Boreoeutheria (, "northern true beasts") is a magnorder of

placental mammals Placental mammals (infraclass Placentalia ) are one of the three extant subdivisions of the class Mammalia, the other two being Monotremata and Marsupialia. Placentalia contains the vast majority of extant mammals, which are partly distinguishe ...

that groups together superorders

Euarchontoglires Euarchontoglires (synonymous with Supraprimates) is a clade and a superorder of mammals, the living members of which belong to one of the five following groups: rodents, lagomorphs, treeshrews, colugos, and primates. Evolutionary affinities wit ...

and

Laurasiatheria Laurasiatheria ("laurasian beasts") is a superorder of placental mammals that groups together true insectivores ( eulipotyphlans), bats ( chiropterans), carnivorans, pangolins ( pholidotes), even-toed ungulates (artiodactyls), odd-toed ungulates ...

. With a few exceptionsExceptional clades whose males lack the usual boreoeutherian scrotum are

moles Moles can refer to: * Moles de Xert, a mountain range in the Baix Maestrat comarca, Valencian Community, Spain * The Moles (Australian band) *The Moles, alter ego of Scottish band Simon Dupree and the Big Sound People *Abraham Moles, French engin ...

hedgehog A hedgehog is a spiny mammal of the subfamily Erinaceinae, in the eulipotyphlan family Erinaceidae. There are seventeen species of hedgehog in five genera found throughout parts of Europe, Asia, and Africa, and in New Zealand by introducti ...

pangolin Pangolins, sometimes known as scaly anteaters, are mammals of the order Pholidota (, from Ancient Greek ϕολιδωτός – "clad in scales"). The one extant family, the Manidae, has three genera: '' Manis'', '' Phataginus'', and '' Smut ...

s, some

pinnipeds Pinnipeds (pronounced ), commonly known as seals, are a widely range (biology), distributed and diverse clade of carnivorous, fin-footed, semiaquatic, mostly marine mammal, marine mammals. They comprise the extant taxon, extant family (biology ...

rhinoceros A rhinoceros (; ; ), commonly abbreviated to rhino, is a member of any of the five extant species (or numerous extinct species) of odd-toed ungulates in the family Rhinocerotidae. (It can also refer to a member of any of the extinct species o ...

es,

tapir Tapirs ( ) are large, herbivorous mammals belonging to the family Tapiridae. They are similar in shape to a pig, with a short, prehensile nose trunk. Tapirs inhabit jungle and forest regions of South and Central America, with one species inhabit ...

hippopotamus The hippopotamus ( ; : hippopotamuses or hippopotami; ''Hippopotamus amphibius''), also called the hippo, common hippopotamus, or river hippopotamus, is a large semiaquatic mammal native to sub-Saharan Africa. It is one of only two extan ...

es, and

cetacea Cetacea (; , ) is an infraorder of aquatic mammals that includes whales, dolphins, and porpoises. Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively carnivorous diet. They propel them ...

ns. male animals in the clade have a

scrotum The scrotum or scrotal sac is an anatomical male reproductive structure located at the base of the penis that consists of a suspended dual-chambered sac of skin and smooth muscle. It is present in most terrestrial male mammals. The scrotum cont ...

, an ancestral feature of the clade. The sub-clade

Scrotifera Scrotifera ("beasts with scrotum") is a clade of placental mammals that groups together grandorder Ferungulata, clade Apo-Chiroptera (aka order Chiroptera), other extinct members and their common ancestors. The clade Scrotifera is a sister gr ...

was named after this feature.

Etymology

The name of this magnorder comes from

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic peri ...

words: * () meaning ' north wind' or 'the North', * () meaning 'good', 'right', or 'true', * and () meaning 'beast'.

Boreoeutherian ancestor

The majority of earliest known fossils belonging to this group date to about 66 million years ago, shortly after the K-Pg extinction event, though molecular data suggest they may have originated earlier, during the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

period. This is further supported with fossils of '' Altacreodus magnus'' and two species from genus ''

Protungulatum ''Protungulatum'' ('first ungulate') is a extinct genus of pan-euungulate mammals within extinct family Protungulatidae, and also one of the earliest known placental mammals in the fossil record, that lived in North America from the Late Creta ...

'' dated about 70.6 million years ago. The

common ancestor Common descent is a concept in evolutionary biology applicable when one species is the ancestor of two or more species later in time. All living beings are in fact descendants of a unique ancestor commonly referred to as the last universal comm ...

of Boreoeutheria lived between 107 and 90 million years ago. The boreoeutherian ancestor gave rise to

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

as diverse as

giraffe The giraffe is a large African hoofed mammal belonging to the genus ''Giraffa''. It is the tallest living terrestrial animal and the largest ruminant on Earth. Traditionally, giraffes were thought to be one species, ''Giraffa camelopardalis ...

dog The dog (''Canis familiaris'' or ''Canis lupus familiaris'') is a domesticated descendant of the wolf. Also called the domestic dog, it is derived from the extinct Pleistocene wolf, and the modern wolf is the dog's nearest living relative. Do ...

mice A mouse ( : mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus' ...

bat Bats are mammals of the order Chiroptera.''cheir'', "hand" and πτερόν''pteron'', "wing". With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in flight than most ...

whale Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and ...

s, and

human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...

s. The concept of a boreoeutherian ancestor was first proposed in 2004 in the journal ''

Genome Research ''Genome Research'' is a peer-reviewed scientific journal published by Cold Spring Harbor Laboratory Press. Disregarding review journals, Genome Research ranks 2nd in the category 'Genetics and Genomics' after Nature Genetics. The focus of the jou ...

''. The paper's authors claimed that the

genome sequence In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding g ...

of the boreoeutherian ancestor could be computationally predicted with 98% accuracy, but would "take a few years and a lot of money". It is estimated to contain three billion

base pairs A base pair (bp) is a fundamental unit of double-stranded nucleic acids consisting of two nucleobases bound to each other by hydrogen bonds. They form the building blocks of the DNA double helix and contribute to the folded structure of both DNA ...

Classification and phylogeny

Taxonomy

* Magnorder: Boreoeutheria ** Superorder:

** Superorder:

Phylogeny

The phylogenetic relationships of magnorder Boreoeutheria are shown in the following cladogram, reconstructed from mitochondrial and nuclear DNA and protein characters, as well as the fossil record.Frank Zachos (2020.
"Mammalian Phylogenetics: A Short Overview of Recent Advances"
In book: "Mammals of Europe - Past, Present, and Future" (pp.31-48)Xue Lv, Jingyang Hu, Yiwen Hu, Yitian Li, Dongming Xu, Oliver A. Ryder, David M. Irwin, Li Yu (2021.
"Diverse phylogenomic datasets uncover a concordant scenario of laurasiatherian interordinal relationships"
Molecular Phylogenetics and Evolution, Volume 157

Etymology

Boreoeutherian ancestor

Classification and phylogeny

Taxonomy

Phylogeny

See also

Notes

References

Additional references

External links