<b>Long bone histology of a non-avialan dinosaur and a Mesozoic bird viewed with polarized microscopy</b> <br><ul><li>A) The femoral microstructure of the small alvarezsaurrid, Shuvuuia deserti (IGM 100–99)</li>
<li>B) Tibial histology of the Early Cretaceous avialan, Confuciusornis sanctus (IVPP V11521)</li></ul><p>Comparision of both show well-vascularized bone owing to the presence of numerous primary vascular canals (large black structures),
and woven fibered matrix characterized by oblong, randomly oriented osteocyte lacunae (numerous small black structures).
Arrows point to growth lines in the form of a line of arrested growth (left) and an annulus (right).
</p>
<hr>
Scale bars = 0.5 mm (A) and 0.1 mm (B)
Erickson GM, Rauhut OWM, Zhou Z, Turner AH, Inouye BD, et al. (2009)
CC BY 2.5
<p>Was Dinosaurian Physiology Inherited by Birds? Reconciling Slow Growth in Archaeopteryx <br></p>
(PLoS ONE 4(10): e7390. <a href="https://en.wikipedia.org/wiki/Digital_object_identifier" class="extiw" title="w:Digital object identifier">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1371%2Fjournal.pone.0007390.g001">10.1371/journal.pone.0007390.g001</a>)