Labechiida is an 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 ...

stromatoporoid Stromatoporoidea is an extinct clade of sea sponges common in the fossil record from the Middle Ordovician to the Late Devonian.Stock, C.W. 2001, Stromatoporoidea, 1926–2000: ''Journal of Paleontology'', v. 75, p. 1079–1089. They can be cha ...

sponge Sponges or sea sponges are primarily marine invertebrates of the animal phylum Porifera (; meaning 'pore bearer'), a basal clade and a sister taxon of the diploblasts. They are sessile filter feeders that are bound to the seabed, and a ...

s. They lived from the

Early Ordovician The Early Ordovician is the first epoch (geology), epoch of the Ordovician period, corresponding to the Lower Ordovician series (stratigraphy), series of the Ordovician system. It began after the Cambrian Stage 10, Age 10 of the Furongian epoch o ...

(

Tremadocian The Tremadocian is the lowest stage of Ordovician. Together with the later Floian Stage it forms the Lower Ordovician Epoch. The Tremadocian lasted from to million years ago. The base of the Tremadocian is defined as the First appearance datum ...

stage) to the

Late Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era during the Phanerozoic eon, spanning 60.3 million years from the end of the preceding Silurian period at million years ago ( Ma), to the beginning of the succeeding ...

(

Famennian The Famennian is the later of two faunal stages in the Late Devonian epoch. The most recent estimate for its duration is that it lasted from around 371.1 to 359.3 million years ago. An earlier 2012 estimate, still used by the International Commis ...

stage),'''' though a few putative fossils have been reported from younger sediments. Labechiids were the first order of stromatoporoids to appear and were probably ancestral to all other orders in the main Paleozoic radiation (Stromatoporoidea ''sensu stricto).'' They were most diverse and abundant during the Middle-Late Ordovician and the Famennian, when they were a major group of

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 ...

-building sponges. However, they were relatively uncommon through most of the Silurian and Devonian, in contrast to other stromatoporoids. Labechiids can be differentiated from other stromatoporoids by having an internal structure emphasizing cysts (pockets roofed by flat or convex cyst plates) and pillars (solid rods perpendicular to the surface).'''' The pillars may extend all the way to the surface and project out a short distance as small bumps known as papillae. Cyst plates may bear denticles (pointed thorns) or crenulations (pinched deflections) pointing upwards within the skeleton. Laminae (regular horizontal plates) are comparatively difficult to distinguish due to the more unorganized internal structure of labechiids compared to other stromatoporoids. Mamelons are found in some species, while astrorhizae are indistinct or absent. Many labechiid fossils are poorly preserved, as their emphasis on cysts affords a lower skeletal density than other stromatoporoids. As a result, some traits used to distinguishing between taxa (such as pillar microstructure) may instead be

taphonomic Taphonomy is the study of how organisms decay and become fossilized or preserved in the paleontological record. The term ''taphonomy'' (from Greek , 'burial' and , 'law') was introduced to paleontology in 1940 by Soviet scientist Ivan Efremov ...

rather than biological in origin.''''

Taxonomy

Evolution

Ordovician

The earliest reported labechiid species are from the Early Ordovician of

South China South China ( zh, s=, p=Huá'nán, j=jyut6 naam4) is a geographical and cultural region that covers the southernmost part of China. Its precise meaning varies with context. A notable feature of South China in comparison to the rest of China is ...

: '' Lophiostroma leizunia'' (late

) and '' Cystostroma primordia'' (Floian). The former species was a reef-builder while the latter was rare and small. Massive reefs appeared simultaneously worldwide in the mid- to upper-

Darriwilian The Darriwilian is the upper stage of the Middle Ordovician. It is preceded by the Dapingian and succeeded by the Upper Ordovician Sandbian Stage. The lower boundary of the Darriwilian is defined as the first appearance of the graptolite species ' ...

stage, near the end of the

Middle Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era, and the second of twelve periods of the Phanerozoic Eon. The Ordovician spans 41.6 million years from the end of the Cambrian Period Ma (milli ...

(~460 Ma). During the Darriwilian, 4 genera occur in the Chazy Group of eastern North America, 9 in the Machiakou Formation of

North China North China () is a list of regions of China, geographical region of the People's Republic of China, consisting of five province-level divisions of China, provincial-level administrative divisions, namely the direct-administered municipalities ...

, and several others are dispersed among Russia,

Kazakhstan Kazakhstan, officially the Republic of Kazakhstan, is a landlocked country primarily in Central Asia, with a European Kazakhstan, small portion in Eastern Europe. It borders Russia to the Kazakhstan–Russia border, north and west, China to th ...

Korea Korea is a peninsular region in East Asia consisting of the Korean Peninsula, Jeju Island, and smaller islands. Since the end of World War II in 1945, it has been politically Division of Korea, divided at or near the 38th parallel north, 3 ...

