| Balaenoptera siberi | |
|---|---|
 | |
| Balaenoptera siberi | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Artiodactyla |
| Suborder: | Whippomorpha |
| Infraorder: | Cetacea |
| Family: | Balaenopteridae |
| Genus: | Balaenoptera |
| Species: | †B. siberi |
| Binomial name | |
| †Balaenoptera siberi Pilleri & Pilleri 1989 | |
Balaenoptera siberi is an extinct species ofbaleen whale from theLate Miocene, described by Pilleri and Pilleri in 1989, based on fossils found in thePisco Formation of thePisco Basin in southwestern Peru.[1]
The baleen whale fossils comprise a complete skeleton, including the skull, baleen, mandibles, flippers, and vertebral column. Theholotype fossils are housed in a private collection, belonging to Allejandro Pezzia Asserto,[1] while aparatype is stored in theStaatliches Museum für Naturkunde inStuttgart, Germany. The skull of the whale has a length of 228 centimetres (7.48 ft) and a width of 111 centimetres (44 in) and intermediate in size betweenBalaenoptera acutorostrata andB. borealis.[2]
Fossils of the species were found in two different locations in the Pisco Formation; Aguada de Lomas,[3] and Sacaco (SAO horizon).[4] At time of description of the species, the sediments at Aguada de Loma ranged in age from the Late Miocene toLate Pliocene,[5] with the layer the fossils were found dated to about 8 Ma (Huayquerian).[3] Subsequent dating of the sediments by Marx and Fordyce in 2015 gave alate Tortonian toearly Messinian range of 7.0 to 8.0 Ma.[3]
The sediments at Sacaco were previously thought to be earlyLate Pliocene (3.9 Ma), while Ehret et al. in 2012 defined aMessinian age of more than 5.75 Ma for this unit of the Pisco Formation.[4]
The Pisco Formation has provided many fossils of marine mammals, including several toothed whales (Acrophyseter,Koristocetus,Scaphokogia,Livyatan and more), other baleen whales (Incakujira,Miocaperea andPiscobalaena, among others),porpoises (Lomacetus andPiscolithax), seals (Hadrokirus,Piscophoca andAustralophoca), marine (Hemisyntrachelus) and river dolphins (Brachydelphis andBrujadelphis), and the swimming slothThalassocnus. Additionally, fossil penguins and other birds (such asPelagornis) and shark teeth, among others ofmegalodon, were found in thefossiliferous Pisco Formation.[3][4]
