Virtual reconstruction and description of the cranial endocast of Pristerodon mackayi (Therapsida, Anomodontia)

J Morphol. 2015 Sep;276(9):1089-99. doi: 10.1002/jmor.20397. Epub 2015 Jun 30.

Abstract

The cranial endocast of Pristerodon mackayi is described, which has been virtually reconstructed on the basis of neutron tomographic data. The gross anatomy of the cranial endocast of Pristerodon resembles other nonmammalian synapsids such as Thrinaxodon liorhinus in having a narrow, tubular forebrain, well developed olfactory bulbs, a large parietal foramen and unossified zone. As it is the case in cynodonts the hindbrain of Pristerodon is broader than the mid- and forebrain. Large paraflocculi are developed. The medulla oblongata can be well distinguished from the pons. The pons is divided by a median ridge into two portions. There is no evidence for a neocortex, which seems to be also reflected in the low encephalization quotient of 0.18 estimated according to the method of Eisenberg.

Keywords: Anomodontia; Late Permian; Therapsida; brain evolution; encephalization quotient.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biological Evolution
  • Brain / anatomy & histology*
  • Brain / diagnostic imaging
  • Fossils / anatomy & histology*
  • Fossils / diagnostic imaging
  • Skull / anatomy & histology*
  • Skull / diagnostic imaging
  • Tomography, X-Ray Computed