Temporal range: Campanian-Miocene, 70.6–17.5 Ma
|Mandible of Sudamerica|
Gondwanatheria is an extinct group of mammals that lived during the Upper Cretaceous through the Miocene in the Southern Hemisphere, including Antarctica. They are known only from isolated teeth, a few lower jaws, two partial skulls and one complete cranium. Because of this fragmentary knowledge their placement is not clear.
For several decades the affinities of the group were not clear, being first interpreted as early xenarthrans, or "toothless" mammals similar to the modern anteater. A variety of studies have since confirmed their position as allotheres related to multituberculates, possibly even true multituberculates, closer to cimolodonts than "plagiaulacidans" are.
There are three known families within Gondwanatheria. The family Sudamericidae was named by Scillato-Yané and Pascual in 1984, and includes the vast majority of named taxa. The family Ferugliotheriidae was named by José Bonaparte in 1986, and includes one genus, Ferugliotherium, and possibly a few other forms like Trapalcotherium. Groeberiidae, originally interpreted as paucituberculate marsupials, has since been understood as gondwanatherians, though only the type genus, Groeberia, has been examined as such.
Gondwanatheres known from cranial remains almost universally have deep, robust snouts, as befitting their specialised herbivorous lifestyle. Groeberia and Vintana both possess bizzare jugal flanges similar to those of xenarthrans like ground sloths, though they had a palinal (front-to-back) chewing method as in most allotheres and unlike almost any therian. Most gondwanatheres are specialised grazers, even being among the first mammals to have specialised for grass-eating long before any therians did, with the exceptions of Groeberidae and Ferugliotheriidae, which lack hyopsodont teeth and therefore had more generalistic herbivorous habits.
An articulated specimen found in the Maevarano Formation offers insight to the postcranial skeleton of these animals. Among the bizarre and unique features are a mediolaterally compressed and antero-posteriorly bowed tibia, a double trochlea on the astragalus, a fully developed humeral trochlea, and an unusually high number of trunk vertebrae. The new taxon has at least 19 rib-bearing (thoracic) and 11 non-rib-bearing (lumbar) vertebrae. Aside from these derived features, the Malagasy mammal has a mosaic pectoral girdle morphology: the procoracoid is lost, the coracoid is extremely well developed (into an enlarged process that contributes to half of the glenoid fossa), the interclavicle is small, and the sternoclavicular joint appears mobile. A ventrally facing glenoid and the well-developed humeral trochlea suggest a relatively parasagittal posture for the forelimbs. Remarkable features of the hind limb and pelvic girdle include a large obturator foramen similar in size to that of therians, a large parafibula, and the presence of an epipubic bone.
- Family †Groeberiidae Patterson, 1952
- Family †Ferugliotheriidae Bonaparte 1986
- Family †Sudamericidae Scillato-Yané & Pascual 1984 [Gondwanatheridae Bonaparte 1986]
- †Greniodon sylvanicum Goin et al. 2012
- †Vintana sertichi Krause et al. 2014
- †Dakshina jederi Wilson, Das Sarama & Anantharaman 2007
- †Gondwanatherium patagonicum Bonaparte 1986
- †Sudamerica ameghinoi Scillato-Yané & Pascual 1984
- †Lavanify miolaka Krause et al. 1997
- †Bharattherium bonapartei Prasad et al. 2007
- †Patagonia peregrina Pascual & Carlini 1987
- †TNM 02067
- Nicolás R. Chimento, Federico L. Agnolin and Fernando E. Novas (2015). "The bizarre 'metatherians' Groeberia and Patagonia, late surviving members of gondwanatherian mammals". Historical Biology: An International Journal of Paleobiology. 27 (5): 603–623. doi:10.1080/08912963.2014.903945.
- Francisco J. Goin, Marcelo F. Tejedor, Laura Chornogubsky, Guillermo M. López, Javier N. Gelfo, Mariano Bond, Michael O. Woodburne, Yamila Gurovich, Marcelo Reguero (2012). "Persistence of a Mesozoic, non-therian mammalian lineage (Gondwanatheria) in the mid-Paleogene of Patagonia". Naturwissenschaften. 99 (6): 449–463. doi:10.1007/s00114-012-0919-z. PMID 22584426.
- Kraus, David W. (2014). Vintana Sertichi (Mammalia, Gondwanatheria) from the Late Cretaceous of Madagascar. [Lincoln, NE]: Society of Vertebrate Paleontology. pp. 1–2.
- Krause, David W.; Hoffmann, Simone; Wible, John R.; Kirk, E. Christopher; Schultz, Julia A.; von Koenigswald, Wighart; Groenke, Joseph R.; Rossie, James B. (2014-11-05). O'Connor, Patrick M., Seiffert, Erik R., Dumont, Elizabeth R., Holloway, Waymon L., Rogers, Raymond R., Rahantarisoa, Lydia J., Kemp, Addison D., Andriamialison, Haingoson. "First cranial remains of a gondwanatherian mammal reveal remarkable mosaicism". Nature. Nature Publishing Group, a division of Macmillan Publishers Limited. 515: 512–517. Bibcode:2014Natur.515..512K. doi:10.1038/nature13922. ISSN 1476-4687. PMID 25383528.
- Drake, Nadia (November 5, 2014). "Fossil From Dinosaur Era Reveals Big Mammal With Super Senses". nationalgeographic.com. National Geographic Society. Retrieved November 5, 2014.
- Wilford, John Noble (November 5, 2014). "Fossil's Unusual Size and Location Offer Clues in Evolution of Mammals". New York Times. Retrieved November 6, 2014.
- SVP 2015
- Krause, David W.; Hoffmann, Simone; Wible, John R.; Kirk, E. Christopher; Schultz, Julia A.; von Koenigswald, Wighart; Groenke, Joseph R.; Rossie, James B. (2014-11-05). O'Connor, Patrick M., Seiffert, Erik R., Dumont, Elizabeth R., Holloway, Waymon L., Rogers, Raymond R., Rahantarisoa, Lydia J., Kemp, Addison D., Andriamialison, Haingoson. "First cranial remains of a gondwanatherian mammal reveal remarkable mosaicism". Nature. Nature Publishing Group, a division of Macmillan Publishers Limited. online. doi:10.1038/nature13922. ISSN 1476-4687.
- HOFFMANN, Simone, THE FIRST POSTCRANIAL REMAINS OF A GONDWANATHERIAN MAMMAL, October 2016
- Mikko's Phylogeny Archive  Haaramo, Mikko (2007). "†Gondwanatheria – gondwanatheres". Retrieved 30 December 2015.
- Paleofile.com (net, info) "Archived copy". Archived from the original on 2016-01-11. Retrieved 2015-12-30.. "Taxonomic lists- Mammals". Retrieved 30 December 2015.