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The caudal fin is the tail fin (from the Latin cauda meaning ... as reversed heterocercal, ... in a tetrapod is already present in the swimming fin of a fish.
The hypural is often fan-shaped. The tail may be heterocercal, reversed heterocercal, protocercal, diphycercal, or homocercal. Heterocercal: vertebrae extend into the upper lobe of the tail, making it longer (as in sharks) Reversed heterocercal: vertebrae extend into the lower lobe of the tail, making it longer (as in the Anaspida)
Male hybodonts possessed fin claspers used in mating, like modern sharks. [10] Hybodonts had a fully heterocercal tail fin, where the upper lobe of the fin was much larger than the lower one due to the spine extending into it. [17] Like living sharks and rays, the skin of hybodonts was covered with dermal denticles. [18]
The anterior part of the dorsal fin supported by spines. spiracles Respiratory openings behind the eyes in sharks and rays. standard length (SL) The length of a fish measured from the tip of the snout to the posterior extremity of the hypurals, the expanded bones at the end of the backbone that support the caudal fin. submarginal Almost at the ...
In chimaerids and rhinochimaerids, the tail is leptocercal, meaning that it is thin and whip-like, edged from above and below by fins of similar size. In callorhinchids, the tail is instead heterocercal, with a larger upper lobe inclined upwards, similar to many sharks. There are two dorsal fins: a large triangular first dorsal fin and a low ...
[29] [30] The rostrum is an extension of the cranium, not of the upper and lower jaws or olfactory system as with the long snouts of other fish. [25] [26] Other distinguishing characteristics include a deeply forked heterocercal caudal fin and dull coloration, often with mottling, ranging from bluish gray to black dorsally grading to a whitish ...
The meaning of terms that are used can change depending on whether an organism is bipedal or quadrupedal. Additionally, for some animals such as invertebrates , some terms may not have any meaning at all; for example, an animal that is radially symmetrical will have no anterior surface, but can still have a description that a part is close to ...
Sarcopterygii (/ ˌ s ɑːr k ɒ p t ə ˈ r ɪ dʒ i. aɪ /; from Ancient Greek σάρξ (sárx) 'flesh' and πτέρυξ (ptérux) 'wing, fin') — sometimes considered synonymous with Crossopterygii (from Ancient Greek κροσσός (krossós) 'fringe') — is a clade (traditionally a class or subclass) of vertebrate animals which includes a group of bony fish commonly referred to as lobe ...