Search results
Results from the WOW.Com Content Network
Tiktaalik roseae model at the Harvard Museum of Natural History. As with other regions of the body, the pelvis (hip) was intermediate in form between earlier lobe-finned fish (like Gooloogongia and Eusthenopteron) and tetrapods (like Acanthostega). The pelvis was much larger than in other fish, nearly the same size as the shoulder girdle, like ...
The body form of Panderichthys and Tiktaalik represents a major step in the transition from fish to tetrapods and they were even able to haul out on land. [5] According to Shultze and Trueb, Panderichthys shares ten features with tetrapods: [6] The skull roof is flat compared to fish skulls. The orbits are more dorsal and lie closer together.
There was a loss of opercular and extrascapular elements, enhancing head mobility in T. roseae compared to other tetrapodomorph fish. [1] The formation of the neck allowed for locomotion in shallow waters. This environment allows for less motility compared to the three-dimensional space that fish are able to orient themselves in.
Ichthyostega (from Greek: ἰχθῦς ikhthûs, 'fish' and Greek: στέγη stégē, 'roof') is an extinct genus of limbed tetrapodomorphs from the Late Devonian of what is now Greenland. It was among the earliest four-limbed vertebrates ever in the fossil record and was one of the first with weight-bearing adaptations for terrestrial locomotion.
The earliest elpistostegalians, combining fishlike and tetrapod-like characters, such as Tiktaalik, are sometimes called fishapods. Although historically Elpistostegalia (referred to as Panderichthyida) was considered an order of prehistoric lobe-finned fishes, it was cladistically redefined to include tetrapods. [7]
In Late Devonian vertebrate speciation, descendants of pelagic lobe-finned fish such as 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, and Ichthyostega, which had limbs.
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
[30] [31] Unlike many previous, more fish-like transitional fossils, the "fins" of Tiktaalik have basic wrist bones and simple rays reminiscent of fingers. They may have been weight-bearing. Like all modern tetrapods, it had rib bones, a mobile neck with a separate pectoral girdle, and lungs, though it had the gills, scales, and fins of a fish ...