Tetractinella trigonella
Quick Summary
Tetractinella trigonella is an extinct brachiopod, or lamp shell, found in Triassic marine rocks. Brachiopods are invertebrates with a bivalve shell, typically found attached to the substrate.12
Tetractinella shells are characterized by radiating ribs and a weblike margin. One notable species, Tetractinella trigonella, is an example of homeomorphy, meaning it closely resembles an unrelated organism in form and function. This species from Italy is strikingly similar to Cheirothyris fleuriausa, a species from Germany that lived millions of years later.1
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