Kuntinaru

Kuntinaru
Temporal occurrence
Upper Oligocene ( Deseadum )
27.5 to 26.2 million years
Locations
South America ( Salla Beds , Bolivia)
Systematics
Higher mammals (Eutheria) Sub-articulated animals (Xenarthra) Armored siderails (Cingulata) Armadillos (Dasypoda) Chlamyphoridae Kuntinaru
Scientific name
Kuntinaru
Billet , Hautier , de Muizon & Valentin , 2011

Kuntinaru is an extinct genus of armadillos . It is documented by two skull finds from the important find region of the Salla Beds in Bolivia . Based on the characteristics of the two skulls, a closer relationship to today's spherical armadillos can be assumed. The site dates from 29.4 and 25.8 million years ago and thus belongs to the Upper Oligocene . With these age values, Kuntinaru is the oldest known representative from the closer family of the spherical armadillos. The genus was established in 2011.

features

Kuntinaru is an early representative of the armadillos. All known finds currently consist of two skulls, each of which is missing the foremost sections of the rostrum . They have characteristics that connect the genus with today's ball armadillos ( Tolypeutes ) and their immediate close relationship from the group of Tolypeutinae . This includes the lower edge of the orbit , especially the lacrimal bone , which in Kuntinaru was oriented vertically and so stood at right angles to the frontal bone . In all other armadillos today this is inclined. In the armadillos, the infraorbital foramen is bounded in the posterior area by a ridge that runs between the anterior attachment of the zygomatic arch and the nasal bone . In most recent representatives of the armadillos, this is strongly developed, but in the Tolypeutinae and Kuntinaru it is rather poorly developed. The antorbital fossa was only slightly visible below the ridge, in line with the rest of the Tolypeutinae. The infraorbital foramen opened in Kuntinaru near the anterior zygomatic arch attachment. This is consistent with most armadillos. Today's Tolypeutinae are an exception in this case, as this is clearly shifted further forward. At the base of the skull, two parallel bone ridges rose on the palatine bone in continuation of the respective row of teeth. Kuntinaru shared this feature with the Tolypeutinae and Dasypodinae , while the ridges of the Euphractinae are concave. The back of the palate itself was flat as in almost all other armadillos, but again with a limitation of the types of Euphractinae in which a dent occurs. The glenoid pit for the joint with the lower jaw was hardly longer than it was wide. With today's forms of the Tolypeutinae it is significantly longer than it is wide, with all other armadillos it is the other way round. The latter also have a small ripple on the posterior edge of the glenoid pit, which is absent in the Tolypeutinae and Kuntinaru . The ear region in Kuntinaru largely corresponded to that of the Tolypeutinae. This can be seen in the barely ossified tympanic bladder and the only flat upper part of the tympanic cavity (epitympanum). A general characteristic shared with all armadillos is the slightly curved course of the zygomatic arch.

Fossil finds

The only known skull finds from Kuntinaru so far came to light in the Salla Beds around 90 km southeast of La Paz in Bolivia . The Salla Beds are one of the most productive sites of the Paleogene in South America . Their research began as early as the early 1960s. They are exposed in the Salla-Luribay Basin of the Andes , which rises at heights of 3485 to 4085 m above sea level and is delimited by deformed and locally metamorphic rocks of the Paleozoic Era . In terms of landscape, it corresponds to the type of badlands . Overall, the Salla Beds consist of a sequence of deposits around 540 m thick, the main components of which are well-consolidated clay and silt stones . Their coloring varies from red-brown to yellowish brown to light gray. Thin lenses made of conglomerates and limestones as well as layers of volcanic sediments are switched on in various ways. The structure of the Salla Beds speaks for a formation in a widely branched river system. The age was determined with the help of various investigation methods such as paleomagnetic and radiometric methods for the Upper Oligocene with absolute values ​​between 29.4 and 25.8 million years. Due to the later unfolding of the Andes, the height at that time during the formation of the Salla Beds was below about 500 m above sea level.

