Pachycormiformes
Pachycormiformes is an extinct order of marine ray-finned fish known from the Early Jurassic to the end of the Cretaceous. It only includes a single family, Pachycormidae. They were characterized by having serrated pectoral fins (though more recent studies demonstrated that fin shape diversity in this group was high[2]), reduced pelvic fins and a bony rostrum. Their exact relations with other fish are unclear, but they are generally considered to be teleosteomorphs, more closely related to teleosts than to Holostei. Pachycormiformes are morphologically diverse, containing both tuna and swordfish-like carnivorous forms, as well as edentulous suspension-feeding forms, with the latter including the largest ray finned fish known to have existed, Leedsichthys, with an estimated maximum length of 16 metres.
| Pachycormiformes Temporal range: Early Jurassic - Late Cretaceous, | |
|---|---|
| Skeleton of Pachycormus | |
| Skeleton of Orthocormus | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | †Pachycormiformes Berg 1937 |
| Family: | †Pachycormidae Woodward, 1895 |
| Type genus | |
| Pachycormus Agassiz, 1833 | |
| Genera | |
| See text | |
| Synonyms[1] | |
| |
Synapomorphies
Pachycormiformes are united by "a compound bone (rostrodermethmoid) forming the anterodorsal border of the mouth; a reduced coronoid process of the mandible; absence of supraorbitals associated with a dermosphenotic defining the dorsal margin of the orbit; two large, plate-like suborbital bones posterior to the infraorbitals; long, slender pectoral fins; asymmetrical branching of pectoral fin lepidotrichia; considerable overlap of the hypurals by caudal fin rays (hypurostegy); and the presence of distinctive uroneural-like ossifications of the caudal fin endoskeleton"[3]
Relationships
Pachycormiformes are generally interpreted as members of Teleosteomorpha, the group that includes all fish more closely related to modern teleosts than to Holostei (the group containing bowfin and gars), often they have been considered to be the sister group of the Aspidorhynchiformes.[4]
Gallery
Reconstruction of Protosphyraena perniciosa
Life restoration of Leedsichthys
Life restoration of Ohmdenia
Life restoration of Bonnerichthys
Taxonomy
Taxonomy according to Cooper et al. (2022):[5]
- Euthynotus Wagner, 1860
- Haasichthys Delsate, 1999
- Notodectes Dolgopol de Saez, 1949
- Pseudoasthenocormus
- Sauropsis Agassiz, 1843
- Hypsocorminae Vetter, 1881
- Australopachycormus Kear, 2007
- Hypsocormus Wagner, 1860
- Kaykay Gouiric-Cavalli & Arratia, 2022[6]
- Orthocormus Weitzel, 1930
- Protosphyraena Leidy, 1857
- Simocormus Maxwell et al., 2020
- Asthenocorminae Cooper et al., 2022
- Germanostomus Cooper et al., 2022[5]
- Ohmdenia Hauff, 1953
- Pachycormus? Agassiz, 1833
- Saurostomus Agassiz, 1843
- Suspension-feeding clade
- Asthenocormus Woodward, 1895
- Bonnerichthys Friedman et al., 2010
- Leedsichthys Woodward, 1889
- Martillichthys Liston, 2008
- Rhinconichthys Friedman et al., 2010
Cladistics according to Friedman et al. (2010).[7]
| Pachycormiformes | |
References
- ^ van der Laan, R. (2018). "Family-group names of fossil fishes". European Journal of Taxonomy (466). doi:10.5852/ejt.2018.466.
- ^ Liston, Jeff J.; Maltese, Anthony E.; Lambers, Paul H.; Delsate, Dominique; Harcourt-Smith, William E. H.; Heteren, Anneke H. van (2019-11-07). "Scythes, sickles and other blades: defining the diversity of pectoral fin morphotypes in Pachycormiformes". PeerJ. 7: e7675. doi:10.7717/peerj.7675. ISSN 2167-8359. PMC 6842561. PMID 31720097.
- ^ Dobson, Claire; Giles, Sam; Johanson, Zerina; Liston, Jeff; Friedman, Matt (2019-09-03). "Cranial osteology of the Middle Jurassic (Callovian) Martillichthys renwickae (Neopterygii, Pachycormiformes) with comments on the evolution and ecology of edentulous pachycormiforms". Papers in Palaeontology. 7: 111–136. doi:10.1002/spp2.1276. hdl:2027.42/167090. ISSN 2056-2802. S2CID 202919395.
- ^ Peskin, Brianna; Henke, Katrin; Cumplido, Nicolás; Treaster, Stephen; Harris, Matthew P.; Bagnat, Michel; Arratia, Gloria (2020-07-20). "Notochordal Signals Establish Phylogenetic Identity of the Teleost Spine". Current Biology. 30 (14): 2805–2814.e3. doi:10.1016/j.cub.2020.05.037. ISSN 0960-9822. PMC 8159021. PMID 32559448.
- ^ a b Cooper, S. L. A.; Giles, S.; Young, H.; Maxwell, E. E. (2022). "A New Large †Pachycormiform (Teleosteomorpha: †Pachycormiformes) from the Lower Jurassic of Germany, with Affinities to the Suspension-Feeding Clade, and Comments on the Gastrointestinal Anatomy of Pachycormid Fishes". Diversity. 14 (12): 1026. doi:10.3390/d14121026.
- ^ Gouiric-Cavalli, S.; Arratia, G. (2022). "A new †Pachycormiformes (Actinopterygii) from the Upper Jurassic of Gondwana sheds light on the evolutionary history of the group". Journal of Systematic Palaeontology. 19 (21): 1517–1550. doi:10.1080/14772019.2022.2049382. S2CID 248454343.
- ^ Matt Friedman; Kenshu Shimada; Larry D. Martin; Michael J. Everhart; Jeff Liston; Anthony Maltese; Michael Triebold (2010). "100-million-year dynasty of giant planktivorous bony fishes in the Mesozoic seas". Science. 327 (5968): 990–993. Bibcode:2010Sci...327..990F. doi:10.1126/science.1184743. PMID 20167784. S2CID 206524637.