Tabulata, commonly known as tabulate corals, are an

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of ...

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

forms of

coral Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and se ...

. They are almost always colonial, forming colonies of individual

hexagon In geometry, a hexagon (from Greek , , meaning "six", and , , meaning "corner, angle") is a six-sided polygon. The total of the internal angles of any simple (non-self-intersecting) hexagon is 720°. Regular hexagon A '' regular hexagon'' has ...

al cells known as

corallite A corallite is the skeletal cup, formed by an individual stony coral polyp, in which the polyp sits and into which it can retract. The cup is composed of aragonite, a crystalline form of calcium carbonate, and is secreted by the polyp. Corall ...

s defined by a

skeleton A skeleton is the structural frame that supports the body of an animal. There are several types of skeletons, including the exoskeleton, which is the stable outer shell of an organism, the endoskeleton, which forms the support structure inside ...

calcite Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on the Mohs scale of mineral hardness, based on scratc ...

, similar in appearance to a honeycomb. Adjacent cells are joined by small pores. Their distinguishing feature is their well-developed horizontal internal partitions (''tabulae'') within each cell, but reduced or absent vertical internal partitions ( ''septa''). They are usually smaller than rugose corals, but vary considerably in shape, from flat to conical to spherical. Around 300 species have been described. Among the most common tabulate corals in the

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

record are ''

Aulopora ''Aulopora'' is an extinct genus of tabulate coral characterized by a bifurcated budding pattern and conical corallite A corallite is the skeletal cup, formed by an individual stony coral polyp, in which the polyp sits and into which it can r ...

'', '' Favosites'', '' Halysites'', '' Heliolites'', '' Pleurodictyum'', ''Sarcinula'' and '' Syringopora''. Tabulate corals with massive skeletons often contain endobiotic symbionts, such as cornulitids and ''

Chaetosalpinx ''Chaetosalpinx'' is an ichnogenus of bioclaustrations (a type of trace fossil). ''Chaetosalpinx'' includes straight to sinuous cavities that are parallel to the host's axis of growth. The cavity is circular to oval in cross-section and it lacks ...

''. Like rugose corals, they lived entirely during the

Paleozoic The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ...

, being found from the Ordovician to the

Permian 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 251.9 Mya. It is the last period of the Paleo ...

. With Stromatoporoidea and rugose corals, the tabulate corals are characteristic of the shallow waters of the

Silurian The Silurian ( ) is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the shortest period of the Paleoz ...

and

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 ...

. Sea levels rose in the Devonian, and tabulate corals became much less common. They finally became extinct in the Permian–Triassic extinction event.

Gallery

Image:HalysitesSilurian.jpg, ''Halysites'' sp. from the

of Ohio. View of colony surface. Image:Tabulate_coral_etched_section.jpg, Etched section of an Ordovician tabulate coral Image:AuloporaDevonianSilicaShale.jpg, ''Aulopora'' from the Silica Shale (Middle

) of northwestern Ohio. Image shows colony origin encrusting a brachiopod. Image:Rafinesquina ponderosa (Hall) ventral.JPG, The coral ''Protaraea richmondensis'' on the brachiopod ''Rafinesquina ponderosa'';

Whitewater Formation The Whitewater Formation is a geologic formation in Ohio and Indiana. It preserves fossils dating back to the Ordovician period.Waynesville Formation The Waynesville Formation is a geologic formation in Ohio and Indiana. It preserves fossils from the Late Ordovician period. See also * List of fossiliferous stratigraphic units in Ohio * List of fossiliferous stratigraphic units in Indiana ...

, Upper Ordovician, Caesar Creek, Ohio.

References

* Invertebrate Fossils; Moore, Lalicker, & Fischer; McGraw-Hill 1952. * Treatise on Invertebrate Paleontology Part F, Coelenterata. Geological Society of America and Univ Kansas Press. R.C. Moore (ed). Hexacorallia Prehistoric animal orders Cnidarian orders {{permian-animal-stub