A Current Update on the Distribution, Morphological Features, and Genetic Identity of the Southeast Asian Mahseers, Tor Species

Abstract

The king of rivers or mahseer comprises three genera: Tor, Neolissochilus, and Naziritor, under the Cyprinidae family. The Tor genus has been classified as the true mahseer due to the presence of a median lobe among the three genera. The Tor species are widely distributed across Southeast (SE) Asia, and 13 Tor species have been reported previously: Tor ater, Tor dongnaiensis, Tor douronensis, Tor laterivittatus, Tor mosal, Tor mekongensis, Tor putitora, Tor sinensis, Tor soro, Tor tambra, Tor tambroides, Tor tor and Tor yingjiangensis. However, the exact number of valid Tor species remains debatable. Different and unstandardized approaches of applying genetic markers in taxonomic identification and morphology variation within the same species have further widened the gap and ameliorated the instability of Tor species taxonomy. Therefore, synchronized and strategized research among Tor species researchers is urgently required to improve and fill the knowledge gap. This review is a current update of SE Asia’s Tor species, outlining their distribution, morphology, and genetic identification. In addition, the present review proposes that there are ten valid Tor species in the SE Asian region. This list will serve as a template and standard to improve the taxonomy of the SE Asian Tor species, which could serve as a basis to open new directions in Tor research.

Kajian Historis Kepercayaan Danyang Telaga Rambut Monte Pada Masyarakat Desa Krisik Blitar

“…Ikan ini dikeramatkan, antara lain di Telaga Rambut Monte Kabupaten Blitar dan Mata Air Banyu Biru Kabupaten Pasuruan (Hasan, 2019b). Keberadaan ikan ini hampir punah karena beberapa sebaba, yaitu; 1) pembangunan bendungan di sungai, 2) penggundulan hutan, 3) pembukaan lahan pertanian, 4) penangkapan ikan berlebihan, 5) polusi, dan 6) kurangnya kebijakan untuk melindungi kelestarian ikan ini menyebabkan hampir punahnya spesies ini (Jaafar et al, 2021).…”

The First High-Quality Genome Assembly and Data Analysis of the Malaysian mahseer (Tor tambroides)

“…The Malaysian mahseer, Tor tambroides (Bleeker, 1854), one of the members of the family Cyprinidae, is a widespread species found in aquaculture and fisheries mainly targeted for human consumption (Kottelat et al ., 2018). It is commonly named Kelah or Empurau in Malaysia and Jurung, Indonesia (Jaafar et al, 2021). As a true mahseer ( Tor spp.…”

“…Although the presence of an upper median projection can be observed in T. tambroides , its other features, including equal caudal fin lobe, long lower median lobe, sub-terminal mouth position and pointed rostrum hood, were shared closely with other Tor spp., making it difficult to be distinguished (Jaafar et al, 2021). Therefore, disentangling Tor spp.…”

“…Studies had been done aiming to resolve the ambiguous taxonomical status of Tor spp. by looking into its phylogenetic relationship through mitochondrial DNA, Cytochrome c Oxidase Subunit I ( COX1 ) gene, Cytochrome b, ATPase 6 /8 gene, 16S rRNA gene, microsatellite, and SNP markers (Walton et al, 2017; Jaafar et al, 2021; Lim et al, 2021a). However, to date, the whole genome and transcriptome sequences of Tor spp.…”

“…are still unavailable, except for a few studies that had reviewed its conservation status, conducted a gut metagenomic analysis, as well as sequenced the transcriptome of T. tambra (Lau et al, 2021a; Lau et al, 2021b; Lau et al, 2021c). Genomic and transcriptomic sequencing of Tor species is necessary to provide a more powerful tool that continues to resolve and address questions of species identification, evolutionary biology, morphological variations, sequences related to sex differentiation, growth, reproduction, and immune, which is helpful for further conservation of Tor species (Jaafar et al, 2021).…”