| Semionotiformes Temporal range:
| |
|---|---|
| |
| Fossil specimen of Macrosemimimus fegerti | |
| |
| Fossil of Macrosemius | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Clade: | Ginglymodi |
| Clade: | Neoginglymodi |
| Order: | †Semionotiformes Arambourg & Bertini 1958 sensu López-Arbarello 2012 |
| Type genus | |
| †Semionotus Agassiz, 1843
| |
| Families | |
| Synonyms | |
|
Macrosemiiformes Grande & Bemis 1998 | |
Semionotiformes is an order of ray-finned fish known from the Middle Triassic (Anisian)[1] to the Late Cretaceous (Maastrichtian).[2] Their closest living relatives are gars (Lepisosteidae), with both groups belonging to the clade Ginglymodi within the Holostei.[1] The group includes both freshwater (Semionotidae) and marine (Callipurbeckiidae, Macrosemiidae) adapted forms.[3] Many members of the family Macrosemiidae (which are usually included in Semionotiformes but sometimes placed in their order), had elongated dorsal fins, often associated with an adjacent area of skin which was free of scales. These fins were likely undulated for use in precision swimming. The body morphology of macrosemiids suggests that they were slow swimmers who were capable of maneuvering around complex topography, such as reef environments.[4]
- ^ a b Romano, Carlo (2021). "A Hiatus Obscures the Early Evolution of Modern Lineages of Bony Fishes". Frontiers in Earth Science. 8: 672. doi:10.3389/feart.2020.618853. ISSN 2296-6463.
- ^ Blanco, Alejandro; Szabó, Márton; Blanco-Lapaz, Àngel; Marmi, Josep (January 2017). "Late Cretaceous (Maastrichtian) Chondrichthyes and Osteichthyes from northeastern Iberia". Palaeogeography, Palaeoclimatology, Palaeoecology. 465: 278–294. Bibcode:2017PPP...465..278B. doi:10.1016/j.palaeo.2016.10.039.
- ^ Cavin, Lionel; Deesri, Uthumporn; Olive, Sébastien (2020-03-18). "Scheenstia bernissartensis (Actinopterygii: Ginglymodi) from the Early Cretaceous of Bernissart, Belgium, with an appraisal of ginglymodian evolutionary history". Journal of Systematic Palaeontology. 18 (6): 513–527. Bibcode:2020JSPal..18..513C. doi:10.1080/14772019.2019.1634649. ISSN 1477-2019. S2CID 199631685.
- ^ Cawley, John J.; Marramà, Giuseppe; Carnevale, Giorgio; Villafaña, Jaime A.; López-Romero, Faviel A.; Kriwet, Jürgen (February 2021). "Rise and fall of †Pycnodontiformes: Diversity, competition and extinction of a successful fish clade". Ecology and Evolution. 11 (4): 1769–1796. Bibcode:2021EcoEv..11.1769C. doi:10.1002/ece3.7168. ISSN 2045-7758. PMC 7882952. PMID 33614003.