Currently, the family includes four genera, Eodelphis, Didelphodon, Fumodelphodon and Hoodootherium, which together include some seven different species.[1][2] In addition, the
Cenomanian species Pariadens kirklandi might be a member of the family.[2] Carneiro and Oliveira (2017) considered the species Eobrasilia coutoi from the early
Eocene (
Itaboraian) of
Brazil to be a stagodontid;[4] if confirmed it would make it the only known
Cenozoic and the only known
South American member of the family. Stagodontids were some of the largest known Cretaceous mammals, ranging from 0.4 to 2.0 kilograms (0.88–4.41 lb) in mass.[5] One of the most unusual features of stagodontids are their robust, bulbous premolars, which are thought to have been used to crush
freshwatermollusks,[6] a diet that apparently evolved independently at least twice within this clade.[7] Postcranial remains suggest that stagodontids may have been semi-aquatic.[8][9] The most well described forms are found in
Laramidia, but they are also present on
Appalachian and
South American sites, further leading credence to their aquatic habits.[10] Cretaceous fossils were also found in
France, suggesting a pan-Laurasian distribution for Cretaceous metatherians.[3]
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.[11] They are considered rare in any given fauna they appear in, probably due to their specialised habits.[12]
Classification
Stagodontids were once thought to be closely related to the
Sparassodonta, but later studies suggest they belong to a more ancient branch of the
metatherian family tree, possibly closely related to
pediomyids,[13][14] being in particular closest to Pariadens, which forms the immediate outgroup to Stagodontidae.[15][16] With the possible exception of Eobrasilia (see above), stagodontids are last known from the
Maastrichtian, and are thought to have gone extinct in the
K-T Extinction.
^
abcdFox, Richard C.; Bruce G. Naylor (2003). "Stagodontid marsupials from the late Cretaceous of Canada and their systematic and functional implications". Acta Palaeontologica Polonica. 51 (1): 13–36.
^
abcdJoshua E. Cohen (2018). "Earliest Divergence of Stagodontid (Mammalia: Marsupialiformes) Feeding Strategies from the Late Cretaceous (Turonian) of North America". Journal of Mammalian Evolution. 25 (2): 165–177.
doi:
10.1007/s10914-017-9382-0.
S2CID18977109.
^"Didelphodon vorax". www.rmdrc.com. Rocky Mountain Dinosaur Resource Center. December 7, 2010. Archived from
the original on 12 December 2013. Retrieved 5 December 2013.
^Chen, Meng; Wilson, Gregory P. (March 2015). "A multivariate approach to infer locomotor modes in Mesozoic mammals". Paleobiology. 41 (2): 280–312.
doi:
10.1017/pab.2014.14.
S2CID86087687.
^G. W. Rougier, B. M. Davis, and M. J. Novacek. 2015. A deltatheroidan mammal from the Upper Cretaceous Baynshiree Formation, eastern Mongolia. Cretaceous Research 52:167-177
^Marshall, L.; Case, J.; Woodburne, M. O. (1990). "Phylogenetic relationships of the families of marsupials". Current Mammalogy. 2: 433–505.
S2CID88876594.
^Forasiepi, Analia M (2009). Osteology of Arctodictis sinclairi (Mammalia, Metatheria, Sparassodonta) and phylogeny of Cenozoic metatherian carnivores from South America. Monografias del Museo argentino de ciencias naturales. Vol. 6. Museo argentino de ciencias naturales.
OCLC875765668.
^Rougier, Guillermo W.; Davis, Brian M.; Novacek, Michael J. (January 2015). "A deltatheroidan mammal from the Upper Cretaceous Baynshiree Formation, eastern Mongolia". Cretaceous Research. 52: 167–177.
doi:
10.1016/j.cretres.2014.09.009.