Stenolaemata are a

class Class, Classes, or The Class may refer to: Common uses not otherwise categorized * Class (biology), a taxonomic rank * Class (knowledge representation), a collection of individuals or objects * Class (philosophy), an analytical concept used d ...

of exclusively marine

bryozoa Bryozoa (also known as the Polyzoa, Ectoprocta or commonly as moss animals) are a phylum of simple, aquatic animal, aquatic invertebrate animals, nearly all living in sedentary Colony (biology), colonies. Typically about long, they have a spe ...

ns. Stenolaemates originated and diversified in the

Ordovician The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era, and the second of twelve periods of the Phanerozoic Eon (geology), Eon. The Ordovician spans 41.6 million years f ...

, and more than 600 species are still alive today.Stenolaemata.
The Digital Atlas of Ordovician Life. All extant (living) species are in the order

Cyclostomatida Cyclostomatida, or cyclostomata (also known as cyclostomes), are an ancient order of stenolaemate bryozoans which first appeared in the Lower Ordovician. It consists of 7+ suborders, 59+ families, 373+ genera, and 666+ species. The cyclostome ...

, the third-largest order of living bryozoans.Ramalho, L. V., G. Muricy, and P. D. Taylor. (2009)
Cyclostomata (Bryozoa, Stenolaemata) from Rio de Janeiro State, Brazil.
''Zootaxa'' 2057 32–52. These animals are stationary suspension feeders that live on the ocean floor. They formed colonies with robust,

calcified Calcification is the accumulation of calcium salts in a body tissue. It normally occurs in the formation of bone, but calcium can be deposited abnormally in soft tissue,Miller, J. D. Cardiovascular calcification: Orbicular origins. ''Nature Mat ...

exoskeleton An exoskeleton () . is a skeleton that is on the exterior of an animal in the form of hardened integument, which both supports the body's shape and protects the internal organs, in contrast to an internal endoskeleton (e.g. human skeleton, that ...

s, allowing for a high potential for fossil preservation. The individual zooids in the colony may be tubular, conical, or sac-shaped. Each individual, or

zooid A zooid or zoöid is an animal that is part of a colonial animal. This lifestyle has been adopted by animals from separate unrelated taxa. Zooids are multicellular; their structure is similar to that of other solitary animals. The zooids can ...

, may extend from the colony at an angle, extending its tentacles to feed. The fossil genus ''Batostoma'' in the order

Trepostomatida Trepostomatida (the trepostomates) is an extinct order of bryozoans in the class Stenolaemata Stenolaemata are a class of exclusively marine bryozoans. Stenolaemates originated and diversified in the Ordovician, and more than 600 species a ...

existed in monticular colonies. Stenolaemates were the predominant bryozoan group during the

Paleozoic The Paleozoic ( , , ; or Palaeozoic) Era is the first of three Era (geology), geological eras of the Phanerozoic Eon. Beginning 538.8 million years ago (Ma), it succeeds the Neoproterozoic (the last era of the Proterozoic Eon) and ends 251.9 Ma a ...

, when many extinct

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

s proliferated within the class. Some grew as lacy or fan-like colonies that became important

reef A reef is a ridge or shoal of rock, coral, or similar relatively stable material lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic component, abiotic (non-living) processes such as deposition (geol ...

builders, and in some regions form an abundant component of

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

s. The extinct Palaeozoic stenolaemate orders are placed in the

superorder Order () is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and recognized ...

Palaeostomata Palaeostomata is a superorder of extinct stenolaemate Stenolaemata are a class (biology), class of exclusively marine (ocean), marine bryozoans. Stenolaemates originated and diversified in the Ordovician, and more than 600 species are still a ...

. Their numbers were greatly reduced during the terminal

Permian extinction event The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years, from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.902 Mya. It is the sixth and last period o ...

, and most stenolaemates were extinct by the start of the Jurassic. However, the basal and previously rare stenolaemate order Cyclostomatida diversified in the Jurassic and became the most abundant group of bryozoans in the late Mesozoic. Cyclostomatida is no longer the most speciose bryozoan group, as the order experienced high rates of extinction during the end-Cretaceous mass extinction, while

ctenostome The Ctenostomatida are an order of bryozoans in the class Gymnolaemata. The great majority of ctenostome species are marine, although '' Paludicella'' inhabits fresh water. They are distinguished from their close relatives, the cheilostomes, by ...

and

cheilostome Cheilostomatida, also called Cheilostomata, is an order of Bryozoa in the class Gymnolaemata. They are exclusively marine, colonial invertebrate animals. Cheilostome colonies are composed of calcium carbonate and grow on a variety of surfaces, ...

bryozoans in the class

Gymnolaemata Gymnolaemata are a class of Bryozoans. Gymnolaemata are sessile, mostly marine organisms and grow on the surfaces of rocks, kelp, and in some cases on animals, like fish. Zooids are cylindrical or flattened. The lophophore is protruded by ac ...

diversified around the same time. Nevertheless, cyclostomates are still major components of modern marine ecosystems. Extant and extinct

orders Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * H ...

in this class include: *

/Cyclostomata (Ordovician-present) *

Cryptostomata Cryptostomata is an order of fossil bryozoans that lived from the Ordovician to the Permian The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years, from the end of the Carboniferous ...

/Cryptostomida † (Ordovician-Triassic) *

Cystoporida Cystoporida, also known as Cystoporata or cystoporates, are an extinct order of Paleozoic bryozoans in the class Stenolaemata. Their fossils are found from Ordovician to Triassic The Triassic ( ; sometimes symbolized 🝈) is a geologic peri ...

/Cystoporata † (Ordovician-Triassic) * Esthonioporata † (Ordovician-Devonian) *

Fenestrata Fenestrata is an extinct order of bryozoa Bryozoa (also known as the Polyzoa, Ectoprocta or commonly as moss animals) are a phylum of simple, aquatic animal, aquatic invertebrate animals, nearly all living in sedentary Colony (biology), co ...

/Fenestrida † (Ordovician-Permian) * Timanodictyina † (Devonian-Permian, may be a

suborder Order () is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and recognized ...

of Cryptostomata) *

/Trepostomata † (Ordovician-Triassic)

References

External links

*Bock, P. (2015)
Stenolaemata.
''In'': Bock, P.; Gordon, D. (2015). World List of Bryozoa. Accessed through the World Register of Marine Species.
Stenolaemata.
Fossil works. {{Authority control Extant Ordovician first appearances Protostome classes