Should Olyra be in its own family? Molecular phylogenetics of ornamental catfishes of North East India

[bekateen]

Patil, G.S., Pinto, N., Nath, R. & M. Goswami. (2024). Decoding the molecular phylogenetics of ornamental catfishes (siluriformes) of North East India using DNA barcoding approach. Molecular Biology Reports, 51(1), p.528.
https://doi.org/10.1007/s11033-024-09487-5
https://link.springer.com/article/10.10 ... 24-09487-5

Abstract
Background Catfishes (order Siluriformes) are among the most diverse and widely distributed fish groups in the world. They are not only used for human consumption but are also a major part of the ornamental fish trade. Being a Biodiversity Hotspot, the North Eastern Region of India is home to a diverse population of ornamental fishes. Catfishes contain a humongous number of species; in this study, the authors have tried to elucidate the phylogenetic relationship of some important ornamental catfishes found in North East India using DNA barcodes.

Methods and results In this study, we have tried to explore the phylogenetic history of 13 species (41 specimens) of ornamental catfishes spanning 12 genera and 9 families of Siluriformes using DNA barcoding. Pairwise genetic distances using Kimura 2-Parameter (K2P) were calculated at intra-specific and inter-specific levels. A Neighbor-Joining tree was constructed to understand the phylogenetic relationship among the nine different catfish families. All the specimens under this study clustered with their respective species under the same family and formed three sub-clades. However,

Olyra longicaudata

, belonging to the Bagridae family, did not cluster with other species from the same family. In this study, the authors have suggested a revision of the classification of O. longicaudata back to its original family, Olyridae.

Conclusions In this study, the maximum intraspecific genetic distance of 0.03 and the minimum interspecific genetic distance of 0.14 were observed among the species. Therefore, it is evident that there is a barcoding gap among the species, which helped in the correct identification of the species. Thus, DNA barcoding helped complement the phenetic approach and also revealed a different phylogenetic relationship among the catfishes belonging to the Bagridae family.

Keywords: BOLD, DNA barcoding, Genetic distances, Molecular phylogeny, Ornamental catfishes

[Narelle]

To answer the title question:

Based on this study? No. It is all based on a single mitochondrial gene (COI) and support values for the (Clarias magur + Olyra longicaudata) clade are consistently low (0.584 or lower).

Previous molecular work has placed Olyra nested within the Bagridae. Sullivan, Lundberg, and Hardman's 2006 study used 2 nuclear genes assessed with multiple different phlyogenetic analysis methods that all strongly supported their placement of Olyra longicaudata within Bagridae.
I haven't gotten to sift through the big all-Actinopterygii paper that was just published, not sure if it included Olyra. If it did, they didn't split it either.

Phylogenetic placement of Olyra (/members of the Bagridae in general) using molecular data has only been considered with very few genes so it certainly warrants further investigation. I'll have a real answer to the title question, just give me a couple years.