Stagodontidae is an extinct family of

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 ...

metatherian

mammals A mammal () is a vertebrate animal of the class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three middle e ...

that inhabited

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

and

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 ...

during the

late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent 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 ''cre ...

, and possibly to the

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

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 ...

Description

Currently, the family includes four genera, '' Eodelphis'', '' Didelphodon'', '' Fumodelphodon'' and '' Hoodootherium'', which together include some seven different species. In addition, the

Cenomanian The Cenomanian is, in the International Commission on Stratigraphy's (ICS) geological timescale, the oldest or earliest age (geology), age of the Late Cretaceous epoch (geology), Epoch or the lowest stage (stratigraphy), stage of the Upper Cretace ...

species '' Pariadens kirklandi'' might be a member of the family. Carneiro and Oliveira (2017) considered the species '' Eobrasilia coutoi'' from the early

( Itaboraian) of

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 ...

to be a stagodontid; if confirmed it would make it the only known

Cenozoic The Cenozoic Era ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterized by the dominance of mammals, insects, birds and angiosperms (flowering plants). It is the latest of three g ...

and the only known

n member of the family. Stagodontids were some of the largest known Cretaceous mammals, ranging from in mass. One of the most unusual features of stagodontids are their robust, bulbous premolars, which are thought to have been used to crush

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mi ...

mollusks, a diet that apparently evolved independently at least twice within this clade. Postcranial remains suggest that stagodontids may have been semi-aquatic. The most well described forms are found in Laramidia, but they are also present on Appalachian and

n sites, further leading credence to their aquatic habits. Cretaceous fossils were also found in

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 ...

, suggesting a pan-Laurasian distribution for Cretaceous metatherians. The evolution of ''Didelphodon'' and other large stagodontids (as well as large deltatheroideans like '' Nanocuris'') occurs after the local extinction of eutriconodont mammals, suggesting passive or direct ecological replacement. They are considered rare in any given fauna they appear in, probably due to their specialised habits.

Classification

Stagodontids were once thought to be closely related to the

Sparassodonta Sparassodonta (from Ancient Greek, Greek to tear, rend; and , gen. , ' tooth) is an extinct order (biology), order of carnivore, carnivorous metatherian mammals native to South America, related to modern marsupials. They were once cons ...

, but later studies suggest they belong to a more ancient branch of the metatherian family tree, possibly closely related to pediomyids, being in particular closest to '' Pariadens'', which forms the immediate outgroup to Stagodontidae. With the possible exception of ''Eobrasilia'' (see above), stagodontids are last known from the

Maastrichtian The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ...

, and are thought to have gone extinct in the K-T Extinction. * Family Stagodontidae ** Genus '' Didelphodon'' *** ''Didelphodon coyi'' *** ''Didelphodon padanicus'' *** ''Didelphodon vorax'' ** Genus '' Eodelphis'' *** ''Eodelphis browni'' *** ''Eodelphis cutleri'' ** Genus '' Fumodelphodon'' *** ''Fumodelphodon pulveris'' ** Genus '' Hoodootherium'' *** ''Hoodootherium praeceps''

References

{{- Metatheria Late Cretaceous mammals of North America Prehistoric mammal families Turonian first appearances Late Cretaceous extinctions