Archaeolamna

Archaeolamna (from Greek arche which turned into archaeo and Lamna, an extinct shark genus)^[2] is an extinct genus of mackerel sharks that lived during the Cretaceous. It contains three valid species (one with two subspecies) which have been found in Europe, North America, and Australia.^[7][8] While it is mostly known from isolated teeth, an associated set of teeth, jaws, cranial fragments, and vertebrae of A. kopingensis is known from the Pierre Shale of Kansas.^[7] Teeth of A. k. judithensis were found with a plesiosaur skeleton with bite marks from the Judith River Formation of Montana.^[2] It was a medium-sized shark with an estimated total body length of 3–4 metres (9.8–13.1 ft).^[9]

Archaeolamna Temporal range: Albian-Maastrichtian PreꞒ Ꞓ O S D C P T J K Pg N
Tooth of Archaeolamna sp.
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Chondrichthyes
Subclass:	Elasmobranchii
Division:	Selachii
Order:	Lamniformes
Family:	†Archaeolamnidae Underwood & Cumbaa, 2010[1]
Genus:	†Archaeolamna Siverson, 1992[2]
Type species
†Archaeolamna kopingensis (Davis, 1890)[3]
Other species and subspecies
†Archaeolamna striata (Rogovich, 1861)[4] †Archaeolamna kopingensis kopingensis (Davis, 1890) †Archaeolamna kopingensis judithensis Siverson, 1992 †Archaeolamna haigi Siverson, 1996[5]
Synonyms
Species synonymy A. striata Otodus striatus Rogovich, 1861 A. kopingensis Odontaspis kopingensis Davis, 1890 Lamna arcuata Woodward, 1894[6]

Archaeolamna likely had an antitropical distribution, being found in the temperate waters of both hemispheres but absent from the tropical waters around the equator, much like the modern porbeagle shark. A similar distribution has been found for the related Cardabiodon.^[7]

Taxonomy

When the family Archaeolamnidae was first named, it contained Archaeolamna, Cretodus, Dallasiella, and Telodontaspis.^[1] However, Cretodus was reassigned to Pseudoscapanorhynchidae,^[10] Dallasiella was reassigned to Lamniformes incertae sedis,^[11] and Telodontaspis was synonymized with Cretoxyrhina.^[12] This leaves Archaeolamna as the sole member of the family.