Search results
Results from the WOW.Com Content Network
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".
With their fusion of a beak-like tooth, there is a continuous series of arrow-shaped dental units that are surrounded by bone. [3] They can move from the base towards the edge as time goes on. Early on, the teeth begin to form a thick layer of enamel that protects the tooth from sustaining damage easily.
Fish jaw: The primary oral jaws open and close the mouth, and a second set of pharyngeal jaws are positioned at the back of the throat. Ichthyology terms; Hallucigenia;
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.
Rhenanida ("Rhine fish") were flattened, ray-like, bottom-dwelling predators with large, upturned mouths that lived in marine environments. The rhenanids were once presumed to be the most primitive, or at least the closest to the ancestral placoderm, as their armour was made of unfused components—a mosaic of tubercles—as opposed to the ...
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]
The lower jaw and maxilla are then pulled back to close the mouth, and the fish is able to grasp the prey. By contrast, mere closure of the jaws would risk pushing food out of the mouth. By contrast, mere closure of the jaws would risk pushing food out of the mouth.
In early fish and in chondrichthyans (cartilaginous fish such as sharks), Meckel's cartilage continued to be the main component of the lower jaw. But in the adult forms of osteichthyans (bony fish) and their descendants ( amphibians , reptiles , birds , and mammals ), the cartilage is covered in bone – although in their embryos the jaw ...