Mitogenome reconstruction of an endangered African seahorse from a Traditional Chinese Medicine market was based on a misidentification

The recently published complete mitochondrial genome of the endangered Knysna seahorse, Hippocampus capensis Boulenger, 1900, was based on a specimen obtained from a Traditional Chinese Medicine market. As H. capensis is endemic to temperate South Africa and exceptionally rare, illegal trade to supply Asian markets would constitute a considerable extinction risk. I investigated the phylogenetic placement of the Chinese specimen using mitochondrial DNA control region and cytochrome b sequences from the H. capensis mitogenome among corresponding published sequences of H. capensis and a number of closely related seahorse species. The Chinese specimen was distinct from H. capensis and instead clustered with H. casscsio, a seahorse that was recently described from the South China Sea. The sequences of H. casscsio clustered randomly among those of specimens identified as H. fuscus, a species whose taxonomic validity is disputed, and which is considered to be a synonym of the widespread Indo-Pacific seahorse H. kuda. Given that the morphological identification of seahorses is difficult, it is recommended that the publication of new species descriptions and genomic resources be preceded by a comprehensive comparison with the available molecular data. The taxonomy of seahorses is far from resolved, and cutting-edge molecular studies will not improve this situation if they do not take existing information into consideration.