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Rana (derived from Latin rana, meaning 'frog') is a genus of frogs commonly known as the Holarctic true frogs, pond frogs or brown frogs. Members of this genus are found through much of Eurasia and western North America .
The New Zealand frog, Leiopelma hochstetteri, uses a supernumerary sex chromosome. With zero of that chromosome, the frog develops into a male. With one or more, the frog develops into a female. One female had as many as 16 of that chromosome. [48] Different populations of the Japanese frog Rana rugosa uses different systems. Two use ...
Several of the genera within the Leptodactylidae lay their eggs in foam nests. These can be in crevices, on the surface of water, or on forest floors. These foam nests are some of the most varied among frogs. When eggs hatch in nests on the forest floor, the tadpoles remain within the nest, without eating, until metamorphosis.
"Fewer than a dozen of the 6455 species of frogs in the world are known to have internal fertilization, and of these, all but the new species either deposit fertilized eggs or give birth to froglets."
In the frog Gastrotheca ovifera, embryos are fed by the mother through specialized gills. The lizard Pseudemoia pagenstecheri and most mammals use this form of viviparity. [1] Thus the definition of oviparity is narrower in the revised scheme, as it does not include the "ovuliparity" found in most fish, most frogs and many invertebrates.
A true toad is any member of the family Bufonidae, in the order Anura (frogs and toads). This is the only family of anurans in which all members are known as toads, although some may be called frogs (such as harlequin frogs). The bufonids now comprise more than 35 genera, Bufo being the best known.
Endangered male frogs with an unconventional approach to child-rearing have 'given birth' to 33 tiny young in the UK as part of an urgent mission to rescue the species from a devastating fungal ...
The oldest fossil "proto-frog" Triadobatrachus is known from the Early Triassic of Madagascar (250 million years ago), but molecular clock dating suggests their split from other amphibians may extend further back to the Permian, 265 million years ago. Frogs are widely distributed, ranging from the tropics to subarctic regions, but the greatest ...