''Boreostemma'' is an extinct

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 ...

glyptodont Glyptodonts are an extinct clade of large, heavily armoured armadillos, reaching up to in height, and maximum body masses of around 2 tonnes. They had short, deep skulls, a fused vertebral column, and a large bony carapace made up of hundreds o ...

s from northern South America. Fossils assigned to the genus were first described as belonging to '' Asterostemma'' from southern South America, but have been placed in the new genus ''Boreostemma'' by Carlini et al. in 2008. 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 ...

is ''B. pliocena''. Fossils of ''Boreostemma'' have been found in the Honda Group of

Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...

, in

Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...

and

Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...

Etymology

The genus name ''Boreostemma'' is a combination of ''stemma'', taken from '' Asterostemma'', and ''boreo'' is derived from borealis, meaning "northern", to distinguish the northern South American genus from the southern ''Asterostemma''.

Taxonomy

''Boreostemma'' has been placed as closely related to the later ''

Glyptodon ''Glyptodon'' (; ) is a genus of glyptodont, an extinct group of large, herbivorous armadillos, that lived from the Pliocene, around 3.2 million years ago, to the early Holocene, around 11,000 years ago, in South America. It is one of, if not th ...

'' and ''

Glyptotherium ''Glyptotherium'' (from Ancient Greek for 'grooved or carved beast') is a genus of glyptodont (an extinct group of large, herbivorous armadillos) in the family Chlamyphoridae that lived from the Early Pliocene, about 5 million years ago, to th ...

''. Cladogram after Barasoain et al. 2022:

Species

Four species have been described in the genus ''Boreostemma''.''Boreostemma''
at

Fossilworks Fossilworks was a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database, a large relational database assembled by hundreds of paleontologists from around the world. History Fossilworks was cr ...

.org Unspecified ''Boreostemma'' fossils were found in the Ipururo Formation of the department of

Ucayali The Ucayali River (, ) is the main headstream of the Amazon River. It rises about north of Lake Titicaca, in the Arequipa region of Peru and becomes the Amazon at the confluence of the Marañón close to Nauta city. The city of Pucallpa is lo ...

, Amazonian

.IN-DTC-28
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.orgIN-DTC-32
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.orgIN007
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.org ''Asterostemma'' contains the type species ''A. depressa'' and several

nomina dubia In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium,'' it may be impossible to determine whether a ...

. The genus has been found in the

Early Miocene The Early Miocene (also known as Lower Miocene) is a sub-epoch of the Miocene epoch (geology), Epoch made up of two faunal stage, stages: the Aquitanian age, Aquitanian and Burdigalian stages. The sub-epoch lasted from 23.03 ± 0.05 annum, Ma to ...

(

Santacrucian The Santacrucian age is a period of geologic time (17.5 – 16.3 Mya (unit), Ma) within the Early Miocene epoch of the Neogene, used more specifically with South American land mammal age, SALMA classification in South America. It follows the Colhue ...

in the SALMA classification)

Santa Cruz Formation The Santa Cruz Formation is a geological formation in the Magallanes Basin, Magallanes/Austral Basin in southern Patagonia in Argentina and adjacent areas of Chile. It dates to the late Early Miocene epoch, and is contemporaneous with the eponym ...

of the

province A province is an administrative division within a country or sovereign state, state. The term derives from the ancient Roman , which was the major territorial and administrative unit of the Roman Empire, Roman Empire's territorial possessions ou ...

of Santa Cruz,

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 ...

and in the

Solimões Formation The Pebas Formation is a lithostratigraphic unit of Miocene age, found in western Amazonia. The formation extends over , including parts of Brazil, Peru, Ecuador and Colombia.Wesselingh et al., 2006 It is interpreted as representing the deposit ...

in the

state State most commonly refers to: * State (polity), a centralized political organization that regulates law and society within a territory **Sovereign state, a sovereign polity in international law, commonly referred to as a country **Nation state, a ...

Acre The acre ( ) is a Unit of measurement, unit of land area used in the Imperial units, British imperial and the United States customary units#Area, United States customary systems. It is traditionally defined as the area of one Chain (unit), ch ...

, Amazonian

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

.Cañadón Jack, Yak-Harvey
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.orgRio Acre
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.org ;''B. pliocena'' The

''B. pliocena'' was described in 2008 by Carlini et al. based on 30 osteoderms palate fragment with M6-7 alveoli.''Boreostemma pliocena''
at

.org Fossils have been described from the type locality along the road to Tío Gregorio in the Codore Formation at the

Lagerstätte A Fossil-Lagerstätte (, from ''Lager'' 'storage, lair' '' Stätte'' 'place'; plural ''Lagerstätten'') is a sedimentary deposit that preserves an exceptionally high amount of palaeontological information. ''Konzentrat-Lagerstätten'' preserv ...

Urumaco Urumaco is a town in Falcón State in Venezuela. It is of interest to paleontologists due to its rich fossil history. The arid climate of the region means that the fossils are not hidden by vegetation. The fossils were first made known to scienc ...

.Road to Tio Gregorio Locality
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.org ;''B. gigantea'' ''B. gigantea'' was described as ''Asterostemma gigantea'' in 1997 by Carlini et al. based on a partial skeleton.''Boreostemma gigantea''
at

.org Fossils have been recovered at the Duke Localities 32, 108, 113, 114 and 121W in the

La Victoria Formation The Honda Group (, Tsh, Ngh) is a geological group of the Upper and Middle Magdalena Basins and the adjacent Central and Eastern Ranges of the Colombian Andes. The group, in older literature also defined as formation, is in its present-day ty ...

of the Honda Group at the Konzentrat-Lagerstätte

La Venta La Venta is a pre-Columbian archaeological site of the Olmec civilization located in the present-day Mexican state of Tabasco. Some of the artifacts have been moved to the museum "Parque - Museo de La Venta", which is in nearby Villaherm ...

.Duke Locality 32
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.orgDuke Locality 108
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.orgDuke Locality 113
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.orgDuke Locality 114
at

.orgDuke Locality 121W
at

.org ;''B. acostae'' ''B. acostae'' was described as ''Asterostemma acostae'' in 1983 by Carlos Villarroel based on a carapace fragment with 44 plates.''Boreostemma acostae''
at

.org Fossils have been found in the Cerbatana Member, and the Chunchullo Sandstone of the

, of the Honda Group at the Konzentrat-Lagerstätte

.Arcillas San Nicolas
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.orgChunchullo Sandstone
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.org ;''B. venezolensis'' ''B. venezolensis'' was described as ''Asterostemma venezolensis'' in 1947 by

George Gaylord Simpson George Gaylord Simpson (June 16, 1902 – October 6, 1984) was an American paleontologist. Simpson was perhaps the most influential paleontologist of the twentieth century, and a major participant in the modern synthesis, contributing '' Tempo ...

,Simpson, 1947, p.2 based on most of the carapace and the anterior end of the lower jaw, including teeth.''Boreostemma venezolensis''
at

.org Fossils have been uncovered from the Santa Inés Formation along the banks of the Güere River in the

Anzoátegui Anzoátegui State (, ) is one of the 23 states of Venezuela, states of Venezuela, located in the northeastern region of the country. Anzoátegui is well known for its beaches that attract many visitors. Its coast consists of a single beach approx ...

in Venezuela.Banks of the Güere River
at

.org

Gallery

References

Bibliography