As the type species of the genus Channa , the identity of the pelvic-finless snakehead Channa orientalis Bloch is important to channid systematics. Although this name has been attached to a Sri Lankan species for the past 160 years, its vaguely specified type locality, ‘India Orientali’, has long cast doubt as to its origin. Here, based on a collection across its range in the island and analysis of the cytochrome c oxidase subunit 1 ( cox1 ) barcoding gene, we show that the Sri Lankan pelvic-finless Channa is composed of two geographically discrete lineages separated by an uncorrected pairwise cox1 genetic distance of 6.9–8.1%. The minimum genetic distance between these two lineages and other species of the Gachua group of Channa is 5.1%. Despite their genetic divergence, the two lineages exhibit remarkable morphological stasis: they are indistinguishable from each other in external morphology. We argue that the type locality of C. orientalis is south-western Sri Lanka, to which the species is endemic. Channa orientalis is distinguished from other species of Channa by the absence of pelvic fins, adult coloration in life, dorsal- and anal-fin ray counts, number of vertebrae, and scale counts.

中文翻译：

---

Ceylon Snakehead, Channa orientalis (Teleostei: Channidae) 的遗传多样性和形态停滞

作为鼩鼯属的模式种，无骨盆鳍鳢鳙（Channa orientalis Bloch）的身份对鼩鼱系统学很重要。尽管在过去的 160 年里，这个名字一直附属于斯里兰卡的一个物种，但其模糊指定的类型产地“印度东方”长期以来一直对其起源产生怀疑。在这里，基于该岛范围内的收集和对细胞色素 c 氧化酶亚基 1 ( cox1 ) 条形码基因的分析，我们表明斯里兰卡无骨盆鳍 Channa 由两个地理上离散的谱系组成，这些谱系被未校正的成对 cox1 分隔遗传距离为 6.9–8.1%。这两个谱系与 Channa 的 Gachua 组的其他物种之间的最小遗传距离为 5.1%。尽管存在遗传差异，这两个谱系仍表现出显着的形态停滞：它们在外部形态上无法区分。我们认为 C. orientalis 的模式产地是斯里兰卡西南部，该物种是当地特有的。Channa orientalis 与其他物种的 Channa 的区别在于没有腹鳍、生活中的成年着色、背鳍和臀鳍射线计数、椎骨数量和鳞片计数。