| Oegopsida | |
|---|---|
 | |
| Moroteuthis ingens | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Superorder: | Decapodiformes |
| Order: | Oegopsida Orbigny, 1845[2] |
| Families | |
See text | |
| Synonyms | |
| |
Oegopsida is one of the twoorders ofsquid in thesuperorderDecapodiformes, in theclassCephalopoda. Together with theMyopsina, it was formerly considered to be a suborder of the order Teuthida, in which case it was known asOegopsina. This reclassification is due to Oegopsina and Myopsina not being demonstrated to form a clade.[3]
The Oegopsida are an often pelagic squid, with some nerito-oceanic species associated with sea mounts.[4] They consist of 24families and 69genera. They have these characters in common: the head is without tentacle pockets, eyes lack a corneal covering, arms and tentacle clubs may have hooks, the buccal supports are without suckers, and oviducts in females are paired.
Two families, theBathyteuthidae andChtenopterygidae, which have features characteristic of theMyopsida while retaining others common to the Oegopsina, were formerly placed in the family, but are now placed in their own orderBathyteuthida.[5]
The Oegopsida differ from the coastal Myopsida, characterised by the genusLoligo, which have corneal coverings over the eyes and tentacle pockets, but lack hooks, have no suckers on the buccal supports, and a single oviduct.
Oegopsid squid are the only decapods that lack a pocket for the tentacles. Otherwise, they share different characters with different decapod groups. Like the Bathyteuthida and Myopsida, the Oegopsida have a brachial canal, which is absent in other forms. As with theSpirulidae andIdiosepiidae, the Oegopsida lack suckers on the buccal supports, and like the Bathyteuthida, Idiosepiidae, and Spirulidae, they have no circular muscle on the suckers.
The earliest fossils of Oegopsida arejaw fragments from theSantonian or earlyCampanian of theYezo Group inHokkaido,Japan. These jaw fragments are extremely large, suggesting that oegopsids could already evolve very large body sizes early on. One of these fossils was described as the genusYezoteuthis, which has been estimated to rival the moderngiant squid in size. Another jaw fragment described in 2023 was found to be twice as long as a giant squid's jaws.[1][6]
The following taxonomic classification was found by Fernández-Álvarezet al., 2021:[5]
The following phylogeny was found by Fernández-Álvarezet al., 2021:[5]
| Oegopsida | |
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