''Streptognathodus'' is an extinct genus of
conodont
Conodonts, are an extinct group of marine jawless vertebrates belonging to the class Conodonta (from Ancient Greek κῶνος (''kōnos''), meaning " cone", and ὀδούς (''odoús''), meaning "tooth"). They are primarily known from their hard ...
s from the
Late Carboniferous
Late or LATE may refer to:
Everyday usage
* Tardy, or late, not being on time
* Late (or the late) may refer to a person who is dead
Music
* Late (The 77s album), ''Late'' (The 77s album), 2000
* Late (Alvin Batiste album), 1993
* Late!, a pseudo ...
to
Early Permian 01 or 01 may refer to:
* The year 2001, or any year ending with 01
* The month of January
* 1 (number)
Music
* '01 (Richard Müller album), ''01'' (Richard Müller album), 2001
* 01 (Urban Zakapa album), ''01'' (Urban Zakapa album), 2011
* ''01011 ...
.
Use in stratigraphy
Late Carboniferous
The top of the
Kasimovian stage is close to the first appearance of ''Streptognathodus zethus''. The
golden spike
The golden spike (also known as the last spike) is the ceremonial 17.6-Carat (purity), karat gold final Rail spike, spike driven by Leland Stanford to join the rails of the first transcontinental railroad across the United States connecting t ...
for the Kasimovian stage has not yet been assigned (in 2008).
The Kasimovian is subdivided into three conodont
biozones:
*''
Idiognathodus toretzianus'' Zone
*''Idiognathodus sagittatus'' Zone
*''Streptognathodus excelsus'' and ''Streptognathodus makhlinae'' Zone
The base of the
Gzhelian is at the first appearance of ''Streptognathodus zethus''. The top of the stage (also the top base of the
Silesian and the base of the Permian system) is at the first appearance of ''Streptognathodus isolatus'' within the ''Streptognathus "wabaunsensis"'' chronocline.
The Gzhelian stage is subdivided into five
biozones, based on the conodont genus ''Streptognathodus'':
* ''Streptognathodus wabaunsensis'' and ''Streptognathodus bellus'' Zone
* ''Streptognathodus simplex'' Zone
* ''Streptognathodus virgilicus'' Zone
* ''Streptognathodus vitali'' Zone
* ''Streptognathodus simulator'' Zone
Early Permian
The base of the
Asselian stage is at the same time the base of the
Cisuralian
The Cisuralian, also known as the Early Permian, is the first series/epoch of the Permian. The Cisuralian was preceded by the Pennsylvanian and followed by the Guadalupian. The Cisuralian Epoch is named after the western slopes of the Ural Mou ...
series and the Permian system. It is defined as the place in the stratigraphic record where
fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...
s of the species ''Streptognathodus isolatus'' first appear. The global reference profile for the base (the
GSSP or golden spike) is located in the valley of the Aidaralash River, near
Aqtöbe in the Ural Mountains of Kazakhstan.
[The GSSP was first proposed by Davydov ''et al.'' (1998)] The top of the Asselian stage (the base of the
Sakmarian stage) is at the first appearance of the species ''Streptognathodus postfusus''.
The Asselian contains five conodont
biozones:
*zone of ''Streptognathodus barskovi''
*zone of ''Streptognathodus postfusus''
*zone of ''Streptognathodus fusus''
*zone of ''Streptognathodus constrictus''
*zone of ''Streptognathodus isolatus''
The base of the
Sakmarian stage is laid with the first appearance of ''Streptognathodus postfusus'' in the fossil record. A global reference profile for the base had in 2009 not yet been appointed. The top of the Sakmarian (the base of the Artinskian) is defined as the place in the stratigraphic record where fossils of conodont species ''
Sweetognathus whitei'' and ''
Mesogondolella bisselli'' first appear.
References
External links
*
*
Ozarkodinida genera
Carboniferous conodonts
Permian conodonts
Asselian life
Gzhelian life
Kasimovian life
Pennsylvanian first appearances
Cisuralian genus extinctions
{{conodont-stub