, and

Malaysia Malaysia is a country in Southeast Asia. Featuring the Tanjung Piai, southernmost point of continental Eurasia, it is a federation, federal constitutional monarchy consisting of States and federal territories of Malaysia, 13 states and thre ...

. Most specialists agree that the ancestral labechiid was a member of the family Rosenellidae, but disagreement persists over which genus serves as the ancestral form. Studies focusing on North America and China generally consider the widespread '' Pseudostylodictyon'' or ''Cystostroma'' to be ancestral to other labechiids, while Russian paleontologists point to the

Siberian Siberia ( ; , ) is an extensive geographical region comprising all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has formed a part of the sovereign territory of Russia and its predecessor states si ...

'' Priscastroma''. Labechiids as a whole may be descended from non-stromatoporoid sponges in the order Pulchrilaminida. In the

Sandbian The Sandbian is the first stage of the Upper Ordovician. It follows the Darriwilian and is succeeded by the Katian. Its lower boundary is defined as the first appearance datum of the graptolite species '' Nemagraptus gracilis'' around million ...

stage of the Late Ordovician, labechiids spread to regions equivalent to

Scotland Scotland is a Countries of the United Kingdom, country that is part of the United Kingdom. It contains nearly one-third of the United Kingdom's land area, consisting of the northern part of the island of Great Britain and more than 790 adjac ...

and Australia, and some former Chinese

endemics Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

(such as the tree-shaped aulaceratids) populated

Laurentia Laurentia or the North American craton is a large continental craton that forms the Geology of North America, ancient geological core of North America. Many times in its past, Laurentia has been a separate continent, as it is now in the form of ...

(North America) for the first time. During the

Katian The Katian is the second stage of the Upper Ordovician. It is preceded by the Sandbian and succeeded by the Hirnantian Stage. The Katian began million years ago and lasted for about 7.6 million years until the beginning of the Hirnantian mill ...

stage, labechiids reached their maximum diversity and were abundant in tropical reef ecosystems worldwide. They were significantly less common in temperate areas corresponding to Central Asia. Most Late Ordovician labechiid genera were cosmopolitan, while endemics were few. Global cooling in the first pulse of the

Late Ordovician mass extinction The Late Ordovician mass extinction (LOME), sometimes known as the end-Ordovician mass extinction or the Ordovician–Silurian extinction, is the first of the "big five" major mass extinction events in Earth's history, occurring roughly 445 mill ...

(~445 Ma) led to the extinction of the short-lived family Stromatoceriidae, and

Hirnantian The Hirnantian is the final internationally recognized stage of the Ordovician Period of the Paleozoic Era. It was of short duration, lasting about 2.1 million years, from to Ma (million years ago). The early part of the Hirnantian was char ...

-age stromatoporoid fossils are limited to only a few localities in Canada and Northern Europe. Only two labechiids ('' Aulacera'' and '' Pachystylostroma'') retain any semblance of commonness during the extinction interval.

Silurian

Labechiids which survived into the Llandovery Epoch (early

Silurian The Silurian ( ) is a geologic period and system spanning 23.5 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 third and shortest period of t ...

) were inconspicuous relative to other diversifying stromatoporoid orders such as clathrodictyids and actinostromatids. South China and Siberia were notable exceptions where labechiids temporarily remained the most diverse group of stromatoporoids. Even as stromatoporoids collectively reached their maximum Silurian diversity in the

Wenlock Epoch The Wenlock Epoch (sometimes referred to as the Wenlockian) is the second epoch of the Silurian. It is preceded by the Llandovery Epoch and followed by the Ludlow Epoch. Radiometric dates constrain the Wenlockian between and million years ago. ...

(middle Silurian), labechiids were not among the beneficiaries. Labechiids were still rare in the

Ludlow Ludlow ( ) is a market town and civil parish in Shropshire (district), Shropshire, England. It is located south of Shrewsbury and north of Hereford, on the A49 road (Great Britain), A49 road which bypasses the town. The town is near the conf ...

and Pridoli epochs (late Silurian), though the typical Ordovician genus '' Lophiostroma'' made an unexpected recovery in

Baltica Baltica is a paleocontinent that formed in the Paleoproterozoic and now constitutes northwestern Eurasia, or Europe north of the Trans-European Suture Zone and west of the Ural Mountains. The thick core of Baltica, the East European Craton, i ...

(Eastern Europe) and

Turkey Turkey, officially the Republic of Türkiye, is a country mainly located in Anatolia in West Asia, with a relatively small part called East Thrace in Southeast Europe. It borders the Black Sea to the north; Georgia (country), Georgia, Armen ...

Devonian

No unambiguously new labechiid genera evolved through the entire

Early Early may refer to: Places in the United States * Early, Iowa, a city * Early, Texas, a city * Early Branch, a stream in Missouri * Early County, Georgia * Fort Early, Georgia, an early 19th century fort Music * Early B, stage name of Jamaican d ...

and

Middle Middle or The Middle may refer to: * Centre (geometry), the point equally distant from the outer limits. Places * Middle (sheading), a subdivision of the Isle of Man * Middle Bay (disambiguation) * Middle Brook (disambiguation) * Middle Creek ...

