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In many respects, fish anatomy is different from mammalian anatomy. However, it still shares the same basic body plan from which all vertebrates have evolved: a notochord, rudimentary vertebrae, and a well-defined head and tail. [5] [6] Fish have a variety of different body plans.
However, using scale morphology alone to distinguish species has some pitfalls. Within each organism, scale shape varies hugely according to body area, [8] with intermediate forms appearing between different areas—and to make matters worse, scale morphology may not even be constant within one area. To confuse things further, scale ...
The skeleton of the head of a perch Parts of a pike's head. 1: liver, 2: gill arch, 3: palate with sharp teeth, 4: in the middle a heart, 5: fragment of spinal cord, 6: brain, 7: spherical lens, 8: scale
Fish fins are distinctive anatomical features with varying structures among different clades: in ray-finned fish (Actinopterygii), fins are mainly composed of bony spines or rays covered by a thin stretch of scaleless skin; in lobe-finned fish (Sarcopterygii) such as coelacanths and lungfish, fins are short rays based around a muscular central ...
A fish (pl.: fish or fishes) is an aquatic, anamniotic, gill-bearing vertebrate animal with swimming fins and a hard skull, but lacking limbs with digits.Fish can be grouped into the more basal jawless fish and the more common jawed fish, the latter including all living cartilaginous and bony fish, as well as the extinct placoderms and acanthodians.
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.
Some fish like carp and zebrafish have pharyngeal teeth only. [30] [31] Sea horses, pipefish, and adult sturgeon have no teeth of any type. In fish, Hox gene expression regulates mechanisms for tooth initiation. [32] [33] While both sharks and bony fish continuously produce new teeth throughout their lives, they do so via different mechanism.
Batoids are flat-bodied, and, like sharks, are cartilaginous fish, meaning they have a boneless skeleton made of a tough, elastic cartilage. Most batoids have five ventral slot-like body openings called gill slits that lead from the gills, but the Hexatrygonidae have six. [3]