“…However, since the study of Köhler et al (2012) that demonstrated the correlation between cyclical bone growth and seasonal physiology in a wide sample of ruminants, the number of histological works in extant ( Marín-Moratalla, Jordana & Köhler, 2013 ; Marín-Moratalla et al, 2014 ; Jordana et al, 2016 ; Nacarino-Meneses, Jordana & Köhler, 2016 ) and extinct mammals ( Martínez-Maza et al, 2014 ; Kolb et al, 2015b ; Amson et al, 2015 ; Moncunill-Solé et al, 2016 ; Orlandi-Oliveras et al, 2016 ) has considerably increased. Among all mammalian clades, members of the family Equidae play a key role in extant and fossil ecosystems ( MacFadden, 1992 ; Downer, 2014 ). Besides, they are a classical group of research in Paleontology due to their characteristic evolution ( MacFadden, 2005 ).…”