''Vieraella'' is an extinct genus of
frog
A frog is any member of a diverse and largely Carnivore, carnivorous group of short-bodied, tailless amphibians composing the order (biology), order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-f ...
from the Lower
Jurassic
The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...
(Early
Pliensbachian
The Pliensbachian is an age of the geologic timescale and stage in the stratigraphic column. It is part of the Early or Lower Jurassic Epoch or Series and spans the time between 190.8 ± 1.5 Ma and 182.7 ± 1.5 Ma (million years ago). The Plien ...
to
Toarcian
The Toarcian is, in the ICS' geologic timescale, an age and stage in the Early or Lower Jurassic. It spans the time between 182.7 Ma (million years ago) and 174.1 Ma. It follows the Pliensbachian and is followed by the Aalenian.
The Toarcian ...
)
Roca Blanca Formation of
Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
, and one of the oldest true frogs known. This genus is known by a single excepcionally well preserved specimen, P.V.L. 2188, with at least eight presacrals vertebrae, free ribs, ulna and radius not fused, bony skull with some discoglossid characters.
Description
Despite living around 188 million years ago, ''Vieraella'' was
anatomically very similar to modern frogs. For example, its hind legs were adapted for jumping, and the skull already possessed the lattice-like form found in modern species. It was, however, an unusually small frog, measuring only in length. Although older frog-like creatures are known, such as ''
Triadobatrachus
''Triadobatrachus'' is an extinct genus of salientian frog-like amphibians, including only one known species, ''Triadobatrachus massinoti''. It is the oldest member of the frog lineage known, and an excellent example of a transitional fossil. It ...
'', these possessed many primitive characteristics, and cannot be said to be "true" frogs.
References
Further reading
* Estes, R., and O. A. Reig. 1973. The early fossil record of frogs: a review of the evidence. pp. 11–63 In J. L. Vial (Ed.), Evolutionary Biology of the Anurans: Contemporary Research on Major Problems. University of Missouri Press, Columbia.
Mesozoic frogs
Early Jurassic amphibians
Jurassic amphibians of South America
Early Jurassic animals of South America
Jurassic Argentina
Fossils of Argentina
Fossil taxa described in 1963
Transitional fossils
{{paleo-anura-stub