Fossils of dyrosaurid crocodyliforms are limited in South America, with only three previously diagnosed taxa including the short-snouted Cerrejonisuchus improcerus from the Paleocene Cerrejó n Formation of north-eastern Colom-bia. Here we describe a second dyrosaurid from the Cerrejó n Formation, Acherontisuchus guajiraensis gen. et sp. nov., based on three partial mandibles, maxillary fragments, teeth, and referred postcrania. The mandible has a reduced seventh alveolus and laterally depressed retroarticular process, both diagnostic characteristics of Dyrosauridae. Acherontisuchus guajiraensis is distinct among known dyrosaurids in having a unique combination of craniomandibular characteristics, and postcranial morphology that suggests it may have occupied a more placid, fluvial habitat than most known Old-World dy-rosaurids. Results from a cladistic analysis of Dyrosauridae, using 82 primarily cranial and mandibular characters, sup-port an unresolved relationship between A. guajiraensis and a combination of New-and Old-World dyrosaurids including Hyposaurus rogersii, Congosaurus bequaerti, Atlantosuchus coupatezi, Guarinisuchus munizi, Rhabdognathus keiniensis and Rhabdognathus aslerensis. Our results are consistent with an African origin for Dyrosauridae with multiple dispersals into the New World during the Late Cretaceous and a transi-tion from marine habitats in ancestral taxa to more fluvial habitats in more derived taxa.