BumastusBarriensis-NaturalHistoryMuseum-August23-08

''Bumastus'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of corynexochid

trilobite Trilobites (; meaning "three-lobed entities") are extinction, extinct marine arthropods that form the class (biology), class Trilobita. One of the earliest groups of arthropods to appear in the fossil record, trilobites were among the most succ ...

s which existed from the Early

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 ...

period Period may refer to: Common uses * Period (punctuation) * Era, a length or span of time *Menstruation, commonly referred to as a "period" Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (o ...

to the Late

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 ...

period. They were relatively large trilobites, reaching a length of . They were distinctive for their highly globular, smooth-surfaced

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 ...

. They possessed well-developed, large compound eyes and were believed to have dwelled in shallow-water sediments in life. ''Bumastus'' fossils have been found in

North North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. ''North'' is a noun, adjective, or adverb indicating Direction (geometry), direction or geography. Etymology T ...

and

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

, and

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

. They are classified under the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Styginidae Styginidae is a family of trilobite in the order Corynexochida. Fossils of the various genera are found in marine strata throughout the world, aged from Ordovician up until the family's extinction during the Silurian. Genera Styginidae conta ...

in the

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 ...

Corynexochida Corynexochida is an order of trilobite that lived from the Lower Cambrian to the Late Devonian. Like many of the other trilobite orders, Corynexochida contains many species with widespread characteristics. Description The middle region of the ...

Description

''Bumastus'' is a large trilobite, reaching a length of . The body is oblong-oval, about twice as long as it is wide, It had a strongly convex profile, giving it its distinctive globular appearance. Like all trilobites, the body is divided into three functional segments known as tagmata (singular: tagma), which in turn are divided into three lobes - the central lobe (axial) and two lateral lobes (pleural). Aside from faint depressions in the

thorax The thorax (: thoraces or thoraxes) or chest is a part of the anatomy of mammals and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main di ...

, ''Bumastus'' is unusual in that the three lobes are barely discernible from each other. The axial lobe of ''Bumastus'' is also very broad in comparison to the pleural lobes. The

cephalon Cephalon, Inc. was an American biopharmaceutical company co-founded in 1987 by pharmacologist Frank Baldino Jr., Frank Baldino, Jr., neuroscientist Michael Lewis, and organic chemist James C. Kauer—all three former scientists with the DuPont ...

(head segment) is very large and strongly convex. The

facial sutures Trilobites (; meaning "three-lobed entities") are extinct marine arthropods that form the class Trilobita. One of the earliest groups of arthropods to appear in the fossil record, trilobites were among the most successful of all early animals, ...

(the divisions by which the cephalon splits when the trilobite molts) is

opisthoparian Trilobites (; meaning "three-lobed entities") are extinct marine arthropods that form the class Trilobita. One of the earliest groups of arthropods to appear in the fossil record, trilobites were among the most successful of all early animals, ...

, with the suture ending along the hind cephalic margin. The

gena Ethiopian Christmas (; ; ) is a holiday celebrated by the Ethiopian Orthodox and Eritrean Orthodox churches, as well as Protestant and Catholic denominations in Ethiopia, on 7 January (Tahsas 29 in the Ethiopian calendar). One of the distinct fe ...

angles Angles most commonly refers to: *Angles (tribe), a Germanic-speaking people that took their name from the Angeln cultural region in Germany *Angle, a geometric figure formed by two rays meeting at a common point Angles may also refer to: Places ...

of the cephalon - the edges where the lateral and rear margins of the cephalon meet - are rounded. The cephalon is effaced (smooth and mostly featureless), an evolutionary trend also seen in ''

Illaenus ''Illaenus'' is a genus of trilobites from Russia and Morocco, from the middle Ordovician. Species included in this genus can reach a length of about . They are without glabella and without articulation of the tail. The cephalon has a high profi ...

'' and ''

Trimerus ''Trimerus'' is an extinct genus of trilobite in the family Homalonotidae. ''Trimerus'' is one of North America's largest trilobites, reaching over in length. It had a thorax composed of 13 segments with weak trilobation, a large subtriangula ...

'', though not as pronounced as that of ''Bumastus''. The

glabella The glabella, in humans, is the area of skin between the eyebrows and above the nose. The term also refers to the underlying bone that is slightly depressed, and joins the two brow ridges. It is a cephalometric landmark that is just superior ...

(the central lobe of the head) is almost fused to the fixigena. The thorax has ten narrow segments while the

pygidium The pygidium (: pygidia) is the posterior body part or shield of crustaceans and some other arthropods, such as insects and the extinct trilobites. In groups other than insects, it contains the anus and, in females, the ovipositor. It is compos ...

