Editing Red panda (section)

===Fossil record===
[[File:Simocyon batalleri head.jpg|right|thumb|Reconstructed skull and head of ''[[Simocyon]]'', a large carnivorous early relative of the modern red panda|alt=Drawing of a skull (above) and head (below) of an extinct animal]] 
The family Ailuridae appears to have evolved in Europe in either the [[Late Oligocene]] or [[Early Miocene]], about {{mya|25|18}}. The earliest member ''[[Amphictis]]'' is known from its {{cvt|10|cm|in|frac=2}} skull and may have been around the same size as the modern species. Its [[dentition]] consists of sharp premolars and [[carnassial]]s (P4 and m1) and [[Molar (tooth)|molar]]s adapted for grinding (M1, M2 and m2), suggesting that it had a generalised [[carnivorous]] diet. Its placement within Ailuridae is based on the grooves on the side of its [[Canine tooth|canine teeth]]. Other early or [[Basal (phylogenetics)|basal]] ailurids include ''[[Alopecocyon]]'' and ''[[Simocyon]]'', whose fossils have been found throughout Eurasia and North America dating from the [[Middle Miocene]], the latter of which survived into the [[Early Pliocene]].  Both have similar teeth to ''Amphictis'' and thus had a similar diet.<ref name="Salesa">{{cite book |author1=Salesa, M. J. |author2=Peigné, S. |author3=Antón, M. |author4=Morales, J. |name-list-style=amp |year=2021 |chapter=The taxonomy and phylogeny of ''Ailurus'' |title=Red Panda: Biology and Conservation of the First Panda |editor=Glatston, A. R. |pages=15–29 |edition=Second |publisher=Academic Press |place=London |isbn=978-0-12-823753-3}}</ref> The [[cougar|puma]]-sized ''Simocyon'' was likely a tree-climber and shared a "false thumb"—an extended wrist bone—with the modern species, suggesting the appendage was an adaptation to [[arboreal locomotion]] and not to feed on [[bamboo]].<ref name="Salesa"/><ref name="PNAS-Salesa-2006">{{cite journal |last1=Salesa |first1=M. J. |last2=Mauricio |first2=A. |last3=Peigné |first3=S. |last4=Morales |first4=J. |name-list-style=amp |title=Evidence of a false thumb in a fossil carnivore clarifies the evolution of pandas |journal=PNAS |year=2006 |volume=103 |pmid=16387860 |issue=2 |pmc=1326154 |pages=379–382 |doi=10.1073/pnas.0504899102 |bibcode=2006PNAS..103..379S |doi-access=free}}</ref>

Later and more [[Apomorphy and synapomorphy|advanced]] ailurids are classified in the subfamily Ailurinae and are known as the "true" red pandas. These animals were smaller and more adapted for an [[omnivorous]] or [[herbivorous]] diet. The earliest known true panda is ''[[Magerictis]]'' from the Middle Miocene of Spain and known only from one tooth, a lower second molar. The tooth shows both ancestral and new characteristics having a relatively low and simple [[Crown (tooth)|crown]] but also a lengthened crushing surface with developed [[Cusp (anatomy)|tooth cusps]] like later species.<ref name="Wallace">{{cite book |author1=Wallace, S. C. |author2=Lyon, L. |name-list-style=amp |year=2021 |chapter=Systemic revision of the Ailurinae (Mammalia: Carnivora: Ailuridae): with a new species from North America |title=Red Panda: Biology and Conservation of the First Panda |editor=Glatston, A. R. |pages=31–52|edition=Second |publisher=Academic Press |place=London |isbn=978-0-12-823753-3}}</ref> Later ailurines include ''[[Pristinailurus bristoli]]'' which lived in eastern North America from the late Miocene to the Early Pliocene<ref name="Wallace"/><ref name="Wallace2004">{{cite journal |last1=Wallace |first1=S. C. |last2=Wang |first2=X. |name-list-style=amp |date=2004 |title=Two new carnivores from an unusual late Tertiary forest biota in eastern North America |journal=Nature |issue=7008 |pages=556–559 |volume=431 |doi=10.1038/nature02819 |pmid=15457257 |bibcode=2004Natur.431..556W |s2cid=4432191|url=http://doc.rero.ch/record/13466/files/PAL_E141.pdf }}</ref> and species of the genus ''[[Parailurus]]'' which first appear in Early Pliocene Europe, spreading across Eurasia into North America.<ref name="Wallace"/><ref>{{cite journal |author=Tedford, R. H. |author2=Gustafson, E. P. |name-list-style=amp |title=First North American record of the extinct panda ''Parailurus'' |journal=Nature |issue=5595 |pages=621–623 |volume=265 |doi=10.1038/265621a0 |year=1977 |bibcode=1977Natur.265..621T |s2cid=4214900}}</ref> These animals are classified as a [[sister taxon]] to the lineage of the modern red panda. In contrast to the herbivorous modern species, these ancient pandas were likely omnivores, with highly cusped molars and sharp [[premolar]]s.<ref name="Wallace"/><ref name="Wallace2004" /><ref>{{cite journal |last1=Sotnikova |first1=M. V. |year=2008|title=A new species of lesser panda ''Parailurus'' (Mammalia, Carnivora) from the Pliocene of Transbaikalia (Russia) and some aspects of ailurine phylogeny|journal=Paleontological Journal |volume=42 |issue=1|pages=90–99|doi=10.1007/S11492-008-1015-X|bibcode=2008PalJ...42...90S |s2cid=82000411}}</ref>

The earliest fossil record of the modern genus ''Ailurus'' dates no earlier than the [[Pleistocene]] and appears to have been limited to Asia. The modern red panda's lineage became adapted for a specialised bamboo diet, having molar-like premolars and more elevated cusps.<ref name="Wallace"/> The false thumb would secondarily gain a function in feeding.<ref name="Salesa"/><ref name="PNAS-Salesa-2006"/>