Gondwanatheria

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Gondwanatheres
Temporal range: Late Cretaceous–Miocene
Adalatherium skull.svg
Skull of Adalatherium
Sudamerica jaw.svg
Mandible of Sudamerica
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Subclass:† Allotheria (?)
Clade:† Gondwanatheria
Mones, 1987
Subgroups

Gondwanatheria is an extinct group of mammaliaforms that lived in parts of Gondwana, including Madagascar, India, South America, Africa, and Antarctica during the Upper Cretaceous through the Miocene (and possibly much earlier, if Allostaffia is a member of this group [3] ). Until recently, they were known only from fragmentary remains. [4] They are generally considered to be closely related to the multituberculates and likely the euharamiyidians, well known from the Northern Hemisphere, with which they form the clade Allotheria. [5]

Contents

Classification

Life reconstruction of Vintana sertichi. Postcranial reconstruction is hypothetical. Vintana NT small.jpg
Life reconstruction of Vintana sertichi. Postcranial reconstruction is hypothetical.

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 placed them as allotheres related to multituberculates, possibly even true multituberculates, closer to cimolodonts than "plagiaulacidans" are. [1] [6] [7] [8] However, a more recent study recovered them as nested among haramiyidans, rendering them as non-mammalian cynodonts. [9] A more recently described specimen has since recovered them as allotheres closely related to multituberculates, [10] but this was soon after followed by a study recovering them as part of Euharamiyida, which itself was placed inside crown-group Mammalia. [11]

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 from the Late Cretaceous of South America. Ferugliotheriidae are considered the most basal gondawanatherians, and are sometimes recovered outside the group. [5]

Gondwanatheria cladogram per Chimento et al. 2015. Allotheria Cladogram Per Chimento 2015.png
Gondwanatheria cladogram per Chimento et al. 2015.

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. [12]

The youngest gondwanatherians are known from the Eocene of South America and Antarctica. [13] [14] The Eocene genus Groeberia and Miocene genus Patagonia, two mammals from South America with unusual tooth morphologies usually considered metatherians, were considered by one paper to be gondwanatheres. [1] However, their conclusions have generally not been accepted. [5]

Biology

Gondwanatheres known from cranial remains almost universally have deep, robust snouts, as befitting their specialised herbivorous lifestyle. Vintana possesses bizarre 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. [1] [6] 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 hypsodont 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 (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 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. [15]

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. [10]

Taxonomy

Order †Gondwanatheria [16] [17] McKenna 1971 [Gondwanatheroidea Krause & Bonaparte 1993]

Related Research Articles

<span class="mw-page-title-main">Multituberculata</span> Extinct order of mammals

Multituberculata 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 reached a peak diversity during the Late Cretaceous and Paleocene. They eventually declined from the mid-Paleocene onwards, disappearing from the known fossil record in the late Eocene. They are the most diverse order of Mesozoic mammals with more than 200 species known, ranging from mouse-sized to beaver-sized. These species occupied a diversity of ecological niches, ranging from burrow-dwelling to squirrel-like arborealism to jerboa-like hoppers. Multituberculates are usually placed as crown mammals outside either of the two main groups of living mammals—Theria, including placentals and marsupials, and Monotremata—but usually as closer to Theria than to monotremes. They are considered to be closely related to Euharamiyida and Gondwanatheria as part of Allotheria.

Ferugliotherium is a genus of fossil mammals in the family Ferugliotheriidae from the Campanian and/or Maastrichtian period of Argentina. It contains a single species, Ferugliotherium windhauseni, which was first described in 1986. Although originally interpreted on the basis of a single brachydont (low-crowned) molar as a member of Multituberculata, an extinct group of small, rodent-like mammals, it was recognized as related to the hypsodont (high-crowned) Sudamericidae following the discovery of additional material in the early 1990s. After a jaw of the sudamericid Sudamerica was described in 1999, these animals were no longer considered to be multituberculates and a few fossils that were previously considered to be Ferugliotherium were assigned to unspecified multituberculates instead. Since 2005, a relationship between gondwanatheres and multituberculates has again received support. A closely related animal, Trapalcotherium, was described in 2009 on the basis of a single tooth.

Lavanify is a mammalian genus from the late Cretaceous of Madagascar. The only species, L. miolaka, is known from two isolated teeth, one of which is damaged. The teeth were collected in 1995–1996 and described in 1997. The animal is classified as a member of Gondwanatheria, an enigmatic extinct group with unclear phylogenetic relationships, and within Gondwanatheria as a member of the family Sudamericidae. Lavanify is most closely related to the Indian Bharattherium; the South American Sudamerica and Gondwanatherium are more distantly related. Gondwanatheres probably ate hard plant material.

