page_title: Tasmaniosaurus
section_title: Brain
hierarchical_section_title: Tasmaniosaurus / Paleobiology / Brain
caption_attribution_description: English: Figure 8. Latex cranial endocast of type specimen (UTGD 54655) of Tasmaniosaurus triassicus. A, latex endocast and B, interpretation of telencephalon areas in dorsal views. Cerebrum (blue), olfactory tract (green), olfactory bulbs (light yellow), and indeterminate soft tissue or lateral portion of the olfactory bulbs (dark yellow). Abbreviations:&#160;?lst; lateral soft tissue or lateral portion of olfactory bulb; ce, cerebrum; ch, cerebral hemisphere; dvs, dural venous sinus; ihf, interhemispheral fissure; lg, longitudinal groove; ob, olfactory bulb; ot, olfactory tract. Scale bar equals 5 mm.
context_page_description: Tasmaniosaurus is an extinct genus of archosauromorph reptile known from the Knocklofty Formation of West Hobart, Tasmania, Australia. The type species is T. triassicus. This genus is notable not only due to being one of the most complete Australian Triassic reptiles known, but also due to being a very close relative of Archosauriformes. Once believed to be a proterosuchid, this taxon is now believed to have been intermediate between advanced non-archosauriform archosauromorphs such as Prolacerta, and basal archosauriforms such as Proterosuchus. Features traditionally used to define Archosauria and later Archosauriformes, such as the presence of an antorbital fenestra and serrated teeth, are now known to have evolved prior to those groups due to their presence in Tasmaniosaurus.
context_section_description: The well-preserved skull roof of Tasmaniosaurus allowed for Ezcurra to reconstruct part of the creature's brain by means of a latex endocast. This endocast showed that the specimen's brain had large olfactory bulbs at the front, which lead into a thin olfactory tract in the middle and a somewhat wider cerebellum in the back. There are also wide and flat extensions at the front of the brain which are separated from the olfactory bulbs by a small groove. These extensions may have been the edge of additional non-brain organs (such as a Jacobson's organ) or alternatively another component of the olfactory bulbs, which would indicate that those parts of the brain were unusually large. Both of these interpretation have significant ramifications on the biology of this animal.
  If they are a Jacobson's organ, then the notion that such an organ was not present in archosauromorphs can be proven false. This notion was originally formed due to the fact that neither crocodilians nor birds (the two extant groups of archosauromorphs) possess such an organ. However, Ezcurra notes that both of these groups have specialized modes of life which may have caused the organ to have been lost.
  If they are parts of the olfactory bulbs, then Tasmaniosaurus would have had a superb sense of smell. It has been noted that aquatic animals have generally diminished olfactory capabilities compared to their terrestrial counterparts. Thus, this interpretation significantly lowers the likelihood that Tasmaniosaurus or its relatives (such as proterosuchids) were mainly aquatic. Other sources have also supported the idea that proterosuchids were terrestrial rather than aquatic or semiaquatic.
caption: A latex endocast of the front part of the specimen's brain.
exif: {}