Orthoceratoidea
Sign in to saveOrthoceratoidea, from Ancient Greek ὀρθός (orthós), meaning "straight", and κέρας (kéras), meaning "horn", is a major subclass of nautiloid cephalopods. Members of this subclass usually have orthoconic (straight) to slightly cyrtoconic (curved) shells, and central to subcentral siphuncles which may bear internal deposits. Orthoceratoids are also characterized by dorsomyarian muscle scars (a small number of large scars concentrated at the top of the body chamber), extensive cameral deposits, and calciosiphonate connecting rings with a porous and calcitic inner layer.
In the Vinony graph
Within Vinony's link graph, Orthoceratoidea is referenced by 35 other articles, and connects out to paraphyly, Morocco and Animalia.
It is catalogued under topics including Mesozoic cephalopods, Mollusc subclasses and Ordovician first appearances.
Its subject is documented across 4 Wikipedia language editions.
Wikidata facts
- Instance of
- taxon
- Parent taxon
- Cephalopod
- Image
- Orthoceras (Maroc).JPG
Show 3 more facts
- Commons category
- Orthoceratoidea
- taxon name
- Orthoceratoidea
- taxon rank
- subclass
Sources (1)
via Wikidata · CC0
~4 min read
Encyclopedic overview
3 sectionsContents
- Taxonomy
- References
- External links
Orthoceratoidea, from Ancient Greek ὀρθός (orthós), meaning "straight", and κέρας (kéras), meaning "horn", is a major subclass of nautiloid cephalopods. Members of this subclass usually have orthoconic (straight) to slightly cyrtoconic (curved) shells, and central to subcentral siphuncles which may bear internal deposits. Orthoceratoids are also characterized by dorsomyarian muscle scars (a small number of large scars concentrated at the top of the body chamber), extensive cameral deposits, and calciosiphonate connecting rings with a porous and calcitic inner layer.
Currently, Orthoceratoidea comprises the orders Riocerida, Dissidocerida, Actinocerida, Pseudorthocerida, Lituitida and Orthocerida. Orthocerida is a noteworthy paraphyletic order which is ancestral to the major cephalopod groups such as the extinct ammonoids and living coleoids (cephalopods without external shells, including squids, octopus, cuttlefish, etc.).
Excerpted from Wikipedia’s “Orthoceratoidea” article, available under the CC BY-SA 4.0 licence.