The first Miocene fossils from coastal woodlands in the southern East African Rift

Abstract

The Miocene is a key time in the evolution of African mammals and their ecosystems witnessing the origin of the African apes and the isolation of eastern coastal forests through an expanding biogeographic arid corridor. Until recently, however, Miocene sites from the southeastern regions of the continent were unknown. Here we report discovery of the first Miocene fossil teeth from the shoulders of the Urema Rift in Gorongosa National Park, Mozambique, at the southern East African Rift System. We provide the first 1) radiometric age determinations of the fossiliferous Mazamba Formation, 2) reconstructions of past vegetation in the region based on pedogenic carbonates and fossil wood, and 3) description of fossil teeth from the southern rift. Gorongosa is unique in the East African Rift System in combining marine invertebrates, marine vertebrates, terrestrial mammals, and fossil woods in coastal paleoenvironments. The Gorongosa fossil sites offer the first evidence of persistent woodlands and forests on the coastal margins of southeastern Africa during the Miocene, and an exceptional assemblage of fossil vertebrates including new species. Further work will allow the testing of hypotheses positing the formation of a northeast-southwest arid corridor isolating species on the eastern coastal forests from those elsewhere in Africa.BriefThe Miocene is a key time in the evolution of African mammals and their ecosystems encompassing hominine origins and the establishment of an arid corridor that isolated eastern Africa’s coastal forests. Until now, however, Miocene sites from southeastern Africa have been unknown. We report the discovery of the first Miocene fossil sites from Gorongosa National Park, Mozambique, and show that these sites formed in coastal settings. We provide radiometric ages for the fossiliferous sediments, reconstructions of past vegetation based on stable isotopes and fossil wood, and a description of the first fossil teeth from the region. Gorongosa is the only paleontological site in the East African Rift that combines fossil woods, marine invertebrates, marine vertebrates, and terrestrial mammals. Gorongosa offers the first evidence of persistent woodlands and forests on the coastal margins of southeastern Africa during the Miocene.

Carbon, nitrogen, and oxygen stable isotopes in modern tooth enamel: A case study from Gorongosa National Park, central Mozambique

“…This illustrates the high potential of our multi-isotope approach for paleontological applications using diagenetically robust tooth enamel. We plan to apply this novel multi-isotope approach to recently discovered vertebrate fossils from GNP, which represent the only Miocene fossil locality in the southern East African Rift (Habermann et al, 2019;Bobe et al, 2021). Thus, the datasets presented here will serve as an excellent comparison for the interpretation of fossil stable isotope data.…”

A network-based analysis of signal use during approach interactions across sexes in chacma baboons (Papio ursinus griseipes)

“…Gorongosa National Park covers 3770 km 2 of the Urema drainage basin in the southern end of the East African Rift System (EARS) [57][58][59][60]. The mosaic ecosystem results in high biodiversity and makes the park a unique and valuable analogue model for the environmental conditions of the EARS during important periods of human evolution [57,61,62].…”

“…Gorongosa National Park covers 3770 km 2 of the Urema drainage basin in the southern end of the East African Rift System (EARS) [57][58][59][60]. The mosaic ecosystem results in high biodiversity and makes the park a unique and valuable analogue model for the environmental conditions of the EARS during important periods of human evolution [57,61,62]. The park's baboons are usually categorized as chacma baboons (Papio ursinus griseipes), but the park lies within a potential hybridization zone between northern chacma baboons and southern yellow baboons [59,63].…”