Tintinnida

Tintinnids are ciliates of the choreotrich order Tintinnida, the name deriving from a Latin source meaning a small tinkling bell. They are distinguished by vase-shaped shells called loricae, which are mostly protein but may incorporate minute pieces of minerals.

== Fossil record == Fossils resembling tintinnid loricas in shape and size, calpionellids, appear as early as the Ordovician period but are formed of calcite and as no extant ciliate taxa forms calcite shells they are unlikely to be tintinnids and probably not ciliates at all. Fossils which can be reliably related to extant tintinnids (e.g. fossils of agglutinated lorica) are in the fossil record during the Jurassic but do not become abundant until the Cretaceous. Tintinnids are an important part of the fossil record because of the rarity with which most other ciliates become preserved under the conditions of the marine environment. The loricae of some tintinnids are easily preserved, giving them a relatively good fossil record.