Abbasites
Encyclopedia
Abbasites is an extinct ammonite genus from the early Middle Jurassic
included in the ammonitid
family Erycitidae.
, and was considered by some to be a subgenus of Erycites. Abbasites was included in the Otoitidae, the ancestral family of the Stephanocerataceae, according to Westermann (1965)Westernamm,G. E. G. 1965.Septal and Sutural Patterns in Evolution and Taxonomy of Thamboceratidae and Clydoniceratidae (M Jurassic Ammonitina).Journal of Paleontology 39(5)864-874, Sept and Imlay (1984) but was previously placed in the Hildoceratacean
family Hammatoceratidae by Arkell et al. (1957). It is currently regarded as a full genus in the Erycitidae subfamily Erycitinae.
.
Middle Jurassic
The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from 176-161 million years ago. In European lithostratigraphy, rocks of this Middle Jurassic age are called the Dogger....
included in the ammonitid
Ammonitida
The Ammonitida is an order of more highly evolved ammonoid cephalopods from the Jurassic and Cretaceous time periods, commonly with intricate ammonitic sutures....
family Erycitidae.
Description
Abbasites is small and subglobular with ribbing that divides high on its sides and which has an interruption on the venter that replaces the keel, generally characteristic of the HammatoceratidaeClassification
Abbasites was originally described by Sydney S. Buckman in 1921, with A. abbas as its type speciesType species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
, and was considered by some to be a subgenus of Erycites. Abbasites was included in the Otoitidae, the ancestral family of the Stephanocerataceae, according to Westermann (1965)Westernamm,G. E. G. 1965.Septal and Sutural Patterns in Evolution and Taxonomy of Thamboceratidae and Clydoniceratidae (M Jurassic Ammonitina).Journal of Paleontology 39(5)864-874, Sept and Imlay (1984) but was previously placed in the Hildoceratacean
Hildocerataceae
Hildocerataceae is a superfamily of compressed or planulate ammonites, some tending to develop acute outer rims; generally with arcuate or sigmoidal ribs. Aptichus were found in place are double-valved....
family Hammatoceratidae by Arkell et al. (1957). It is currently regarded as a full genus in the Erycitidae subfamily Erycitinae.
Valid species
- Abbasites abbas , found in southern SpainSpainSpain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
. - A. platystomus, found in southern AlaskaAlaskaAlaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
. - A. sparsicostatus (described by Ralph Imlay)
Dubious and excluded species
- ?Abbasites cestiferus; type specimen too small to be certain about classification.
- (Abbasites) challinori; originally thought to be closely related to A. abbas, but following subsequent study has been removed from Abbasites to the genus Opuatia
Phylogeny
The genus Erycites is believed to be ancestral to Abbasites. However, Abbasites is believed to have left its own descendants in the ammonite family OtoitidaeOtoitidae
Otoidtidae: stephanoceratacean ammonitina from the early Middle Jurassic that begin as cadicones but become more planualte with age; derived from the Hammitoceratidae , probably through Erycites by way of Abbasites....
.