View source for Protypotherium

{{Short description|Extinct genus of notoungulates}}
{{Automatic taxobox
| fossil_range = [[Oligocene|Late Oligocene]] [[Miocene|Early-Late Miocene]] ([[Deseadan]]-[[Huayquerian]])<br />~{{fossil range|29|6.8}}
| image = Protypotherium australe - National Museum of Nature and Science, Tokyo - DSC07782.JPG
| image_caption = Fossil of ''P. australe''. Exhibit in the [[National Museum of Nature and Science]], [[Tokyo]], [[Japan]]
| taxon = Protypotherium
| authority = [[Florentino Ameghino|Ameghino]] 1882
| subdivision_ranks = Species
| subdivision = [[#Species|See text]]
| synonyms =
* ''Toxodontophanus'' {{small|Moreno 1882}}
| type_species = 	†'''''Protypotherium antiquum'''''
| type_species_authority = Moreno 1882
}}

'''''Protypotherium''''' is an extinct genus of [[Notoungulata|notoungulate]] mammals native to South America during the [[Oligocene]] and [[Miocene]] [[epoch (geology)|epochs]]. A number of closely related animals date back further, to the [[Eocene]]. Fossils of ''Protypotherium'' have been found in the [[Deseadan]] [[Fray Bentos Formation]] of [[Uruguay]], [[Muyu Huasi Formation|Muyu Huasi]] and [[Nazareno Formation]]s of [[Bolivia]], [[Cura-Mallín Formation|Cura-Mallín]] and [[Río Frías Formation]]s of [[Chile]], and [[Santa Cruz Formation|Santa Cruz]], [[Salicas Formation|Salicas]], [[Ituzaingó Formation|Ituzaingó]], [[Aisol Formation|Aisol]], [[Cerro Azul Formation|Cerro Azul]], [[Cerro Bandera Formation|Cerro Bandera]], [[Cerro Boleadoras Formation|Cerro Boleadoras]], [[Chichinales Formation|Chichinales]], [[Sarmiento Formation|Sarmiento]] and [[Collón Curá Formation]]s of [[Argentina]].

The [[taxonomy (biology)|taxonomy]] of the genus and the species within has a long and complicated history. Other genera of interatheriids such as ''Epipatriarchus'', ''Eudiastatus'', and ''Toxdontophanus'', have been named, but no complete specimens exist, making comparison and classification difficult. Most modern scientists consider these genera to be [[junior synonym]]s of ''Protypotherium'', and it is thought to contain the following species; ''P. australe'', ''P. praerutilum'', ''P. antiquum'', ''P. altum'', ''P. attenuatum'', ''P. claudum'', ''P. colloncurensis'', ''P. diastematum'', ''P. distinctum'', ''P. minutum'', ''P. endiadys'', ''P. sinclairi'', and ''P. concepcionensis''. The most completely-known species is ''P. australe'', so most reconstructions of the genus are based on it.

