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Amphistium Temporal range: Ypresian,
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Actinopterygii |
Order: | Carangiformes |
Suborder: | Pleuronectoidei |
Family: | †Amphistiidae Boulenger, 1902 |
Genus: | †Amphistium Agassiz, 1835 |
Species: | †A. paradoxum
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Binomial name | |
†Amphistium paradoxum Agassiz, 1835
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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 and the family Amphistiidae, 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]
Amphistium is among the many fossil fish species known from the Monte Bolca Lagerstätte of Ypresian Italy. Heteronectes is a related, and very similar fossil from a slightly earlier strata of France. Heteronectes is sometimes also placed in the family Amphistiidae, though other studies find it to be more basal than any other flatfish taxon.[4][5]