thecodactyl

from The Century Dictionary.

• Having thecal digits, as a gecko; having thick toes whose scales furnish a sheath for the claw. See cut under gecko.
• noun A thecodactyl gecko.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Zoöl.) Any one of a group of lizards of the Gecko tribe, having the toes broad, and furnished with a groove in which the claws can be concealed.