Fossil-rich sites are found mainly in the middle section of the Salla Beds , while the lower and upper third are largely free of finds. As a rule, isolated fragments appear in the form of parts of the skull and teeth; to a lesser extent, individual articulated skeletal elements have also been discovered. The fauna of the Salla Beds is very extensive, it consists of amphibians , reptiles , birds and mammals . More than 40 species have been identified among mammals alone. They represent all higher groups known from South America, so in addition to the marsupials also the higher mammals with rodents , primates , South American ungulates and articulated animals . Outstanding among other things was the discovery of Branisella , the oldest known representative of the New World monkeys in South America until the 2000s . The articulated animals occur relatively abundantly in the Salla Beds with evidence of sloths and armored articulated animals . The latter include the skull of a horned armadillo from the Peltephilidae group and individual remains of representatives of the Glyptodontidae .

Systematics

Internal systematics of Dasypoda according to Billet et al. 2011  Cingulata    Peltephilidae   Dasypoda    Stegotherium      Dasypus      Kuntinaru      Tolypeutes      Priodontes      Cabassous      Prozaedyus      Chlamyphorus      Eutatus      Proeutatus      Pampatheriidae / Glyptodontidae      Chaetophractus      Zaedyus      Euphractus      Paleuphractus      Doellotatus      Macroeuphractus      Proeuphractus

Kuntinaru is a genus from the group of armadillos (Dasypoda) within the order of the secondary articulated animals (Xenarthra), one of the four main lines of the higher mammals . Due to the characteristics mentioned, the genus is classified as closely related to the subfamily of the Tolypeutinae , which in turn is composed of the spherical armadillos ( Tolypeutes ), the bare- tailed armadillos ( Cabassous ) and the giant armadillos ( Priodontes ). They form part of the Chlamyphoridae family , which is the sister group of the long-nosed armadillos (Dasypodidae). According to molecular genetic studies, the two armadillo families separated from each other in the Middle Eocene around 45 million years ago. The Chlamyphoridae then differentiated beginning in the Upper Eocene about 37 million years ago, with the Tolypeutinae a little later, in the Lower Oligocene a good 33 million years ago. The age of the skull finds from Kuntinaru refers the genus to the genetically determined origin of the Tolypeutinae. The combination of diagnostic features with some deviations from today's tolypeutin representatives of the armadillos, for example in the position of the infraorbital foramen, makes a sister group relationship between Kuntinaru and today's kinship group of the globular armadillos probable.

The genus Kuntinaru was first scientifically described in 2011 by Guillaume Billet and other research colleagues . The two skulls from the Salla Beds in Bolivia served as the basis. One of the two skulls forms the holotype of the genus (specimen number MNHN -SAL 1024), it was discovered by one of the first authors. It is a largely complete object that lacks the tip of the snout and the right row of teeth. The other skull came to light as early as the 1960s and is considered a paratype. The generic name Kuntinaru is borrowed from the Aymara language ( Condenado ) and means something like "spirit". He refers to the isolated early occurrence of tolypeutin armadillos as early as the Oligocene . The next most recent find is only documented with Pedrolypeutes from the Miocene of La Venta in Colombia around 12 million years later. Together with the genus, Billet's team of scientists established the species K. boliviensis . The specific epithet is a reference to the find region. Robert Hoffstetter had already mentioned the skull used today as a paratype in the 1960s . He referred him only generally to the armadillos, but suspected a closer relationship to the extinct forms Prozaedyus or Proeutatus .

literature

• Guillaume Billet, Lionel Hautier, Christian de Muizon and Xavier Valentin: Oldest cingulate skulls provide congruence between morphological and molecular scenarios of armadillo evolution. Proceedings of the Royal Society B 278, 2011, pp. 2791-2797, doi: 10.1098 / rspb.2010.2443

