Table 2 All previously described occurrences of purported MB in Mesozoic fossils scored across the nine features (Table 1) that, together, should allow identification of preserved tissue as MB (present indicated by x, absence with a dash)

From: Medullary bone in an Early Cretaceous enantiornithine bird and discussion regarding its identification in fossils

Taxon Collection # Clade Element(s) 1 2 3 4 5 6 7 8 9 10 11 Identification Revised Reference
Confuciusornis DNHM D1874 Aves Humerus x ? ? x ? x ? ? MB Unlikely 37
Pengornithid enantiornithine IVPP V15576 Aves Femur, tibiotarsus x x x x x x x x x ? ? MB This study
Transylvanian dinosaur BM R 5505 Dinosauria long bone x x x ? x ? ? ? ? ? Osteopetrosis   18
Tenontosaurus OMNH 34784 Ornithopoda Femur, tibia x x ? x ? x x ? ? ? ? MB Unlikely 9
Dysalotosaurus SMNS T3 Ornithopoda Tibia x x x x x ? x ? ? ? MB Unlikely 10
Dysalotosaurus GPIT/RE/5109 Ornithopoda Fibula x x x x x ? x ? ? ? MB? Unlikely 10
Mussaurus MLP 61-III-20-22 Sauropoda Femur x x x x ? x ? ? ? MB Pathological 12, 20
Saltasaurus PVL 4017–140 Sauropoda caudal vertebra x x x/– x ? ? ? ? ? Not MB   13
Saltasaurus PVL 4017–113 Sauropoda osteoderm x x x ? ? ? ? ? Not MB   13
Saltasaurus PVL 4017– 127 Sauropoda metatarsal x x x x x ? ? ? ? ? Pathology   13
Wealden Sauropod   Sauropoda vertebra x x x ? ? ? ? ? ? ? Pathology   48
Allosaurus UUVP 5300 Theropoda Tibia x x x ? x ? ? ? ? ? MB Osteopetrosis 9, 18
Tyrannosaurus rex MOR 1125 Theropoda Femur x x x x ? x ? x x ? ? MB   6, 21
Tyrannosaurus rex BMRP 2006.4.4 Theropoda Tibia x ? ? ? ? ? ? ? ? Pathology   11
Bakonydraco MTM V PAL 2007.111.1 Pterosauria mandibular symphysis x x x x x ? ? Not MB Pathological? 13, 15
Pterodaustro MHIN-UNSL-GEO V 382 Pterosauria Femur x x x x ? x ? x ? ? ? MB? Unlikely 14
  1. Published data often did not allow for some characters to be scored. Characters 10 and 11 cannot be utilized at this time but may prove useful in the future with better understanding of bone histochemistry and the development of new protocols. The column 'identification' refers to the original identification; the 'revised' column presents alternative interpretations published after the initial identification with those in italics representing new views presented in this paper