Cornulitida is an extinct order of encrusting animals from class

Tentaculita Tentaculita is an extinct class of uncertain placement ranging from the Early Ordovician to the Middle Jurassic. They were suspension feeders with a near worldwide distribution. For a more thorough discussion, see '' Tentaculites''. The presen ...

, which were common around the globe in the

Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. T ...

Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, wh ...

oceans, and survived until the

Carboniferous The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carboniferou ...

. The organisms had shells, and were subject to predation by boring and other means from the Ordovician onwards. Many survived attacks by predators. Several cornulitids were endobiotic symbionts in the

stromatoporoid Stromatoporoidea is an extinct clade of sea sponges common in the fossil record from the Ordovician through the Devonian. They were especially abundant and important reef-formers in the Silurian and most of the Devonian.Stock, C.W. 2001, Stromat ...

s and tabulates. Their affinity is unknown; they have been placed in many phyla, and have been considered worms, corals, molluscs and more. They appear to be closely related to other taxa of uncertain affinity, including the

microconchid The order Microconchida is a group of small, spirally-coiled, encrusting fossil "worm" tubes from the class Tentaculita found from the Upper Ordovician to the Middle Jurassic (Bathonian) around the world. They have lamellar calcitic shells, ...

s, trypanoporids and tentaculitids.

References

{{Taxonbar, from=Q5171922 Tentaculita Middle Ordovician first appearances Pennsylvanian extinctions Prehistoric animal orders