First report of fossil turtle eggshell west of the Colorado Plateau
| Autor: | Ashley W. Poust |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
0106 biological sciences
010506 paleontology biology Colorado plateau biology.organism_classification Width ratio 010603 evolutionary biology 01 natural sciences Hesperotestudo law.invention Paleontology law Carapace Eggshell Turtle (robot) General Agricultural and Biological Sciences Geology 0105 earth and related environmental sciences |
| Zdroj: | Historical Biology. 29:473-479 |
| ISSN: | 1029-2381 0891-2963 |
| DOI: | 10.1080/08912963.2016.1189911 |
| Popis: | The first fossil turtle eggshell from North America west of the Colorado Plateau (UCMP 218504) is described, adding to the growing global record of chelonian eggshell. Ten blocks of mudstone were collected from the Upper Miocene (Clarendonian) Orinda Formation, Contra Costa County, California, during the excavation of the Caldecott Tunnel Fourth Bore. They contain rigid eggshell averaging 500 μm in thickness. Closely packed shell units with a height/width ratio of 2:1 are composed of radiating, acicular crystals originating from a basal core, a set of characters that support the identification of the eggshell as chelonian, and further as testudinoid. Egg diameter is estimated at between 34.2 and 42.4 mm based on shell curvature. Adult carapace length is estimated to be 70.7 cm, a size similar to fossils of Hesperotestudo known from California and present in the Orinda Formation. UCMP 218504 greatly extends the geographic record of turtle fossil eggshell and adds to the limited number of mid-Neogen... |
| Databáze: | OpenAIRE |
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