150323 20251017144612.0 doi 10.1016/j.palaeo.2021.110526 sideral 125859 ART-2021-125859 eng Moreno-Azanza M. (orcid)0000-0002-7210-1033 Recognizing a lost nesting ground: First unambiguous Testudines eggshells from the Eocene, associated with the pleurodiran Eocenochelus (Huesca, Northern Spain) 2021 Access copy available to the general public Unrestricted The Eocene record of turtle eggshells is scarce, with a single unconfirmed report from France. This scarcity contrasts with the great abundance of osteological remains, distributed over a wide palaeogeographical range as a result of climatic warmth. In this paper, we describe the first definitive Eocene Testudoolithidae eggshell fragments attributable to Testudines, most likely pleurodiran turtles, from the Eocene Sobrarbe Formation at the Castejón de Sobrarbe fossil site (CS-41) in northern Spain. The eggshells were found in association with osteological remains of at least four individuals of Eocenochelus eremberti (Pleurodira, Erymnochelyini) in an otherwise sirenian-dominated bonebed. Analysis of eggshell ultra- and microstructure allows comparison with eggshells from fossil and extant turtles. The eggshells are highly recrystallized but preserve relics of their original aragonitic radial ultrastructure as crystal phantoms. The barrel-shaped shell units, which are taller than wide, with compactituberculate ornamentation and funnel-shaped pore openings are similar to those of the Palaeocene ootaxon Haininchelys curiosa, whose holotype and paratype have been lost. The CS-41 eggshells are most similar to those of the pleurodiran Erymnochelys madagascariensis from Madagascar, the closest living relative to Eocenochelus, further supporting our attribution. Sedimentological and taphonomic analysis of the assemblage supports the hypothesis that the CS-41 fossil site was formed as the infilling of an abandoned tributary channel in the deltaic plain by an overbank or debris-flow deposit associated with a storm event. This storm resulted in the exhumation and subsequent re-sedimetation of the remains of a nesting ground of Eocenochelus eremberti, an otherwise coastal turtle, which would have entered inland streams to nest in the sand bars at the mouth of the Sobrarbe Deltaic Complex. © 2021 Elsevier B.V. info:eu-repo/grantAgreement/ES/DGA/E18-17R info:eu-repo/grantAgreement/ES/MINECO/CGL2013-47521-P info:eu-repo/grantAgreement/ES/MINECO/CGL2017-85038-P info:eu-repo/semantics/openAccess by-nc-nd https://creativecommons.org/licenses/by-nc-nd/4.0/deed.es 3.565 2021 PALEONTOLOGY 2 / 54 = 0.037 2021 Q1 T1 GEOGRAPHY, PHYSICAL 22 / 50 = 0.44 2021 Q2 T2 GEOSCIENCES, MULTIDISCIPLINARY 78 / 202 = 0.386 2021 Q2 T2 1.076 2021 Earth-Surface Processes 2021 Q1 Paleontology 2021 Q1 Ecology, Evolution, Behavior and Systematics 2021 Q1 5.7 2021 info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion Díaz-Berenguer E. Universidad de Zaragoza Silva-Casal R. Pérez-García A. Badiola A. Canudo J.I. Universidad de Zaragoza (orcid)0000-0003-1732-9155 2000 655 Universidad de Zaragoza Dpto. Ciencias de la Tierra Área Paleontología 576 (2021), 110526 [15 pp] Palaeogeogr. palaeoclimatol. palaeoecol. PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY 0031-0182 1843207 http://zaguan.unizar.es/record/150323/files/texto_completo.pdf Postprint 936362 http://zaguan.unizar.es/record/150323/files/texto_completo.jpg?subformat=icon icon Postprint oai:zaguan.unizar.es:150323 articulos driver 2025-10-17-14:17:45 ARTICLE