The mammal fauna of Hainin is particularly interesting as the oldest in the Cenozoic of Europe, and the earliest reference level (MP1–5) of the mammalian biochronological scale for the European Palaeogene. This paper summarizes the mammal taxa discovered in the fauna, presents an analysis of the fauna as a whole (relative abundance and species richness), and describes four new eutherians: Belgoryctes thaleri gen. et sp. nov., Eurolestes dupuisi gen. et sp. nov., Quadratodon sigei gen. et sp. nov. and Cingulodon magioncaldai gen. et sp. nov. The assemblage is relatively small (about 400 dental specimens), characterized by a high diversity and abundance of small insectivorous species and very low abundance of ‘plesiadapiforms’ and ‘condylarths’. By comparison with younger European Paleocene faunas, ‘condylarths’ and ‘plesiadapiforms’ became more and more abundant and diverse through the Paleocene but collapsed at the Paleocene–Eocene Boundary. ‘Proteutherians’ declined steadily, while multituberculates remained diverse, although the early Paleocene was populated mainly by Kogaionidae whereas the late Paleocene was dominated by Neoplagiaulacidae. The palaeoecology of Hainin is deduced from the mammal assemblage: the local environment was likely a forested area. Stratigraphically, the Hainin deposits are most likely of late Danian age, and biochronologically its fauna represents a partial equivalent of the North American Torrejonian Land Mammal Age. When compared to younger Paleocene faunas of Europe, the composition of the Hainin fauna reveals that a relatively important intercontinental dispersal of mammals occurred around the Danian–Selandian boundary, roughly corresponding to the Torrejonian–Tiffanian boundary. This dispersal is marked by the arrival in Europe of typically North American taxa such as arctocyonids, plesiadapids and neoplagiaulacid multituberculates. Additional exchanges of lesser magnitude probably also occurred around the Selandian–Thanetian boundary (i.e. during the Tiffanian), although the evidence is less compelling and mainly concerns the plesiadapids Chiromyoides and Plesiadapis.
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RBINS Staff Publications 2016
With approximately 1,500 extant species, freshwater crabs (Decapoda: Brachyura) are among the most diverse decapod crustaceans. nevertheless, their fossil record is extremely limited: only potamidae, potamonautidae and trichodactylidae are reported up to the eocene of the neotropics so far. this work documents unusually large decapod claws from the Upper Cretaceous (Campanian) continental deposits of Velaux and vicinity (southern France), in close association with large vertebrate remains. In addition to (1) the systematic assignment of these claws, the study addresses (2) the salinity trends in the deposit environment from its faunal assemblage and the elementary chemical patterns of fossils, and (3) the likely scenario for their auto/allochthony in the Velaux fuvial system. These claws belong to a new taxon, Dinocarcinus velauciensis n. gen. n. sp., referred to as Portunoidea sensu lato, a group of “true” crabs nowadays linked to marine systems. However, the faunal assemblage, the claw taphonomy and the carbonates Y/Ho signatures support their ancient freshwater/terrestrial ecology, making them the oldest reported continental brachyurans and extending the presence of crabs in freshwater environments by 40 Ma. Either as primary or as secondary freshwater crabs, the occurrence of these portunoids in Velaux is an evidence for the independent colonizations of continental environments by multiple brachyuran clades over time, as early as the campanian.
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RBINS Staff Publications 2019
