Cypriniformes. The complete mitogenome of M. jeoni was 16,602 bp in length and consisted of 13 protein-coding genes (PCGs), 22 tRNAs, and two rRNAs. The gene order was identical with other Microphysogobio species. The overall nucleotide composition of M. jeoni was A + T: 56.1% and G + C: 43.9%, with slightly AT bias. In the phylogenetic tree, M. jeoni and other congeneric species clearly formed a monophyletic clade, and each species distinguished against each other well. [ABSTRACT FROM AUTHOR]

The Gobioninae are a group of morphologically and ecologically diverse Eurasian freshwater cyprinid fishes. The intergeneric relationships of this group are unresolved and the possible monophyly of this subfamily remains to be established. We used complete mitochondrial cytochrome b gene sequences from most genera within the gobionine group, in addition to a selection of cyprinid outgroups, to investigate the possible monophyly of this group and resolve the interrelationships within the group. Our results support the monophyly of the Gobioninae and identify four monophyletic groups within the subfamily; the Hemibarbus group, the Sarcocheilichthys group, the Gobio group, and the Pseudogobio group. The morphologically aberrant genera Gobiobotia, Xenophysogobio and Gobiocypris are included in the Gobioninae, with the latter a sister group of Gnathopogon. [ABSTRACT FROM AUTHOR]

We developed and characterized 11 polymorphic microsatellite loci in Gobiobotia brevibarba (Cypriniformes: Gobioninae), an endangered freshwater fish in Korea. The number of observed alleles per locus ranged from 3 to 20 within 20 individuals, the observed and expected heterozygosities per locus ranged from 0.150 to 0.950 and 0.145 to 0.958, respectively. Nine of the microsatellite loci were applicable to other endangered Korean fishes in the Gobioninae genera. The developed microsatellite loci will be useful in the investigation of genetic diversity and population genetic structure, which will enhance future conservation strategies. [ABSTRACT FROM AUTHOR]