Agathiceras
Encyclopedia
Agathiceras is a subglobose goniatitid from the family Agathiceratidae
, widespread and locally abundant in Lower Pennsylvanian to Middle Permian sediments, e.g. the Urals, Sicily, and Texas.
Agathiceras, named by Gemmellaro in 1887 from the Middle Permian Sicilian species, A. suessi, has a broadly rounded outer edge, known as the venter, being at the lower side of the animal during life, and a deeply impressed innerside, the dorsum which corresponds with the back or dorsal side of the animal. The sutures are goniatitic with 3 lateral and one dosolateral lobes on either side. Those that are external are spatulate, those hidden are V-shaped. The siphuncle is primitive with the septal necks pointing to the rear, a condition known as retrosiphonate.
Agathiceras is thought to be derived from Proshumardites according to Saunders et al. (1999), which is thought to be derived from Dombaties; all of which are included in the Agathiceratidae
. Dombarites is presumed to have its origin in Goniatites
, type genus of the Goniatitidae
Agathiceratidae
The Agathiceratidae as revised makes up the goniatitid superfamily Agathicerataceae. The Agathiceratidae, which lived from the Upper Carboniferous to the Middle Permian, combine related genera with subdiscoidal to globular shells that have a small umbilicus and goniatitic sutures and are...
, widespread and locally abundant in Lower Pennsylvanian to Middle Permian sediments, e.g. the Urals, Sicily, and Texas.
Agathiceras, named by Gemmellaro in 1887 from the Middle Permian Sicilian species, A. suessi, has a broadly rounded outer edge, known as the venter, being at the lower side of the animal during life, and a deeply impressed innerside, the dorsum which corresponds with the back or dorsal side of the animal. The sutures are goniatitic with 3 lateral and one dosolateral lobes on either side. Those that are external are spatulate, those hidden are V-shaped. The siphuncle is primitive with the septal necks pointing to the rear, a condition known as retrosiphonate.
Agathiceras is thought to be derived from Proshumardites according to Saunders et al. (1999), which is thought to be derived from Dombaties; all of which are included in the Agathiceratidae
Agathiceratidae
The Agathiceratidae as revised makes up the goniatitid superfamily Agathicerataceae. The Agathiceratidae, which lived from the Upper Carboniferous to the Middle Permian, combine related genera with subdiscoidal to globular shells that have a small umbilicus and goniatitic sutures and are...
. Dombarites is presumed to have its origin in Goniatites
Goniatites
Goniatites is genus of the Goniatitaceae superfamily. They are an extinct group of ammonoid, which are shelled cephalopods related to squids, belemnites, octopuses, and cuttlefish, and more distantly to the nautiloids.-References:* accessed on 10/01/07...
, type genus of the Goniatitidae
Goniatitidae
Goniatitidae is one of three families of the Goniatitaceae superfamilies. They are an extinct group of ammonoid, which are shelled cephalopods related to squids, belemnites, octopuses, and cuttlefish, and more distantly to the nautiloids.-References:...