Kingdom Animalia Infraorder Cetacea Order Even-toed ungulate | Class Mammalia Phylum Chordata | |
 | ||
Family Cetotheriidae
G. Pilleri and H. J. Siber, 1989 Genus †Piscobalaena nana
G. Pilleri and H. J. Siber, 1989 Similar Cetotheriidae, Cetotherium, Diorocetus, Thalassocnus, Miocaperea | ||
Piscobalaena is an extinct genus of cetacean which lived between the Miocene and the upper Pliocene (about 10 to 5 million years ago). Its fossils have been found in the Pisco Formation of Peru. At least some individuals of this diminutive whale were preyed on by the shark C. megalodon.
Contents
Description
This animal looked much like whales today, particularly small whales. The length was less than 5 meters, and the skull of an adult was about one meter. Piscobalaena is known for some well-preserved specimens, including three young individuals and an adult. Some characteristics of the skull distinguish Piscobalaena from modern whales (such as the shape of the supraorbital process).
Classification
Described for the first time in 1989 by Pilleri and Siber, Piscobalaena is known from fossils found in the Pisco formation in Peru, an area that corresponds with the late Miocene (c. 10 Ma) to late Pliocene (c. 2 Ma). Piscobalaena is considered a representative of Cetotheriidae a group of baleen whales with primitive characteristics similar to that of Balaenoptera, fossil species of which have been found mainly in the northern hemisphere. The closest relative of Piscobalaena appears to have been Herpetocetus, from the Mio-Pliocene of the northern hemisphere.
Palaeogeography
Other fragmentary remains attributed to Piscobalaena are also from Peru, but date a little older (late Miocene, about 10 million years ago). So it seems that this kind of whales were located in the Pacific coast of South America and evolved for at least five million years. Other fossils attributed with some doubt to Piscobalaena come from the Pliocene of Florida: If so, then Piscobalaena might have had a wider distribution than the Peruvian coast. This could have been because the Isthmus of Panama was open until at least late Pliocene, allowing the passage of marine species from the Atlantic to the Pacific and vice versa. Other marine mammals found in the Pisco formation include the odd dolphin Odobenocetops, the long-necked seal Acrophoca, and aquatic sloth Thalassocnus.