== Taxonomy ==
''Protypotherium'' was a typical representative of the [[Interatheriidae]], a group of [[Typotheria|typotherian]] notoungulates with [[rodent|rodent-like]] appearances, usually with slender forms. The genus has a wide stratigraphic and geographic distribution, around 29 million years. Fossils assigned to ''Protypotherium'' have been found in numerous localities in Argentina, Bolivia, Chile, and Uruguay.<ref name="Barrioetal1989">{{Cite journal |last1=Barrio |first1=Claudio |last2=Carlini |first2=Alfredo A. |last3=Goin |first3=Francisco J. |date=1989 |title=Litogénesis y antigüedad de la Formación Chichinales de Paso Córdoba (Río Negro, Argentina) |url=https://www.researchgate.net/publication/284902990 |journal=Actas, IV Congreso Argentino de Paleontología y Bioestratigrafía, Mendoza |volume=4 |pages=149–156}}</ref><ref name="CerroBanderaFmstratigraphy">{{Cite journal |last1=Kramarz |first1=Alejandro |last2=Garrido |first2=Alberto |last3=Forasiepi |first3=Analía |last4=Bond |first4=Mariano |last5=Tambussi |first5=Claudia |date=2005 |title=Stratigraphy and vertebrates (Aves and Mammalia) from the Cerro Bandera Formation, Early Miocene of Neuquén Province, Argentina. |url=http://www.andeangeology.cl/index.php/revista1/article/view/V32n2-a06/html |journal=[[Andean Geology|Revista Geológica de Chile]] |volume=32 |issue=2 |doi=10.4067/S0716-02082005000200006 |doi-access=free |access-date=2022-11-17 |archive-date=2022-10-01 |archive-url=https://web.archive.org/web/20221001182253/http://www.andeangeology.cl/index.php/revista1/article/view/V32n2-a06/html |url-status=live }}[[File:CC-BY_icon.svg|50x50px]] Material was copied from this source, which is available under a [[creativecommons:by/3.0/|Creative Commons Attribution 3.0 International License]]</ref><ref name="NewmammalfaunaatthetopofGranBarranca">{{Cite book |last1=A. G. Kramarz |url=https://www.researchgate.net/publication/233955394 |title=The Paleontology of Gran Barranca. Evolution and Environmental Change Through the Middle Cenozoic of Patagonia |last2=M. G. Vucetich |last3=A. A. Carlini |last4=M. R. Ciancio |last5=M. A. Abello |last6=C. M. Deschamps |last7=J. N. Gelfo |publisher=Cambridge University Press |year=2010 |isbn=978-0-521-87241-6 |editor-last=Richard H. Madden |pages=143–151 |chapter=A new mammal fauna at the top of the Gran Barranca sequence and its biochronological significance. |editor-last2=Alfredo A. Carlini |editor-last3=Maria Guiomar Vucetich |editor-last4=Richard F. Kay}}</ref><ref name="Scarano et al. 2021">{{Cite journal |last1=Scarano |first1=Alejo C. |last2=Vera |first2=Bárbara |last3=Reguero |first3=Marcelo |date=2021-09-01 |title=Evolutionary Trends of Protypotherium (Interatheriidae, Notoungulata) Lineage throughout the Miocene of South America |url=https://doi.org/10.1007/s10914-020-09534-5 |journal=Journal of Mammalian Evolution |language=en |volume=28 |issue=3 |pages=885–895 |doi=10.1007/s10914-020-09534-5 |s2cid=230986107 |issn=1573-7055 |access-date=2022-11-17 |archive-date=2023-02-06 |archive-url=https://web.archive.org/web/20230206215106/https://link.springer.com/article/10.1007/s10914-020-09534-5 |url-status=live |url-access=subscription }}</ref> The oldest occurrence of ''Protypotherium'' dates back to the [[Chattian|Late Oligocene]] ([[Deseadan]]) [[Fray Bentos Formation]] of Uruguay.<ref name="MonesandUbilla1978">{{Cite journal |last1=Mones |first1=A. |last2=Ubilla |first2=M. |date=1978 |title=La Edad Deseadense (Oligoceno inferior) de la Formación Fray Bentos y su contenido paleontológico, con especial referencia a la presencia de Proborhyaena cf. gigantea Ameghino (Marsupialia: Borhyaenidae) en el Uruguay. Nota preliminar. |url=https://www.researchgate.net/publication/36891196 |journal=Comunicaciones Paleontológicas del Museo de Historia Natural de Montevideo |volume=7 |issue=1 |pages=151–158}}</ref>
