Adults of this species reach 48 mm in males and 50 mm snout-vent-length in females. The species has been recorded from Gunung Mulu NP and Crocker Range NP at elevations from 155 m to 1450 m asl. 

The name "separatus" refers to the fact that this species has been recorded from two separated areas, that is Mulu and Crocker Range.

In the description by Matsui et al. (2024), I (AH) could not find a morphological comparison section that compares specifically L. separatus and the sympatric L. mocquardi. This could indicate that the two species have basically been established on genetic evidence and are morphologically not significantly different (note some differences in size). For the time being, please refer to the description of L. mocquardi.