Figure 3 in Chemistry supports the identification of gender-specific reproductive tissue in Tyrannosaurus rex

Figure 3. Alcian blue histochemical stain capitalizes on the differential presence of sulfated glycosaminoglycans found in MB vs CB. Low (A) and high (B) magnification of demineralized, sectioned bone from a laying hen femur show MB (black arrows), forming along the borders of CB. Alcian blue stains MB intensely, but only lightly stains CB and TB, reflecting the differences in matrix composition. MB is shown to form around ovate vacancies that may represent vessels (red arrowheads). MB is sometimes found as islands within spicules of TB or CB (yellow arrows), possibly representing centripetal infilling of pre-existing vessel channels or erosion rooms with forming MB. Ostrich (C), shown at a lower magnification to encompass internal-most cortical bone and developing spicules of MB. The developmental pattern differs from that of chicken, reflecting macroscopic differences seen in hand sample, where MB and CB are not distinct, but more gradational in nature. Forming MB (black arrows) can be seen lining secondary osteons (leftmost black arrow), and as pockets of bone within pre-existing cortical bone (yellow arrows). Ovate open spaces within completely formed MB spicules are also seen (red arrowheads). Low (D) and high (E) magnifications of demineralized and sectioned T. rex CB show fibrous matrix that is lightly stained. Dinosaur MB in low (F), and high (G) magnifications show much more intense staining (black arrows). Matrix is fibrous, but is penetrated by ovate forms within deeply staining bone (F, red arrows). White spaces in F are sectioning artifact, where tissue and embedding material have pulled away from bone. Scale bars as indicated.