''Megalolamna'' is an extinct genus of

lamniform The Lamniformes (, from Greek ''lamna'' "fish of prey") are an order of sharks commonly known as mackerel sharks (which may also refer specifically to the family Lamnidae). It includes some of the most familiar species of sharks, such as the gre ...

shark that belongs to the family Otodontidae. Its name comes from the similarity of its teeth to those of the extant shark genus '' Lamna.'' It is known from the early Miocene Chilcatay Formation of Peru, Oi and O'oshimojo Formations of

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

, and the Jewett Sand Formation of California and

Pungo River Formation The Pungo River Formation is a geologic formation in North Carolina. It preserves fossils dating back to the Middle Miocene. Economic significance The Pungo River Formation is mined extensively for its phosphorite deposits. See also * List ...

, North Carolina in the United States, implying a cosmopolitan distribution. The largest specimen is estimated to have measured about long.

Taxonomy

It is considered to be the

sister genus In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and t ...

of '' Otodus''. The study of ''Megalolamna'''s taxonomic relationships also demonstrates the possibility that ''Otodus'' needs to include the species sometimes assigned to ''

Carcharocles ''Otodus'' is an extinct genus of mackerel shark which lived from the Paleocene to the Pliocene epoch. The name ''Otodus'' comes from Ancient Greek (, meaning "ear") and (, meaning "tooth") – thus, "ear-shaped tooth". Anatomy This shark is k ...

'' (i.e., the megatoothed lineage, including megalodon) in order to be

monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...

References

{{Taxonbar, from=Q27092801 Otodontidae Prehistoric marine animals Miocene fish of Asia Fossils of Japan Miocene fish of North America Neogene California Fossils of North Carolina Prehistoric fish of South America Miocene animals of South America Neogene Peru Fossils of Peru Fossil taxa described in 2016