''Mesohedenstroemia'' is a genus of

ammonite Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids (i.e., octopuses, squid and cuttlefish) ...

s. It was described by Chao in 1959, who described three species; ''M. kwangsiana'' (the type species), ''M. inflata Chao, 1959'', and ''M. planata'', from the

Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...

of what is now

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

. A new species, ''M. olgae'', was described from the Olenekian of

Russia Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...

by Yuri D. Zakharov and Nasrin Mousavi Abnavi in 2012, and was named in honour of Olga P. Smyshyaeva.

Distribution

China and Russia

References

Hedenstroemiidae Triassic ammonites Ceratitida genera {{Ceratitida-stub