The Tetragonoceratidae is a small family of
nautilitids constituting a part of the superfamily
Tainocerataceae
The Tainoceratoidea are a superfamily in the cephalopod order Nautilida characterized by straight to loosely coiled shells, generally to a degree such that the width is greater than the height, to quadrate whorl section. Many bore spines, ribs, f ...
in which shells are coiled with a generally quadrate whorl section. Coiling is either gyroconic or evoluute with a slight dorsal impression. Flanks diverge from the umbilical to the ventral shoulders so as to make the whorl sections widest close to the venter. Nodes made develop on the flanks and shoulders. The siphuncle is tubular, typically found near the venter. Sutures are with lateral lobes and may possess dorsal and ventral lobes as well.
The Tetragonoceratidae, which is an early offshoot of the
Rutoceratidae
Rutoceratidae is a family of prototypical nautilids, derived probably from either Brevicoceratidae or Acleistoceratidae of the order Oncocerida early in the Devonian. Rutoceratidae comprise a family within the oncocerid superfamily Tainoceratac ...
, contains three genera (as of 1964), all confined to the Middle Devonian: ''
Tetragonoceras'', ''
Nassauoceras'', and ''
Wellsoceras''.
References
* Bernhard Kummel, 1964. Nautiloidea -Nautilida. Treatise on Invertebrate Paleontology, Part K. R.C. Moore and Curt Teichert eds. Geological Society of America.
Nautiloids
Middle Devonian first appearances
Middle Devonian extinctions
Taxa named by Rousseau H. Flower
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