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Actinopterygii (/ ˌ æ k t ɪ n ɒ p t ə ˈ r ɪ dʒ i aɪ /; from actino- 'having rays' and Ancient Greek πτέρυξ (ptérux) 'wing, fins'), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish [2] that comprise over 50% of living vertebrate species. [3]
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Evolution of ray-finned fishes, Actinopterygii, from the Devonian to the present as a spindle diagram. The width of the spindles are proportional to the number of families as a rough estimate of diversity. The diagram is based on Benton, M. J. (2005) Vertebrate Palaeontology, Blackwell, 3rd edition, Fig 7.13 on page 185.
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The snout contains a unique rostral organ, believed to be electro-sensory in nature, although its exact function is unknown. [10] [11] The mouth is larger than that of herrings and silversides, two fish which anchovies closely resemble in other respects. The anchovy eats plankton and recently hatched fish.
Osteichthyes is divided into the ray-finned fish (Actinopterygii) and lobe-finned fish (Sarcopterygii). The oldest known fossils of bony fish are about 420 million years ago, which are also transitional fossils , showing a tooth pattern that is in between the tooth rows of sharks and bony fishes.
Chloroplasts in leaf cells of the moss Mnium stellare. Plant anatomy or phytotomy is the general term for the study of the internal structure of plants.Originally, it included plant morphology, the description of the physical form and external structure of plants, but since the mid-20th century, plant anatomy has been considered a separate field referring only to internal plant structure.
The idea of a tree of life arose from ancient notions of a ladder-like progression from lower into higher forms of life (such as in the Great Chain of Being).Early representations of "branching" phylogenetic trees include a "paleontological chart" showing the geological relationships among plants and animals in the book Elementary Geology, by Edward Hitchcock (first edition: 1840).