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Panderichthys
From Wikipedia, the free encyclopedia
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 Panderichthys
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| Panderichthys rhombolepis Gross, 1941 |
Panderichthys is a 90–130 cm long fish from the Late Devonian period (Frasnian epoch) of Latvia. It has a large tetrapod-like head. Panderichthys exhibits transitional features between lobe-finned fishes and early tetrapods such as Acanthostega. The evolution from fish to land dwelling tetrapods required many changes in physiology, most importantly the legs and their supporting structure, the girdles. Well preserved fossils of Panderichthys clearly show these transitional forms, making Panderichthys a rare and important find in the history of life.
Fish like Panderichthys were the ancestors of the first tetrapods, air-breathing, terrestrial animals from which the land vertebrates, including humans, are descended. The most notable characteristic of Panderichthys was its spiracle, a vertical tube used to breathe water through the top of its head, while its body was submerged in mud. This spiracle is a transitional organ that led, through evolution, to the development of the stirrup bone, one of the three bones (stirrup, hammer, and anvil) in the human inner ear.
- "Panderichthys rhombolepis". FishBase. Ed. Ranier Froese and Daniel Pauly. November 2005 version. N.p.: FishBase, 2005.
- ^ The pelvic fin and girdle of Panderichthys and the origin of tetrapod locomotion
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In Late Devonian vertebrate speciation, descendants of pelagic lobe-finned fish – like Eusthenopteron – exhibited a sequence of adaptations:
- Panderichthys, suited to muddy shallows;
- Tiktaalik with limb-like fins that could take it onto land;
- Early tetrapods in weed-filled swamps, such as:
- Acanthostega which had feet with eight digits,
- Ichthyostega with limbs.
