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Nautilid nurseries: hatchlings and juveniles of Eutrephoceras dekayi from the lower Maastrichtian (Upper Cretaceous) Pierre Shale of east‐central Montana

2017; Wiley; Volume: 51; Issue: 1 Linguagem: Inglês

10.1111/let.12222

1502-3931

Neil H. Landman, James W. Grier, J. Kirk Cochran, Joyce C. Grier, Jack G. Petersen, Henry Towbin,

Aquatic Invertebrate Ecology and Behavior

LethaiaVolume 51, Issue 1 p. 48-74 Original Article Nautilid nurseries: hatchlings and juveniles of Eutrephoceras dekayi from the lower Maastrichtian (Upper Cretaceous) Pierre Shale of east-central Montana Neil H. Landman, Neil H. Landman landman@amnh.org orcid.org/0000-0003-0038-8079 Division of Paleontology (Invertebrates), American Museum of Natural History, Central Park West at 79th Street, New York, NY, 10024 USASearch for more papers by this authorJames W. Grier, James W. Grier james.grier@ndsu.edu Department of Biological Sciences, North Dakota State University, Fargo, ND, 58102 USASearch for more papers by this authorJ. Kirk Cochran, J. Kirk Cochran kirk.cochran@stonybrook.edu School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, 11794-5000 USASearch for more papers by this authorJoyce C. Grier, Joyce C. Grier jcgrier@earthlink.net 7648 57th Ave. N, Hawley, MN, 56549 USASearch for more papers by this authorJack G. Petersen, Jack G. Petersen jcgrier@earthlink.net 1256 Hammond Ave., Waterloo, IA, 50702 USASearch for more papers by this authorW. Henry Towbin, W. Henry Towbin whtowbin@gmail.com Interdepartmental Facility for Imaging and Technology, American Museum of Natural History, Central Park West at 79th Street, New York, NY, 10024 USASearch for more papers by this author Neil H. Landman, Neil H. Landman landman@amnh.org orcid.org/0000-0003-0038-8079 Division of Paleontology (Invertebrates), American Museum of Natural History, Central Park West at 79th Street, New York, NY, 10024 USASearch for more papers by this authorJames W. Grier, James W. Grier james.grier@ndsu.edu Department of Biological Sciences, North Dakota State University, Fargo, ND, 58102 USASearch for more papers by this authorJ. Kirk Cochran, J. Kirk Cochran kirk.cochran@stonybrook.edu School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, 11794-5000 USASearch for more papers by this authorJoyce C. Grier, Joyce C. Grier jcgrier@earthlink.net 7648 57th Ave. N, Hawley, MN, 56549 USASearch for more papers by this authorJack G. Petersen, Jack G. Petersen jcgrier@earthlink.net 1256 Hammond Ave., Waterloo, IA, 50702 USASearch for more papers by this authorW. Henry Towbin, W. Henry Towbin whtowbin@gmail.com Interdepartmental Facility for Imaging and Technology, American Museum of Natural History, Central Park West at 79th Street, New York, NY, 10024 USASearch for more papers by this author First published: 22 June 2017 https://doi.org/10.1111/let.12222Citations: 13Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Abstract The nautilid Eutrephoceras dekayi (Morton 1834) is relatively abundant in the lower Maastrichtian (Upper Cretaceous) Pierre Shale of east-central Montana. We analysed the morphology, size frequency distribution, and isotope composition of a large collection of 220 well-preserved specimens including hatchlings, juveniles and adults. The newly hatched shell is approximately 14 mm in diameter with a body chamber one-third whorl in angular length terminating in the nepionic constriction. Internally, the embryonic shell contains five septa. Juveniles are abundant and comprise two-thirds of the sample whereas sub-adults, defined by the incipient flattening of the venter, are rare. Adults comprise approximately one-third of the sample and average 100 mm in diameter. The co-occurrence of newly hatched shells, small juveniles and adults suggests that the eggs were laid in the same area in which the hatchlings developed. Based on the excellent preservation of the juveniles, we conclude that they did not float into the area after death, but lived in the region, implying that this area served as a nursery for young animals. The calculated temperatures of the embryonic shells are similar to those of the post-embryonic shells and generally range from 16 to 18 °C. Upon hatching, the nautilids probably followed a demersal mode of life and lived in well-oxygenated water ≤50 m deep. An examination of lethal injuries (puncture holes) suggests that all ontogenetic stages were equally vulnerable to predation. The proximity of the site to the Sheridan Delta suggests that the specimens were smothered by sudden pulses of sediment transported into the area by major storms. Citing Literature Volume51, Issue1January 2018Pages 48-74 RelatedInformation