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Rarity of gastroliths in sauropods–study of Late Jurassic Morrison Formation (free pdf)
A new paper in open access:
O. Wings (2015)
The rarity of gastroliths in sauropod dinosaurs – a case study in the
Late Jurassic Morrison Formation, western USA.
Fossil Record 18: 1-16
Occurrences of suspected sauropod geo-gastroliths and "exoliths"
(exotic clasts) are compared with authentic finds of stomach stones in
the sauropods Diplodocus, Cedarosaurus, and Camarasaurus.
Sedimentological and taphonomical evidence from classic sauropod
dinosaur localities in the Late Jurassic Morrison Formation
(Cleveland-Lloyd Dinosaur Quarry, Dry Mesa Dinosaur Quarry, Carnegie
Quarry/Dinosaur National Monument, Howe Quarry, Como Bluff, and Bone
Cabin Quarry) reveals very few sauropod finds with unambiguous
gastroliths. The scarcity of clasts in the fine-grained sediments of
most of the localities suggests that only a small number of sauropods
possessed gastroliths. The occurrence of a hypothetical avian-style
gastric mill in sauropods is not supported by taphonomical evidence.
Exoliths that are abundant in the Early Cretaceous of the western USA
are nearly absent in Late Jurassic sediments. Without an association
with fossil bone, there is no convincing evidence that such clasts
represent former gastroliths. It is more plausible that most exoliths
have been transported in hyperclastic flows or that surface-collected
stones are weathering relicts of former conglomerate layers.