Lingula

…fossils”—for instance, the lamp shell Lingula, a genus of brachiopod (a phylum of shelled invertebrates) that appears to have remained essentially unchanged since the Ordovician Period, some 450 million years ago; or the tuatara (Sphenodon punctatus), a reptile that has shown little morphological evolution for nearly 200 million years, since…

Lingula lives from the tidal zone to 23 fathoms (about 42 metres [138 feet]). Most modern branchiopods anchor by the pedicle to pebbles, to the undersides of stones, or to other hard objects. They prefer quiet water and protected surroundings. Lingula lives in mud or…