You can help expand this article with text translated from the corresponding article in French. (January 2025) Click [show] for important translation instructions. View a machine-translated version of the French article. Machine translation, like DeepL or Google Translate, is a useful starting point for translations, but translators must revise errors as necessary and confirm that the translation is accurate, rather than simply copy-pasting machine-translated text into the English Wikipedia. Do not translate text that appears unreliable or low-quality. If possible, verify the text with references provided in the foreign-language article. You must provide copyright attribution in the edit summary accompanying your translation by providing an interlanguage link to the source of your translation. A model attribution edit summary is Content in this edit is translated from the existing French Wikipedia article at [[:fr:Isurus desori]]; see its history for attribution. You may also add the template {{Translated|fr|Isurus desori}} to the talk page. For more guidance, see Wikipedia:Translation.

Isurus desori Temporal range: Early Oligocene-Middle Miocene, 32.5–12.1 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Teeth in Natural History Museum, London.
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Chondrichthyes
Subclass:	Elasmobranchii
Division:	Selachii
Order:	Lamniformes
Family:	Lamnidae
Genus:	Isurus
Species:	†I. desori
Binomial name
†Isurus desori (Agassiz, 1843)[1]
Synonyms
Oxyrhina desori Agassiz, 1843

Isurus desori, commonly known as the Desori mako shark or Desori shark, is an extinct species of mako shark, that lived in the Early Oligocene and Middle Miocene, between 32.5 and 12.1 million years ago. It measured 4.2 m (14 ft) long.

The Isurus desori hunted squids, fish and marine mammals. The fossil of I. desori was discovered in the Chesapeake Bay region.^[2]

Isurus desori belongs to the family Lamnidae in the genus Isurus, and it is believed that it was the ancestor of the present-day mako shark (I. oxyrinchus). It is believed to be related to Cosmopolitodus hastalis and Carcharodon plicatilis as well.^[3]

Scientists believe that I. desori it evolved into the only two contemporary species, I. paucus and I. oxyrinchus, the only surviving species of the genus Isurus. It was once believed that I. desori belonged to the genus Oxyrhina, which is now considered a likely invalid or doubtful genus.^{[citation needed]} Some paleontologist suggest that I. desori is a junior synonym of I. oxyrinchus.

• Louis Agassiz (1843). Recherches Sur Les Poissons Fossiles (in French). Vol. 3. Neuchâtel: Imprimerie de Petitpierre. pp. 282–283. LA1..
• Eugenio Sismonda (1849). "Descrizione dei Pesci e dei Crostacei Fossili nel Piemonte". Memorie della Reale Accademia delle Scienze di Torino. 2 (in Italian). 10. Turin: 1–88. ISSN 1120-1592. ES1. Retrieved 2024-09-21..
• "Les fossiles oligocènes-miocènes des environs de Rennes". Fossiles (in French) (30). 2017.

• Shark references.com: Isurus desori