Engorthoceratidae is a small family of Devonian orthocerids

Orthocerida

Orthocerida is an order of extinct nautiloid cephalopods also known as the Michelinocerda that lived from the Early Ordovician possibly to the Late Triassic . A fossil found in the Caucasus suggests they may even have survived until the Early Cretaceous...

 found in eastern North America (Ohio

Ohio

Ohio is a Midwestern state in the United States. The 34th largest state by area in the U.S.,it is the 7th‑most populous with over 11.5 million residents, containing several major American cities and seven metropolitan areas with populations of 500,000 or more.The state's capital is Columbus...

 and Indiana

Indiana

Indiana is a US state, admitted to the United States as the 19th on December 11, 1816. It is located in the Midwestern United States and Great Lakes Region. With 6,483,802 residents, the state is ranked 15th in population and 16th in population density. Indiana is ranked 38th in land area and is...

), containing only the genus Engorthoceras.

Taxonomy

Engorthoceratidae was named by Flower (1962) to contain the genus Engorthoceras, also named by Flower (1962), and assigned to the Michelinceratida. The genotype is Orthoceras worthoni.

Morphology

Engorthoceras produced straight conical shells with a subcircular cross section and a small completely marginal siphuncle. . The conical shell is suggestive of belemnite

Belemnoidea

Belemnoids are an extinct group of marine cephalopod, very similar in many ways to the modern squid and closely related to the modern cuttlefish. Like them, the belemnoids possessed an ink sac, but, unlike the squid, they possessed ten arms of roughly equal length, and no tentacles...

 phragmocones and of its possible ancestry to Eobelemites. Nothing is known of the animal itself.