The sequencing of ancient DNA has enabled the reconstruction of speciation, migration and admixture events for extinct taxa¹. However, the irreversible post-mortem degradation² of ancient DNA has so far limited its recovery—outside permafrost areas—to specimens that are not older than approximately 0.5 million years (Myr)³. By contrast, tandem mass spectrometry has enabled the sequencing of approximately 1.5-Myr-old collagen type I⁴, and suggested the presence of protein residues in fossils of the Cretaceous period⁵—although with limited phylogenetic use⁶. In the absence of molecular evidence, the speciation of several extinct species of the Early and Middle Pleistocene epoch remains contentious. Here we address the phylogenetic relationships of the Eurasian Rhinocerotidae of the Pleistocene epoch^7,8,9, using the proteome of dental enamel from a Stephanorhinus tooth that is approximately 1.77-Myr old, recovered from the archaeological site of Dmanisi (South Caucasus, Georgia)¹⁰. Molecular phylogenetic analyses place this Stephanorhinus as a sister group to the clade formed by the woolly rhinoceros (Coelodonta antiquitatis) and Merck’s rhinoceros (Stephanorhinus kirchbergensis). We show that Coelodonta evolved from an early Stephanorhinus lineage, and that this latter genus includes at least two distinct evolutionary lines. The genus Stephanorhinus is therefore currently paraphyletic, and its systematic revision is needed. We demonstrate that sequencing the proteome of Early Pleistocene dental enamel overcomes the limitations of phylogenetic inference based on ancient collagen or DNA. Our approach also provides additional information about the sex and taxonomic assignment of other specimens from Dmanisi. Our findings reveal that proteomic investigation of ancient dental enamel—which is the hardest tissue in vertebrates¹¹, and is highly abundant in the fossil record—can push the reconstruction of molecular evolution further back into the Early Pleistocene epoch, beyond the currently known limits of ancient DNA preservation.

Paleoenvironmental variations that occurred in Italy from the Middle Pliocene to the Late Pleistocene are described. The number of large mammal species seems increased moderately, especially from the Galerian to the Late Aurelian biochronological units. On the contrary, the paleobotanical data show a decrease of the forest cover from the Middle Pliocene to the late Early Pleistocene and an increase of lands occupied by prairies and steppes. This change is also supported by the appearance of hypsodont taxa among mammals. The distribution of mammal faunas between the Adriatic and Tyrrhenian sides of Central Italy, during the Middle and Late Pleistocene, seems not to be influenced by climatic and environment differences. When the Adriatic data are more complete, it is possible, in fact, to observe a trend that is fairly close to that of the Tyrrhenian. The majority of megaherbivorous taxa has an Asian origin, and it can be hypothesized that in the interglacial phases, the Tosco-Emilian Apennines all... RÉSUMÉ Biochronologie et variations paléo-environnementales en Italie centrale du Pliocène moyen à la fin du Pléistocène. Les variations paléo-environnementales qui ont eu lieu en Italie du Pliocène moyen au Pléistocène supérieur sont décrites. Il semblerait que le nombre des espèces de mammifères de grande taille ait peu augmenté, surtout pour les unités biochronologiques du Galérien à l'Aurélien supérieur. Au contraire, les données paléobotaniques montrent une diminution progressive des espèces arborées depuis le Pliocène moyen jusqu'au début du Pléistocène inférieur et une augmentation des surfaces occupées par les prairies et les steppes. Ces derniers évènements sont attestés par l'apparition des espèces hypsodontes parmi les mammifères. La répartition des faunes de mammifères entre les côtes adriatique et tyrrhénienne de l'Italie centrale, pendant le Pléistocène moyen et supérieur, semble ne pas avoir été influencée par des différences climatiques et environnementales. Quand les données sur l'Adriati...