Leoptobrachella fritinniens is a common Slender Litter Frog of lowland rainforests in Sabah. It has recently been delimited from L. dringi and L. gracilis. It is distinguished from the latter most importantly by its bipartite vocal sac and call characteristics. It seem to tolerate secondary forests and mild human alterations of the habitat. 

L. fritinniens is medium sized frog. Males reach ~34 mm, females 48 mm in snout-vent length. 

The coloration ranges from shades of brown to grey with dark markings on the dorsum. The flanks bear light warts and dark spots. The upper sector of the iris is orange to amber. The upper arm and elbow is cream in color.

Tadpoles are unkonwn.