The Habitat of the Sauropod Dinosaurs

Abstract

In the study of the sauropod dinosaurs which has been carried on by the writer for a number of years under the direction of Professor H. F. Osborn in connection with the preparation of the latter's monograph on these reptiles, some problems have presented themselves upon which a study of the habitat, or immediate environment, has a bearing. The course, or trend, of evolution in a group of organisms is limited, or controlled, by two things: (i) the heritage or assemblage of characters inherited from the ancestors; and (2) the environment. The environment offers the organism opportunities for developing along a limited number of lines. What these lines will be depends upon the general character of the environment. For instance, upon inland plains advanced aquatic adaptations, such as are characteristic of marine organisms, will be barred out, and under strictly marine conditions the development of cursorial locomotor apparatus is impossible. This is true no matter what may be the heritage of the organism under discussion. Within certain limits, however, the environment offers the possibilities or opportunities for evolution along a number of lines. The heritage furnishes the material or instruments by which, or by a modification of which, the organism may evolve along one or more of these lines. In working out adaptations and habits in a group of animals such as the Sauropoda, morphology, together with comparison with living forms, will be the most important guide. Morphological structures have meanings, and if these meanings can be interpreted the habits of the animals possessing the given structures can be determined to a certain extent. A study of the environment of 459

Taphonomy and Paleoecology of the Dinosaur Beds of the Jurassic Morrison Formation

“…His reconstruction favors relatively abundant water in the fluvial systems, but he noted the presence of eolian sands. Mook (1918) clearly preferred an aquatic mode of life for the sauropods, based on his analysis of their geological context.…”

Articulated bone sets of manus and pedes of Camarasaurus (Sauropoda, Dinosauria)

“…Although many geological studies on the Morrison Formation have been undertaken (e.g., Darton, 1906;Mook, 1918;Moberly, 1960;Mirsky, 1962;Carpenter et al, 1998;Ayer, 2000;Michelis, 2004;Turner et al, 2004), long distance correlation between the various sites of the Morrison Formation is still unclear (Trujillo, 2006). Some studies on Morrison Formation stratigraphy included the Howe-Stephens Quarry (e.g., Turner and Peterson, 1999;Ikejiri, 2005), but the relative position reported there was based on a change in clay mineralogy, which was interpreted to be continuous throughout the entire formation.…”