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The numbers of species cited above follows Frost and the total number of known (living) amphibian species as of March 31, 2019, is exactly 8,000, [12] of which nearly 90% are frogs. [ 13 ] With the phylogenetic classification, the taxon Labyrinthodontia has been discarded as it is a polyparaphyletic group without unique defining features apart ...
The list below largely follows Darrel Frost's Amphibian Species of the World (ASW), Version 5.5 (31 January 2011). Another classification, which largely follows Frost, but deviates from it in part is the one of AmphibiaWeb, which is run by the California Academy of Sciences and several of universities. The major differences between these two ...
The list of organisms by chromosome count describes ploidy or numbers of chromosomes in the cells of various plants, animals, protists, and other living organisms.This number, along with the visual appearance of the chromosome, is known as the karyotype, [1] [2] [3] and can be found by looking at the chromosomes through a microscope.
[21] [22] There has been, however, no other physical indicating factors for male-male combat as in other species of amphibians, such as horns or spines. [22] Some populations do not show these sexual dimorphic traits, and in certain locations female and male bodies do not exhibit any traits with significant differences.
The species is a tetrapod, its four legs adapting the fish-like body plan for walking on land. The specimen is 26 m (85 ft) long. The specimen is 26 m (85 ft) long. As embryos, vertebrates still have a notochord; as adults, all but the jawless fishes have a vertebral column, made of bone or cartilage , instead. [ 7 ]
The N and Q lineages contribute two blast cells for each segment, while the M, O, and P lineages only contribute one cell per segment. [5] Finally, the number of segments within the embryo is defined by the number of divisions and blast cells. [2]
Frog populations have declined significantly since the 1950s. More than one third of species are considered to be threatened with extinction and over 120 are believed to have become extinct since the 1980s. The number of malformations among frogs is on the rise and an emerging fungal disease, chytridiomycosis, has spread around the world.
Amphibians are ectothermic, anamniotic, four-limbed vertebrate animals that constitute the class Amphibia. In its broadest sense, it is a paraphyletic group encompassing all tetrapods excluding the amniotes (tetrapods with an amniotic membrane , such as modern reptiles , birds and mammals ).