[[File:Protypotheriump.jpg|thumb|left|Cranium of ''Protypotherium praerutilum'']]
The genus ''Protypotherium'' was first described in [[1882]] by [[Florentino Ameghino]], based on fossil remains found in the [[Ituzaingó Formation]] in [[Entre Ríos Province]], [[Argentina]], in soils dating from the Late Miocene. The [[type species]] is '''''Protypotherium antiquum'''''. Another well-known species is ''P. australe,'' also from the Santa Cruz Formation,<ref name="Sinclair 1909">{{Cite book |last=Sinclair |first=William John |url=https://archive.org/details/reportsofp61319091912prin/mode/2up|title=Mammalia of the Santa Cruz Beds, part 1: Typotheria of the Santa Cruz Beds.|chapter=Reports of the Princeton University Expeditions to Patagonia, 1896-1899.|date=1909 |publisher=The University |location=Princeton |doi=10.5962/bhl.title.12486|doi-access=free|volume=7|pages=1–110}}</ref> but several other species have been attributed to this genus, such as ''P. altum'', ''P. attenuatum'', ''P. claudum'', ''P. colloncurensis'', ''P. diastematum'', ''P. distinctum'', ''P. endiadys'', ''P. minutum'', ''P. praerutilum'', and ''P. sinclairi,''<ref name="Kramarzetal2015">{{Cite journal |last1=Kramarz |first1=Alejandro G. |last2=Bond |first2=Mariano |last3=Arnal |first3=Michelle |date=2015 |title=Systematic Description of Three New Mammals (Notoungulata and Rodentia) from the Early Miocene Cerro Bandera Formation, Northern Patagonia, Argentina |url=http://naturalis.fcnym.unlp.edu.ar/repositorio/_documentos/sipcyt/bfa005267.pdf |journal=Ameghiniana |volume=52 |issue=6 |pages=585–597 |doi=10.5710/AMGH.27.06.2015.2906 |issn=0002-7014 |doi-access=free |access-date=2019-10-19 |archive-date=2020-09-07 |archive-url=https://web.archive.org/web/20200907165846/http://naturalis.fcnym.unlp.edu.ar/repositorio/_documentos/sipcyt/bfa005267.pdf |url-status=live }}</ref> all found in various localities in Argentina in Lower and Middle Miocene deposits. A species from [[Chile]], ''P. concepcionensis'' was described in [[2019 in paleomammalogy|2019]].<ref name="Solórsano et al. 2019">{{Cite journal |last1=Solórzano |first1=Andrés |last2=Encinas |first2=Alfonso |last3=Bobe |first3=René |last4=Maximiliano |first4=Reyes |last5=Carrasco |first5=Gabriel |date=2019-12-01 |title=The Early to late Middle Miocene mammalian assemblages from the Cura-Mallín Formation, at Lonquimay, southern Central Andes, Chile (~38°S): Biogeographical and paleoenvironmental implications |url=https://www.sciencedirect.com/science/article/pii/S0895981119302160 |journal=Journal of South American Earth Sciences |language=en |volume=96 |pages=102319 |doi=10.1016/j.jsames.2019.102319 |bibcode=2019JSAES..9602319S |s2cid=202174453 |issn=0895-9811 |access-date=2022-11-17 |archive-date=2019-10-17 |archive-url=https://web.archive.org/web/20191017214144/https://www.sciencedirect.com/science/article/pii/S0895981119302160 |url-status=live |url-access=subscription }}</ref> 
[[File:Protypotherium.jpg|thumb|Mandible of ''Protypotherium australe'']]

