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GEOREF RECORD

Alamosaurus and the sauropod hiatus in the Cretaceous of the North American Western Interior

Spencer G. Lucas and Adrian P. Hunt
Alamosaurus and the sauropod hiatus in the Cretaceous of the North American Western Interior (in Paleobiology of the dinosaurs, James O. Farlow (editor))
Special Paper - Geological Society of America (1989) 238: 75-85

Abstract

Sauropod dinosaurs have a temporally disjunct distribution in the North American Western Interior during Cretaceous time, here referred to as the sauropod hiatus. Sauropod body and ichnofossils are present in inland basinal and coastal deposits of Aptian-Albian age in Wyoming, Texas, Oklahoma, and Arkansas. Body fossils of sauropods (the titanosaurid Alamosaurus) occur in inland basinal deposits of Maastrichtian age in Texas, New Mexico, Utah, and Wyoming. No sauropods of Cenomanian-Campanian age are known from a Western Interior sedimentary record dominated by coastal deposits and essentially devoid of inland basinal deposits. Dinosaur ichnofaunas from late Albian coastal deposits in New Mexico, Oklahoma, and Colorado lack sauropod footprints, and thus suggest sauropod disappearance from Western Interior coastal environments by the end of Early Cretaceous time. These observations suggest two scenarios: (1) sauropods abandoned Western Interior coastal environments at the end of the Albian, but persisted in Western Interior inland basinal environments throughout Cretaceous time, or (2) sauropods became extinct in the Western Interior at the end of the Albian and reinvaded during the Maastrichtian. Choosing between these scenarios depends on an evaluation of negative evidence. However, the close phylogenetic relationship of Alamosaurus to South American titanosaurids, the absence of sauropod fossils in inland deposits of the Campanian Two Medicine and Judith River Formations, and the availability of a dispersal route between North and South America near the end of Cretaceous time support the second scenario. Thus, sauropods apparently became extinct in the Western Interior near the end of the Albian, then reinvaded from South America during the Maastrichtian but were only able to establish themselves in inland basinal environments. The extinction of sauropods in the Western Interior at the end of Early Cretaceous time may reflect an unrecognized terrestrial extinction coincident with the well-known severe marine extinction caused by a major late Albian regression.


ISSN: 0072-1077
EISSN: 2331-219X
Coden: GSAPAZ
Serial Title: Special Paper - Geological Society of America
Serial Volume: 238
Title: Alamosaurus and the sauropod hiatus in the Cretaceous of the North American Western Interior
Title: Paleobiology of the dinosaurs
Author(s): Lucas, Spencer G.Hunt, Adrian P.
Author(s): Farlow, James O.editor
Affiliation: N.M. Mus. Nat. Hist., Albuquerque, NM, United States
Affiliation: Indiana Univ.-Purdue Univ. at Fort Wayne, Dep. Earth and Space Sci., Fort Wayne, IN, United States
Pages: 75-85
Published: 1989
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
ISBN: 0-8137-2238-1
References: 57
Accession Number: 1989-073313
Categories: Stratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. charts, sketch maps
N33°00'00" - N36°30'00", W94°40'00" - W89°40'00"
N37°00'00" - N41°00'00", W109°00'00" - W102°00'00"
N31°30'00" - N37°00'00", W109°04'60" - W103°00'00"
N33°34'60" - N37°00'00", W103°00'00" - W94°25'00"
N25°45'00" - N36°30'00", W106°30'00" - W93°30'00"
N37°00'00" - N42°00'00", W114°04'60" - W109°04'60"
N41°00'00" - N45°00'00", W111°04'60" - W104°04'60"
Secondary Affiliation: Univ. N.M., USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from Bibliography of Fossil Vertebrates, Society of Vertebrate Paleontology, Berkeley, CA, United States
Update Code: 1989
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