Placoderm brain

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Placoderm brain and cranial nerves

Brain of Devonian placoderm Macropetalichthys (Romer 1966, fg.9, after Stensio).

Macropetalichthus was a Devonian Placoderm ("plate-skin"), a class of armored fish that were among the first jawed vertebrates (gnathostomes), who lived in the Early Silurian through Late Devonian periods (443-359 mya). Their skull was flattened (the name means "large, flattened fishes" ) and they were bottom-feeders.
This diagram shows the brain of Macropetalichthus as seen from above (dorsal view) and from the side (lateral view). Among the main components are the brain stem or medulla oblongata; the cerebellum; the optic lobe or visual cortex; the cerebral hemisphere; the pineal organ, a direction-finding sense; and the olfactory bulb. Also shown are several of the cranial nerves, including I (nostril), II (eyes), and VIII (ears).
This basic organization of cranial nerves has persisted through the history of vertebrates. The underside of the human brain, revealing the brain stem, shows the cranial nerves in the same order.

References:

Romer, A.S. 1966. Vertebrate Paleontology. University of Chicago Press.
Stensio, E. 1925. The Downtonian and Devonian Vertebrates of Spitzbergen. Stockholm.

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Copyright © 1996-2020 Rust Family Foundation (All Rights Reserved).

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	Placoderm brain and cranial nerves Brain of Devonian placoderm Macropetalichthys (Romer 1966, fg.9, after Stensio).

	Macropetalichthus was a Devonian Placoderm ("plate-skin"), a class of armored fish that were among the first jawed vertebrates (gnathostomes), who lived in the Early Silurian through Late Devonian periods (443-359 mya). Their skull was flattened (the name means "large, flattened fishes" ) and they were bottom-feeders. This diagram shows the brain of Macropetalichthus as seen from above (dorsal view) and from the side (lateral view). Among the main components are the brain stem or medulla oblongata; the cerebellum; the optic lobe or visual cortex; the cerebral hemisphere; the pineal organ, a direction-finding sense; and the olfactory bulb. Also shown are several of the cranial nerves, including I (nostril), II (eyes), and VIII (ears). This basic organization of cranial nerves has persisted through the history of vertebrates. The underside of the human brain, revealing the brain stem, shows the cranial nerves in the same order. References: Romer, A.S. 1966. Vertebrate Paleontology. University of Chicago Press. Stensio, E. 1925. The Downtonian and Devonian Vertebrates of Spitzbergen. Stockholm.
	Athena Review Image Archive™ Main index of Athena Review Copyright © 1996-2020 Rust Family Foundation (All Rights Reserved).

Athena Review Image Archive ™

Placoderm brain and cranial nerves

Brain of Devonian placoderm Macropetalichthys (Romer 1966, fg.9, after Stensio).

This basic organization of cranial nerves has persisted through the history of vertebrates. The underside of the human brain, revealing the brain stem, shows the cranial nerves in the same order.References:

Romer, A.S. 1966. Vertebrate Paleontology. University of Chicago Press.

Stensio, E. 1925. The Downtonian and Devonian Vertebrates of Spitzbergen. Stockholm.

Athena Review Image Archive ^™

This basic organization of cranial nerves has persisted through the history of vertebrates. The underside of the human brain, revealing the brain stem, shows the cranial nerves in the same order.

References: