Abstract
This chapter presents a detailed review of works published on Artiodactyla endocasts and provides a comprehensive examination of artiodactyl brain evolutionary history, including Cetacea, from the early Eocene (c.a. 45 Ma) onwards. Artiodactyl endocasts have been studied from the second half of the nineteenth century to the 1970s. These works on natural or artificial endocasts widely took place outside the frame of phylogenetic concerns. We compile the data available, including recent works using μCT-scan imagery techniques, and place them in a phylogenetic framework. We also provide new data regarding Paleogene representatives of North American extinct clades (Homacodon, Helohyus, Leptauchenia, Agriochoerus), endemic European clade (Mouillacitherium, Dichobune), and Suoidea (Palaeochoerus). The brain of modern artiodactyls is remarkable by the expansion and by the folding of the neopallium. Their brains are highly gyrencephalic and differ in their neocortical pattern. We highlight diversity of neopallium patterns of Artiodactyla and their convergent nature on the last 45 millions years and show that encephalization increases with time, but with different modes between terrestrial and fully aquatic taxa (i.e. Cetacea). Each clade shows a mosaic pattern of derived and plesiomorphic features that now has to be put in perspective with both the history and ecology of taxa