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The evolution of tetrapods began about 400 million years ago in the Devonian Period with the earliest tetrapods evolved from lobe-finned fishes. [1] Tetrapods (under the apomorphy-based definition used on this page) are categorized as animals in the biological superclass Tetrapoda, which includes all living and extinct amphibians, reptiles, birds, and mammals.
The tetrapod tongue is built from muscles that once controlled gill openings. The tongue is anchored to the hyoid bone, which was once the lower half of a pair of gill bars (the second pair after the ones that evolved into jaws). [89] [90] [91] The tongue did not evolve until the gills began to disappear.
Phylogenetic analyses distribute the features that developed along the tetrapod stem and display a stepwise process of character acquisition, rather than abrupt. [1] The complete transition occurred over a period of 30 million years beginning with the tetrapodomorph diversification in the Middle Devonian (380 myr).
The first tetrapods appeared in the fossil record over a period, the beginning and end of which are marked with extinction events. This lasted until the end of the Devonian 359 mya. The ancestors of all tetrapods began adapting to walking on land, their strong pectoral and pelvic fins gradually evolved into legs (see Tiktaalik). [38]
The universal tetrapod characteristics of front limbs that bend backward at the elbow and hind limbs that bend forward at the knee can plausibly be traced to early tetrapods living in shallow water. [18] Panderichthys is a 90–130 cm (35–50 in) long fish from the Late Devonian period (380 Mya). It has a large tetrapod-like head.
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It is the developer of the 2011 and 2022 Prodigy Math, a roleplaying game where players solve math problems to participate in battles and cast spells, and Prodigy English, a sandbox game where players answer English questions to earn currency to gain items. Although each game is standalone, both are accessible through a single Prodigy account.
This allowed giant forms of pterygotes, millipedes and scorpions to exist, making the newly arrived tetrapods remain small until the Carboniferous Rainforest Collapse. However, a large griffinfly with a wingspan about 43–47 cm (1 ft 5 in – 1 ft 7 in) is known from the late Permian, when the oxygen level was much lower. [27]