Devonian, nor the

Frasnian The Frasnian is one of two faunal stages in the Late Devonian Period. It lasted from million years ago to million years ago. It was preceded by the Givetian Stage and followed by the Famennian Stage. Major reef-building was under way during ...

stage (the first part of the

). Labechiid fossil occurrences during this time were spotty and consist entirely of hardy relicts which purportedly originated in the Ordovician. Stromatoporoid specialists have mixed interpretations of this phenomenon. The Devonian relicts may truly be the same as their Ordovician predecessors, persisting as rare and reclusive ‘ Lazarus taxa’. Alternatively, they could be misidentified fragments or new labechiid lineages acquiring a similar set of characteristics, so-called ‘ Elvis taxa’. In any case, Devonian labechiids never managed to repopulate southeast

Laurussia Laurasia () was the more northern of two large landmasses that formed part of the Pangaea supercontinent from around (Million years ago, Mya), the other being Gondwana. It separated from Gondwana (beginning in the late Triassic period) during ...

(eastern North America) or high-latitude environments at any time during the period. Unlike other stromatoporoids, labechiids were not adversely affected by the

Kellwasser event The Late Devonian mass extinction, also known as the Kellwasser event, was a mass extinction event which occurred around 372 million years ago, at the boundary between the Frasnian and Famennian ages of the Late Devonian period.Racki, 2005McGhee, ...

(Late Devonian mass extinction) at the end of the Frasnian (~372 Ma). Instead, they experienced a diversification in the

stage, reacquiring a level of diversity and dominance in their niche not experienced since the Ordovician. Most new genera arose from the families Stylostromatidae and Platiferostromatidae, which helped to form dense reef habitats alongside the older relict forms. The labechiid resurgence was strongest in shallow water and the

Eastern Hemisphere The Eastern Hemisphere is the half of the planet Earth which is east of the prime meridian (which crosses Greenwich, London, United Kingdom) and west of the antimeridian (which crosses the Pacific Ocean and relatively little land from pole to p ...

. Despite being reinvigorated after the Kellwasser event, labechiids and their reef ecosystems presumably did not survive the

Hangenberg event The Hangenberg event, also known as the Hangenberg crisis or end-Devonian extinction, is a mass extinction that occurred at the end of the Famennian stage, the last Stage (stratigraphy), stage in the Devonian Period (roughly 358.9 ± 0.4 million y ...

(~359 Ma), a second mass extinction which marked the end of the Famennian stage and Devonian period. This extinction is generally considered absolute, but several possible exceptions have been reported to imply post-Devonian survival: '' Labechia carbonaria'' (from the

Viséan The Visean, Viséan or Visian is an age in the ICS geologic timescale or a stage in the stratigraphic column. It is the second stage of the Mississippian, the lower subsystem of the Carboniferous. The Visean lasted from to Ma. It follows ...

stage of

Carboniferous The Carboniferous ( ) is a Geologic time scale, geologic period and System (stratigraphy), system of the Paleozoic era (geology), era that spans 60 million years, from the end of the Devonian Period Ma (million years ago) to the beginning of the ...

England) and '' Lophiostroma boletiformis'' (from

Triassic The Triassic ( ; sometimes symbolized 🝈) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is t ...

rocks of the

Pamir Mountains The Pamir Mountains are a Mountain range, range of mountains between Central Asia and South Asia. They are located at a junction with other notable mountains, namely the Tian Shan, Karakoram, Kunlun Mountains, Kunlun, Hindu Kush and the Himalaya ...

). These discontinuous reports pose the same set of questions applied to Early and Middle Devonian occurrences. Labechiid-like fossils are abundant in early

Pennsylvanian Pennsylvanian may refer to: * A person or thing from Pennsylvania * Pennsylvanian (geology) The Pennsylvanian ( , also known as Upper Carboniferous or Late Carboniferous) is, on the International Commission on Stratigraphy, ICS geologic timesc ...

(

Bashkirian The Bashkirian is in the International Commission on Stratigraphy geologic timescale the lowest stage (stratigraphy), stage or oldest age (geology), age of the Pennsylvanian (geology), Pennsylvanian. The Bashkirian age lasted from to Mega annu ...

) reef deposits of the

Akiyoshi Limestone Group Akiyoshi (written: or ) is a Japanese surname. Notable people with the surname include: *, Japanese motorcycle racer *, Japanese actress *, Japanese baseball player *, Japanese golfer *, Japanese footballer *, Japanese American musician *, Japanes ...

in Japan, representing a Panthalassan

seamount A seamount is a large submarine landform that rises from the ocean floor without reaching the water surface (sea level), and thus is not an island, islet, or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise abruptly a ...

References

{{Taxonbar, from=Q35132691 Stromatoporoidea Darriwilian first appearances Famennian extinctions Prehistoric animal orders Sponge orders