Leucism is a colour aberration that results from a lack of melanin and alteration in the development or distribution of chromophores. The study records for the first time the occurrence of leucistic larvae of Arabian toad (Sclerophrys arabica) in AlUla, Kingdom of Saudi Arabia. The specimens were reared in the lab until the end of metamorphosis, which lasted for four months. Genomic DNA extraction, Polymerase Chain Reaction (PCR) amplification, and sequencing of the mitochondrial 16S ribosomal RNA gene were done for molecular identification of the normal and leucistic larvae. The leucistic individuals were transparent and the internal organs were visible. The histological study showed that the skin of leucistic individuals suffers from epidermic alterations, absence or decrease of melanophores, decrease in carbohydrate content, and decrease in Connective tissue growth factor (CTGF) and Glial fibrillary acidic Protein (GFAP) expressions. The phylogenetic tree showed that normal and leucistic toads cluster in a single group and are identified as S. arabica (Heyden, 1827). We conclude that pigment cells play an important role during metamorphosis and recommend further investigation to understand the reasons underlying this phenomenon.
Alansari et al. (2026) studied this question.