Eye features and retinal photoreceptors of the nocturnal aardvark (Orycteropus afer, Tubulidentata).

ABSTRACT: The nocturnal aardvark Orycteropus afer is the only extant species in the mammalian order Tubulidentata. Previous studies have claimed that it has an all-rod retina. In the retina of one aardvark, we found rod densities ranging from 124,000/mm² in peripheral retina to 214,000/mm² in central retina; the retina of another aardvark had 163,000 - 245,000 rods/mm². This is moderate in comparison to other nocturnal mammals. With opsin immunolabelling we found that the aardvark also has a small population of cone photoreceptors. Cone densities ranged from about 300 to 1,300/mm² in one animal, and from 1,100 to 1,600/mm² in a limited sample of the other animal, with a central-peripheral density gradient and some local variations. Overall, cones comprised 0.25-0.9% of the photoreceptors. Both typic

SUBMITTER: Peichl L 

PROVIDER: S-EPMC11932471 | biostudies-literature | 2025

REPOSITORIES: biostudies-literature