''Piscobalaena'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

cetacean Cetacea (; , ) is an infraorder of aquatic mammals that includes whales, dolphins, and porpoises. Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively carnivorous diet. They propel them ...

s, which lived from the Middle to Late Miocene epochs (about 11.6 to 5.3 million years ago) in

Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = Seal (emblem), National seal , national_motto = "Fi ...

and

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

.''Piscobalaena''
at

Fossilworks Fossilworks is a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals ...

.org Its fossils have been found in the

Pisco Formation The Pisco Formation is a geologic formation located in Peru, on the southern coastal desert of Ica, Peru, Ica and Arequipa. The approximately thick formation was deposited in the Pisco Basin, spanning an age from the Miocene, Middle Miocene up to ...

and the

Bone Valley Formation The Bone Valley Formation is a geologic formation in Florida. It is sometimes classified as the upper member of the Peace River Formation of the Hawthorn Group. It contains economically important phosphorite deposits that are mined in west-central ...

of Florida. At least some individuals of this diminutive whale were preyed on by the shark '' C. megalodon''.

Description

This animal looked much like

whales Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and ...

today, particularly small whales. The length was probably less than , and the

skull The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, the ...

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,Pilleri, G. and Siber, H.J. 1989. Neuer Spättertiärer cetotherid (Cetacea, Mysticeti) aus der Pisco-Formation Perus. In: G. Pilleri (ed.), Beiträge zur Paläontologie der Cetaceen Perus, 109–115. Hirnanatomisches Institut, Ostermundigen, Bern. ''Piscobalaena'' is known from fossils found in the Pisco Formation in Peru. ''Piscobalaena'' is considered a representative of

Cetotheriidae Cetotheriidae is a family of baleen whales (parvorder Mysticeti). The family is known to have existed from the Late Oligocene to the Early Pleistocene before going extinct. Although some phylogenetic studies conducted by recovered the living py ...

a group of baleen whales with primitive characteristics similar to that of ''

Balaenoptera ''Balaenoptera'' () is a genus of rorquals containing eight extant species. ''Balaenoptera'' comprises all but two of the extant species in its family (the humpback whale and gray whale); the genus is currently polyphyletic, with the two aforem ...

'', fossil species of which have been found mainly in the northern hemisphere. The closest relative of ''Piscobalaena'' appears to have been ''

Herpetocetus ''Herpetocetus'' is a genus of cetotheriid mysticete in the subfamily Herpetocetinae. Taxonomy There are four recognized species of ''Herpetocetus'': ''H. scaldiensis'', ''H. transatlanticus'',Whitmore, F.C., and L.G. Barnes. 2008. The Herpet ...

'', 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 Miocene

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 The Isthmus of Panama ( es, Istmo de Panamá), also historically known as the Isthmus of Darien (), is the narrow strip of land that lies between the Caribbean Sea and the Pacific Ocean, linking North and South America. It contains the country ...

was open until at least Late Pliocene, allowing the passage of marine species from the

Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...

to the Pacific and vice versa. Other marine mammals found in the Pisco Formation include the odd dolphin ''

Odobenocetops ''Odobenocetops'' () is an extinct genus of small toothed whale known from Peru and Chile. Its fossils are found in Neogene-aged marine strata dating from the Tortonian to the Zanclean. It had two tusks, and, in some fossils, one tusk was longer t ...

'', the long-necked seal '' Acrophoca'', and aquatic

sloth Sloths are a group of Neotropical xenarthran mammals constituting the suborder Folivora, including the extant arboreal tree sloths and extinct terrestrial ground sloths. Noted for their slowness of movement, tree sloths spend most of their li ...

Thalassocnus ''Thalassocnus'' is an extinct genus of semiaquatic ground sloths from the Miocene and Pliocene of the Pacific South American coast. It is monotypic within the subfamily Thalassocninae. The five species—''T. antiquus'', ''T. natans'', ''T. lit ...

''.

References

Baleen whales Prehistoric cetacean genera Miocene mammals of South America Huayquerian Chasicoan Mayoan Neogene Peru Fossils of Peru Miocene mammals of North America Clarendonian Neogene United States Fossil taxa described in 1989 {{paleo-whale-stub