''Protypotherium'' was a rather specialized member of the interatheriids, akin to the bizarre ''Miocochilius''; these two forms, according to a 2017 study,  formed a [[monophyletic]] derived clade within the family [[Interatheriidae]]. In the same study, it is indicated that the species ''P. australe'' would be the most basal known species of the genus and may be ancestral to the other species of ''Protypotherium'' and the genus ''Miocochilius''. In spite of its name, ''Protypotherium'' was not an ancestor of ''"Typotherium"'', a genus that is now considered to be a synonym of ''[[Mesotherium]]'', another notoungulate belonging to another family, the [[Mesotheriidae]].

The following cladogram of the [[Interatheriinae]] is based on Vera ''et al.'' 2017, showing the position of ''Protypotherium''.<ref name="InteratheriinaefromtheCollónCuráFormation">{{Cite journal |last1=Vera |first1=Bárbara Soledad |last2=Reguero |first2=Marcelo Alfredo |last3=Gonzalez |first3=Laureano Raul |date=December 2017 |title=The Interatheriinae notoungulates from the middle Miocene Collón Curá Formation in Argentina |journal=Acta Palaeontologica Polonica |volume=62 |doi=10.4202/app.00373.2017 |doi-access=free |hdl=11336/56874|hdl-access=free }}[[File:CC-BY_icon.svg|50x50px]] Material was copied from this source, which is available under a [[creativecommons:by/4.0/|Creative Commons Attribution 4.0 International License]]</ref>

{{clade
|label1=[[Interatheriinae]]
|1={{clade
|1=''[[Eopachyrucos|Eopachyrucos pliciferus]]''
|2={{clade
 |1=''[[Santiagorothia|Santiagorothia chiliensis]]''
 |2={{clade 
  |1=''[[Federicoanaya|Federicoanaya sallaensis]]''
  |2={{clade
   |1=''[[Brucemacfaddenia|Brucemacfaddenia boliviensis]]''
   |2={{clade
    |1=''[[Archaeophylus|Archaeophylus patrius]]''
    |2=''[[Progaleopithecus tournoueri]]''
    |3=''[[Argyrohyrax|Argyrohyrax proavus]]''
    |4={{clade
     |1=''[[Interatherium|Interatherium robustum]]''
     |2=''[[Cochilius|Cochilius volvens]]'' }}
     |5={{clade
      |1='''''Protypotherium australe''''' 
      |2={{clade
       |1='''''Protypotherium endiadys'''''
       |2={{clade
        |1='''''Protypotherium distinctum'''''
        |2='''''Protypotherium sinclairi'''''
        |3=''[[Miocochilius|Miocochilius federicoi]]''
        |4=''[[Miocochilius|Miocochilius anamopodus]]''
        |5={{clade
         |1='''''Protypotherium minutum'''''
         |2='''''Protypotherium colloncurensis'''''
}} }} }} }} }} }} }} }} }} }}

{{clearleft}}

== Species ==
The following species of ''Protypotherium'' have been described:<ref name="FWProtypotherium">[https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=43422 ''Protypotherium'']  at [[Fossilworks]].org</ref>
{{div col|colwidth=20em}}
* ''P. altum'' {{small|Ameghino 1891}}
* ''P. antiquum'' {{small|Ameghino 1882}}
* ''P. attenuatum'' {{small|Ameghino 1887}}
* ''P. australe'' {{small|Moreno 1882}}
* ''P. claudum'' {{small|Ameghino 1889}}
* ''P. colloncurensis'' {{small|Vera et al. 2017<ref name="InteratheriinaefromtheCollónCuráFormation"/>}}
* ''P. diastematum'' {{small|Ameghino 1891}}
* ''P. distinctum'' {{small|Cabrera & Kraglievich 1931}}
* ''P. endiadys'' {{small|Roth 1898}}
* ''P. minutum'' {{small|Cabrera & Kraglievich 1931}}
* ''P. praerutilum'' {{small|Ameghino 1887}}
* ''P. sinclairi'' {{small|Kramarz et al. 2015<ref name="Kramarzetal2015"/>}}
{{div col end}}
* ''P. concepcionensis'' {{small|Solórzano et al. 2019}}

{{clearboth}}

== Description ==
[[File:Protypotherium australe.jpg|thumb|left|Restoration of ''P. australe'' and ''[[Stegotherium tesselatum]]'']]
''Protypotherium'' was slightly larger than a [[rabbit]], measuring about {{convert|40|cm|ft}} in length. The body and legs as well as the tail of this animal were relatively long, while its neck was short. It probably resembled a [[rodent]], possessing slender limbs with four, [[digitigrade]] [[claw]]ed feet.<ref name="Croft et al. 2021">{{Cite journal |last1=Croft |first1=Darin A. |last2=Lorente |first2=Malena |date=2021-08-17 |title=No evidence for parallel evolution of cursorial limb adaptations among Neogene South American native ungulates (SANUs) |journal=[[PLOS ONE]]|language=en |volume=16 |issue=8 |pages=e0256371 |doi=10.1371/journal.pone.0256371 |issn=1932-6203 |pmc=8370646 |pmid=34403434|bibcode=2021PLoSO..1656371C |doi-access=free }}</ref> Its [[rat]]-like [[skull]] contained a set of 44 unspecialized teeth.

