Specimens of Tyrannosaurus and colleagues announced the recovery of soft tissue from the marrow cavity of a fossilized leg bone (a 1.15 m long femur), from a 68-million-year-old "Tyrannosaurus". The bone had been intentionally, though reluctantly, broken for shipping and then not preserved in the normal manner, specifically because Schweitzer was hoping to test it for soft tissue. Designated MOR 1125 (and known informally as B-rex), the dinosaur had been excavated from the Hell Creek Formation. Flexible, bifurcating blood vessels and fibrous but elastic bone matrix tissue were recognized. In addition, microstructures resembling blood cells were found inside the matrix and vessels. The
Stroma (tissue) gel, made mainly from proteoglycan aggregates - and connective tissue fibers. There are three types of fibers commonly found within the stroma: collagen type I, elastic, and reticular (collagen type III) fibres. Stroma (tissue) Stroma () is the part of a tissue or organ with a structural or connective role. It is made up of all the parts without specific functions of the organ - for example, connective tissue, blood vessels, nerves, ducts, etc. The other part, the parenchyma, consists of the cells that perform the function of the tissue or organ. There are multiple ways of classifying tissues: one