(the tail) is smooth and very rounded. It is isopygous - that is, the pygidium is about the same size as the cephalon. The pygidium completely lacks any visible trilobation. It is usually semicircular in shape but can be pointed in some species like '' B. niagarensis''. The smooth

compound eye A compound eye is a Eye, visual organ found in arthropods such as insects and crustaceans. It may consist of thousands of ommatidium, ommatidia, which are tiny independent photoreception units that consist of a cornea, lens (anatomy), lens, and p ...

s are large and peculiarly well-developed. This, along with the rounded contours of their body, suggests that ''Bumastus'' may have spent most of its time buried in sediment with its eyes protruding. The surface of the exoskeleton of most species is studded with minute punctures. Bumastus morphology

Paleoecology

The rounded smooth shape of ''Bumastus'', as well as the almost complete effacement of its cephalon, is believed to have been an adaptation for burrowing. The presence of well-developed eyes also suggest that it may have kept them above the substrate by burrowing into

sediments Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of ...

backward. They are situated in such a way that they provide the trilobite with a semicircular

field of vision The visual field is "that portion of space in which objects are visible at the same moment during steady fixation of the gaze in one direction"; in ophthalmology and neurology the emphasis is mostly on the structure inside the visual field and it i ...

on each side, keeping them aware of movements near them. Trilobite - Bumastus reconstruction 3d scene

''Bumastus'' could also curl up (known as enrollment) into a ball-like shape. This is believed to indicate that its habitat might have been the shallow waters of the

Littoral zone The littoral zone, also called litoral or nearshore, is the part of a sea, lake, or river that is close to the shore. In coastal ecology, the littoral zone includes the intertidal zone extending from the high water mark (which is rarely flood ...

. When

waves United States Naval Reserve (Women's Reserve), better known as the WAVES (for Women Accepted for Volunteer Emergency Service), was the women's branch of the United States Naval Reserve during World War II. It was established on July 21, 1942, ...

wash them out from the sediments it could simply roll up and be carried along. Enrollment protects the softer body parts below the exoskeleton, while the spherical shape offers the least resistance to wave action. ''Bumastus'' is a

bottom-dwelling The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from the Ancient Greek word (), meaning "the depths". ...

( nektobenthic) trilobite. It was probably either detritivorous, feeding on decomposing organic material drifting down in the currents, or

carnivorous A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose nutrition and energy requirements are met by consumption of animal tissues (mainly mu ...

Occurrence

''Bumastus'' existed during the

Paleozoic era The Paleozoic ( , , ; or Palaeozoic) Era is the first of three 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 at the start of ...

, from the Arenigian

epoch In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided b ...

of the Early Ordovician period to the

Ludlow epoch In the geological timescale, the Ludlow Epoch (from 427.4 ± 0.5 million years ago to 423.0 ± 2.3 million years ago) occurred during the Silurian Period, after the end of the Homerian Age. It is named for the town of Ludlow in Shropshire, Engl ...

of the Late Silurian period (approximately 478.6 ± 1.7 to 418.7 ± 2.8

million years ago Million years ago, abbreviated as Mya, Myr (megayear) or Ma (megaannum), is a unit of time equal to (i.e. years), or approximately 31.6 teraseconds. Usage Myr is in common use in fields such as Earth science and cosmology. Myr is also used w ...

). Their

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 preserve ...

s can be found worldwide. Specimens have been recorded from the Silurian of

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

, the

Czech Republic The Czech Republic, also known as Czechia, and historically known as Bohemia, is a landlocked country in Central Europe. The country is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the south ...

Estonia Estonia, officially the Republic of Estonia, is a country in Northern Europe. It is bordered to the north by the Gulf of Finland across from Finland, to the west by the Baltic Sea across from Sweden, to the south by Latvia, and to the east by Ru ...

Greenland Greenland is an autonomous territory in the Danish Realm, Kingdom of Denmark. It is by far the largest geographically of three constituent parts of the kingdom; the other two are metropolitan Denmark and the Faroe Islands. Citizens of Greenlan ...

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 ...

Norway Norway, officially the Kingdom of Norway, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. The remote Arctic island of Jan Mayen and the archipelago of Svalbard also form part of the Kingdom of ...

, the

Russian Federation Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

Sweden Sweden, formally the Kingdom of Sweden, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. It borders Norway to the west and north, and Finland to the east. At , Sweden is the largest Nordic count ...

