Taxonomy
Sisoridae is recognized as a natural, monophyletic group based on morphological and molecular evidence. Sisoridae is divided into two subfamilies, Sisorinae and Glyptosterninae (glyptosternoids). Sisorinae contains the five genera Bagarius, Gagata, Gogangra, Nangra, and Sisor. Glyptosterninae contains three tribes. Glyptothoracini contains only the genus Glyptothorax and Pseudecheneidina contains only the genus Pseudecheneis. The remaining genera, Euchiloglanis, Exostoma, Glaridoglanis, Glyptosternon, Myersglanis, Oreoglanis, Parachiloglanis, Pareuchiloglanis, and Pseudexostoma, are contained in the tribe Glyptosternina. The monophyly of the entire family and the tribe Glyptosterninae are well supported by osteological morphology and molecular data.
In the genera Glyptothorax (tribe Glyptothoracini) and Pseudecheneis (tribe Pseudecheneidina), the species have a thoracic adhesive apparatus to attach to objects in the stream bed; in Glyptothorax, grooves of this apparatus run parallel or oblique to the axis of the body, while in Pseudecheneis groovs run transverse to the axis of the body. The thoracic adhesive apparatus is not present in the other sisorid genera. The paired fins may be plaited to form an adhesive apparatus in Pseudecheneis, glyptosternoids, and variably in Glyptothorax. Thus, glyptosternoids lack a thoracic adhesive apparatus but do have plaited paired fins, and members of the subfamily Sisorinae lack either a thoracic adhesive apparatus or plaited paired fins.
The monophyly of certain glyptosternoid genera is doubtful. The paraphyly of Pareuchiloglanis, Oreoglanis, and Pseudexostoma (with the possible inclusion of Myersglanis and Parachiloglanis) has been demonstrated and a rediagnosis of glyptosternine genera is needed.
Evidence from a 2007 molecular analysis supports polyphyly of Pareuchiloglanis. Glaridoglanis might be a basal member of the tribe Glyptosternina. Pseudecheneis may be placed in the tribe Glyptosternina, but its sister-group relationship between it and the monophyletic glyptosternoids cannot be rejected.
It has been proposed to move the genera of Erethistidae into Sisoridae.
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