Editing Paleontology (section)

===Paleohistology===
{{main|Paleohistology}}
[[File:Bone histology of Shuvuuia and Confuciusornis.png|thumb|Bone microstructure of dinosaurs ''[[Shuvuuia]]'' and ''[[Confuciusornis]]'' showing lines of arrested growth]]
Paleohistology is the study of the hard tissues of fossils, analogous to the field of histology that studies biological tissues. The field is comparatively restricted as fossils preserve only superficial tissue structure and not molecules that can be found in modern histology, but it still has a long history following the use of [[microscopes]] to study both living and extinct organisms. Fossilization changes the composition of bones and to a lesser extent teeth, though their histology can still be examined through [[thin section]]s. The first use of thin sections in studying tissues in fossils was that of [[Richard Owen]] in a set of volumes in the 1840s that included dinosaurs and pterosaurs, which was simultaneously the first large comparative study of hard tissue histology. The microscopic structure of the bones, [[armour (zoology)|dermal armor]], and teeth of early vertebrates and fossil fish was studies soon after, though polished bone surfaces were used rather than thin sections. The hard tissue structure of these early vertebrates has been used to classify them and separate jawless vertebrates ([[ostracoderm]]s) from those with jaws such as [[placoderms]] and [[acanthodian]]s. Similarly, the paleohistology of [[tetrapods]] has been used as evidence of both their classifications and their function. The internal structure of bones of many tetrapods can be used to identify their age quantitatively through the count of [[growth arrest lines]]. Paleohistology combines structural knowledge with functional interpretations and evolutionary processes to help understand evolution.<ref name="ricqles2021"/>