Retinal microarchitecture and neuronal distribution in the Pied Crow (Corvus albus): A histological and NeuN immunohistochemical study

Objective The Pied Crow ( Corvus albus ) is a visually guided diurnal corvid widely distributed across sub-Saharan Africa, yet detailed anatomical descriptions of its ocular tissues are lacking. This study provides a brief histological and immunohistochemical characterization of the retina of an adult male Pied Crow, forming part of an ethically approved wildlife surveillance project. Routine H&E and Alcian Blue staining, together with NeuN immunolabeling, were employed. The objective was to document key structural features that may underlie the species’ visual adaptations. Results The retina exhibited a well-organized multilayered structure supported by a prominent hyaline scleral cartilage plate. The retinal pigment epithelium and choroid were heavily pigmented, consistent with enhanced contrast sensitivity in bright environments. The outer nuclear layer comprised 3–4 rows of nuclei, indicating a cone-rich photoreceptor population. The inner nuclear layer showed distinct stratification, while the ganglion cell layer was thick and heterogeneous. NeuN immunolabeling revealed strong neuronal expression in the ganglion cell layer and moderate positivity in the inner nuclear layer, reflecting abundant amacrine and ganglion cell populations. These findings provide baseline morphological data for Corvus albus and contribute to the limited comparative literature on African corvid retinal structure.