A new Varanus species (Reptilia: Squamata: Varanidae) from the Early Pliocene of Langebaanweg, South Africa

Varanid material from the Varswater Formation (Early Pliocene, 5.1 Ma) of Langebaanweg (LBW), Western Cape Province, South Africa, is described. The presence of Varanus in the LBW fauna was first reported by Hendey in 1981, but no further study has been conducted. The abundant material (consisting of 31 cranial remains, 38 vertebrae, one humerus and three ilia), allowed for a good understanding of the skeletal morphology of the LBW monitor lizard. The LBW material belongs to a single, extinct, previously undescribed, species, Varanus varswater sp. nov., which is diagnosed by the combination of six features, located on the premaxilla, maxilla, vomer, and vertebrae. A phylogenetic analysis was conducted to identify the affinities of the new species with other extant and extinct monitor lizards, using a matrix with 78 taxa and 6225 characters (495 of which are morphological). The results retrieve the new species in the African Varanus clade, together with the extinct Varanus rusingensis and the extant Varanus niloticus, Varanus albigularis, and Varanus exanthematicus, the new species being the earliest-branching member of a clade also including the latter two. Its phylogenetic position is of palaeobiogeographical interest and implies that a dispersal event from Southern Africa occurred for this clade. Lastly, the new Varanus from LBW represents both the first confirmed evidence for a monitor lizard inhabiting the south-westernmost region of the African continent, and the oldest Varanus record in South Africa.