thamnasterioid
Thamnasterioid is a term used in the study of marine biology and paleontology to describe a specific group of extinct sea urchins, or echinoids, that belong to the order Thamnasteroida. This group is notable for its distinctive body morphology and evolutionary significance within the broader classification of echinoids.
Thamnasterioids are characterized by their elongated, cylindrical test (the hard, external skeleton) and a unique arrangement
Fossil records indicate that thamnasterioids flourished during the Jurassic and Cretaceous periods, spanning roughly 200 to
The classification of thamnasterioids has evolved over time, with taxonomic revisions reflecting new fossil discoveries and
Thamnasterioids are of interest not only for their unique anatomical features but also for their role in