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Osteichthyes (/ ˌ ɒ s t iː ˈ ɪ k θ iː z / ost-ee-IK-theez; from Ancient Greek ὀστέον (ostéon) ' bone ' and ἰχθύς (ikhthús) ' fish '), [2] also known as osteichthyans or commonly referred to as the bony fish, is a diverse clade of vertebrate animals that have endoskeletons primarily composed of bone tissue.
The bony fish lineage shows more derived anatomical traits, often with major evolutionary changes from the features of ancient fish. They have a bony skeleton, are generally laterally flattened, have five pairs of gills protected by an operculum, and a mouth at or near the tip of the snout. The dermis is covered with overlapping scales. Bony ...
The cleithrum (pl.: cleithra) is a membrane bone which first appears as part of the skeleton in primitive bony fish, where it runs vertically along the scapula. [1] Its name is derived from Greek κλειθρον = " key (lock) ", by analogy with " clavicle " from Latin clavicula = "little key".
In ichthyology the difference between Euteleostomi and Osteichthyes is that the former presents a cladistic view, i.e. that the terrestrial tetrapods evolved from lobe-finned fish (Sarcopterygii). Until recently, the view of most ichthyologists has been that Osteichthyes were paraphyletic and include only bony fishes. [ 8 ]
Fish bone is any bony tissue in a fish, although in common usage the term refers specifically to delicate parts of the non-vertebral skeleton of such as ribs, fin spines and intramuscular bones. Not all fish have fish bones in this sense; for instance, eels and anglerfish do not possess bones other than the cranium and the vertebrae.
Osteichthyes — a superclass containing the Bony fish, formerly in the now obsolete clade Teleostomi. It is divided into two classes: Actinopterygii − Ray-finned fish — contains most of the superclass's species.
In amphibians and some primitive bony fish, the larvae bear external gills branching out from the gill arches. [3] These regress upon adulthood, their function taken over by the gills proper in fish, or by lungs (which are homologous to swim bladders) and cutaneous respiration in most amphibians.
Bony fish have fin spines called lepidotrichia or "rays" (due to how the spines spread open). They typically have swim bladders, which allow the fish to alter the relative density of its body and thus the buoyancy, so it can sink or float without having to use the fins to swim up and down. [14]