A new sandstone-dwelling leaf-toed gecko (Gekkonidae: Dixonius mekongensis) from the Thai-Lao border.

We describe Dixonius mekongensis sp. nov. from sandstone formations in Khong Chiam District, Ubon Ratchathani Province, in extreme eastern Thailand along the Laotian border. The new species differs from all currently recognized Dixonius by the following combination of morphological characters and pattern: maximal known snout-vent length of 51.2 mm; 16 longitudinal rows of dorsal tubercles; 32 to 34 paravertebral scales; 22 to 24 longitudinal rows of ventral scales across the abdomen; seven precloacal pores in males, no pores in females; a marked canthal stripe; and a spotted to uniform dorsal pattern. This description brings the number of Dixonius species to 13, with six species endemic to Thailand.