Search Results (8)

The inconsistency between traditional morphological taxonomy and molecular phylogenetic data is a major issue that puzzles the study of fish classification and evolution. Although mitochondrial genes are commonly used in phylogenetic analyses to compare fish species, the mitochondrial evolution and diversity of Schistura are still not well understood. To better understand the evolution of Schistura, we sequenced the mitochondrial genome of Schistura fasciolata and compared it with other species of Schistura. A 16,588 bp circular mitochondrial genome of S. fasciolata was obtained and it contains 13 protein-coding, 22 transfer RNA, and two ribosomal RNA genes, and a non-coding control region. The gene arrangement in the mitochondrial genomes of all Schistura species was consistent. However, we also found that S. fasciolata was not monophyletic. Although mitochondrial genes can be effectively used for Schistura species identification, they may not be suitable for inferring the evolutionary process of Schistura species. These results provide support for the use of mitochondrial genes in identifying Schistura species, and also serve as a warning against mistakenly using them to evaluate the evolution process of Schistura species. Full article

Nemacheilid fishes in the genus Turcinoemacheilus are physically small members of the ichthyofauna communities of high-altitude and mountainous freshwater ecosystems. They are all distributed in Western Asia apart from a single species, described in the Himalayas. They are usually very similar in appearance, which complicates their proper identification and/or description. This is why it is important to use multidisciplinary and integrative taxonomical approaches in order to study their true diversity. In this study, three new species of Turcinoemacheilus are described from Iran, raising the total number of valid species to nine. Turcinoemacheilus ansari new species, is distinguished by the anus being situated behind the midpoint of the pelvic-fin and anal-fin origins and the short anal-fin base length. Turcinoemacheilus christofferi new species, differs by the anus being situated behind the midpoint of the pelvic-fin and anal-fin origins, with a complete lateral line reaching to the anterior part of the caudal fin. Turcinoemacheilus moghbeli new species, is distinguished by the anus being situated at or in front of the midpoint of the pelvic-fin and anal-fin origins, with a great pre-pelvic distance and a caudal peduncle length 1.5–2.3 times its length. In Western Asia, all Turcinoemacheilus species are well separated by molecular characters, showing between 3.6 and 14.1% uncorrected p genetic distances in the COI barcode region. This work shows the importance of studying the hidden diversity of under-sampled and understudied groups of organisms to have a clear image of true biodiversity in order to effectively conserve and protect it. Full article

We investigated the Gyrodactylus ectoparasites on relict fishes in the isolated endorheic Central Asian Internal drainage basin in Mongolia (The Hollow) and placed them into the global phylogenetic framework based on internal transcribed spacer regions of the nuclear ribosomal DNA (ITS). Much of the rich Pliocene lacustrine ichthyofauna is extinct. We sampled five riverine survivors: Altai osmans Oreoleuciscus humilis and O. potanini (Leuciscidae), Mongolian grayling Thymallus brevirostris (Salmonidae), and stone loaches Barbatula conilobus and B. cobdonensis (Nemacheilidae). We found eight species of the subgenus Gyrodactylus (Limnonephrotus) and four of G. (Gyrodactylus). Nine species were identified as taxa described earlier, and three were described as new. The endemic Mongolian grayling carried four species, only one of wageneri group typical to salmonids (Gyrodactylus radimi sp. nov.), two of nemachili group (G. zavkhanensis sp. nov., G. pseudonemachili Ergens and Bychowsky, 1967), and G. amurensis Akhmerov, 1952 of subgenus G. (Gyrodactylus). G. pseudonemachili was also found on osman and loach. A parasite clade typical for Nemacheilidae was overrepresented by five species (G. tayshirensis sp. nov. on Barbatula conilobus, G. mongolicus Ergens and Dulmaa, 1970, G. nemachili Bychowsky, 1936). Relaxed host specificity mentioned already by Ergens and Dulmaa was evident. In the updated global ITS phylogenies of the two freshwater-restricted subgenera, the parasites from the Mongolian relict populations assumed positions concordant with a hypothesis of multiple ancient introductions from the Euro-Siberian fauna, strong rarefaction and three cases of endemic divergence. Full article

