Preliminary taphonomic studies were conducted on three different early hominid Chadian sites aged... more Preliminary taphonomic studies were conducted on three different early hominid Chadian sites aged between 5 Ma and 3 Ma (KB, KL, KT fossil areas). Specific excavations and taphonomic sampling protocols were established. Research of the various alterations and the origins of bone modifications were carried out. All fossil assemblages bear traces of carnivore tooth marks as well as weathering and wind/water polishing. Digestion is present on bones from the KB & KL sites. Rootmark traces were found only on bones from the KB and KT sites. All three sites display various polishing patterns among which much of the abrasion results from wind polishing on the top surface, on the exposed face of large flat bones difficult to move. By contrast water action works on all faces of polished bones. KL seems to show more water transport influence than the two other sites. Weathering stages are light to heavy (stages 2-4) and the presence of gnawing, and traces of roots plus tooth marks indicates that bones stayed sometimes on the soil surface and that the assemblages may be of attritional origin. But the low density of bones and the presence of a very thin fossil layer are very exceptional and it is not clear weather the fossil sites have been condensed during the past or if this is the result of present day extreme desert conditions. More detailed work on other Djourab sites should allow to refine the taphonomic history concerning these early hominid accumulations and formation.
Fish remains are abundant and easily recognizable in many archaeological sites. But, the origin o... more Fish remains are abundant and easily recognizable in many archaeological sites. But, the origin of such assemblages is generally poorly known. However, the ability to create small fish bone accumulations is restricted to a small number of predators (including raptors, carnivores, and humans). In order to recognize the agents responsible for these concentrations in archaeological sites, we have investigated the taphonomy of the fish remains from otter spraints to determine the potential role of otters in the formation of fossil assemblages. Currently, few data are available to characterize the accumulation of otter remains in natural or archaeological sites. We analyzed a collection of 29 otter spraints from Bugeat (Correze) in central France. We identified the remains of nine fish species including, brown trout ((Salmo trutta, Salmonidae), perch (Perca fluviatilis, Percidae), pumpkinseed (Lepomis gibbosus, Centrarchidae), and several Cyprinidae, rudd (Scardinius erythrophthalmus), m...
Depuis 225 millions d’années, l’ordre des mammifères a conquis notre planète et résisté à tous le... more Depuis 225 millions d’années, l’ordre des mammifères a conquis notre planète et résisté à tous les changements survenus. D’après le dernier décompte, les mammifères seraient représentés par 5 416 espèces, dont 80 % ayant un poids inférieur à 20 kg. Cette dernière catégorie est dominée par les rongeurs, dont on dénombre 2 277 espèces, et qui ont conquis tous les habitats terrestres, des déserts aux zones humides. Adaptation à la vie désertique et semi-aquatique L’eau constitue ..
RÉSUMÉ — L'étude des microvertébrés fossiles récemment découverts dans le site pléistocène de... more RÉSUMÉ — L'étude des microvertébrés fossiles récemment découverts dans le site pléistocène de Peninj (Ouest-Natron) en Tanzanie du Nord donne d'importants résultats concernant le paléoenvironnement, la paléobiogéographie et l'âge de ce gisement célèbre pour avoir livré une mandibule & Australopithecus boisei. L'association caractéristique comprend un assemblage de Thallomys -Arvicanthis -Aethomys ainsi que pour la première fois une molaire de Graphiurus, genre qui n'avait pu jusqu'à présent être découvert dans le Plio-Pléistocène d'Afrique orientale. Un lièvre et un primate arboricole (Galago) sont également signalés dans cette faune. Cet assemblage indique un milieu de savane sèche à Acacia avec cependant des formations plus arborées de bush ou woodland qui pourraient s'être développées le long de la rivière ou de son delta à proximité des bords du lac Natron. La faune de l'Ouest-Natron partage 6 genres en commun parmi lesquels 3 espèces avec les...
Recent taphonomic studies have shown that avian predators such as owls are responsible for most s... more Recent taphonomic studies have shown that avian predators such as owls are responsible for most small-mammal fossil accumulations, and that predators cause bone loss and breakage as well as modification to the surface of bones that are preserved. However, the specific physiochemical alterations and the alterations of bone microstructures that predators induce remain poorly understood. In order to better separate and characterize the effects of bone digestion by owls, we performed an experimental study to simulate digestion by a predator. We put fresh rodent long bones into various solutions to simulate the digestive effects of predators. We first tested an acid solution, followed by other solutions containing key enzymes such as trypsin, lipase, and trypsin + lipase. Next, we compared the results of the simulated digestion experiments with partly digested long bones recovered from Tyto alba and Bubo bubo pellets. We observed that acid action alone did not reproduce the modifications...
