| Ionoscopus Temporal range: | |
|---|---|
 | |
| Specimen of I. petrarojae | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Clade: | Halecomorphi |
| Order: | †Ionoscopiformes |
| Family: | †Ionoscopidae |
| Genus: | †Ionoscopus Costa, 1853 |
| Species | |
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See text | |
Ionoscopus is an extinct genus of marine halecomorph ray-finned fish from the Late Jurassic to Early Cretaceous of Europe. It is the type genus of the order Ionoscopiformes, a diverse group of halecomorph fish from the Mesozoic that were distantly related to the modern bowfin.
The following species are known:
- ?I. analibrevis Stuetzer, 1972 - Late Jurassic (Tithonian) of Germany (Solnhofen Formation)
- I. desori (Thiollière, 1858) - Late Jurassic (Kimmeridgian) of France (Cerin Lagerstätte)
- ?I. muensteri (Giebel, 1848) - Tithonian of Germany (Solnhofen Formation)
- I. petrarojae Costa, 1853 (type species) - Early Cretaceous (Albian) of Italy (Pietraroja Plattenkalk)
- ?I. striatissimus (Münster, 1842) - Tithonian of Germany (Solnhofen Formation)
In a 2016 review, both I. desori and I. petrarojae were identified as the only definitively valid members of the genus. Three other German species were found to have remains too poorly-preserved or less-studied to allow for a proper taxonomic assignment. 'I.' cyprinoides (Wagner, 1863), a well-known species from the Late Jurassic of Germany, was found to be morphologically distinct from Ionoscopus and warrant reclassification into its own genus.
The closest relative of Ionoscopus is thought to be Quetzalichthys from the Early Cretaceous of Mexico.
