Retinal Ganglion Cell Distribution and Spatial Resolution in the Dybowski's Frog Rana dybowskii (Günther, 1876)

ABSTRACT Visual system is of crucial importance for the majority of frogs and toads. The location of retinal specializations and visual acuity are directly related to a species' ecology. However, these aspects of the visual system are poorly studied in Anura. I studied the topography of retinal ganglion cells (GCs) and estimated spatial resolution (SR) in the Dybowski's frog. GCs exhibited a heterogeneous distribution across the retinal surface. Their spatial density (SD) was lowest in the dorsal and ventral periphery (below 4000 cells/mm 2 ). It increased progressively towards the retinal equator, where a moderate visual streak emerged. The greatest GC SD (10,000–10,200 cells/mm 2 ) was found in the temporal retina, close to the equator. The respective zone was identified as area retinae temporalis . The total number of GCs was 308.7 × 10 3 in the smaller retina and 400.5 × 10 3 cells in the larger one. The maximum SR as estimated from eye geometry and GC SD was observed in area retinae temporalis (2.66 and 3.04 cpd in smaller and larger frogs, respectively). The retinal specializations and SR estimates in the Dybowski's frog align with its biology.