Vertebral monstrosities: Phenotypically shortened fish with deformed vertebrae in endemic fish genus Hypselobarbus (Bleeker 1860), (Teleostei: Cyprinidae) from Western Ghats, India

Abstract The vertebral deformity in four fish species of genus Hypselobarbus (Bleeker 1860), collected from three different river systems of the Western Ghats, biodiversity hotspot of India, are reported here. The radiographic images revealed reduced intra-vertebral space in comparison with the normal vertebrae. The phenotypic deformities have led to the deepening of the body with a more robust and reduced length. The deformed vertebrae were between 25 and 32. Slight genetic divergence of 1.1% between normal and deformed specimens in Mitochondrial cytochrome oxidase subunit 1 gene of Hypselobarbus lithopidos and H. thomassi and no divergence in H. dobsoniand H. jerdoni was observed. Several environmental and genetic factors might have influenced the development of these robust short-bodied phenotypes in these rivers and possess slight genetic divergence from normal specimens. The specimens were collected from areas with high anthropogenic stresses, abate water quality, and habitat, which could also be a possible reason. However, these deformities may also be the result of the stress during embryonic and early life stages.