Ukraine Ukraine is a country in Eastern Europe. It is the List of European countries by area, second-largest country in Europe after Russia, which Russia–Ukraine border, borders it to the east and northeast. Ukraine also borders Belarus to the nor ...

, the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...

, and the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

. They can also be found in the Ordovician formations of

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

, the Czech Republic, the Russian Federation,

Spain Spain, or the Kingdom of Spain, is a country in Southern Europe, Southern and Western Europe with territories in North Africa. Featuring the Punta de Tarifa, southernmost point of continental Europe, it is the largest country in Southern Eur ...

, the

; with specific occurrences from the Dobrotivian

age Age or AGE may refer to: Time and its effects * Age, the amount of time someone has been alive or something has existed ** East Asian age reckoning, an Asian system of marking age starting at 1 * Ageing or aging, the process of becoming older ...

stage Stage, stages, or staging may refer to: Arts and media Acting * Stage (theatre), a space for the performance of theatrical productions * Theatre, a branch of the performing arts, often referred to as "the stage" * ''The Stage'', a weekly Brit ...

(

Llandeilo Llandeilo () is a town and Community (Wales), community in Carmarthenshire, Wales, situated where the River Towy is crossed by the A483 road, A483 on a 19th-century stone bridge. At the 2021 United Kingdom census, 2021 census the community had ...

age) of China and

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

, and the

Whiterockian The Whiterockian, often referred to simply as the Whiterock, is an earliest or lowermost stage of the Middle Ordovician. Although the Whiterockian or Whiterock Stage refers mainly to the early Middle Ordovician in North America, it is often used in ...

stage of the United States. They are typically found in reef limestone, though they are sometimes found in

crinoid Crinoids are marine invertebrates that make up the class Crinoidea. Crinoids that remain attached to the sea floor by a stalk in their adult form are commonly called sea lilies, while the unstalked forms, called feather stars or comatulids, are ...

al limestone.

Discovery

''Bumastus'' was first described by the

Scottish Scottish usually refers to something of, from, or related to Scotland, including: *Scottish Gaelic, a Celtic Goidelic language of the Indo-European language family native to Scotland *Scottish English *Scottish national identity, the Scottish ide ...

geologist A geologist is a scientist who studies the structure, composition, and History of Earth, history of Earth. Geologists incorporate techniques from physics, chemistry, biology, mathematics, and geography to perform research in the Field research, ...

, Sir Roderick Impey Murchison in 1839. The

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

, ''

Bumastus barriensis ''Bumastus'' is an extinct genus of Corynexochida, corynexochid trilobites which existed from the Early Ordovician Period (geology), period to the Late Silurian period. They were relatively large trilobites, reaching a length of . They were dist ...

'' was recovered from the

Coalbrookdale Coalbrookdale is a town in the Ironbridge Gorge and the Telford and Wrekin borough of Shropshire, England, containing a settlement of great significance in the history of iron ore smelting. It lies within the civil parish called The Gorge, Shro ...

Formation Formation may refer to: Linguistics * Back-formation, the process of creating a new lexeme by removing or affixes * Word formation, the creation of a new word by adding affixes Mathematics and science * Cave formation or speleothem, a secondary ...

of the

Wenlock Group The Wenlock Group (Wenlockian), in geology, is the middle series of stratum, strata in the Silurian (Upper Silurian) of Great Britain. This group in the typical area in the Wales, Welsh border counties contains the following formations: Much Wenlo ...

England England is a Countries of the United Kingdom, country that is part of the United Kingdom. It is located on the island of Great Britain, of which it covers about 62%, and List of islands of England, more than 100 smaller adjacent islands. It ...

. Murchison first believed that the specimens he discovered (including a large by specimen) belonged to the genus ''

Isotelus is an extinct genus of large Asaphida, asaphid trilobites from the Middle and Late Ordovician Period, fairly common in the northeastern United States, northwest Manitoba, southwestern Quebec and southeastern Ontario. Isotelus is the state fossil ...

'' because of the size, shape, and almost featureless cephalon. But he noted the almost absent trilobation of body and the difference in the number of segments in the thorax (10 in ''B. barriensis'' and 8 in ''Isotelus''). He also recognized its close relationship with the genus ''

'', but ultimately classified it as a new genus based on the extremely advanced state of effacement in the cephalon of ''Bumastus''. The genus is so named because of its curious resemblance to a large round

grape A grape is a fruit, botanically a berry, of the deciduous woody vines of the flowering plant genus ''Vitis''. Grapes are a non- climacteric type of fruit, generally occurring in clusters. The cultivation of grapes began approximately 8,0 ...

