Lawver, Daniel R.Jackson, Frankie D.2017-04-132017-04-132017-01Lawver, Daniel R, and Frankie D Jackson. "An accumulation of turtle eggs with embryos from the Campanian (Upper Cretaceous) Judith River Formation of Montana." Cretaceous Research 69 (January 2017): 90-99. DOI:https://dx.doi.org/10.1016/j.cretres.2016.08.012.0195-6671https://scholarworks.montana.edu/handle/1/12720A weathered accumulation of turtle eggs, interpreted as remnants of a single clutch composed of at least 16 turtle eggs (MOR 710) from the Campanian (Upper Cretaceous) Judith River Formation of north-central Montana, USA, represents a new oospecies Testudoolithus zelenitskyae. This ootaxon is diagnosed by the following unique combination of characters: spherical eggs 34–39 mm in diameter, 660–760 μm thick eggshell, shell unit height-to-width ratio of 3.15:1–5.5:1, and domed shell units. Estimated egg mass indicates that the egg-laying adult likely possessed a carapace 35.0–54.4 cm in length. Similarities between T. zelenitskyae oosp. nov. and Adocus sp. eggs, along with comparable body size, suggest that this taxon might have produced MOR 710. One egg exhibits abnormal multilayered eggshell, likely resulting from prolonged egg retention by the female turtle. At least five of these eggs, including the multilayered specimen, preserve embryonic remains that demonstrate a late stage of embryonic development. This suggests that death occurred just prior to hatching.en-US"NOTICE: this is the author’s version of a work that was accepted for publication in Cretaceous Research. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Cretaceous Research, 69, (2017), https://dx.doi.org/10.1016/j.cretres.2016.08.012"Article