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 mammalian order. The best-known representative of Ferugliotheriidae is the genus Ferugliotherium from the Late Cretaceous epoch in Argentina. A second genus, Trapalcotherium, is known from a single tooth, a first lower molariform, from a different Late Cretaceous Argentinean locality. Another genus known from a single tooth, Argentodites, was first described as an unrelated multituberculate, but later identified as possibly related to Ferugliotherium. Finally, a single tooth from the Paleogene of Peru, LACM 149371, perhaps a last upper molariform, and a recent specimen from Mexico, may represent related animals.

<span class="mw-page-title-main">Allotheria</span> Extinct subclass of mammals

Allotheria is an extinct clade of mammals known from the Mesozoic and early Cenozoic. Shared characteristics of the group are the presence of lower molariform teeth equipped with longitudinal rows of cusps and enlarged incisors. Typically, the canine teeth are also lost. Allotheria includes Multituberculata, Gondwanatheria, and probably Haramiyida, although some studies have recovered haramiyidans to be basal mammaliaforms unrelated to multituberculates. Allotherians are often placed as crown group mammals, more closely related to living marsupials and placentals (Theria) than to monotremes or eutriconodonts, though some studies place the entirety of Allotheria outside of crown Mammalia.

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 varying discharges. Notable animal fossils recovered include the theropod dinosaur Majungasaurus, the early bird Vorona, the paravian Rahonavis, the titanosaurian sauropod Rapetosaurus, and the giant frog Beelzebufo.

Several mammals are known from the Mesozoic of Madagascar. The Bathonian Ambondro, known from a piece of jaw with three teeth, is the earliest known mammal with molars showing the modern, tribosphenic pattern that is characteristic of marsupial and placental mammals. Interpretations of its affinities have differed; one proposal places it in a group known as Australosphenida with other Mesozoic tribosphenic mammals from the southern continents (Gondwana) as well as the monotremes, while others favor closer affinities with northern (Laurasian) tribosphenic mammals or specifically with placentals. At least five species are known from the Maastrichtian, including a yet undescribed species known from a nearly complete skeleton that may represent a completely new group of mammals. The gondwanathere Lavanify, known from two teeth, is most closely related to other gondwanatheres found in India and Argentina. Two other teeth may represent another gondwanathere or a different kind of mammal. One molar fragment is one of the few known remains of a multituberculate mammal from Gondwana and another has been interpreted as either a marsupial or a placental.

Sudamericidae is a family of gondwanathere mammals that lived during the late Cretaceous to Miocene. Its members include Lavanify and Vintana from the Cretaceous of Madagascar, Bharattherium (=Dakshina) from the Cretaceous of India, Gondwanatherium from the Cretaceous of Argentina, Sudamerica from the Paleocene of Argentina, and unnamed forms from the Eocene of Antarctica and Cretaceous of Tanzania. More recently, Patagonia, a mammal from the Colhuehuapian stage of the Miocene of southern South America, has been suggested to be a sudamericid.

Argentodites is a possible multituberculate mammal from the Cretaceous of Argentina. The single species, Argentodites coloniensis, is known from a single blade-like fourth lower premolar (p4) from the La Colonia Formation, which is mostly or entirely Maastrichtian in age. The p4 is 4.15 mm long and bears eight cusps on its upper margin and long associated ridges on both sides. The enamel consists of prisms that are completely or partly surrounded by a sheath and that are on average 6.57 μm apart. Zofia Kielan-Jaworowska, who described and named the fossil in 2007, regarded it as a multituberculate, perhaps a cimolodontan—and thus, a member of a mostly Laurasian (northern) group and an immigrant to Argentina from North America—on the basis of the shape of the tooth and features of its enamel. In 2009, however, two teams argued that Argentodites may in fact be close to or identical with Ferugliotherium, a member of the small Gondwanan (southern) group Gondwanatheria; although their relationships are disputed, gondwanatheres may themselves be multituberculates.

Bharattherium is a mammal that lived in India during the Maastrichtian and possibly the Paleocene. The genus has a single species, Bharattherium bonapartei. It is part of the gondwanathere family Sudamericidae, which is also found in Madagascar and South America during the latest Cretaceous. The first fossil of Bharattherium was discovered in 1989 and published in 1997, but the animal was not named until 2007, when two teams independently named the animal Bharattherium bonapartei and Dakshina jederi. The latter name is now a synonym. Bharattherium is known from a total of eight isolated fossil teeth, including one incisor and seven molariforms.

