Eubostrychoceras
Encyclopedia
Eubostrychoceras is a genus of helically wound, corkscew form, heteromorph ammonite
which lived during the Upper Cretaceous (M Turonian
- Campanian
). The genus is included in the ancycleratid family Nostoceratidae
.
The shell of Eubostrychoceras is a loosely to tightly wound spiral forming a corkscrew with an open, empty umbilicus in the middle. coiling is commonly dextral (right hand). Coils are covered by moderately strong, straight transverse ribs. The aperture, or apertural end, reverses general direction and points upwards or back towards to apex. Sutures are moderately complex. The siphuncle is located mid flank.
Eubostrychoceras has a wide spread distribution in the Upper Createous and has been found in Antarctica, Japan, Spain, the far east of Russia, Alaska, U.S. western interior, Madagascar, Germany, and Madagascar.
In 2001 it was reported from Alaska's Matanuska Formation
as well. E. japonicum is Turonian, and likely confined to the middle Turonian.
Related genera include Anaklinoceras
, Bostychocdras, Didymoceras
, and Nostoceras
Ammonite
Ammonite, as a zoological or paleontological term, refers to any member of the Ammonoidea an extinct subclass within the Molluscan class Cephalopoda which are more closely related to living coleoids Ammonite, as a zoological or paleontological term, refers to any member of the Ammonoidea an extinct...
which lived during the Upper Cretaceous (M Turonian
Turonian
The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous epoch, or a stage in the Upper Cretaceous series. It spans the time between 93.5 ± 0.8 Ma and 89.3 ± 1 Ma...
- Campanian
Campanian
The Campanian is, in the ICS' geologic timescale, the fifth of six ages of the Late Cretaceous epoch . The Campanian spans the time from 83.5 ± 0.7 Ma to 70.6 ± 0.6 Ma ...
). The genus is included in the ancycleratid family Nostoceratidae
Nostoceratidae
Family Nostoceratidae was a diverse group of heteromorph ammonites found throughout the oceans of the world during the Late Cretaceous. The nostoceratids are famous for the bizarre coiling of their shells...
.
The shell of Eubostrychoceras is a loosely to tightly wound spiral forming a corkscrew with an open, empty umbilicus in the middle. coiling is commonly dextral (right hand). Coils are covered by moderately strong, straight transverse ribs. The aperture, or apertural end, reverses general direction and points upwards or back towards to apex. Sutures are moderately complex. The siphuncle is located mid flank.
Eubostrychoceras has a wide spread distribution in the Upper Createous and has been found in Antarctica, Japan, Spain, the far east of Russia, Alaska, U.S. western interior, Madagascar, Germany, and Madagascar.
In 2001 it was reported from Alaska's Matanuska Formation
Matanuska Formation
The Matanuska Formation consists of more than of sedimentary strata exposed in the northern Chugach Mountains, Matanuska Valley, and southern Talkeetna Mountains of South-Central Alaska. The Matanuska Formation contains strata from Early Cretaceous to Late Cretaceous . Parts of the formation...
as well. E. japonicum is Turonian, and likely confined to the middle Turonian.
Related genera include Anaklinoceras
Anaklinoceras
Anaklinoceras is a genus of extinct heteromorph ammonite cephalopod that lived in marine environments in what is now Western North America during the Campanian division of the Cretaceous period...
, Bostychocdras, Didymoceras
Didymoceras
Didymoceras is an extinct genus of ammonite cephalopod. It is one of the most bizarrely shaped genera, with a shell that spirals upwards into a loose, hooked tip...
, and Nostoceras
Nostoceras
Nostoceras is an extinct genus of ammonite from the Nostoceratidae family....