anuran

Any amphibian of the order Anura; a frog, a toad.

The fact that the higher Batrachia go on metamorphosing until several of their structures are so perfect as to require but the gentlest modification to make them fit for the Mammal, does not require one to suppose that the Toad and the Frog lie in the direct route from the Ichthyic to the Mammalian types. That such power of variation, such aptitude for transformation exists in these essential but metamorphic Fish, suggests the probability that some of the very earliest of the Amphibia, filial perhaps to forms far lower than the Lamprey, did not stop at the last metamorphic stage of an Anuran, but changed still further, and thus laid the foundation of the higher classes.

Inactivity may dominate an anuran’s life. Spea hammondii in the deserts of southwestern North America spend >90% of their life inactive; they appear explosively and breed with the first heavy summer rains, then feed for 2–3 weeks before becoming inactive for another year.

Of or relating to the order Anura.

As a further illustration, we may take the results of experiments in which a Urodele organiser (from Triton alpestris) is grafted into an Anuran embryo (Bufo vulgaris).

It is well known that an anuran tadpole or an insect larva will never turn into its adult form if the respective endogenous metamorphic hormones, thyroxine and ecdysone, were withdrawn or prevented from reaching the target tissues.