Amphistium paradoxum (from Greek: ἀμφί amphi, 'on both sides', Greek: ιστίον istion 'sail', and Greek: παράδοξος paradoxus 'extraordinary'),[1] the only species classified under the genus Amphistium, is a fossil fish which has been identified as a Paleogene relative of the flatfish, and as a transitional fossil.[2] In a typical modern flatfish, the head is asymmetric with both eyes on one side of the head. In Amphistium, the transition from the typical symmetric head of a vertebrate is incomplete, with one eye placed near the top of the head.[3]

Temporal range: Middle Eocene
Scientific classification edit
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Pleuronectiformes
Genus: Amphistium
Agassiz, 1835
A. paradoxum
Binomial name
Amphistium paradoxum
Agassiz, 1835

Amphistium is among the many fossil fish species known from the Monte Bolca Lagerstätte of Lutetian Italy. Heteronectes is a related, and very similar fossil from a slightly earlier strata of France.


  1. ^ Roberts, George (1839). An etymological and explanatory dictionary of the terms and language of geology. London: Longman, Orme, Brown, Green, & Longmans. p. 7, 145. Retrieved 29 December 2021.
  2. ^ "Odd Fish Find Contradicts Intelligent-Design Argument". National Geographic. July 9, 2008. Retrieved 2008-07-17.
  3. ^ Matt Friedman (2008-07-10). "The evolutionary origin of flatfish asymmetry". Nature. 454 (7201): 209–212. Bibcode:2008Natur.454..209F. doi:10.1038/nature07108. PMID 18615083. S2CID 4311712.