PREPARATION TECHNIQUES APPLIED TO A STEGOSAURIAN DINOSAUR FROM PORTUGAL

Abstract

General vertebrate paleontological techniques that have been used in the Museum of Lourinhã (Portugal) are presented here, in particular those applied to a stegosaurian dinosaur skeleton, Miragaia longicollum. A monolith jacket technique using polyurethane foam and plaster is presented. Mechanical preparation techniques combining the use of an electric grinder and airscribes proved effective during the initial phases of preparation on well-preserved bone embedded in hard matrix. We also present a technique to mould monoliths in the early stages of preparation, creating a thin silicone rubber mould in several contiguous parts. To mould and cast monoliths before removing individual bones has proven valuable for the preservation of taphonomic data and for display purposes. Polyurethane resin combined with plaster is useful for small casts, while polyester resin applied in four layers is the preferred technique for larger casts. The four layers are composed of: a first thin layer of polyester resin with bone colour; followed by another layer of polyester resin of sediment colour and containing glass microspheres to make it thicker. The third layer is composed of fibre glass chopped strands, and the fourth is composed of fibre glass mats embedded in plain polyester resin. 3D scanning and digitization techniques where tested for the storage of osteological information of individual bones and proved very promising.