Ganoine
_(3149758934).jpg)
Ganoine or ganoin is a glassy, often multi-layered mineralized tissue that covers the scales, cranial bones and fin rays in some basal ray-finned fishes.[1] It is composed of rod-like, pseudoprismatic apatite crystallites, with less than 5% of organic matter.[2] Existing fish groups featuring ganoin are bichirs and gars, but ganoin is also characteristic of several extinct taxa.[3] It is a characteristic component of ganoid scales.
Ganoine is an ancient feature of ray-finned fishes, being found for example on the scales of stem group actinopteryigian Cheirolepis.[3] While often considered a synapomorphic character of ray-finned fishes, ganoine or ganoine-like tissues are also found on the extinct acanthodii.[3]
It has been suggested that ganoine is homologous to tooth enamel in vertebrates[1] or even considered a type of enamel.[2] Ganoine indeed contains amelogenin-like proteins[1] and has a mineral content similar to that of tetrapod tooth enamel.[4]
References
| About fish |
 |
||||
|---|---|---|---|---|---|
| Anatomy and physiology |
|
||||
| Sensory systems |
|||||
| Reproduction | |||||
| Locomotion | |||||
| Other behaviour |
|||||
| Habitats | |||||
| Other types | |||||
| Commercial |
|
||||
| Major groups | |||||
| Lists | |||||
