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’Ceratodontid’ lungfishes have a wide Gondwanan distribution during the Mesozoic, and are well-known from a variety of Cretaceous sites in northern and western Africa. Despite this relatively broad occurrence, significant gaps remain in our knowledge of Mesozoic African lungfish palaeodiversity and palaeogeography, particularly from subequatorial Africa. Ongoing field research in the Cretaceous Galula Formation (Red Sandstone Group), which outcrops in the Rukwa Rift Basin (a segment of the greater East Africa Rift System) of southwestern Tanzania, has led to the discovery of a diverse vertebrate fauna, including a well-preserved lungfish toothplate. This specimen is described here as a new taxon, Lupaceratodus useviaensis gen. et sp. nov., on the basis of its unique combination of morphological features relative to other ’ceratodontids.’ L. useviaensis represents the first Cretaceous record of a ’ceratodontid’ lungfish from Tanzania, and more broadly from the southwestern portion of the East African Rift System. The new Tanzanian form adds further diversity and a new datum to the evolutionary history of lungfishes in Africa, and it suggests possible regional differentiation between the Cretaceous fishes of East Africa and the better-known fish faunas of the period from northern and western Africa, perhaps related to the Cretaceous establishment of the Trans-Sahara Seaway.