<span class="mw-page-title-main">Paratheria (mammals)</span> Former taxonomic group including xenarthran and similar mammals

Paratheria is an obsolete term for a taxonomic group including the xenarthran mammals and various groups thought to be related to them. It was proposed by Oldfield Thomas in 1887 to set apart the sloths, anteaters, armadillos, and pangolins, usually classified as placentals, from both marsupial and placental mammals, an arrangement that received little support from other workers. When teeth of the extinct gondwanathere mammals were first discovered in Argentina in the 1980s, they were thought to be related to xenarthrans, leading to renewed attention for the hypothesis that xenarthrans are not placentals. However, by the early 1990s, gondwanatheres were shown to be unrelated to xenarthrans, and xenarthrans are still considered to be placentals.

Greniodon is a genus of extinct gondwanatherian mammal known from the Early to Middle Eocene of Argentina. A single species, Greniodon sylvaticus, is known, described in 2012 on the basis of two teeth found in the Andesitas Huancache Formation.

<span class="mw-page-title-main">Euharamiyida</span> Extinct clade of mammaliaforms

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 Multituberculata, or part of an earlier divergence within the synapsid line. It is disputed whether or not they are related to the Haramiyids from the Late Triassic, such as Haramiyavia. The morphology of their teeth indicates that they were herbivorous or omnivorous. Some members of the group are known to be arboreal, including gliding forms similar to modern flying squirrels or colugos.

<i>Vintana</i> Extinct species of mammal

Vintana sertichi is an early gondwanatherian mammal dating from the Late Cretaceous, approximately 66 million years ago. Scientists found the lone fossil, a skull, on Madagascar's west coast in the Maastrichtian Maevarano Formation.

<span class="mw-page-title-main">Theriimorpha</span> Clade of mammals

Theriimorpha is a clade of mammals defined as including all mammals more closely related to therians than to monotremes. Eutriconodonta is usually considered among the most basal members of this group, with other members more closely related to therians like Allotherians placed in the subclade Theriiformes, though Eutriconodonta has also been recovered as less closely related to therians than monotremes are in some analyses, placing them outside the crown group of Mammalia. The unusual Late Jurassic digging mammal Fruitafossor has also been suggested to be a basal theriimorph in some studies. The position of Allotheria within Theriimorpha is controversial. While many studies recover Allotheria within crown Mammalia as more closely related to therians than to monotreme as a member of the clade Theriiformes, some studies recover the group as outside of crown Mammalia.

Groeberiidae is a family of strange non-placental mammals from the Eocene and Oligocene epochs of Patagonia, Argentina and Chile, South America. Originally classified as paucituberculate marsupials, they were suggested to be late representatives of the allothere clade Gondwanatheria. However, the relationship of the type genus, Groeberia, to Gondwanatheria has been firmly rejected by other scholars.

Patagonia is an extinct genus of non-placental mammal from the Miocene of Argentina. Traditionally considered a metatherian incertae sedis, one analysis suggested it to be a gondwanathere. However, this has been rejected by other authors.

Cifelliodon is an extinct genus of mammaliaforms from the Lower Cretaceous of North America. In the describing paper, it was considered one of the latest surviving haramiyids yet known, belonging to the family Hahnodontidae. Its discovery led to the proposal to remove hahnodontids from the larger well-known group, the multituberculates. However, later papers have considered it to be a basal allotherian outside of Haramiyida.

<i>Adalatherium</i> Extinct genus of mammals

Adalatherium is an extinct gondwanatherian that lived on Madagascar during the Maastrichtian stage of the Late Cretaceous. The discovery of the first nearly-complete Adalatherium skeleton from the Maevarano Formation was announced in April 2020.

<i>Patagomaia</i> Extinct genus of mammals

Patagomaia is an extinct mammal of uncertain affinities, originally described as a therian mammal, from the Maastrichtian Chorrillo Formation of Argentina. It is the largest Mesozoic mammal yet known, with weight estimates of around 14 kilograms (31 lb). The type species is P. chainko.

