It’s not the size of the brain, but how wrinkly is the brain.
Find out more from the email forward below.
From: Lorraine Dorn [mailto:lorraine.dorn@uwa.edu.au]
Sent: Tuesday, 8 May 2012 2:37 PM
To: Lorraine Dorn
Subject: FW: SESE/OI Seminar Series – Kara Yopak – 10th May 2012
School of Environmental Systems Engineering and The UWA Oceans Institute Seminar Series
Dr Kara E. Yopak
The University of Western Australia
School of Animal Biology and The UWA Oceans Institute
Neuroecology Group
Sending Sharks to School: Brain Evolution in Sharks and Their Relatives
Cartilaginous fishes are comprised of approximately 1185 species worldwide and occupy a range of niches and primary habitats. It is a widely accepted view that neural development can reflect morphological adaptations and sensory specializations and it has been shown that similar patterns of brain organization, termed cerebrotypes, exist in species of that share certain lifestyle characteristics. Clear patterns of brain organization exist across cartilaginous fishes, irrespective of phylogenetic grouping. Examination of brain size (encephalization, n = 151) and interspecific variation in brain organization (n = 84) across this group suggests that similar patterns of brain organization, termed “cerebrotypes”, exist in species that share certain lifestyle characteristics. Clear patterns of brain organization exist across cartilaginous fishes, irrespective of phylogenetic grouping and, although this study was not a functional analysis, it provides further evidence that chondrichthyan brain structures might have developed in conjunction with specific behaviours or enhanced cognitive capabilities. Larger brains, with well-developed telencephala and large, highly foliated cerebella are reported in species that occupy complex reef or oceanic habitats, such as Prionace glauca and Sphyrna zygaena. In contrast, benthic and benthopelagic demersal species comprise the group with the smallest brains, such as Cephaloscyllium spp. and Squatina californica, with a relatively reduced telencephalon and a smooth cerebellar corpus. There is also evidence of a bathyal cerebrotype; deep-sea benthopelagic sharks, such as Centroselachus crepidater and Harriotta raleighana possess relatively small brains and show a clear relative hypertrophy of the medulla oblongata. Despite the patterns observed and documented, significant gaps in the literature have been highlighted. Brain mass data are only currently available on c. 16% of all chondrichthyan species, and only 8% of species have data available on their brain organization, with far less on subsections of major brain areas that receive distinct sensory input. The interspecific variability in brain organization further stresses the importance of performing functional studies on a greater range of species. Only an expansive data set, comprised of species that span a variety of habitats and taxonomic groups, with widely disparate behavioural repertoires, combined with further functional analyses, will help shed light on the extent to which chondrichthyan brains have evolved as a consequence of behaviour, habitat and lifestyle in addition to phylogeny.
4.00 pm Thursday, 10th May 2012
Lecture Theatre 1, G17 Mathematics Building
ALL WELCOME
Convenor: Anya Waite (6488 3082)
Host: tba (6488 1690)
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Lorraine Dorn
Academic Services (South Division)
School of Environmental Systems Engineering
The University of Western Australia
M015, 35 Stirling Highway
Crawley 6009 Western Australia
Phone: 6488 3701
Fax: 6488 1015
Email: lorraine.dorn@uwa.edu.au
