Athena Review Image Archive ™
Skull and brain of the Atlantic codfish (Gadus morhua)
Skull and brain of Gadus morhua (drawing after Evans 1935.
Gadus morhua, the Atlantic cod, is a ray-finned fish of the family Gadidae, whose fossil record dates from the Paleocene period (65-55 mya). Their habitat ranges from the coastal shoreline down to 300 m (1000 ft) along the continental shelf.
This figure shows a rendering of the brain of Gadus morhua, indicating that the cerebellum is folded to back toward the brain stem, and does not overlie the optic lobe, which is relatively large. From the cerebellum emerge a pair of large nuclei from which arise the acoustic and lateral-line nerves.
Many researchers have noted that brain development is very plastic in teleost fishes. Evans (1935) reported that the brainstem or medulla oblongata of Gadidae varied according to their different feeding habits. More dramatic changes may occur in fish brain morphology due to rapid alterations in social and environmental conditions. Mayer et al (2011) reported significant changes in brain as well as heart morphology occur following aquaculture domestication of Atlantic cod (Gadus morhua). Juvenile farmed cod developed significantly smaller brains, by weight, compared to their wild conspecifics.
References:
Evans, H.M. 1935. The Brain of Gadus, with Special Reference to the Medulla Oblongata and its Variations according to the Feeding Habits of Different Gadidae. Proceedings of the Royal Society of London. Series B, Biological Sciences.
Mayer, I. et al. 2011. Domestication causes rapid changes in heart and brain morphology in Atlantic cod (Gadus morhua):Environmental Biology of Fishes 92(2):181-186.
Romer, A.S. 1966. Vertebrate Paleontology. University of Chicago Press.
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