ASSESSMENT OF THE PHENOTYPIC VARIATION IN COLOUR AMONG TORTOISE SPECIES FROM DIVERSE ECOLOGICAL ZONES IN DELTA STATE, NIGERIA

Abstract

The variation in carapace colour pattern of tortoises is a crucial feature for species identification. The experiment was conducted at the Research Farm of Animal Production Department,  Southern Delta University, Ozoro, to examine the phenotypic variation in colour of tortoise found among three major ecological zones in Delta State, Nigeria. A total of 180 tortoises were sampled. Six species of tortoises were identified in the study area. These species were; marginated tortoise (Testudo marginata), African spurred tortoise (Centrochlys sulcata), Serrated hinged Terrapin (Pelusios sinuatus), Greek tortoise (Testudo graeca), West African mud tortoise (Pelusios casteneus) and Pancake tortoise (Malacochersus torneri). The pancake tortoise which made up about 33.33% of the samples were found in mangrove swamp, the West African mud tortoise (29.45%) and Greek tortoise (3.86%) were found in the freshwater swamp. The lowland rainforest had the marginated tortoise (15.55%), African spurred tortoise (10.0%) and serrated hinged terrapin (7.78%).  The result revealed that dark brown, yellowish brown, chestnut brown, black, brown and black laced up with brown tortoise had 100% for both carapace and plastron. All (100%) had black laced up with brown spot for beak and head. The beak is 100% black, while the head is 100% brown laced with black spot and eye is 100% grey. The head colour pattern is mostly ash and piebald. Majority (80%) of the tortoises possessed black eye colour variant, while 20% had grey eye colour. Carapace and plastron phenotype reflect the intricate variations in colour that the tortoises exhibit in their ecological zones.