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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 etymology of the word "morphology" is from the Ancient Greek μορφή (morphḗ), meaning "form", and λόγος (lógos), meaning "word, study, research". [2] [3]While the concept of form in biology, opposed to function, dates back to Aristotle (see Aristotle's biology), the field of morphology was developed by Johann Wolfgang von Goethe (1790) and independently by the German anatomist ...
A few species deposit eggs on land or bypass the tadpole stage. Adult frogs generally have a carnivorous diet consisting of small invertebrates, but omnivorous species exist and a few feed on plant matter. Frog skin has a rich microbiome which is important to their health. Frogs are extremely efficient at converting what they eat into body mass.
These three groups form segments by using a "growth zone" to direct and define the segments. While all three have a generally segmented body plan and use a growth zone, they use different mechanisms for generating this patterning. Even within these groups, different organisms have different mechanisms for segmenting the body.
After internal fertilization and the habit of laying eggs in terrestrial environments became a reproduction strategy amongst the amniote ancestors, the next major breakthrough appears to have involved a gradual replacement of the gelatinous coating covering the amphibian egg with a fibrous shell membrane. This allowed the egg to increase both ...
The largest living amphibian is the 1.8 m (5 ft 11 in) South China giant salamander (Andrias sligoi), but this is dwarfed by prehistoric temnospondyls such as Mastodonsaurus which could reach up to 6 m (20 ft) in length. The study of amphibians is called batrachology, while the study of both reptiles and amphibians is called herpetology.
The world’s frogs, salamanders, newts and other amphibians remain in serious trouble. A new global assessment has found that 41% of amphibian species that scientists have studied are threatened ...
This is a node-based clade, a group with a common ancestry descended from a single "node" (the node being the nearest common ancestor of living species). [16] Defining tetrapods based on the crown group would exclude many four-limbed vertebrates which would otherwise be defined as tetrapods.