the primary publications supporting the distinctiveness of the West African crocodiles. Evolution Although originally thought to be the same species as the West African crocodile, genetic studies using DNA sequencing have revealed that the Nile crocodile is actually more closely related to the crocodiles of the Americas, namely the American (C. acutus), Cuban (C. rhombifer), Morelet's (C. moreletii), and Orinoco crocodiles (C. intermedius). The fossil species C. checchiai from the Miocene in Kenya was about the same size as the modern Nile crocodiles and shared similar physical characteristics to the modern species, and analysis of C. checchiai supports their close relationship and the theory of the Nile crocodile being the base of the evolutionary radiation of the New World crocodiles. Dispersal across the Atlantic from Africa is thought to have occurred 5 to 6 million years ago. At one time, the fossil species Rimasuchus lloydi was thought to be the ancestor of the Nile crocodile, but more recent research has indicated that Rimasuchus, despite its very large size (about 20–30% bigger than a Nile crocodile with a skull length estimated up to ), is more closely related to the dwarf crocodile (Osteolaemus tetraspis) among living species. Two other fossil species from Africa retained in the genus Crocodylus appear to be closely related to the Nile crocodile: C. anthropophagus from Plio-Pleistocene Tanzania and C. thorbjarnarsoni from Plio-Pleistocene Kenya. C. anthropophagus and C. thorbjarnarsoni were both somewhat larger, with projected total lengths up to . As well as being larger, C. anthropophagus and C. thorbjarnarsoni, as well as Rimasuchus spp., were all relatively broad-snouted, indicating a specialization at hunting sizeable prey, such as large mammals and freshwater turtles, the latter much larger than any in present-day Africa. Studies have since shown these other African crocodiles to be only more distantly related to the Nile crocodile. Below is a cladogram based on a 2018 tip dating study by Lee & Yates simultaneously using morphological, molecular (DNA sequencing), and stratigraphic (fossil age) data, as revised by the 2021 Hekkala et al. paleogenomics study using DNA extracted from the extinct Voay. Characteristics and physiology Adult Nile crocodiles have a dark bronze colouration above, with faded blackish spots and stripes variably appearing across the back and a dingy off-yellow on the belly, although mud can often obscure the crocodile's actual colour. The flanks, which are yellowish-green in colour, have dark patches arranged in oblique stripes in