From the shape of its claws, ''Protypotherium'' would have been adept at digging and likely took over the burrows of other animals.<ref name=EoDP>{{cite book |editor=Palmer, D.|year=1999 |title= The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals|publisher= Marshall Editions|location=London|page= 251|isbn= 1-84028-152-9}}</ref>

=== Skull and dentition ===
[[File:Protypotherium endiadys - lower dentition - Collón Curá Formation, Argentina.jpg|thumb|right|Lower dentition of ''Protypotherium endiadys'']][[File:Protypotherium colloncurensis - lower and upper dentition - Collón Curá Formation, Argentina.jpg|thumb|left|Lower and upper dentition of ''Protypotherium colloncurensis'']]
The skull of ''Protypotherium'' was about halfway up the cranial vault, was slightly descending in the anterior part; the posterior part, on the other hand, lowered abruptly, in contrast to similar forms such as ''[[Cochilius]]'' (whose cranial vault was not inclined). The orbit was in a nearly median position, very open posteriorly, and the nasal bones were very advanced. The orbital arch was robust and was the direct extension of the lambdoid ridges. The maxillary bone alone formed the lower margin of the skull. At the back of the skull, the squamous bone and mastoid were highly developed. Seen from above, the skull had an oval outline but narrowed sharply at the beginning of the snout.<ref name="Ameghino 1891">{{Cite journal |last=Ameghino |first=Florentino |date=1891 |title=Nuevos restos de mamíferos fósiles descubiertos por Carlos Ameghino en el Eoceno inferior de la Patagonia austral. — Especies nuevas, adiciones y correcciones |url=https://www.biodiversitylibrary.org/part/76088 |journal=Revista argentina de historia natural |volume=1 |pages=289–328 |access-date=2022-11-17 |archive-date=2022-10-05 |archive-url=https://web.archive.org/web/20221005190540/https://www.biodiversitylibrary.org/part/76088 |url-status=live }}</ref> The temporal fossa continued backward in a deep reinforcement between the lambdoid and sagittal ridges. The auditory region was characterized by a hypotympanic sinus much smaller than the tympanic cavity. In some species, the inner wall of the [[tympanic membrane]] was thick and filled with a fine [[spongy bone|spongy tissue]]. The [[Epitympanic recess|epitympanic]] sinus was of medium size. The two branches of the [[mandible]] were firmly joined in the anterior part; the posterior part of the mandible was very elevated. 
[[File:Protypotherium endiadys - skull and upper dentition - Collón Curá Formation, Argentina.jpg|thumb|180px|Skull and upper dentition of ''Protypotherium endiadys''|right]]

The [[dentition]] is complete, with the mandible having 44 teeth and no [[diastema]]. The upper [[incisors]] were rooted and provided with  [[Tooth enamel|enamel]] on the outer surface. The [[Canine tooth|canines]] were incisor-shaped, while the [[premolars]] had weak roots. The molars had two ribs on the outer wall. An internal groove divided the tooth into two almost equal lobes. An unworn molar showed an ectoloph, two convex inner crescents, and a ridge departing from the ectoloph. The anterior margin of each crescent joined the ectoloph. The lower incisors were divided longitudinally by a deep groove and resembled those of present-day [[hyraxes]]. The teeth were partially overlapping: one molar covered the posterior-external margin of the previous molar. An opposite outer and inner groove divided the molars into two lobes; the posterior lobe was shorter. A slight anterior-internal groove disappeared over time as tooth wear progressed.
[[File:Protypotherium endiadys - dentition detail - Collón Curá Formation, Argentina.jpg|thumb|right|Dentition detail of ''Protypotherium endiadys'']]
The upper incisors of ''Protypotherium'' are characterized by a three-layered [[enamel prism|schmelzmuster]] represented by outer radial enamel. The prism diameter is ~6 [[Micrometre|μm]]. The [[Hunter-Schreger band]]s are thin (20–50 μm thick) and oblique. The interprismatic matrix forms closed coats near the outer enamel service and interrow sheets near the [[enamel dentine junction]], and is intermediate to modified in the Hunter-Schreger bands. Lower incisors of ''Protypotherium'' are characterized by a one-layered schmelzmuster with Hunter-Schreger bands. Prism diameter is ~6 μm. Hunter-Schreger Bands are generally oblique and steady, even if they present a low decussation on both sections and are less discernible on some transverse sections. The [[interprismatic matrix]] forms closed coats in the entire thickness, but it is also slightly [[Anastomosis|anastomosing]] near the enamel dentine junction. The thickness of its dentition suggest that it was a grazer, eating mainly grass.<ref name="Filippo et al. 2020">{{Cite journal |last1=Filippo |first1=Andréa |last2=Kalthoff |first2=Daniela C. |last3=Billet |first3=Guillaume |last4=Gomes Rodrigues |first4=Helder |date=2020-06-01 |title=Evolutionary and Functional Implications of Incisor Enamel Microstructure Diversity in Notoungulata (Placentalia, Mammalia) |journal=Journal of Mammalian Evolution |language=en |volume=27 |issue=2 |pages=211–236 |doi=10.1007/s10914-019-09462-z |issn=1573-7055 |doi-access=free}}[[File:CC-BY_icon.svg|50x50px]] Material was copied from this source, which is available under a [[creativecommons:by/4.0/|Creative Commons Attribution 4.0 International License]]</ref> 