. It comes from

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

''būmastus'' (large grapes that resemble the

udder An udder is an organ formed of two or four mammary glands on the females of dairy animals and ruminants such as cattle, goats, and sheep. An udder is equivalent to the breast in primates, elephantine pachyderms and other mammals. The udder is ...

s of a cow), which in turn came from

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

βοῦς (''bous'' - cow) and μαστός (''mastós'' - breasts). The word was familiar in the

English language English is a West Germanic language that developed in early medieval England and has since become a English as a lingua franca, global lingua franca. The namesake of the language is the Angles (tribe), Angles, one of the Germanic peoples th ...

during Murchison's time, being a word encountered in book two of

Virgil Publius Vergilius Maro (; 15 October 70 BC21 September 19 BC), usually called Virgil or Vergil ( ) in English, was an ancient Rome, ancient Roman poet of the Augustan literature (ancient Rome), Augustan period. He composed three of the most fa ...

Georgics The ''Georgics'' ( ; ) is a poem by Latin poet Virgil, likely published in 29 BCE. As the name suggests (from the Greek language, Greek word , ''geōrgiká'', i.e. "agricultural hings) the subject of the poem is agriculture; but far from bei ...

. The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

of the type species, ''barriensis'', roughly meaning "of Barr", comes from its common name among collectors. It was then known as the "Barr trilobite" referring to the plentiful occurrence of ''B. barriensis'' in the limestone formations of

Great Barr Great Barr is a large and loosely defined area to the north-west of Birmingham, in the county of the West Midlands (county), West Midlands, England. The area was historically in Staffordshire, and the parts now in Birmingham were once known as ...

Staffordshire Staffordshire (; postal abbreviation ''Staffs''.) is a Ceremonial counties of England, ceremonial county in the West Midlands (region), West Midlands of England. It borders Cheshire to the north-west, Derbyshire and Leicestershire to the east, ...

Taxonomy

''Bumastus'' is classified under the

by P.A. Jell and J.M. Adrain in 2003, and under the

of trilobites by

Jack Sepkoski Joseph John Sepkoski Jr. (July 26, 1948 – May 1, 1999) was a University of Chicago paleontologist. Sepkoski studied the fossil record and the diversity of life on Earth. Sepkoski and David Raup produced a new understanding of extinction events ...

in 2002.

Species

Listed below are the

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

classified under ''Bumastus'' and the countries of their recorded type localities. The list is incomplete and may be inaccurate. *''Bumastus armatus'' - United States *''Bumastus barriensis'' - Estonia, Kazakhstan, Ukraine, United Kingdom, United States *''Bumastus beckeri'' - United States *''Bumastus bellmanni'' - Argentina *''Bumastus bouchardi'' - Czech Republic, Ukraine *''Bumastus chicagoensis'' - United States *''Bumastus cuniculus'' - United States **''Bumastus cuniculus, Bumastus cuniculus vieillensis'' - Canada *''Bumastus dayi'' - United States *''Bumastus erastusi'' - Canada *''Bumastus globosus'' - Canada, United States (Synonym (biology), synonym?:''Illaenus globosus'') *''Bumastus graftonensis'' - United States *''Burmatus Harrisi'' - United states *''Bumastus hornyi'' - Czech Republic *''Bumastus indeterminatus'' - Canada *''Bumastus insignis'' - United Kingdom, United States *''Bumastus ioxus'' - United States *''Bumastus lenzi'' - Canada *''Bumastus limbatus'' - United States *''Bumastus milleri'' - United States *''Bumastus niagarensis'' - United States *''Bumastus orbicaudatus'' - Canada, United States *''Bumastus phrix'' - Estonia, Ukraine, United Kingdom *''Bumastus springfieldensis'' - United States *''Bumastus sulcatus'' - Sweden *''Bumastus tenuirugosus'' - Canada *''Bumastus tenuis'' - United States *''Bumastus transversalis'' - United States *''Bumastus trentonensis'' - United States

References

External links

*
Order Corynexochida
fro
A Guide to the Orders of Trilobites
{{Taxonbar, from=Q44049 Styginidae Corynexochida genera Silurian trilobites of South America Ordovician trilobites Wenlock series fossils Early Ordovician first appearances Silurian extinctions Silurian trilobites of Europe Silurian trilobites of North America Silurian trilobites of Asia Bromide Formation Paleozoic life of Ontario Paleozoic life of Nunavut Paleozoic life of Quebec Taxa named by Roderick Murchison

Description

Paleoecology

Occurrence

Discovery

Taxonomy

Species

See also

References

External links