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Poster De Conférence Année : 2015

Reality or fantasy? Assessing the condition of fossil specimens with CT data

Résumé

Fossil specimens collected decades, or even centuries ago, are still critically important to modern scientific study. Unfortunately, the preparatory history of these specimens is commonly unrecorded, leading to confusion over morphological features. An excellent example is found in Simocyon primigenius, the type species of the genus Simocyon. This genus is closely related to the red panda (Ailurus fulgens) and lived during the Middle Miocene to the Early Pliocene in North America, Europe, and Asia. The holotype of S. primigenius is a skull with associated lower jaws from the Turolian (Late Miocene) deposits of Pikermi, Greece, and is stored at the Bavarian State Collection of Palaeontology and Geology, Munich. In addition to lateral deformation during fossilization, this holotype has several parts superficially filled by artificial material which partially hide its original morphology. We obtained high resolution three-dimensional data of the holotype using a CT scanner. We were able to identify clear density differences between not only the bone and matrix, but also the reconstructed anatomy – which was impossible to differentiate externally from bone by macroscopy. Artificial fillings are found in the right parietal and temporal (4-5 cm in certain areas), the dorsal premaxilla, nasals, maxilla, most of the left zygomatic arch (temporal), and the left upper and lower canines. As these elements do not constitute original anatomy of this holotype, their potential impact on former systematic studies needs to be checked and future use of the specimen in fossil comparisons, identifications, or studies of the intraspecific variation of Simocyon requires selective evaluation. An additional example for which CT data unravel the past history of fossils can be found in the holotype of Sinopa lania (Creodonta) AMNH 13142, from the middle Bridgerian NALMA (middle Eocene) of southwestern Wyoming. The anterior rostrum and palate of this specimen has been filled in with artificial material, sculpted and colored in various areas to closely resemble natural bone. CT scanning not only revealed the large extent of artificial material, but also revealed that the left upper incisors were buried within this material. As this is the only skull this increases our morphological knowledge of this taxon. Our study thus highlights the importance of CT data for assessing preservation status of specimens and investigating their history from the point of discovery in the field to their management in museum collections.
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Dates et versions

hal-03608981 , version 1 (15-03-2022)

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  • HAL Id : hal-03608981 , version 1

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Camille Grohé, Gertrud E Rössner, Michelle Spaulding. Reality or fantasy? Assessing the condition of fossil specimens with CT data. 75th Society of Vertebrate Paleontology, Oct 2015, Dallas, United States. ⟨hal-03608981⟩
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