References

  1. 1 2 3 4 Chimento, Nicolás R.; Agnolin, Federico L.; Novas, Fernando E. (22 April 2014). "The bizarre 'metatherians' Groeberia and Patagonia, late surviving members of gondwanatherian mammals". Historical Biology. 27 (5): 603–623. doi:10.1080/08912963.2014.903945. hdl: 11336/85076 . S2CID   216591096.
  2. ↑ 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. Bibcode:2012NW.....99..449G. doi:10.1007/s00114-012-0919-z. PMID   22584426. S2CID   14077735.
  3. 1 2 Chimento, Nicolas; Agnolin, Federico; Martinelli, Agustin (May 2016). "Mesozoic Mammals from South America: Implications for understanding early mammalian faunas from Gondwana". Historia Evolutiva y Paleobiogeográfica de los Vertebrados de América del Sur. pp. 199–209.
  4. ↑ Kraus, David W. (2014). Vintana Sertichi (Mammalia, Gondwanatheria) from the Late Cretaceous of Madagascar. [Lincoln, NE]: Society of Vertebrate Paleontology. pp. 1–2.
  5. 1 2 3 Hoffmann, Simone; Beck, Robin M. D.; Wible, John R.; Rougier, Guillermo W.; Krause, David W. (2020-12-14). "Phylogenetic placement of Adalatherium hui (Mammalia, Gondwanatheria) from the Late Cretaceous of Madagascar: implications for allotherian relationships". Journal of Vertebrate Paleontology. 40 (sup1): 213–234. Bibcode:2020JVPal..40S.213H. doi:10.1080/02724634.2020.1801706. ISSN   0272-4634. S2CID   230968231.
  6. 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.; O'Connor, Patrick M.; Seiffert, Erik R.; Dumont, Elizabeth R.; Holloway, Waymon L.; Rogers, Raymond R.; Rahantarisoa, Lydia J.; Kemp, Addison D.; Andriamialison, Haingoson (5 November 2014). "First cranial remains of a gondwanatherian mammal reveal remarkable mosaicism". Nature. 515 (7528): 512–517. Bibcode:2014Natur.515..512K. doi:10.1038/nature13922. PMID   25383528. S2CID   4395258.
  7. ↑ "Fossil From Dinosaur Era Reveals Big Mammal With Super Senses". National Geographic News. 5 November 2014. Archived from the original on November 5, 2014.
  8. ↑ 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.
  9. ↑ Huttenlocker, Adam K.; Grossnickle, David M.; Kirkland, James I.; Schultz, Julia A.; Luo, Zhe-Xi (23 May 2018). "Late-surviving stem mammal links the lowermost Cretaceous of North America and Gondwana". Nature. 558 (7708): 108–112. Bibcode:2018Natur.558..108H. doi:10.1038/s41586-018-0126-y. PMID   29795343. S2CID   43921185.
  10. 1 2 Krause, David W.; Hoffmann, Simone; Hu, Yaoming; Wible, John R.; Rougier, Guillermo W.; Kirk, E. Christopher; Groenke, Joseph R.; Rogers, Raymond R.; Rossie, James B.; Schultz, Julia A.; Evans, Alistair R.; von Koenigswald, Wighart; Rahantarisoa, Lydia J. (29 April 2020). "Skeleton of a Cretaceous mammal from Madagascar reflects long-term insularity". Nature. 581 (7809): 421–427. Bibcode:2020Natur.581..421K. doi:10.1038/s41586-020-2234-8. PMID   32461642. S2CID   216650606.
  11. ↑ King, Benedict; Beck, Robin M. D. (2020). "Tip dating supports novel resolutions of controversial relationships among early mammals". Proceedings of the Royal Society B: Biological Sciences. 287 (1928). doi:10.1098/rspb.2020.0943. PMC   7341916 . PMID   32517606.
  12. ↑ SVP 2015[ full citation needed ]
  13. ↑ Goin, Francisco J.; Reguero, Marcelo A.; Pascual, Rosendo; Koenigswald, Wighart von; Woodburne, Michael O.; Case, Judd A.; Marenssi, Sergio A.; Vieytes, Carolina; Vizcaíno, Sergio F. (2006-01-01). "First gondwanatherian mammal from Antarctica". Geological Society, London, Special Publications. 258 (1): 135–144. Bibcode:2006GSLSP.258..135G. doi:10.1144/GSL.SP.2006.258.01.10. ISSN   0305-8719. S2CID   129493664.
  14. ↑ Goin, Francisco J.; Tejedor, Marcelo F.; Chornogubsky, Laura; López, Guillermo M.; Gelfo, Javier N.; Bond, Mariano; Woodburne, Michael O.; Gurovich, Yamila; Reguero, Marcelo (2012-06-01). "Persistence of a Mesozoic, non-therian mammalian lineage (Gondwanatheria) in the mid-Paleogene of Patagonia". Naturwissenschaften. 99 (6): 449–463. Bibcode:2012NW.....99..449G. doi:10.1007/s00114-012-0919-z. ISSN   1432-1904. PMID   22584426. S2CID   14077735.
  15. ↑ HOFFMANN, Simone, THE FIRST POSTCRANIAL REMAINS OF A GONDWANATHERIAN MAMMAL, October 2016[ verification needed ]
  16. ↑ Mikko's Phylogeny Archive Haaramo, Mikko (2007). "†Gondwanatheria – gondwanatheres" . Retrieved 30 December 2015.
  17. ↑ Paleofile.com (net, info) "Paleofile.com". Archived from the original on 2016-01-11. Retrieved 2015-12-30.. "Taxonomic lists- Mammals" . Retrieved 30 December 2015.
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