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The morphology of a scale can be used to identify the species of fish it came from. Scales originated within the jawless ostracoderms , ancestors to all jawed fishes today. Most bony fishes are covered with the cycloid scales of salmon and carp , or the ctenoid scales of perch , or the ganoid scales of sturgeons and gars .
External anatomy of a bony fish (Hector's lanternfish): 1. operculum (gill cover), 2. lateral line, 3. dorsal fin, 4. adipose fin, 5. caudal peduncle, 6. caudal fin, 7. anal fin, 8. photophores, 9. pelvic fins (paired), 10. pectoral fins (paired) Internal anatomy of a bony fish. Fish anatomy is the study of the form or morphology of fish. It ...
Cosmine was first described in the Osteolepiform Megalichthys hibberti by Williamson in 1849, in a purely descriptive, pre-Darwinian, non-evolutionary framework. [4] Goodrich [5] expanded on Williamson's descriptions, hypothesizing a transition from a monoodontode scale (like a chondryicthian placoid scale) to a complex polyodontode scale through fusion of discrete units.
Lepidophagy. Lepidophagy is a specialised feeding behaviour in fish that involves eating the scales of other fish. [1] Lepidophagy is widespread, having evolved independently in at least five freshwater families and seven marine families. [2] A related feeding behavior among fish is pterygophagy: feeding on the fins of other fish.
Coelacanth. Coelacanths (/ ˈsiːləkænθ / ⓘ SEE-lə-kanth) (order Coelacanthiformes) are an ancient group of lobe-finned fish (Sarcopterygii) in the class Actinistia. [2][3] As sarcopterygians, they are more closely related to lungfish and tetrapods (which includes amphibians, reptiles, birds and mammals) than to ray-finned fish.
The evolution of fish began about 530 million years ago during the Cambrian explosion. It was during this time that the early chordates developed the skull and the vertebral column, leading to the first craniates and vertebrates. The first fish lineages belong to the Agnatha, or jawless fish. Early examples include Haikouichthys.
There are also many types of osteoderm structures. They can form in isolated groups creating a partial coverage of the organism, [31] but they can also form a structure more similar to the fish scales, where they overlap each other to form a more complete armor. [31] Depending on the macroscale structure of armor the osteoderm morphology ...
Fish jaws, like vertebrates in general, normally show bilateral symmetry. An exception occurs with the parasitic scale-eating cichlid Perissodus microlepis. The jaws of this fish occur in two distinct morphological forms. One morph has its jaw twisted to the left, allowing it to eat scales more readily on its victim's right flank.