Systematic Paleontology
Class: Cephalopoda
Subclass: Coleoidea
Superorder: Belemnoidea
The Belemnoidea constitutes a superorder (alt. infraclass) of coleoid cephalopods fond primarily in marine sediments of the Mesozoic, characterized by an internal skeleton with a more-or-less cylindrical rostrum that projects posteriorly from the rear of the animal/fossil, often all that remains and therefor the primary diagnostic feature in determining lesser taxa.
The rostrum, also known as the guard, was connected to the conotheca which includes a posterior chambered phragmocone and a dorsal plate-like structure, the pro-ostracum that projects forward from it. Pro-ostraca overlaid the upper side of belemnoid bodies which during life were largely exposed to the sea.
Belemnoids had ten moderately short arms in five pairs, each armed with two rows of small hooks used for snagging prey. In the rear a pair of horizontal fins.
As predators belemnites (vernacular for Belemnidea) fed predominantly on crustaceans, other cephalopods, and fishes. They also served as prey for sharks, bony fishes, ichthyosaurs, and other marine reptiles.
Perhaps as many as seven orders fall within the Belemnoidea, those being the Hematitida, Donovaniconida, Aulacoceratida, Phragmoteuthida, Belemnoteuthida, Belemnitida,and Diplobelida. Derivation is from the Bactritida.
References
Phylogeny and Systematics of the Coleoidea. P. Doyle, D. T. Donovan, and M. Nixon 1994. University of Kansaws Paleontological Contributions. [1]
Late Cretaceous record of large soft-bodied coleoids based on lower jaw remains from Hokkaido, Japan. Tanabe, K., Misaki, A., and Ubukata, T. 2015. Acta Palaeontologica Polonica. [2]
Belemnoidea in fossilworks. [3] given erroneously as a superfamily.