Fossil Record and Biogeography
The oldest known sisorid fossil is B. bagarius found in Sumatra and India of the Pliocene. The origin of glyptosternoid fishes could be in the later Pliocene. Another study proposes glyptosternoids possibly originated in the Oligocene-Miocene boundary (19–24 Mya) and radiated from the Miocene to Pleistocene along with several rapid speciation events in a relatively short time. The three great uplifts of the Qinghai/Tibet Plateau destroyed the pattern of river systems in the late Pliocene to the early Pleistocene. The ancestor of Euchiloglanis originated from the allied Glyptosternon in the second uplift and Pareuchiloglanis, Pseudexostoma, Oreoglanis, Exostoma, and Glaridoglanis originated with the third uplift. The Exostoma group (Exostoma, Pseudexostoma, and Oreoglanis) originated after the outline of the Qinghai/Tibet Plateau was formed. The speciation of this group was not strong and the distribution limited.
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