Cedarosaurus weiskopfae

Etymology: "Weiskopf's Cedar Mountain lizard" (after the Cedar Mountain Formation in Utah and "for the Late Carol Weiskopf for her hard work in the field and lab")

Time horizon: Early Cretaceous, Barremian epoch (~126 mya)

Length: ~16m (~53 ft.)

Probable mass: 17 tons, perhaps more based on maturity


The slender brachiosaur known as Cedarosaurus is a subadult specimen, so how large the adults got is anyone's guess. We do know that it was native to the Yellow Cat Member of the Cedar Mountain Formation, and thus making it a few million years older than the basal somphospondylian Venenosaurus. Its vertebrae and limbs closely resemble those of English brachiosaurs from around the same time, such as Eucamerotus and Pelorosaurus (most of which are also known from mid-sized immature specimens)

Cedarosaurus is known from a type specimen (shown here) and possibly also a referred foot described by d'Emic (2013), although this could belong to any number of cretaceous brachiosaur species. Cedarosaurus overall appears to follow the classic "Abydosaurine" body plan of most Cretaceous brachiosaurs, with a compact torso, slender limbs, "perky" neural spines tilted forward relative to the articulation axis of the centrum, and overall taller neural arches on the dorsals than in most Jurassic brachiosaurs. This tendency towards taller arches, which translates to a more elevated ribcage and a wider back, was also evolved independently in somphospondylians, eventually culminating in the extreme dorsals of the Acrofornica like Phuwiangosaurus, whose vertebrae were nearly 70% neural arch and almost NO neural spine.

Also notable was the discovery of 115 "clasts" or gastroliths in the stomach region, which are worn smooth by internal grinding and acid-etching just like in other sauropods. Unusually, some of these stones actually contained fossils of small plants and invertebrates that were already ancient and long-dead when the Cedarosaurus swallowed them. For a long time gastroliths were only known from diplodocids, and it was unknown whether brachiosaurs swallowed stones to grind food in their stomachs. Their teeth, more massive and numerous than those of diplodocids, seemed to argue against this, but the discovery of these belly-stones with Cedarosaurus shows that the animal still swallowed its food with a minimum of biting or chewing. Even the toothy mouths of brachiosaurs were primarily designed for hacking through branches, not actually chewing the food.

I was unable to locate any good information about the late Carol Weiskopf, the species' namesake, other than that she was probably one of Dr. Bakker's eponymous "museum people" toiling long hours with little recognition in the vaults and specimen labs, who are "always overworked, always underpaid, and they deserve sainthood, each and every one".

This image has also been credited as inspiration by:
spinoinwonderland.deviantart.c…


REFERENCES:

d’Emic, Michael D. (2013). "Revision of the sauropod dinosaurs of the Lower Cretaceous Trinity Group, southern USA, with the description of a new genus". Journal of Systematic Palaeontology 11 (6): 707–726.

Sanders, F.; Manley, K.; Carpenter, K. (2001). "Gastroliths from the Lower Cretaceous sauropod Cedarosaurus weiskopfae". In Tanke, Darren; Carpenter, Ken. Mesozoic Vertebrate Life: New Research Inspired by the Paleontology of Philip J. Currie. Indiana University Press. pp. 166–180.

Tidwell, V., Carpenter, K. and Brooks, W. (1999). "New sauropod from the Lower Cretaceous of Utah, USA". Oryctos 2: 21-37

Tidwell, V., Carpenter, K. & Meyer, S. 2001. New Titanosauriform (Sauropoda) from the Poison Strip Member of the Cedar Mountain Formation (Lower Cretaceous), Utah. In: Mesozoic Vertebrate Life. D. H. Tanke & K. Carpenter (eds.). Indiana University Press, Eds. D.H. Tanke & K. Carpenter. Indiana University Press. 139-165.