The only complete articulated early Miocene chameleon skull (Rusinga Island, Kenya) suggests an African origin for Madagascar’s endemic chameleons

We here present the first detailed study of the specimen KNM-RU 18340 from
Rusinga Island (Kenya), the only known complete early Miocene chameleon
skull, using micro-CT. This specimen represents one of the oldest
chameleon fossils ever recovered. For the first time, the skull bone
internal surfaces, their sutures, and elements contained inside the rocky
matrix are observed. Our morphological comparisons and phylogenetic
analyses place this specimen confidently in the genus Calumma and a new
species, Calumma benovskyi sp. nov., is erected for it. Since all species
of this genus are endemic to Madagascar, this fossil uniquely demonstrates
the existence of Calumma on continental Africa in prehistoric time. Our
results challenge the long-held view that chameleons originated on
Madagascar and dispersed over water to Africa, and provide a strong
evidence of an African origin for some Malagasy lineages. The
Oligocene–early Miocene dispersal to Madagascar, using oceanic currents
that favoured eastward dispersal at that time, is a highly supported
scenario matching the suggested dispersal of lemurs to this island. This
is consistent with a previously suggested hypothesis based on molecular
data.