Cteniogenys is a genus of choristodere, a morphologically diverse group of aquatic reptiles.

[2] The holotype, VP.001088, was collected in the Morrison Formation (Como Bluff), Wyoming in 1881 by William H. Reed.

It is mostly known from freshwater sites (rivers and ponds), and is a rare find in the formation (only 60 specimens out of over 2,800 total vertebrate specimens known from the formation), mostly known from northern outcrops (particularly Wyoming); this may reflect a preservation bias against small animals in terrestrial settings, rather than an accurate reflection of Cteniogenys populations in the Morrison.

[7] Given the long gap in time, however, Gao et al. (2005) cautioned that these remains could constitute a different, as-yet undetermined genus.

[3] New material of Cteniogenys from Europe prompted Susan E. Evans to reclassify it as an early choristodere in 1989.