Thanks for the second photo, which allows a positive ID. Can’t locate my original info., however I think it is important to be able to distinguish between these very similar looking snakes, so have provided the following.
Note: Loreal scales prevent the preocular scales in front of the eye being in direct contact with the scale edging the nostril. When absent, the nostril scale directly contacts at least one preocular scale.
Keelback:
· Possesses a loreal scale
· Dark edges between larger upper lip scales (supralabials)
· Rear part of mouth curves distinctly upwards
· Anal scale and scales underneath the tail are all divided (paired)
· Dark bands across body not all in a line (some are a checker board pattern)
Rough-scaled:
· No loreal scale
· No dark edges to supralabials
· Line of mouth is straight
· Anal scale and scales underneath the tail are all single
· Dark bands across body relatively in line (parallel pattern)