In order to resolve the long-standing controversy surrounding the relationships within the Triplophysa genus, we conducted an extensive analysis of the complete mitogenome of Triplophysa labiata using DNBSEQ short reads. Additionally, we reconstructed the phylogeny of the Nemacheilidae family using mitogenome data. By comparing all available mitogenomes within the Triplophysa genus, we gained valuable insights into its evolutionary history. Our findings revealed that the mitogenome sequence of T. labiata is circular, spanning a length of 16,573 bp. It encompasses 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), 2 ribosomal RNAs (rRNAs), and a control region (D-loop). Among the PCGs, the start codon ATG was commonly observed, except in cox1, while the stop codons TAA/TAG/T were found in all PCGs. Furthermore, purifying selection was evident across all PCGs. Utilizing maximum likelihood (ML) methods, we employed the 13 PCGs and the concatenated nucleotide sequences of 30 Triplophysa mitogenomes to infer the phylogeny. Our results strongly supported the division of the Triplophysa genus into four primary clades. Notably, our study provides the first evidence of the close relationship between T. labiata and T. dorsalis. These findings serve as a significant foundation for future investigations into the mitogenomics and phylogeny of Nemacheilidae fishes, paving the way for further advancements in this field of research. Full article

A new species of the genus Troglonectes is described based on specimens from a karst cave in Andong Town, Xincheng County, Liuzhou City, Guangxi, China. Troglonectes canlinensis sp. nov. can be distinguished from its congener species by the following combination of characteristics: eye degenerated into a black spot; whole body covered by scales, except for the head, throat, and abdomen; incomplete lateral line; forked caudal fin; 8–10 gill rakers on the first gill arch; 13–14 branched caudal fin rays; 8–9 branched dorsal fin rays; 5–6 anal fin rays; 9–10 pectoral fin rays; upper adipose keel depth mostly 1/2 of the caudal peduncle depth; and caudal fin forked. Full article

In the last decade, the phylogenetic relationships within the genus Triplophysa have become controversial, due to a lack of molecular data. The mitochondrial genome plays a vital role in the reconstruction of phylogenetic relationships and in revealing the molecular evolution of bony fishes. Herein, we obtained the complete mitogenome of Triplophysa bombifrons via HiFi reads of the Pacbio Sequel II system and DNBSEQ short-reads. We compared all available mitogenomes of the Triplophysa genus and reconstructed the phylogeny of Nemacheilidae, based on the mitogenomes, using maximum likelihood (ML) methods. The results show that the complete mitogenome sequence of T. bombifrons was circular and 16,568 bp in length, including 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA), 2 ribosomal RNA (rRNA), and a typical control region (D-loop). The most common start codons were ATG, except for cox1, and TAA/TAG were the stop codons for all PCGs. In total, 677 SNPs and 9 INDELs have been found by comparing the sequence divergence between this study and previous reports. Purity selection was found in all PCGs. Phylogeny was inferred by analyzing the 13 PCGs and the concatenated nucleotide sequences of 30 mitogenomes. The phylogenetic analyses based on the nucleotides of the 13 PCGs supported the assumption that the Triplophysa genus can be divided into 4 main clades and demonstrated that T. bombifrons and T. tenuis are closely related species for the first time. This study laid the foundation for further study on the mitogenome and phylogeny of Nemacheilidae fishes. Full article

Four obligate cave fish species have been recorded from Zagros in Iran: Garra typhlops (Bruun and Kaiser, 1944), G. lorestanensis (Mousavi-Sabet and Eagderi, 2016), G. tashanensis (Mousavi-Sabet, Vatandoust, Fatemi and Eagderi, 2016) and Eidinemacheilus smithi (Greenwood, 1976). So far, the only known locality of the latter has been the Loven cave. Here, we extend the known range of the Zagros blind loach (E. smithi) by reporting a new locality, the Tuveh spring, located 31 km south of Loven. We combine morphological evidence with the calculated K2P genetic divergences of 1.39% between Tuveh and Loven to confirm that these populations are conspecific. Our discovery of the second E. smithi population has implications for the conservation of this rare and vulnerable species. Full article

Large animal families with unresolved taxonomy are notoriously difficult to handle with respect to their biodiversity, systematics, and evolutionary history. We approach a large and taxonomically unresolved family of freshwater fishes (Nemacheilidae, >600 species) by proposing, on the basis of morphologic data, a species group within the family and study its phylogeny with conclusions regarding its diversity, taxonomy, and biogeographic history. Phylogenetic analyses of two mitochondrial and three nuclear genes of 139 specimens, representing about 46 species (17 candidate species from the proposed species-group, plus 29 comparative species), revealed that the proposed species group does not form a distinct monophyletic lineage, but that the candidate and comparative species mixed in three different lineages. However, the results revealed more than 20% of undescribed species within the ingroup and showed that species do not cluster according to the presently recognised genera. At least one of the genetic clades shows signs of an eastward range expansion during the second half of Miocene from north India via Myanmar into Laos, western China, and western Thailand. We conclude that the approach of picking monophyletic lineages to study biodiversity, systematics, and evolutionary history helps to open the door to large animal families. Full article