Actinopteri
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Bake fish ( Lepisosteus sp. ) |
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| Scientific name | ||||||||||||
| Actinopteri | ||||||||||||
| Cope , 1872 |
The Actinopteri are a large taxon of the bony fish . With the exception of the cladistia, they include all ray fins (Actinopterygii). The Actinopteri sub-taxa are the cartilaginous organoids (Chondrostei) with the sturgeon-like (Acipenseriformes) and the Neuflosser (Neopterygii), which also include the real bony fish (Teleostei) and thus the large number of fish species living today.
features
In the Actinopteri, a single lung or swim bladder is connected dorsally to the foregut . Originally all bony fish had air sacs with lung function. In the cartilaginous organoids and the real bony fish, these have been transformed into a gas-filled swim bladder. The connection between the swim bladder and the digestive tract has been lost secondarily in many real bony fish.
In other bony fish taxa, such as the cladista and the meat-finsher (Sarcopterygii), as well as in the terrestrial vertebrates (Tetrapoda), a pair of lungs is ventrally connected to the digestive tract.
In every fin of the Actinopteri, the foremost fin ray is covered with modified scales, which reinforce the leading edge of the fin and prevent them from losing their stability when swimming quickly. The paired fins of the Actinopteri are without a fleshy base. With the supraangular a new lower jaw bone appears in the Actinopteri.
Systematics
The systematic position is illustrated by the following cladogram :
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literature
- Guillaume Lecointre, Hervé Le Guyader: Biosystematics. (All organisms at a glance. The new order in life). Springer, Berlin et al. 2005, ISBN 3-540-24037-3 .
Web links
- Palæos: Actinopteri