DNA barcoding and species delimitation of the genus Oxynoemacheilus (Teleostei: Nemacheilidae) in Anatolia

Abstract

The DNA barcoding approach was used for the determination of evolutionary relationships and species delimitation of the genus Oxynoemacheilus (Teleostei: Nemacheilidae). The COI barcode region (615 bp amplicon) was used to barcode 444 individuals from 64 morphologically identified species in the genus Oxynoemacheilus and 189 haplotypes were identified. The average of the interspecific p distance (9.59%) was about 21-fold higher than the average intraspecific distance (0.44%). A general genetic threshold of 1.46% sequence divergence was defined for species delimitation. The multiple species delimitation methods (BCM, GMYC, bPTP and TCS) revealed a total of 62 molecular operational taxonomic units for 64 morphospecies with a new loach species from the BuyukMelen River.Neighbour-joining, maximum likelihood and Bayesian inference analyses indicated that all haplotypes were clustered into 62 clades, which corresponded to Oxynoemacheilus species, with strong bootstrap support (≥95%). Furthermore, all samples grouped in concurrence with the taxonomic status of the species except for species groups (O. germencicus-O. cinicus-O. mesudae and O. leontinae-O. namiri) that were showed intraspecific overlap in genetic diversity for COI-based barcodes. In conclusion, our analyses indicate that COI-based barcodes provide reliable species discrimination. Therefore, we currently recommend COI barcodes as the suitable barcode for genus Oxynoemacheilus.

Oxynoemacheilus marmaraensis, a new species from the Susurluk River, Türkiye (Teleostei: Nemacheilidae)

“…This study reflected that the phylogenetic relationships of Oxynoemacheilus based on the COI barcoding gene region are in agreement with the previous research (Bektaş et al, 2022; Geiger et al, 2014; Sayyadzadeh et al, 2016; Turan et al, 2019). Similar to the previous study by Bektaş et al (2022) Oxynoemacheilus genus was determined to be polyphyletic. Bektaş et al (2022) determined the COI‐based threshold value of 1.46% based on the genetic distance range.…”

“…Similar to the previous study by Bektaş et al (2022) Oxynoemacheilus genus was determined to be polyphyletic. Bektaş et al (2022) determined the COI‐based threshold value of 1.46% based on the genetic distance range. Also, Sayyadzadeh et al (2016) suggested an appropriate species‐level threshold for the Oxynoemacheilus COI genetic divergences of 1.4%.…”

“…For molecular taxonomy analysis, six newly produced COI barcodes and 122 sequences from previously published studies (Bektaş et al, 2022; Freyhof et al, 2022; Geiger et al, 2014; Turan et al, 2019) were used. Outgroup taxa, Seminemacheilus lendlii (GenBank number: MT077008) and Turcinoemacheilus kosswigi (GenBank number: KJ179258), were chosen for rooting the phylogenetic tree.…”

“…This genus is represented by a total of 64 valid species (Freyhof et al, 2021; Turan et al, 2023). Forty‐one of these species are found in Türkiye, and 32 of them are endemic (Bektaş et al, 2022; Çiçek et al, 2018; Erk'akan, 2012; Freyhof et al, 2011, 2017, 2019, 2021; Freyhof & Geiger, 2021; Freyhof & Özuluğ, 2017; Kaya et al, 2020; Saygun et al, 2021; Sungur et al, 2017; Turan et al, 2019, 2023; Yoğurtçuoğlu et al, 2021a,b, 2022).…”

“…Cytochrome oxidase subunit I (COI), described as DNA barcodes, has been used for the genetic identification of many Oxynoemacheilus species in Türkiye. Recently, the COI barcoding gene has been largely used for the taxonomy and identification of loaches (Bektaş et al, 2022; Kaya et al, 2020; Rakıcı et al, 2020; Sayyadzadeh et al, 2016; Turan et al, 2019).…”