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The upper jaw, or maxilla [12] [13] is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible (lower jaw), which is also a fusion of two halves at the mandibular symphysis. In bony fish, the maxilla is called the "upper maxilla," with the mandible being the "lower maxilla".
In all jawed fish (gnathostomes), the first arch pair (mandibular arches) develops into the jaw, the second gill arches (the hyoid arches) develop into the hyomandibular complex (which supports the back of the jaw and the front of the gill series), and the remaining posterior arches (simply called branchial arches) support the gills.
After the appearance of jawed fish (placoderms, acanthodians, sharks, etc.) about 420 million years ago, most ostracoderm species underwent a decline, and the last ostracoderms became extinct at the end of the Devonian period. More recent research indicates that fish with jaws had far less to do with the extinction of the ostracoderms than ...
In practice, fish anatomy and fish physiology complement each other, the former dealing with the structure of a fish, its organs or component parts and how they are put together, such as might be observed on the dissecting table or under the microscope, and the latter dealing with how those components function together in living fish. The ...
Jawless fish and sharks possess only a cartilaginous endocranium, with both the upper and lower jaws being separate elements. Bony fishes have an additional dermal bone, forming a more or less coherent skull roof in lungfish and holost fish. The lower jaw defines a chin. [1]
Osteichthyes (/ ˌ ɒ s t iː ˈ ɪ k θ iː z / ost-ee-IK-theez), [2] also known as osteichthyans or commonly referred to as the bony fish, is a diverse superclass of vertebrate animals that have endoskeletons primarily composed of bone tissue.
The Syngnathidae is a family of fish which includes seahorses, pipefishes, and seadragons (Phycodurus and Phyllopteryx). The name is derived from Ancient Greek: σύν (syn), meaning "together", and γνάθος (gnathos), meaning "jaw". [1] The fused jaw is one of the traits that the entire family have in common. [2]
They have an olive brown to green, torpedo-shaped body armored with ganoid scales, elongated jaws that form a needle-like snout nearly three times the length of its head, and a row of numerous sharp, cone-shaped teeth on each side of the upper jaw.