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The ability to distinguish between the taphonomic patterns inflicted by different carnivore taxa in the fossil record is currently underdeveloped. Previous efforts to identify taxon-specific taphonomic damage to prey bones inflicted by larger felids have largely focused on tooth marks. Recent work, however, which considers patterns of chewing damage are only beginning to yield methods that can consistently distinguish between species, or even families, of large predators. Here we present a new low-cost, low-tech, semi-quantitative method for coding carnivore-inflicted chewing damage patterns using a basic 5-stage scale (0 = no damage, 1 = tooth marks only, 2 = minimal chewing damage, 3 = moderate chewing damage, 4 = severe chewing damage, fragmentation, or destruction), including a photographic guide to different levels of bone damage inflicted on different skeletal elements and portions. An independent test of this method by three experienced taphonomic analysts indicates that this method is easy to use and results in consistent data across analysts. We also apply this method to document and describe the intensity of damage that free-ranging African lions inflicted on a sample of zebra bones. This method can be used in conjunction with efforts to distinguish taxon-specific tooth mark shapes or patterns to more confidently infer the identity of different predators based on their chewing damage.
This study includes the first neoichnologic characterization of the burrow systems of Tympanoctomys barrerae (Rodentia: Octodontidae) and also considers sedimentologic features of the modern nebkhas where they occur. Tympanoctomys is a South American solitary and fossorial rodent that has ecomorphofunctional adaptations for living in saline environments and constructs its burrow in nebkhas with halophyte shrubs. The purpose of this work is to identify the ichnologic signatures of T. barrerae burrow systems and to provide combined ichnologic-sedimentologic criteria for identification of Cenozoic nebkha deposits. Tympanoctomys barrerae burrow systems are subhorizontal, typically with ten or more entrances, two or three levels, closed circuits, average complexity of 48, average tortuosity of 3.25, and an average ratio of total chamber volume to total tunnel volume of 0.04. The size of the tunnels averages 85 mm in horizontal diameter and 64 mm in vertical diameter, and cross-section shape ranges from elliptical flattened to plano-convex with incipient bilobed floor. Surface ornamentation is typified by a coexistence of primary (sets of four claw traces forming an arcuate pattern produced during digging) and secondary (numerous arthropod burrows excavated from the burrow lumen) surface ornamentation. Nebkha deposits in upper Cenozoic sequences can be recognized by the combination of ichnologic and sedimentologic features: fossil burrows having the ichnologic features characteristic of T. barrerae burrow systems and presence of rhizoliths of shrubby plants occurring in well-sorted sandy deposits with low-angle crossbedding. These criteria can be potentially applied to fossil sequences dating back to the early Oligocene.
Seeds are plant organs commonly found worldwide in late Paleozoic deposits. In Gondwana, the seeds are found in deposits from Southern Africa, Antarctica, Oceania, and South America, and are widely reported in the well-known “Glossopteris Flora”. Even with a significant record of these plant organs, little is known about plant-insect interactions with seeds during the Pennsylvanian and Permian periods. In the present paper, we recorded the first formal record of seed consumption by arthropods in Cordaicarpus and Samaropsis-like seeds for Gondwana from lower Permian (Artinskian) deposits in Southern Brazil. The material analyzed was collected from the Itanema II outcrop of Santa Catarina State and consisted of 34 seed specimens. Of these, eight specimens presented evidence for plant-insect interaction, representing 23.5% of all specimens that were attacked by seed predators. The consumption was inflicted by insects with stylate mouthparts, probably belonging to hemipteroid or paleodictyopteroid lineages. The damage is described as perforations and scale-insect marks along the seed body. We recorded one damage type as DT74 and three others as new damage types DT399, DT400, and DT401, some of which are specific to a few seed morphotypes, including one morphotype with subtending cupule still attached to the seed. The elevated frequency of seed predation indicates that seed consumption by insects was well established during the early Permian.