''Protypotherium'' has euhypsodont (well high-crowned) premolars and molars, and [[premolariform]] premolars. The upper molars have a lingual sulcus that separates the protolophs from the metalophs. The third and fourth premolars have a sub-triangular shape, with the mesio-distal length shorter than the labio-lingual breadth and a smaller size than the first and second molars. The first and third [[incisor]]s are compact (i.e. lacking spaces between the teeth) and are imbricated another mesiodistally. The second premolar has a shorter [[talonid]] than the [[trigonid]]. The third and fourth premolars are relatively smaller than the first and second molars. The first and third molars have sub-triangular trigonids, while the first and second molars have longer talonids than the trigonids.<ref name="Viscainoetal2022">{{Cite journal |last1=Vizcaino |first1=Sergio F. |last2=Bargo |first2=M. Susana |last3=Pérez |first3=M. Encarnación |last4=Aramendía |first4=Inés |last5=Cuitiño |first5=José I. |last6=Monsalvo |first6=Eduardo S. |last7=Vlachos |first7=Evangelos |last8=Noriega |first8=Jorge I. |last9=Kay |first9=Richard F. |date=2022-09-30 |title=Fossil vertebrates of the early-middle Miocene Cerro Boleadoras Formation, northwestern Santa Cruz Province, Patagonia, Argentina |url=http://www.andeangeology.cl/index.php/revista1/article/view/V49n3-3425 |url-status=live |journal=Andean Geology |language=en |volume=49 |issue=3 |pages=382–422 |doi=10.5027/andgeoV49n3-3425 |issn=0718-7106 |archive-url=https://web.archive.org/web/20221002152643/http://andeangeology.cl/index.php/revista1/article/view/V49n3-3425 |archive-date=2022-10-02 |access-date=2022-11-17 |doi-access=free}}[[File:CC-BY_icon.svg|50x50px]] Material was copied from this source, which is available under a [[creativecommons:by/3.0/|Creative Commons Attribution 3.0 International License]]</ref>
[[File:Protypotherium sinclairi.png|left|thumb|Mandibular fragment of ''Protypotherium sinclairi'']]

Compared with the related ''[[Interatherium]]'' and ''[[Cochilius]]'', ''Protypotherium'' had well-differentiated third and fourth premolars compared to molars, and numerous other dental features. In contrast to ''[[Miocochilius]]'', moreover, ''Protypotherium'' possessed the canine-shaped lower first premolar and shorter lower third molar.<ref name="InteratheriinaefromtheCollónCuráFormation"/>