Individual evidence

1. ↑ ^{a b c d} Guillaume Billet, Lionel Hautier, Christian de Muizon and Xavier Valentin: Oldest cingulate skulls provide congruence between morphological and molecular scenarios of armadillo evolution. Proceedings of the Royal Society B 278, 2011, pp. 2791-2797
2. ^ ^{A b} Robert Hoffstetter: Un gisement de mammifère Déséadiens (Oligocène Inférieur) en Bolivie. Comptes rendus des séances de l'Académie des Sciences D 267, 1968, pp. 1095-1097 ( [1] )
3. ↑ ^{a b c} Bruce J. Shockey and Federico Anaya: Postcranial Osteology of Mammals from Salla, Bolivia (Late Oligocene): Form, Function, and Phylogenetic Implications. In: EJ Sargis and M. Dagosto (Eds.): Mammalian Evolutionary Morphology: A Tribute to Frederick S. Szalay. Springer Science, 2008, pp. 135-157
4. ↑ ^{a b c} Bruce J. MacFadden, Kenneth E. Campbell Jr., Richard L. Cifelli, Oscar Siles, Noye M. Johnson, Charles W. Naeser and Peter K. Zeitler: Magnetic Polarity Stratigraphy And Mammalian Fauna Of The Deseadan (Late Oligocene-Early Miocene) Salla Beds Of Northern Bolivia. Journal of Geology 93 (3), 1985, pp. 223-250
5. ↑ Richard F. Kay, Bruce J. MacFadden, Richard H. Madden, Hamish Sandeman and Federico Anaya: Revised age of the Salla Beds, Bolivia, and is bearing on the age of the Deseadan South American Land Mammal "age". Journal of Vertebrate Paleontology 18 (1), 1998, pp. 189-199
6. ↑ Bruce J. MacFadden, Yang Wang, Thure E. Cerling and Federico Anaya: South American fossil mammals and carbon isotopes: a 25 million-year sequence from the Bolivian Andes. Palaeogeography, Palaeoclimatology, Palaeoecology 107, 1994, pp. 257-268
7. ↑ Robert Hoffstetter: Un primate de l'Oligocene interieur sud-american: Branisella boliviana gen. Et sp. nov. Comptes rendus des séances de l'Académie des Sciences D 269, 1969, pp. 434–437 ( [2] )
8. ↑ Kellyn Kearney and Bruce J. Shockey: Oldest cranium of a horned armadillo (Peltephilidae, late Oligocene, Bolivia): clues regarding basal cingulate morphology. Journal of Vertebrate Paleontology 28 (suppl.). 2008, p. 99A
9. ↑ Maren Möller-Krull, Frédéric Delsuc, Gennady Churakov, Claudia Marker, Mariella Superina, Jürgen Brosius, Emmanuel JP Douzery and Jürgen Schmitz: Retroposed Elements and Their Flanking Regions Resolve the Evolutionary History of Xenarthran Mammals (Armadillos, Anteaters, and Sloths). Molecular Biology and Evolution 24 (11), 2007, pp. 2573-2582
10. ↑ Frederic Delsuc, Mariella Superina, Marie-Ka Tilak, Emmanuel JP Douzery and Alexandre Hassanin: Molecular phylogenetics unveils the ancient evolutionary origins of the enigmatic fairy armadillos. Molecular Phylogenetics and Evolution 62, 2012, pp. 673-680
11. ↑ Gillian C. Gibb, Fabien L. Condamine, Melanie Kuch, Jacob Enk, Nadia Moraes-Barros, Mariella Superina, Hendrik N. Poinar and Frédéric Delsuc: Shotgun Mitogenomics Provides a Reference Phylogenetic Framework and Timescale for Living Xenarthrans. Molecular Biology and Evolution 33 (3), 2015, pp. 621-642
12. ^ Alfredo A. Carlini, Sergio F. Vizcaíno and Gustavo J. Scillato-Yané: Armored Xenarthrans: A unique taxonomic and ecologic assemblage. In: Richard F. Kay, Richard H. Madden, Richard L. Cifelli, and John J. Flynn (Eds.): Vertebrate Paleontology in the Neotropics. The Miocene Fauna of La Venta, Colombia. Smithsonian Institution Press, Washington, 1997, pp. 213-226