File:Caudipteryx STM4-3 chondrocytes (2).png

English: Photographs of H&E stained paraffin sections of the cartilage of STM4-3 and that of an extant chicken. a A slide of STM4-3 cartilage (5 µm thick) stained with H&E. Few extracellular matrix (ECM) and few chondrocytes are seen. b A slide of adult chicken cartilage (5 µm thick) stained with the same method and shown at the same scale for comparison with Caudipteryx. c A close-up on three Caudipteryx cells shows one cartilage cell with stained intracellular structures and chromatin threads in dark purple. d Line drawing of (c) showing different fossilized cellular structures, like the unstained cytoplasm (cy), the unstained nuclear membrane (nm), and the stained nucleus (nu). e A close-up on two chicken cells. f Accompanying line drawing of (e) showing similar cellular structures sharing the same staining pattern as the Caudipteryx cell. Because the chicken cells are still within their ECM, their lacunae (lac) with potential intralacunar matrix (ilm) can be seen. g High-magnification photograph (at ×100 with immersion oil) on the three Caudipteryx cells seen under transmitted light (TL). h Corresponding image taken under the polarized light (PL). Abbreviations: bicc, brown ironized cartilage cell; bm, bone marrow; bt, bone trabeculae; cc, calcified cartilage; cm, cell membrane; ct, chromatin thread/chromocenter; ECM/Fe, extracellular matrix/Iron; hc, hyaline cartilage; tscc, transparent silicified cartilage cell.