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The features it shares with modern frogs include a forward-sloping ilium, the fusion of the frontal and parietal bones into a single structure known as the frontoparietal, and a lower jaw bone with no teeth. [11] Czatkobatrachus is another proto-frog with some characteristics similar to Triadobatrachus. It is from the early Triassic in Poland ...
Bicuspid teeth (two cusps per tooth, also found in juvenile dissorophoids) Operculum (small bone in the skull, linked to shoulder girdle by the opercularis muscle; perhaps involved in hearing and balance; absent in caecilians and some salamanders, fused to the columella (ear bone) in most anurans)
Gastrotheca guentheri is the only known frog with true teeth in its lower jaw. [ 2 ] [ 6 ] Its teeth have re-evolved after being absent for over 200 million years, challenging Dollo's law . [ 6 ] Re-evolution of teeth in the lower jaw may have been made easier because the frogs have teeth in their upper jaw so there was already a biochemical ...
Salamanders, caecilians and some frogs have one or two rows of teeth in both jaws, but some frogs (Rana spp.) lack teeth in the lower jaw, and toads (Bufo spp.) have no teeth. In many amphibians there are also vomerine teeth attached to a facial bone in the roof of the mouth. [144] Edible frog (Pelophylax esculentus) exhibiting cannibalism
Frogs have no tail, except as larvae, and most have long hind legs, elongated ankle bones, webbed toes, no claws, large eyes, and a smooth or warty skin. They have short vertebral columns, with no more than 10 free vertebrae and fused tailbones (urostyle or coccyx). [ 47 ]
A June 2021 study found that some species of frogs have lost and again evolved teeth ... The critter’s robust skull had additional bones and elements that have likely disappeared with evolution ...
The archaeobatrachians are the most primitive of frogs. These frogs have morphological characteristics which are found mostly in extinct frogs, and are absent in most of the modern frog species. Most of these characteristics are not common between all the families of Archaeobatrachia, or are not absent from all the modern species of frogs.
The hairy frog is also notable in possessing retractable "claws", which it may project through the skin, apparently by intentionally breaking the bones of the toe. [5] These are not true claws, as they are made of bone, not keratin. In addition, there is a small bony nodule nestled in the tissue just beyond the frog's fingertip.