Megalolamna

Megalolamna is an extinct genus of lamniform 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, and the Jewett Sand Formation of California and Pungo River Formation, North Carolina in the United States, implying a cosmopolitan distribution. The largest specimen is estimated to have measured about 5.1 metres (17 ft) long.

Megalolamna Temporal range: Early to Mid Miocene ~
Fossil teeth from the Dos Bocas Formation, Ecuador
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Chondrichthyes
Subclass:	Elasmobranchii
Order:	Lamniformes
Family:	†Otodontidae
Genus:	†Megalolamna
Species:	†M. serotinus
Binomial name
†Megalolamna serotinus (Probst, 1879)
Synonyms
Megalolamna paradoxodon Shimada et al., 2016

Taxonomy

Life restoration

It is considered to be the sister genus of Otodus. The study of Megalolamna's taxonomic relationships also demonstrates the possibility that Otodus needs to include the species sometimes assigned to Carcharocles (i.e., the megatoothed lineage, including megalodon) in order to be monophyletic.

The genus was originally described by Shimada et al. (2016) with the type species as M. paradoxodon. It was later discovered by Pollerspöck and Shimada (2024) that a tooth belonging to the same species was already described in 1879 under the name 'Otodus serotinus'. Following the ICZN's principle of priority, M. paradoxodon was henceforth recombined into M. serotinus.