The genus is recognized to be paraphyletic. The speciesofOmpok have been grouped into species groups, such as the Ompok bimaculatus group (i.e. O. bimaculatus, O. malabaricus and O. miostoma), the O. eugeneiatus group (i.e. O. eugeneiatus and O. pinnatus), the O. hypophthalmus group (i.e. O. hypophthalmus, O. rhabdinurus and O. urbaini) and the O. leiacanthus group (O. fumidus, O. jaynei and O. leiacanthus).[2][3][4] On the other hand, the monophyly of these species groups is not strong enough to reassign species to other genera.[5]
The O. eugeneiatus group is likely to be more closely related to Kryptopterus than the other Ompok species.[2] According to Ferraris O. eugeneiatus has been reclassified into Kryptopterus, however O. pinnatus has not.[6]
^ abBornbusch, A.H. (1995): Phylogenetic relationships within the Eurasian catfish family Siluridae (Pisces: Siluriformes), with comments on generic validities and biogeography. Zoological Journal of the Linnean Society, 115 (1): 1–46.
^Ng, H.H. (2003): A review of the Ompok hypophthalmus group of silurid catfishes with the description of a new species from South-East Asia. Journal of Fish Biology, 62 (6): 1296–1311.
^Ng, H.H. (2003): Ompok pinnatus, a new species of silurid catfish (Teleostei: Siluriformes: Siluridae) from mainland Southeast Asia. Proceedings of the Biological Society of Washington, 116 (1): 47-51.
^Ng, H.H. & Tan, H.H. (2004): Ompok platyrhynchus, a new silurid catfish (Teleostei: Siluridae) from Borneo. Zootaxa, 580: 1–11.
^ abSudasinghe, H. & Meegaskumbura, M. (2016): Ompok argestes, a new species of silurid catfish endemic to Sri Lanka (Teleostei: Siluridae). Zootaxa, 4158 (2): 261–271.
^Ng, H.H. (2013): Ompok karunkodu, a new catfish (Teleostei: Siluridae) from southern India. Zootaxa, 3694 (2): 161–166.
