Jovellaniidae
Encyclopedia
Jovellaniidae was established as a family within the Oncocerida
Oncocerida
The Oncocerida comprise a diverse group of generally small nautiloid cephalopods known from the Middle Ordovician to the Mississippian ,in which the connecting rings are thin and siphuncle segments are variably expanded...

 to include genera characterized by longiconic orthocones and cyrtocones with a subtriangular to depressed cross-section in which the ventral (siphuncular) side is typically angular or more acutely rounded than the dorsal (antisiphuncular) side, and in which the siphuncle is generally large, ventral, and with lamellar actinosiphonate deposits (Flower 1950, Sweet 1964)

Jovelaniids have a range that extends from the Middle Silurian to the Upper Ordovician and are known from North America Europe. (Sweet 1964) They are thought to be derived from the Valcouroceratidae
Valcouroceratidae
The Valcouroceratidae is an oncocerid family from the middle and upper Ordovician, mainly of North America, consisting of genera characterized by exogastricly curved cyrtoconic and breviconic shells that change ontogeneticially from compressed to depressed or subtriangular and in which the...

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Jovellaniidae was given its name by Foord in 1888; its type is the genus Jovellania
Jovellania
Jovellania is an extinct prehistoric nautiloid genus from the order Oncocerida known from the Lower Devonian of Europe . Nautiloids form a broad group of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species in two genera.Jovellania was named...

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