Lethenia

Lethenia is an extinct genus of mackerel shark from the Rupelian age of the Oligocene epoch.^[1] It is a monotypic genus, containing only L. vandenbroeki.^[2] It is considered closely related to Isurolamna and sometimes included within it. It differs in the morphology of its teeth, which are much more gracile than Isurolamna and has larger spacing between its crown and lateral cusps. Lethenia is rare and only known from isolated teeth. It is best known from the Boom Clay Formation of Belgium and the Uzunbas Formation of Kazakhstan.^[3][4]

Lethenia Temporal range: Early Oligocene PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Chondrichthyes
Subclass:	Elasmobranchii
Division:	Selachii
Order:	Lamniformes
Family:	Lamnidae
Genus:	†Lethenia Baut & Génault, 1999
Species
Lethenia vandenbroeki