''Protoprioniodus'' is an extinct genus of
conodonts.
Use in stratigraphy
The
Whiterock Stage
The Whiterockian, often referred to simply as the Whiterock, is an earliest or lowermost stage of the Middle Ordovician. Although the Whiterockian or Whiterock Stage refers mainly to the early Middle Ordovician in North America, it is often used in ...
refers mainly to the early Middle Ordovician in North America. It is often used in the older literature in a global sense. The Whiterock Stage is given a range from 471.8 (ca. 472) to 462 m.y.a., spanning close to 10 million years. Officially its start is defined by the potentially lowest occurrence of the conodonts ''Protoprioniodus aranda'' or ''
Baltoniodus triangularis
''Baltoniodus'' is an extinct genus of conodonts.
Use in stratigraphy
The base of the Dapingian, the third stage of the Middle Ordovician, is defined as the first appearance of ''Baltoniodus triangularis''.
The Whiterock Stage refers mainly ...
''.
References
External links
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Prioniodontida genera
Ordovician conodonts
{{conodont-stub