Geisonoceras

Geisonoceras is an ancient group of sea creatures that lived long ago. It was first given its name by a scientist named Hyatt in 1884. This group is very important because it helps scientists understand more about old life in the oceans. Geisonoceras belongs to a bigger family of creatures called Geisonoceratidae, which was set up by another scientist, Zhuravleva, in 1959. Studying these fossils helps us learn about how life has changed over millions of years.

Fossil record

Fossils of Geisonoceras have been found in old sea layers from the Ordovician to the Devonian, which means they lived between 460.9 and 383.7 million years ago. These fossils come from places in Europe, North America, and Asia.

Species

Some known species of Geisonoceras include:

• †Geisonoceras heintzi Strand 1934
• †Geisonoceras maclareni Murchison 1859
• †Geisonoceras shumardi Billings 1859
• †Geisonoceras wegelini Teichert 1930

Description

The shells of Geisonoceras are long, straight or slightly curved, and widen slowly. They have a round or nearly round shape when looked at from the side, with a circular opening and a small curve near the front. The surface shows wide bands with thin lines running across. The connections between shell sections are straight or slightly angled. The siphuncle, a tube running through the shell, is near the center with short, straight sections and slightly wider rings where it meets the chambers.