The brain of the basking shark (Cetorhinus maximus).
The brain of a basking shark is described for the first time. Allometrical analysis of brain-body weight relationships indicates that Cetorhinus maximus shows by far the lowest degree of cerebralization of any shark investigated to date, possibly reflecting its plankton-feeding mode of life. Furthermore, some external morphological features of the brain appear to be species-specific. The proportions of brain parts indicate a primitive vertebrate brain organization. The size of the telencephalon, 34% of the total brain, equals that in some other sharks, whereas the cerebellum, 30% of the total brain in the basking shark, is significantly larger than in any other shark investigated. Furthermore, C. maximus shows some peculiarities concerning the nuclear expansion in the telencephalon. A rather large caudal interhemispheric region is especially striking. The relation of brain volume to brain cavity volume is approximately 1:16.
Kruska
D C
DC
Institut für Haustierkunde, Christian-Albrechts-Universität, Kiel, BRD.
D000818:Animals; D005075:Biological Evolution; D001921:Brain / Q000033:anatomy & histology*; D002552:Cerebral Ventricles / Q000033:anatomy & histology; D009929:Organ Size; D012754:Sharks / Q000033:anatomy & histology*; D013045:Species Specificity; D013687:Telencephalon / Q000033:anatomy & histology