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Gondwanatheria is an extinct group of
mammaliaform Mammaliaformes ("mammalian forms") is a clade that contains the crown group mammals and their closest extinct relatives; the group radiated from earlier probainognathian cynodonts. It is defined as the clade originating from the most recent comm ...
s that lived in parts of Gondwana, including Madagascar, India, South America, Africa and Antarctica during the Upper Cretaceous through the Paleogene (and possibly much earlier, if '' Allostaffia'' is a member of this group). Until recently, they were known only from isolated teeth, a few lower jaws, two partial skulls and one complete cranium. They are generally considered to be closely related to the
multituberculates 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, ...
and likely the euharamiyidians, well known from the Northern Hemisphere, with which they form the clade
Allotheria Allotheria (meaning "other beasts", from the Greek , '–other and , '–wild animal) is an extinct branch of successful Mesozoic mammals. The most important characteristic was the presence of lower molariform teeth equipped with two longitudin ...
.


Classification

For several decades the affinities of the group were not clear, being first interpreted as early
xenarthra Xenarthra (; from Ancient Greek ξένος, xénos, "foreign, alien" + ἄρθρον, árthron, "joint") is a major clade of placental mammals native to the Americas. There are 31 living species: the anteaters, tree sloths, and armadillos. Exti ...
ns, or "toothless" mammals similar to the modern
anteater Anteater is a common name for the four extant mammal species of the suborder Vermilingua (meaning "worm tongue") commonly known for eating ants and termites. The individual species have other names in English and other languages. Together wit ...
. A variety of studies have placed them as allotheres related to
multituberculates 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, ...
, possibly even true multituberculates, closer to
cimolodonts Cimolodonta is a taxon of extinct mammals that lived from the Cretaceous to the Eocene. They were some of the more derived members of the extinct order Multituberculata. They probably lived something of a rodent-like existence until their ecolo ...
than "
plagiaulacida Plagiaulacida is a group of extinct multituberculate mammals. Multituberculates were among the most common mammals of the Mesozoic, "the age of the dinosaurs". Plagiaulacids are a paraphyletic grouping, containing all multituberculates that lie o ...
ns" are. However, a more recent study recovered them as nested among
haramiyida Haramiyida ("thief" from Arabic الحرامية (al ḥarāmiyah), "thief, bandit") is a possibly polyphyletic order of mammaliaform cynodonts or mammals of controversial taxonomic affinites. Their teeth, which are by far the most common remains ...
ns, rendering them as non-mammalian cynodonts. A more recently described specimen has since recovered them as allotheres closely related to
multituberculates 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, ...
, but this was soon after followed by a study recovering them as part of
Euharamiyida Euharamiyida also known as Eleutherodontida, is clade of early mammals or mammal-like cynodonts from the Middle Jurassic to Early Cretaceous of Eurasia and possibly North America. The group is sometimes considered a sister group to Multitubercula ...
, remaining inconclusive as to whether they belong in crown-group Mammalia. 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 José Fernando Bonaparte (14 June 1928 – 18 February 2020) was an Argentine paleontologist who discovered a plethora of South American dinosaurs and mentored a new generation of Argentine paleontologists . One of the best-known Argentine paleo ...
in 1986, and includes one genus, ''
Ferugliotherium ''Ferugliotherium'' is a genus of fossil mammals in the family Ferugliotheriidae from the Campanian and/or Maastrichtian period (Late Cretaceous; around 70 million years ago) of Argentina. It contains a single species, ''Ferugliotherium windhaus ...
'', and possibly a few other forms like ''
Trapalcotherium ''Trapalcotherium'' is a fossil mammal from the Cretaceous of Argentina in the family Ferugliotheriidae. The single species, ''T. matuastensis'', is known from one tooth, a first lower molar. It is from the Allen Formation, which is probably Ma ...
'' from the Late Cretaceous of South America. Ferugliotheriidae are considered the most basal gondawanatherians, and are sometimes recovered outside the group. Further fossils have come from India, Madagascar and Antarctica. A possible ''Ferugliotherium''-like species occurs in Maastrichtian deposits of Mexico, extending the clade to North America. The youngest gondwanatherians are known from the Eocene of South America and Antarctica. The Eocene genus '' Groeberia'' and Miocene genus '' Patagonia,'' two mammals from South America with unusual tooth morphologies usually considered
metatherians Metatheria is a mammalian clade that includes all mammals more closely related to marsupials than to placentals. First proposed by Thomas Henry Huxley in 1880, it is a more inclusive group than the marsupials; it contains all marsupials as well ...
, were considered by one paper to be gondwanatheres. However, their conclusions have generally not been accepted.


