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A tetrapod is a form of wave-dissipating concrete block used to prevent erosion caused by weather and longshore drift, primarily to enforce coastal structures such as seawalls and breakwaters. Tetrapods are made of concrete , and use a tetrahedral shape to dissipate the force of incoming waves by allowing water to flow around rather than ...
The water-based lateral line system was used substantially by these aquatic tetrapods to detect danger from predators. [2] Within the Osteichthyan diversification, there were no changes related to respiration in the transition as can be seen by the nasal region and palatal morphology in elpistostegalid fishes.
Shoreline indicators may be morphological features such as the berm crest, scarp edge, vegetation line, dune toe, dune crest and cliff or the bluff crest and toe. Alternatively, non-morphological features may be used such as water level (high water line (HWL), mean high water line) wet/dry boundary and the physical water line. [30]
Several groups of tetrapods have undergone secondary aquatic adaptation, an evolutionary transition from being purely terrestrial to living at least part of the time in water. These animals are called "secondarily aquatic" because although their ancestors lived on land for hundreds of millions of years, they all originally descended from ...
However, most tetrapod species today are amniotes, most of which are terrestrial tetrapods whose branch evolved from earlier tetrapods early in the Late Carboniferous. The key innovation in amniotes over amphibians is the amnion , which enables the eggs to retain their aqueous contents on land, rather than needing to stay in water.
Tetrapodomorpha (also known as Choanata [3]) is a clade of vertebrates consisting of tetrapods (four-limbed vertebrates) and their closest sarcopterygian relatives that are more closely related to living tetrapods than to living lungfish.
The tetrapods evolved from the lobe-finned fishes about 395 million years ago in the Devonian. [23] The specific aquatic ancestors of the tetrapods, and the process by which land colonization occurred, remain unclear, and are areas of active research and debate among palaeontologists at present.
Eotetrapodiformes is a clade of tetrapodomorphs including the four-limbed vertebrates ("tetrapods" in the traditional sense) and their closest finned relatives, two groups of stem tetrapods called tristichopterids and elpistostegalids.