''Jugulator'' is an extinct genus of mammals from 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 ...

of North America. It contains one species, ''Jugulator amplissimus''. A

eutriconodont Eutriconodonta is an order of early mammals. Eutriconodonts existed in Asia, Africa, Europe, North and South America during the Jurassic and the Cretaceous periods. The order was named by Kermack ''et al.'' in 1973 as a replacement name for the p ...

, it is known from the

Cedar Mountain Formation The Cedar Mountain Formation is the name given to a distinctive sedimentary geologic formation in eastern Utah, spanning most of the early and mid- Cretaceous. The formation was named for Cedar Mountain in northern Emery County, Utah, where Will ...

, and is both a large sized and possibly ecologically specialised taxon, showcasing the diversity of mammals in the

Mesozoic The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretace ...

Description

''Jugulator'' is known primarily from isolated teeth and dentaries. The species is most distinctive in regards to its large size, being among the largest mammals in the region, some lower molars exceeding 5 mm in length and with an estimated body weight of about 750 g. The medial lower incisor is greatly enlarged, with a mitten-shaped crown that bears sharp cutting surfaces.

Phylogeny

Always recognised as a

triconodontid Triconodontidae is an extinct family of small, carnivorous mammals belonging to the order Eutriconodonta, endemic to what would become Asia, Europe, North America and probably also Africa and South America during the Jurassic through Cretaceo ...

, the most recent phylogenetic studies recover ''Jugulator'' as the sister taxon of a clade comprising ''

Volaticotherium ''Volaticotherium antiquum'' (meaning "ancient gliding beast") is an extinct, gliding, insectivorous mammal that lived in Asia during the Jurassic period, around 164 mya. It is the only member of the genus ''Volaticotherium''. The discovery of ...

'', '' Ichthyoconodon'', '' Triconolestes'', and '' Argentoconodon'', known as

Volaticotherini Volaticotherini is a clade of eutriconodont mammals from the Mesozoic. In addition to the type genus '' Volaticotherium'', it includes the genera '' Argentoconodon'', '' Ichthyoconodon'', and potentially '' Triconolestes''. Since most remains ...

.A. O. Averianov and A. V. Lopatin. 2011. Phylogeny of Triconodonts and Symmetrodonts and the Origin of Extant Mammals. Doklady Biological Sciences 436:32-35 . Uhen/M. Uhen/ref>

Cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to ...

after Gaetano & Rougier, 2011:

Biology

''Jugulator'' is noted as being a rather large mammal for Mesozoic standards. Combined with the general adaptations for carnivory that eutriconodonts display, it is safe to say that it was a predator of other vertebrates like mammals, lizards and small dinosaurs. Other large eutriconodonts like ''

Repenomamus ''Repenomamus'' (Latin: "reptile" (reptilis), "mammal" (mammalis)) is a genus of opossum- to badger-sized gobiconodontid mammal containing two species, ''Repenomamus robustus'' and ''Repenomamus giganticus''. Both species are known from fossils ...

'' and ''

Gobiconodon ''Gobiconodon'' is an extinct genus of carnivorous mammal from the Middle Jurassic to Early Cretaceous. It weighed , had a skull of in length, and had in presacral body length. It was one of the largest mammals known from the Mesozoic. Like o ...

'' show evidence of scavenging and direct predation on such creatures, so it is likely that ''Jugulator'' also displayed these behaviours.

Ecology

''Jugulator'' occurs in the mid-Cretaceous deposits of the

, where several of North America's more iconic dinosaurs like ''

Utahraptor ''Utahraptor'' (meaning "Utah's thief") is a genus of large dromaeosaurid dinosaur that lived in North America during the Early Cretaceous period. It was a heavy-built, ground-dwelling, bipedal carnivore. It contains a single species, ''Utah ...

'' and ''

Cedarosaurus ''Cedarosaurus'' (meaning "Cedar lizard" - named after the Cedar Mountain Formation, in which it was discovered) was a nasal-crested macronarian dinosaur genus from the Early Cretaceous Period (Valanginian). It was a sauropod which lived in what i ...

'' occur. A large variety of mammal species are known from here as well, including other eutriconodonts like ''

Astroconodon ''Astroconodon'' is an extinct genus of mammal from the Cretaceous of North America. Part of Eutriconodonta, it was a small sized predator, either a terrestrial insectivore and carnivore, or a semi-aquatic piscivore. It is the first Cretaceou ...

'' and '' Corviconodon'' as well as

multituberculate Multituberculata (commonly known as multituberculates, named for the multiple tubercles of their teeth) is an extinct order of rodent-like mammals with a fossil record spanning over 130 million years. They first appeared in the Middle Jurassic, a ...

s like ''

Cedaromys ''Cedaromys'' ("Cedar mouse") is an extinct mammal which lived during the Upper Cretaceous, at the same time as many dinosaurs. It was a member of the also extinct order of Multituberculata. It's within the suborder of Cimolodonta, and a possibl ...

'' and ''

Janumys ''Janumys'' is a genus of extinct mammal of the middle Cretaceous. It was a member of the order of Multituberculata (also extinct). It lived in North America during the Mesozoic era, also known as the "age of the reptiles." It has been provi ...

'' and several

theria Theria (; Greek: , wild beast) is a subclass of mammals amongst the Theriiformes. Theria includes the eutherians (including the placental mammals) and the metatherians (including the marsupials) but excludes the egg-laying monotremes. ...

n mammals such as ''

Montanalestes ''Montanalestes'' is an extinct mammal known from the Cretaceous in North America. Classification Known from only six fossil teeth, ''Montanalestes'' is an example of the less well-preserved early eutherian Eutheria (; from Greek , 'good, r ...

'' and '' Atokatheridium''. These diverse mammal faunas offer a transition from dominant taxa in the Early Cretaceous and the multituberculate and therian dominated laurasian mammalian faunas of the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', ...

References

{{Taxonbar, from=Q22285226 Eutriconodonts Early Cretaceous mammals Mesozoic mammals of North America Cretaceous animals of North America Fossil taxa described in 1998