Quick Facts

Plesiosaur bonebed


 

Nickname: "TMBB"
Discovery Central Montana
Diet: Various
Period: Late Cretaceous
Age: 75 million years
Formation: Judith River
Length: Various
Location of Original Specimens: RMDRC, Woodland Park, CO

Discovered and collected in 2004, this site is truly remarkable. There were over 300 bones recovered, belonging to both Elasmosaurs (long neck plesiosaurs) and Polycotylids (short necked plesiosaurs), adult and juvenile material together. There were also bones from an assortment of different animals including Champsosaurus (relative of a crocodile), Sharks, Enchodus (AKA the sabre toothed herring), two species of mosasaur, and even meat eating dinosaurs.

Pictures

The X-acto knife points to a plesiosaur vertebra in the rock. There are two more in the upper left area of the photo.


Another plesiosaur vertebra in the rock. The neural arch is missing, and most bones show some evidence of transport by water. Most likely the site was fluvial (river sistem). Were the plesiosaurs swimming upstream to give birth?


The site sloped down steeply from the crest of this hill. During the day, the small trees to the right were the only sources of shade.

A plesiosaur scapula (shoulder blade) after preparation.


This cervical (neck) vertebra shows the shape typical of Elasmosaurs.


Field Notes

Digging at the site commenced in 2004, and continued during the summer. At the end of field season it looked like there was still much to uncover, however that turned out to be false. When the crew returned to the site in June 2005, a half day's dig by four people turned up just one more vertebra.

Lab Notes

Preparation is finished, and we made some very interesting discoveries. The sandstone was very hard, and because of the jumbled nature of the material, progress was slow. There are enough pieces of juvenile plesiosaurs in this bonebed, that we may attempt a reconstruction of a small (3 foot long) individual in the future. The original material is awaiting study.