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The external gills seen in salamanders differs greatly from that of amphibians with internalized gills. Unlike amphibians with internalized gills which typically rely on the changing of pressures within the buccal and pharyngeal cavities to ensure diffusion of oxygen onto the gill curtain, neotenic salamanders such as Necturus use specified ...
A number of features distinguish the plethodontids from other salamanders. Most significantly, they lack lungs, conducting respiration through their skin, and the tissues lining their mouths. [3] Some species of cave salamanders are neotenic, and keep their larval gills even as adults. Gills are absent in all other adult plethodontids. [13]
External gills are the gills of an animal, most typically an amphibian, that are exposed to the environment, rather than set inside the pharynx and covered by gill slits, as they are in most fishes. Instead, the respiratory organs are set on a frill of stalks protruding from the sides of an animal's head. The axolotl has three pairs of external ...
[15] [16] The common mudpuppy never leaves its aquatic environment and therefore does not undergo morphogenesis; however, many salamanders do and develop differentiated teeth. [17] Aquatic salamander teeth are used to hinder escape of the prey from the salamander; they do not have a crushing function. [17] This aids the salamander when feeding.
Pharyngeal clefts resembling gill slits are transiently present during the embryonic stages of tetrapod development. The presence of pharyngeal arches and clefts in the neck of the developing human embryo famously led Ernst Haeckel to postulate that " ontogeny recapitulates phylogeny "; this hypothesis, while false, contains elements of truth ...
The greater siren is the third longest salamander in the Western Hemisphere. [4] S. lacertina is paedomorphic, as are all sirens. They lack hindlimbs as well as a pelvic girdle, and have external gills all throughout their lives along with small lungs. They lack eyelids, and have an unfused pectoral girdle. [5]
Sirenidae, the sirens, are a family of neotenic aquatic salamanders. Family members have very small fore limbs and lack hind limbs altogether. [1] In one species, the skeleton in their fore limbs is made of only cartilage. In contrast to most other salamanders, they have external gills bunched together on the neck in both larval and adult
The olm (German: ⓘ) or proteus (Proteus anguinus) is an aquatic salamander which is the only species in the genus Proteus of the family Proteidae [2] and the only exclusively cave-dwelling chordate species found in Europe; the family's other extant genus is Necturus.