Pachycormiformes

From Wikipedia, the free encyclopedia
(Redirected from Pachycormiform)
Jump to navigation Jump to search

Pachycormiformes
Temporal range: Early Jurassic - Late Cretaceous, Toarcian–Maastrichtian
File:Pachycormus bollensis - Naturmuseum Senckenberg - DSC02210 (cropped).JPG
Skeleton of Pachycormus
File:Orthocormus cornutus 1.JPG
Skeleton of Orthocormus
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Infraclass: Teleosteomorpha
Division: Aspidorhynchei
Order: Pachycormiformes
Berg 1937
Family: Pachycormidae
Woodward, 1895
Type genus
Pachycormus
Agassiz, 1833
Genera

See text

Synonyms[1]
  • Diphyodontidae Jordan, 1923
  • Erisichtheidae Cope, 1877b
  • Microlepidoti Zittel, 1887
  • Pelecopteridae Cope, 1875
  • Protosphyraenidae Lydekker, 1889
  • Sauropsidae Cope, 1877a
  • Saurotomini [Saurostomini] Bonaparte, 1846 corrig. Bonaparte 1850a

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. Pachycormiformes are morphologically diverse, containing both tuna and swordfish-like carnivorous forms, as well as edentulous suspension-feeding forms.

Description

[edit | edit source]
File:Pachycormidae assortment.png
Size comparison of various species of Pachycormiform fish

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] Pachycormiformes varied substantially in size, from medium-sized fishes around 40–111 centimetres (1.31–3.64 ft) in length like the macropredator Pachycormus,[4] to the largest known ray-finned fish, the suspension feeding Leedsichthys, which is estimated to have reached a maximum length of around 16 metres (52 ft).[5]

Relationships

[edit | edit source]

Pachycormiformes are generally interpreted as basal 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.[6][7]

[edit | edit source]

Taxonomy

[edit | edit source]

Taxonomy according to Cooper et al. (2022):[8]

Cladistics according to Friedman et al. (2010).[10]

Pachycormiformes

References

[edit | edit source]
  1. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  2. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  3. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  4. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  5. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  6. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  7. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  8. ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  9. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  10. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).

Lua error in Module:Taxonbar at line 165: attempt to index field 'wikibase' (a nil value).