Preliminary taphonomic studies were conducted on three different early hominid Chadian sites aged... more Preliminary taphonomic studies were conducted on three different early hominid Chadian sites aged between 5 Ma and 3 Ma (KB, KL, KT fossil areas). Specific excavations and taphonomic sampling protocols were established. Research of the various alterations and the origins of bone modifications were carried out. All fossil assemblages bear traces of carnivore tooth marks as well as weathering and wind/water polishing. Digestion is present on bones from the KB & KL sites. Rootmark traces were found only on bones from the KB and KT sites. All three sites display various polishing patterns among which much of the abrasion results from wind polishing on the top surface, on the exposed face of large flat bones difficult to move. By contrast water action works on all faces of polished bones. KL seems to show more water transport influence than the two other sites. Weathering stages are light to heavy (stages 2-4) and the presence of gnawing, and traces of roots plus tooth marks indicates that bones stayed sometimes on the soil surface and that the assemblages may be of attritional origin. But the low density of bones and the presence of a very thin fossil layer are very exceptional and it is not clear weather the fossil sites have been condensed during the past or if this is the result of present day extreme desert conditions. More detailed work on other Djourab sites should allow to refine the taphonomic history concerning these early hominid accumulations and formation.
Fish remains are abundant and easily recognizable in many archaeological sites. But, the origin o... more Fish remains are abundant and easily recognizable in many archaeological sites. But, the origin of such assemblages is generally poorly known. However, the ability to create small fish bone accumulations is restricted to a small number of predators (including raptors, carnivores, and humans). In order to recognize the agents responsible for these concentrations in archaeological sites, we have investigated the taphonomy of the fish remains from otter spraints to determine the potential role of otters in the formation of fossil assemblages. Currently, few data are available to characterize the accumulation of otter remains in natural or archaeological sites. We analyzed a collection of 29 otter spraints from Bugeat (Correze) in central France. We identified the remains of nine fish species including, brown trout ((Salmo trutta, Salmonidae), perch (Perca fluviatilis, Percidae), pumpkinseed (Lepomis gibbosus, Centrarchidae), and several Cyprinidae, rudd (Scardinius erythrophthalmus), m...
Depuis 225 millions d’années, l’ordre des mammifères a conquis notre planète et résisté à tous le... more Depuis 225 millions d’années, l’ordre des mammifères a conquis notre planète et résisté à tous les changements survenus. D’après le dernier décompte, les mammifères seraient représentés par 5 416 espèces, dont 80 % ayant un poids inférieur à 20 kg. Cette dernière catégorie est dominée par les rongeurs, dont on dénombre 2 277 espèces, et qui ont conquis tous les habitats terrestres, des déserts aux zones humides. Adaptation à la vie désertique et semi-aquatique L’eau constitue ..
RÉSUMÉ — L'étude des microvertébrés fossiles récemment découverts dans le site pléistocène de... more RÉSUMÉ — L'étude des microvertébrés fossiles récemment découverts dans le site pléistocène de Peninj (Ouest-Natron) en Tanzanie du Nord donne d'importants résultats concernant le paléoenvironnement, la paléobiogéographie et l'âge de ce gisement célèbre pour avoir livré une mandibule & Australopithecus boisei. L'association caractéristique comprend un assemblage de Thallomys -Arvicanthis -Aethomys ainsi que pour la première fois une molaire de Graphiurus, genre qui n'avait pu jusqu'à présent être découvert dans le Plio-Pléistocène d'Afrique orientale. Un lièvre et un primate arboricole (Galago) sont également signalés dans cette faune. Cet assemblage indique un milieu de savane sèche à Acacia avec cependant des formations plus arborées de bush ou woodland qui pourraient s'être développées le long de la rivière ou de son delta à proximité des bords du lac Natron. La faune de l'Ouest-Natron partage 6 genres en commun parmi lesquels 3 espèces avec les...
Recent taphonomic studies have shown that avian predators such as owls are responsible for most s... more Recent taphonomic studies have shown that avian predators such as owls are responsible for most small-mammal fossil accumulations, and that predators cause bone loss and breakage as well as modification to the surface of bones that are preserved. However, the specific physiochemical alterations and the alterations of bone microstructures that predators induce remain poorly understood. In order to better separate and characterize the effects of bone digestion by owls, we performed an experimental study to simulate digestion by a predator. We put fresh rodent long bones into various solutions to simulate the digestive effects of predators. We first tested an acid solution, followed by other solutions containing key enzymes such as trypsin, lipase, and trypsin + lipase. Next, we compared the results of the simulated digestion experiments with partly digested long bones recovered from Tyto alba and Bubo bubo pellets. We observed that acid action alone did not reproduce the modifications...
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