Talk:Oncocerida

Ecology
States: The group is most common in shallow waters near the equator, and around reefs They swum backwards, and their siphuncle was thin (resulting in its increased efficiency, but decreasing the organisms' ability to change buoyancy quickly. They could spend more time in the water column than many of their contemporaries, which spent much time on the bottom.  B Kroger (2008) "Pulsed cephalopod diversification during the Ordovician". Palaeogeography Palaeoclimatology Palaeoecology is cited as the reference.

This was added to the original article and while the subject adds to the overall contents I question some of the conclusions (or interprestions as the case may be).

That they swam backwards almost goes without saying, being cephalopods. The thin-walled siphuncle would have had an increased efficiency over previous thick-walled forms which would have increased the organisms' ability to change buoyancy quickly, not decrease it. The efficiency in changing buoyancy was a direct function of the ability to move fluid (sea water) in and out of the chambers.

Some oncocerids may have spent time in the water column above the bottom along with some contemporary barrandeocerids and nautilids, and more so than contemporary orthocerids and actinocerids which probably spend their lives prowling the sea floor.

John M 4/25/09 —Preceding undated comment added 21:56, 25 April 2009 (UTC).

Taxonomic Range
These would easily extend to the end of the Carboniferous with Poterioceras curtum in the group. The article seems largely based on the Treatise, which was valid when published in 1964, but quickly changed less than a decade later.

See:

Windle, D. L. Jr., 1973: Studies in Carboniferous nautiloids: cyrtocones and annulate orthocones. Thesis for Degree of Doctor of Philosophy in the University of Iowa, 427 p.

SHUJI NIKO and ROYAL H. MAPES "Redescription and New Information on the Carboniferous Cephalopod Brachycycloceras normale Miller, Dunbar and Condra, 1933," Paleontological Research 13(4), 337-343, (1 December 2009). https://doi.org/10.2517/1342-8144-13.4.337 Cngodles (talk) 13:32, 19 July 2022 (UTC)