page_title: Cretalamna
section_title: Research History
hierarchical_section_title: Cretalamna / Taxonomy / Research History
caption_attribution_description: .^ ^ 1-. \, «&#160;- Vol. 3 To"b.32 ? . \i
context_page_description: Cretalamna is a genus of extinct otodontid shark lived about 103 to 46 million years ago from the Late Cretaceous to Eocene epochs. It is considered by many to be the ancestor of the largest sharks to have ever lived, Carcharocles angustidens, and Carcharocles megalodon.
context_section_description: Cretalamna was first described by Swiss naturalist Louis Agassiz using five teeth previously identified as the common smooth-hound and collected by English paleontologist Gideon Mantell from the Southerham Grey Pit near Lewes, East Sussex. In his 1835 publication Rapport sur les poissons fossiles découverts en Angleterre, he reidentified them as a new species of porbeagle shark under the taxon Lamna appendiculata. In 1843, Agassiz published Recherches sur les poissons fossiles, which reexamined Mantell's five teeth. Using them, eight additional teeth collected by Mantell, and twenty more teeth collected by various paleontologists in various locations (One tooth found by the 3rd Earl of Enniskillen from the Speeton Clay in Yorkshire; one tooth of the collection of a Strasbourg Museum from an unspecified location; one tooth of the collection of the Hancock Museum from the Marly Chalk near Cambridge; and six teeth of the collection of German paleontologist Heinrich Georg Bronn from chalk around Aachen), he described a species whose teeth had thick bulged roots, lateral cusplets, and extreme variability. Agassiz remarked that some of the examined teeth may be variable enough to belong to a separate species, but ultimately unified them under a new taxon Otodus appendiculatus. The species would later be found in 1958 by Soviet paleontologist Leonid Glickman to belong to a distinct new genus- Cretalamna.
  Despite Agassiz's remarks on variability, his ultimately broad interpretation of O. appendiculatus subsequently led the species to become a wastebasket taxon culminating to an interpretation of C. appendiculata as a variable cosmopolitan species with a 50 million year range. This changed when paleontologist Mikael Siversson found that the twenty-five syntypes actually represented a mix of at least six or more different species including three additional genera Dwardius, Cretoxyrhina, and Cretodus. To remedy the taxonomic issue, he redesignated one of the syntypes as the sole lectotype of C. appendiculata in 1999. In 2015, he led a study which revisited the taxonomic situation and established a renewed description of the species, which led to the erection of six additional Cretalamna species- C. catoxodon, C. deschutteri, C. ewelli, C. gertericorum, C. hattini, and C. sarcoporthea.
  Before Siversson, other Cretalamna species have been described. Another species described by Agassiz under the taxon Otodus latus was demoted to a variation of C. appendiculata in 1908, promoted into a subspecies in 1977 by French paleontologist Jaques Herman, and finally elevated to the species level as Cretolamna lata by Herman and paleontologist Van Waes Hilde in 2012. In 1897, French paleontologist Fernand Priem described a single tooth from the Köpinge Sandstone in Scania, Sweden under the taxon Lamna borealis. This would be revised to  'Cretolamna borealis'  by Glickman in a 1980 paper. In 1902, German paleontologist Johannes Wanner described teeth from Egyptian Cretaceous deposits near the Dakhla Oasis and Farafra. He noted that the teeth are almost identical with that of the Otodus appendiculatus teeth, except that the Egyptian teeth also contained two clear pairs of lateral cusplets (a feature not seen in Otodus appendiculatus). Wanner concluded that the teeth were of a closely related new species and placed it under the taxon Otodus biauriculatus. In 1935, French Paleontologist Camille Arambourg described a new subspecies of C. biauriculata from teeth found in Moroccan phosphates under the taxon Lamna biauriculata maroccana, which was elevated into its own species in 1997. In 1972, French ichthyologist Henri Cappetta described teeth from Maastrichtian deposits near the Mentès well in Tahoua, Niger, which he assigned to the subspecies Lamna biauriculata nigeriana. This subspecies would also be elevated to its own species in 1991. In 1975, Cappetta and American paleontologist Gerard Case examined Cretalamna teeth described by Arambourg in 1952 from Danian deposits in Morocco and proposed that it represents a new subspecies of the type species 
caption: Original syntypes of Otodus appendiculatus (Fig. 1-25) and holotype of C. lata (Fig. 26) in the third volume of Recherches sur les poissons fossiles; the tooth in Fig. 10 is the sole lectotype of C. appendiculata
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