Unexpected heterochrony in Edible Frog (Pelophylax esculentus Linnaeus 1758) and Pallas’ Spadefoot (Pelobates vespertinus Pallas 1771) in Eastern Ukraine

Abstract

M etamorphosis is a crucial process in anuran ontogenesis, through which the larva (tadpole) develops its adult morphology. During the climax stage, the tadpole skeleton, internal organs, and skin restructure, the tail is totally resorbed, and the tadpole loses weight (mostly due to significant water loss) (Brown and Cai 2007). It is quite important that these processes progress quickly and be coordinated in order to shorten the highly vulnerable period of the meta-Unexpected Heterochrony in the Edible Frog, Pelophylax esculentus (Linnaeus 1758), and Pallas' Spadefoot, Pelobates vespertinus (Pallas 1771), in Eastern Ukraine