Instead, they are typical in bones dispatched by crocodylians. The bisected pits and punctures observed in the tibia does not match with the heterodont dentition of borhyaenids. Thirteen million years ago, South America was an island continent placental carnivorans have not yet reached its shores, and borhyaenid marsupials occupied niches of large carnivores. These particular marks are usually associated with dismemberment of the carcass by ‘death rolling' or inertial feeding. parabolic depressions, sensu ) are not observed. Parallel scores suggest grasping and dragging but also attempted disarticulation. They are flat-bottomed, roughly parallel between them and transverse to the main axis of the diaphysis. Scavenging usually produces abundant scores and comparatively few scores are rare. The four scores represent only 8.9% of the total number of bite marks. On the anterior surface, at least two serial pits (#1 and 5) are identified. The serial marking was produced by a violent, powerful bite that simultaneously fractured and depressed large areas of the surrounding cortical bone ( figure 1 c). multiple marks inflicted by adjacent teeth in one bite ) along the shaft. Some punctures (#30, 40 and ?45) and pits (#31, 34 and ?37) of the posterior surface comprise a serial marking (i.e. Large punctures are restricted to the posterior side. Most of the tooth marks present on the anterior side of the tibia are relatively small and shallow pits. Bisected pits and punctures are produced by carinated crown teeth of crocodylians and are not recorded in bones modified by mammals. Most often they are round, but some are clearly bisected (e.g. Pits and punctures vary in diameter from 3 (#44) to 15 mm (#30). Five are large punctures that reached the trabecular bone, 36 are shallow pits and four are wide scores. Highly tooth-marked bones probably represent grasping elements during capturing or dismembering. In ( e) and ( f), the white arrows indicate the bisection.įorty-six tooth marks are identified on the shaft of the tibia ( figure 1 c–f electronic supplementary material). In ( c)( iv), grey colour indicates collapsed areas of cortical bone. ( f) Deep, large puncture (#30) of the posterior side. ( e) Shallow, blunt pits (#1,2) of the anterior side. ( d) Transversal, wide score (#11) of the anterior side. (MUSM 1587) and mapping of the bite marks: photograph and schematic drawing in anterior ( i, ii) and posterior ( iii, iv) views. ( c) Left tibia of Pseudoprepotherium sp. ( b) Location of Na069 on the Napo River, northeastern Peru. Reprinted with permission from AAAS), showing the estimated position of locality Na069.
13 Ma) in northwestern South America (from. ( a) The Pebas Mega-Wetland System (approx. The record includes a plethora of fossil evidence, among which crocodylians showed notable disparity and diversity.
Several lignitic localities of the Pebas Formation near the Peruvian city of Iquitos have yielded geological and palaeontological data regarding the life within this vast complex of lakes and swamps, named the Pebas Mega-Wetland System. This animal exceeded 10 m long and inhabited South America during the middle and late Miocene ( ca 13–6 Ma), when a system of wetlands flourished in northwestern Amazonia ( figure 1 a). This discovery from the Peruvian Amazonia provides an unusual snapshot of the dietary preferences of Purussaurus and reveals that prior to reaching its giant size, young individuals might have fed upon terrestrial mammals of about the size of a capybara.įollowing the extinction of non-avian dinosaurs, the largest Cenozoic continental predator was neither a mammal nor a bird, but the giant caiman Purussaurus.
The pattern of tooth marks suggests that the perpetrator attacked and captured the ground sloth from the lower hind limb, yet an attempt of dismembering cannot be ruled out. Other known crocodylians of the Pebas System were either too small at adulthood or had discordant feeding anatomy to be considered. The combination of round and bisected, shallow pits and large punctures that collapsed extensive portions of cortical bone points to a young or sub-adult Purussaurus (approx. Here, we report a tibia of the mylodontid sloth Pseudoprepotherium bearing 46 predation tooth marks. In these Miocene swamps where reptiles and mammals coexisted, evidence of their agonistic interactions is extremely rare. Thirteen million years ago in South America, the Pebas Mega-Wetland System sheltered multi-taxon crocodylian assemblages, with the giant caiman Purussaurus as the top predator.
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