A Plesiosaur Containing an Ichthyosaur Embryo as Stomach Contents from the Sundance Formation of the Bighorn Basin, Wyoming

  title={A Plesiosaur Containing an Ichthyosaur Embryo as Stomach Contents from the Sundance Formation of the Bighorn Basin, Wyoming},
  author={F. Robin O'Keefe and Hallie Street and Jean Pierre Cavigelli and John J. Socha and R O'keefe},
Herein we report the discovery of an ichthyosaur embryo from the Upper Member of the Sundance Formation (Oxfordian) of the Bighorn Basin, Wyoming. The specimen is the first known ichthyosaur embryo from the Upper Jurassic, and is the first Jurassic ichthyosaur embryo from North America. The embryo was discovered in close association with the abdomen of an articulated partial plesiosaur skeleton, and several lines of evidence support the interpretation of the embryo as plesiosaur stomach… 

Palaeoecology of the marine reptiles of the Redwater Shale Member of the Sundance Formation (Jurassic) of central Wyoming, USA

Abstract The Redwater Shale Member (Oxfordian) of the Sundance Formation was deposited in the foreland basin of the Cordillera during the last and largest marine transgression of the Jurassic in

The youngest occurrence of ichthyosaur embryos in the UK: A new specimen from the Early Jurassic (Toarcian) of Yorkshire.

The remains of between six and eight ichthyosaur embryos, still situated within a fragment of the rib-cage of the parent animal, are described. Each is represented by a string of vertebral centra,

Ichthyosaurs from the Jurassic of Skye, Scotland

Fossils of Mesozoic vertebrates are rare in Scotland, particularly specimens of marine reptiles such as plesiosaurs and ichthyosaurs. We describe a suite of ichthyosaur fossils from the Early to

A New Partial Skeleton of a Cryptocleidoid Plesiosaur from the Upper Jurassic Sundance Formation of Wyoming

These specimens represent the first significant adult material provisionally referable to Pantosaurus striatus, as well as the first posterior axial column and pelvic girdle from the Bighorn Basin of Wyoming.

Gastroliths associated with a juvenile elasmosaur (Plesiosauria, Elasmosauridae) from the Snow Hill Island Formation (upper Campanian–lower Maastrichtian), Vega Island, Antarctica

José P. O'Gorman, Eduardo Olivero & Daniel A. Cabrera. December 2012. Gastroliths associated with a juvenile elasmosaur (Plesiosauria, Elasmosauridae) from the Snow Hill Island Formation (upper

Piscivory in a Miocene Cetotheriidae of Peru: first record of fossilized stomach content for an extinct baleen-bearing whale

This fossil record corresponds to one of the geologically oldest records of Sardinops worldwide, occurring near the Tortonian peak of oceanic primary productivity and cooling phase, and evokes a link between the rise of Cetotheriidae; the setup of modern coastal upwelling systems; and the radiation of epipelagic, small-sized, schooling clupeiform fish in such highly productive environments.

Viviparity and K-Selected Life History in a Mesozoic Marine Plesiosaur (Reptilia, Sauropterygia)

Quantitative analysis indicates that plesiosaurs gave birth to large, probably single progeny, and the combination of viviparity, large offspring size, and small brood number differs markedly from the pattern seen in other marine reptiles but does resemble the K-selected strategy of all extant marine mammals and a few extant lizards.

In utero foetal remains of the Cretaceous ichthyosaurian Platypterygius: ontogenetic implications for character state efficacy

Ontogenetic continuity amongst the majority of other phylogenetically pertinent skeletal structures advocates their application for cladistic analyses, and suggests that many classic characters used to differentiate Platypterygius remain diagnostic irrespective of growth stage.

Dietary palaeoecology of an Early Cretaceous armoured dinosaur (Ornithischia; Nodosauridae) based on floral analysis of stomach contents

Details of the dietary palaeoecology of this nodosaur are revealed, including: selective feeding on ferns to the exclusion of Osmundaceae and eusporangiate f Ferns such as Marattiaceae; and incidental consumption of cycad–cycadophyte and conifer leaves.




Abstract:  A new fauna of Lower Cretaceous (Albian) ichthyosaurs, which includes at least one new genus and species, was recovered from deposits of the Loon River Formation at Hay River, Northwest

Preliminary Report on the Osteology and Relationships of a New Aberrant Cryptocleidoid Plesiosaur from the Sundance Formation, Wyoming

The cryptocleidoid plesiosaur Taktwcflts laram.eruiS, new genus, is described from the Redwater Shale: Member of the Sundance fonnation. Narrona County, Wyommg.. The bolotypc of this species was a

An Elasmosaur with Stomach Contents and Gastroliths from the Pierre Shale (Late Cretaceous) of Kansas

Abstract A nearly complete skeleton of an elasmosaurid plesiosaur (NJSM 15435) from the Sharon Springs Member (Middle Campanian) of the Pierre Shale, Logan County, Kansas, is associated intimately

The Reptilia of the Baptanodon beds

THE Baptanodoll beds fot'm a distinct horizon in the Jurassic of the Rocky monntain region, their position being just above the red Triassic sandstones, on which they rest nnconformably, and

First record of live birth in Cretaceous ichthyosaurs: closing an 80 million year gap

  • E. MaxwellM. Caldwell
  • Environmental Science, Geography
    Proceedings of the Royal Society of London. Series B: Biological Sciences
  • 2003
New fossils of embryonic ichthyosaurs are both the geologically youngest and the physically smallest known ichysosaur embryos, and are located within the body cavity of an adult, presumably the mother.


We report the rediscovery of Wilbur Knight’s 1895 excavation site of the large Jurassic (Oxfordian) pliosaur Megalneusaurus rex from the Sundance Formation. The type specimen (UW4602) is housed at

A review of gastrolith function with implications for fossil vertebrates and a revised classification

The definitions and ascribed functions of gastroliths are reviewed and the term “exolith” is introduced for isolated clasts with a possible history as geo−gastroliths.

Middle Jurassic (Bajocian and Bathonian) Dinosaur Megatracksites, Bighorn Basin, Wyoming, U.S.A

Abstract Two previously unknown rare Middle Jurassic dinosaur megatracksites are reported from the Bighorn Basin of northern Wyoming in the Western Interior of the United States. These trace fossils

Bottom-Feeding Plesiosaurs

Two elasmosaurid specimens from Aptian and Albian deposits in Queensland, Australia, include fossilized gut contents dominated by benthic invertebrates: bivalves, gastropods, and crustaceans, which point to a wider niche than has previously been supposed for these seemingly specialized predators.

A Descriptive Catalogue of the Marine Reptiles of the Oxford Clay

THE scientific value of the remains obtained by Messrs. Leeds from the Oxford Clay near Peter-borough is exemplified by the groups forming the subject of the present, and concluding, volume of this