''Sweetognathus'' is an extinct genus of

conodont Conodonts (Greek ''kōnos'', "cone", + ''odont'', "tooth") are an extinct group of agnathan (jawless) vertebrates resembling eels, classified in the class Conodonta. For many years, they were known only from their tooth-like oral elements, which ...

s in the family

Sweetognathidae Sweetognathidae is an extinct family of conodonts in the order Ozarkodinida. References External links * Ozarkodinida families {{Conodont-stub ...

that evolved at the beginning of the Permian period (298.9 Ma), in near-equatorial, shallow-water seas. The genus is characterized by pustulose ornamentation on a wide, flat-topped

carina Carina may refer to: Places Australia * Carina, Queensland, a suburb in Brisbane * Carina Heights, Queensland, a suburb in Brisbane * Carina, Victoria, a locality in Mildura Serbia * Carina, Osečina, a village in the Kolubara District ...

. It originated in the earliest

Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleoz ...

as ''S. expansus'' from ''

Diplognathodus edentulus ''Diplognathodus'' is an extinct genus of conodonts in the family Anchignathodontidae. Specimens are found in Carboniferous and Permian formations. The genus ''Sweetognathus'' originated in the earliest Permian as ''Sweetognathus expansus, S. e ...

''. ''Sweetognathus'' forms a species complex. The genus is named after paleontologist Walter C. Sweet. It has been found that recurrent parallel species pairs have occurred throughout ''Sweetognathus'' evolution between populations originating in Bolivia, the Mid-Western Unitied States, and Russia. Parallelisms have been found to occur in the denticle morphologies of their platform elements.

Use in stratigraphy

According to the

List of Global Boundary Stratotype Sections and Points This is a list of Global Boundary Stratotype Sections and Points. Since 1977, Global Boundary Stratotype Sections and Points (abbreviated GSSPs) are internationally agreed upon reference points on stratigraphic sections of rock which define the ...

, the species ''Sweetognathus whitei'' made its first appearance during the

Artinskian In the geologic timescale, the Artinskian is an age or stage of the Permian. It is a subdivision of the Cisuralian Epoch or Series. The Artinskian likely lasted between and million years ago (Ma) according to the most recent revision of the ...

(some 290.1 ± 0.26 mya), in the Permian of the

Ural mountains The Ural Mountains ( ; rus, Ура́льские го́ры, r=Uralskiye gory, p=ʊˈralʲskʲɪjə ˈɡorɨ; ba, Урал тауҙары) or simply the Urals, are a mountain range that runs approximately from north to south through western ...

.
The species ''Sweetognathus merrelli'' is near first appearance during the

Sakmarian In the geologic timescale, the Sakmarian is an age or stage of the Permian. It is a subdivision of the Cisuralian Epoch or Series. The Sakmarian lasted between 293.52 and million years ago (Ma). It was preceded by the Asselian and followed by t ...

(some 295.0 ± 0.18 mya) in the Permian of Kondurovsky,

Orenburg Orenburg (russian: Оренбу́рг, ), formerly known as Chkalov (1938–1957), is the administrative center of Orenburg Oblast, Russia. It lies on the Ural River, southeast of Moscow. Orenburg is also very close to the Kazakhstan-Russia bor ...

, Russia.Proposal for the base of the Sakmarian Stage: GSSP in the Kondurovsky Section, southern Urals, Russia. BI Chuvashov, VV Chernykh, EY Leven, VI Davydov, Permophiles, 2002

References

External links

* Ozarkodinida genera {{Conodont-stub