Biology

Gondwanatheres known from cranial remains almost universally have deep, robust snouts, as befitting their specialised herbivorous lifestyle. '' Vintana'' possesses bizarre
jugal The jugal is a skull bone found in most reptiles, amphibians and birds. In mammals, the jugal is often called the malar or zygomatic. It is connected to the quadratojugal and maxilla, as well as other bones, which may vary by species. Anatomy ...
flanges similar to those of
xenarthra Xenarthra (; from Ancient Greek ξένος, xénos, "foreign, alien" + ἄρθρον, árthron, "joint") is a major clade of placental mammals native to the Americas. There are 31 living species: the anteaters, tree sloths, and armadillos. Exti ...
ns 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 Ferugliotheriidae is one of three known families in the order Gondwanatheria, an enigmatic group of extinct mammals. Gondwanatheres have been classified as a group of uncertain affinities or as members of Multituberculata, a major extinct mammal ...
, which lack hypsodont teeth and therefore had more generalistic herbivorous habits. An articulated specimen found in the
Maevarano Formation The Maevarano Formation is a Late Cretaceous sedimentary rock formation found in the Mahajanga Province of northwestern Madagascar. It is most likely Maastrichtian in age, and records a seasonal, semiarid environment with rivers that had greatly ...
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 Trochlea (Latin for pulley) is a term in anatomy. It refers to a grooved structure reminiscent of a pulley's wheel. Related to joints Most commonly, trochleae bear the articular surface of saddle and other joints: * Trochlea of humerus (part of t ...
(grooved structure) on the talus bone, 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 A coracoid (from Greek κόραξ, ''koraks'', raven) is a paired bone which is part of the shoulder assembly in all vertebrates except therian mammals (marsupials and placentals). In therian mammals (including humans), a coracoid process is prese ...
is extremely well developed (into an enlarged process that contributes to half of the
glenoid fossa The glenoid fossa of the scapula or the glenoid cavity is a bone part of the shoulder. The word ''glenoid'' is pronounced or (both are common) and is from el, gléne, "socket", reflecting the shoulder joint's ball-and-socket form. It is a sh ...
), the interclavicle is small, and the
sternoclavicular joint The sternoclavicular joint or sternoclavicular articulation is a synovial saddle joint between the manubrium of the sternum, and the clavicle, as well as the first rib. The joint possesses a joint capsule, and an articular disk, and is reinfor ...
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 Epipubic bones are a pair of bones projecting forward from the pelvic bones of modern marsupials, monotremes and fossil mammals like multituberculates, and even basal eutherians (the ancestors of placental mammals, who lack them). They first oc ...
bone. The fully described animal, now named '' Adalatherium hui'', is a comparatively large sized mammal, compared in size to a large cat. It has more erect limbs than other allotheres.


Taxonomy

Order †GondwanatheriaMikko's Phylogeny Archiv

Paleofile.com (net, info) . McKenna 1971 ondwanatheroidea Krause & Bonaparte 1993*?†'' Allostaffia'' *†'' Adalatherium'' *?†''
Galulatherium ''Galulatherium'' is an extinct genus of possibly gondwanathere mammal, from the Late Cretaceous (Turonian-Campanian)-aged Galula Formation of Tanzania.P. M. O'Connor, D. W. Krause, N. J. Stevens, J. R. Groenke, R. D. E. MacPhee, D. C. Kalthoff, ...
'' *Family †
Ferugliotheriidae Ferugliotheriidae is one of three known families in the order Gondwanatheria, an enigmatic group of extinct mammals. Gondwanatheres have been classified as a group of uncertain affinities or as members of Multituberculata, a major extinct mammal ...
Bonaparte 1986 ** †'' Ferugliotherium windhauseni'' Bonaparte 1986a 'Vucetichia''_Bonaparte_1990;_''Vucetichia_gracilis.html" ;"title="Vucetichia.html" ;"title="'Vucetichia">'Vucetichia'' Bonaparte 1990; ''Vucetichia gracilis">Vucetichia.html" ;"title="'Vucetichia">'Vucetichia'' Bonaparte 1990; ''Vucetichia gracilis'' Bonaparte 1990] ** †''Trapalcotherium matuastensis'' Rougier et al. 2008 **? †''Magallanodon baikashkenke'' Goin et al. 2020 *Family †Sudamericidae Scillato-Yané & Pascual 1984 ondwanatheridae Bonaparte 1986** †'' Greniodon sylvanicum'' Goin et al. 2012 ** †'' Vintana sertichi'' Krause et al. 2014 ** †'' Dakshina jederi'' Wilson, Das Sarama & Anantharaman 2007 ** †''
Gondwanatherium patagonicum ''Gondwanatherium'' is a genus of stem-mammal from the extinct suborder Gondwanatheria that lived in Patagonia, South America during the "Age of Dinosaurs", specifically during the Late Cretaceous (Campanian to Maastrichtian epochs). Descript ...
'' Bonaparte 1986 ** †''
Sudamerica ameghinoi ''Sudamerica'', literally " South America" in Spanish, is a genus of mammal from the extinct suborder Gondwanatheria that lived in Patagonia, Argentina (Salamanca Formation) and Antarctica (La Meseta Formation) from the Middle Paleocene (Peligra ...
'' Scillato-Yané & Pascual 1984 ** †'' Lavanify miolaka'' Krause et al. 1997 ** †'' Bharattherium bonapartei'' Prasad et al. 2007 ** †'' Patagonia peregrina'' Pascual & Carlini 1987 ** †''
Galulatherium ''Galulatherium'' is an extinct genus of possibly gondwanathere mammal, from the Late Cretaceous (Turonian-Campanian)-aged Galula Formation of Tanzania.P. M. O'Connor, D. W. Krause, N. J. Stevens, J. R. Groenke, R. D. E. MacPhee, D. C. Kalthoff, ...
'' O'Connor et al. 2019


References


External links


Mesozoic Mammals - Gondwanatheria
{{Taxonbar, from=Q133234 Burdigalian extinctions Extinct animals of Antarctica Fossil taxa described in 1987 Taxa named by Álvaro Mones Maastrichtian first appearances