{"pk":41719,"title":"Faunal change in Cretaceous endemic shallow-marine bivalve genera/subgenera of the northeast Pacific","subtitle":null,"abstract":"Endemic shallow-marine Cretaceous bivalves in the northeast Pacific region (NEP), extending from southwestern Alaska to the northern part of Baja California Sur, Mexico, are tabulated and discussed in detail for the first time. Twenty-three genera/subgenera are recognized. Their first appearance was in the Valanginian, and their biodiversity continued to be very low during the rest of the Early Cretaceous. The bivalves of the middle Albian Alisitos Formation in northern Baja California are excluded because they did not live in the NEP. The highest number (13) of NEP endemic bivalve genera/subgenera occurred during the Turonian, which was the warmest time of the Cretaceous. At the Turonian/Coniacian boundary, when cooler waters migrated southward, there was a moderate dropoff in endemics that persisted until an origination event near the beginning of the early Maastrichtian, when 11 were present. Five of the 11 were present also during the Turonian, but the others were newcomers. Only three survived the turnover associated with the “Middle Maastrichtian Event” (MME), and none survived the K/Pg boundary mass-extinction event.","language":"en","license":{"name":"Creative Commons Attribution-NonCommercial-ShareAlike 4.0","short_name":"CC BY-NC-SA 4.0","text":"<p><!-- x-tinymce/html --></p>\n<p>Readers are free to:</p>\n<ul>\n<li><strong>Share</strong> — copy and redistribute the material in any medium or format</li>\n<li><strong>Adapt</strong> — remix, transform, and build upon the material<br><br>The licensor cannot revoke these freedoms as long as you follow the license terms.</li>\n</ul>\n<p>Under the following terms:</p>\n<ul>\n<li><strong>Attribution</strong> — You must give appropriate credit , provide a link to the license, and indicate if changes were made . You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.</li>\n<li><strong>NonCommercial</strong> — You may not use the material for commercial purposes .</li>\n<li><strong>ShareAlike</strong> — If you remix, transform, or build upon the material, you must distribute your contributions under the same license as the original.<br><br>No additional restrictions — You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.</li>\n</ul>\n<p>Notices:</p>\n<p>You do not have to comply with the license for elements of the material in the public domain or where your use is permitted by an applicable exception or limitation.</p>\n<p>No warranties are given. The license may not give you all of the permissions necessary for your intended use. For example, other rights such as publicity, privacy, or moral rights may limit how you use the material.</p>","url":"https://creativecommons.org/licenses/by-nc-sa/4.0"},"keywords":[{"word":"biodiversity, Carditida, Myida, Mytilida, origination, Trigoniida, turnover, Venerida"}],"section":"Article","is_remote":true,"remote_url":"https://escholarship.org/uc/item/3830h29g","frozenauthors":[{"first_name":"Richard","middle_name":"L.","last_name":"Squires","name_suffix":"","institution":"Professor Emeritus, Department of Geological Sciences, California State University, 18111 Nordhoff Street, Northridge, California, 91330-8266, USA; Research Associate, Invertebrate Paleontology, Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, California, 90007, USA.","department":"None"}],"date_submitted":"2020-05-19T23:58:28Z","date_accepted":"2020-05-19T23:58:28Z","date_published":"2020-05-19T07:00:00Z","render_galley":null,"galleys":[{"label":"","type":"pdf","path":"https://journalpub.escholarship.org/ucmp_paleobios/article/41719/galley/31207/download/"}]}