Kingdom Animalia Class Hydrozoa Family Heterastridiidae | Phylum Cnidaria Order Anthoathecata Rank Genus | |
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Similar Arcestes, Hydrozoa, Fire coral, Conodont | ||
Heterastridium is a genus of fossil marine hydrozoan from the Upper Triassic. They are mostly discoid or spherical and some forms found in the Karakorum mountains are called Karakorum stones. They vary in diameter from 1 to 35 cm and appear to follow Cope's rule for the prehistoric climate.
References
Heterastridium Wikipedia(Text) CC BY-SA