![]() The middle Miocene witnessed the development of the “Gomphothere landbridge”, and with it, progressive faunal exchange. Near the end of the Paleogene, the Arabian Peninsula closely approximated Eurasia, facilitating periodic faunal interchange between the African continent and Eurasia. During the Paleogene, Afro-Arabia was relatively isolated from other landmasses and hyaenodonts featured as apex predators in a largely endemic fauna that included Afro-Arabian radiations of afrotherians, anthracotheres, rodents, and primates. Instead, carnivore niches in Afro-Arabia throughout the Paleogene were primarily occupied by species of the extinct mammalian clade Hyaenodonta. Yet carnivorans were absent from the African landscape for the first two-thirds of the Cenozoic. Today, terrestrial carnivore niches in Africa-and in most terrestrial ecosystems-are primarily occupied by species from the mammalian order Carnivora. The description of Pakakali is important for exploring hyaenodont ontogeny and potential influences of Afro-Arabian tectonic events upon mammalian evolution, providing a deep time perspective on the stability of terrestrial carnivore niches through time.Ĭarnivores occupy vital ecological roles in modern terrestrial ecosystems, stabilizing community structure and shaping patterns of biodiversity. Notably, Pakakali is in the size range of carnivoran forms that arrived and began to diversify in the region by the early Miocene. A Bayesian biogeographic analysis of phylogenetic results resolve the Pakakali clade as Afro-Arabian in origin, demonstrating that this small carnivorous mammal was part of an endemic Afro-Arabian lineage that persisted into the Miocene. Using a hyaenodont character-taxon matrix that includes deciduous dental characters, Bayesian phylogenetic methods resolve Pakakali within the clade Hyainailouroidea. Based on alveolar morphology, the two more distal teeth successively increased in size and had relatively large protocones. The crown of dP 3 bears an elongate parastyle and metastyle and a small, blade-like metacone. ![]() ![]() nov., a bobcat-sized taxon known from a portion of the maxilla that preserves a deciduous third premolar and alveoli of dP 4 and M 1. Here we describe a new hyaenodont from the Nsungwe Formation, Pakakali rukwaensis gen. Fossil bearing deposits in the Nsungwe Formation in southwestern Tanzania are precisely dated to ~25.2 Ma (late Oligocene), preserving a late Paleogene Afro-Arabian fauna on the brink of environmental transition, including the earliest fossil evidence of the split between Old World monkeys and apes. The transition from a hyaenodont-carnivore fauna to a carnivoran-carnivore fauna coincides with other ecological changes in Afro-Arabia as tectonic conditions in the African Rift System altered climatic conditions and facilitated faunal exchange with Eurasia. By the end of the Miocene, terrestrial carnivore niches had shifted to members of Carnivora, a clade with Eurasian origins. Throughout the Paleogene, most terrestrial carnivore niches in Afro-Arabia were occupied by Hyaenodonta, an extinct lineage of placental mammals. ![]()
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