The species ''Protypotherium sinclairi'' can be distinguished from other species of ''Protypotherium'' by its dentition, with all teeth having a thick cementum covering. The third and fourth premolar both have a shorter anteroposterior diameter of the talonid than the [[Molar (tooth)|trigonid]], while the first and second premolars are short and non-molariform. The teeth of this species are smaller than those of ''P. australe'', but larger than those of'' P. praerutilum'' and ''P. attenuatum'', all of which are [[Santacrucian]] in age. The posterior lower premolars show proportionally larger buccolingual diameter of the talonid than those in the Santacrucian species.<ref name="CerroBanderaFmstratigraphy"/>

===Postcranial skeleton===
[[File:ProtypotheriumSinclair 1.jpg|thumb|left|Reconstructed skeleton]]
The skeleton of ''Protypotherium'' is well known, especially regarding the species ''Protypotherium australe''. Fifteen dorsal [[vertebrae]], seven lumbar vertebrae and five sacral vertebrae were probably present. The tail was long, with at least eighteen vertebrae.

The [[scapula]] possessed a slightly convex coracoid margin. The scapular spine was tall and narrow, with a small [[Tubercle (bone)|apophysis]] of the [[acromion]] and a large metacromion. The [[humerus]] was very stout in the proximal region, with two low tuberosities; the distal end was enlarged, with the entepicondyle developed and provided with a large foramen. The [[radius (anatomy)|radius]] was strongly curved antero-posteriorly and rather gracile; the [[ulna]], on the other hand, was curved laterally. The hand was tetradactylous, as opposed to the related ''Miocochilius,'' which had only three fingers, two of which were functional, with an alternating structure of the [[carpus]] and relationships between the [[Metacarpus|metacarpals]]. The weight was discharged between the second and third metacarpals, which were almost equal in length, while the fourth was shorter and the fifth was much reduced. The [[scaphoid bone]] had a strong articulation for the radius and rested on the [[greater trochanter]] and the [[Trapezoid bone|trapezoid]]. In the outer part, the scaphoid articulated with the [[Lunate bone|lunar bone]] by means of a small facet of the apophysis related to the great bone. The lunate bone was in contact distally with the great bone and the [[hamate]], and laterally it was in contact with the [[Cuneiform|cuneiform bone]] via a large surface. The joints of the first phalanges were limited to the plantar and distal surfaces. The [[Phalanx|phalanges]] nail joints were laterally compressed and provided with a small incision at the end.
[[File:Protypotherium endiadys - post-cranial bones - Collón Curá Formation, Argentina.jpg|thumb|Post-cranial bones of ''P. endiadys'']]

The [[ischium]] was broad posteriorly, and the [[Pubis (bone)|pubical area]] was small. The [[femur]] was straight and somewhat flattened anteroposteriorly. The greater [[trochanter]] slightly exceeded the articular head, while the third trochanter was well developed and in a fairly proximal position. The condyles were large. The [[tibia]] and [[fibula]] were usually separated, but sometimes distal co-ossification was present. The distal joint of the tibia was divided by a prominent ridge into two equal cavities. The fibula was thin. The trochlea of the [[Talus bone|astragalus]] was long and medium deep; the ridges of the talus were equal to each other, the neck long and the head globular. The [[calcaneus]] did not articulate with the [[navicular|navicular bone]] and had a large facet for the fibula. The phalanges possessed the same structure as those of the hand, but were larger. It is likely that the feet of ''Protypotherium'' were [[digitigrade]].<ref name="InteratheriinaefromtheCollónCuráFormation"/>

== Paleobiology ==
''Protypotherium'' was mainly a herbivore, but it is possible that ''Protypotherium'' fed occasionally on [[carrion]] as well. The legs clearly show robust nail phalanges, thanks to which the animal could dig burrows or modify those abandoned by other animals.<ref name=EoDP/>

A 2021 study concerning numerous fossils of the teeth of various species of ''Protypotherium'' showed that there is a trend in the preservation of tooth pattern, increase in size and decrease in number of species over time. This could be correlated with a global trend of cooling temperatures, indicating a deterioration of paleoenvironmental conditions during the Miocene. There also appears to have been a [[latitude]] shift in the distributional range of these animals: from Lower Miocene Patagonia to northern areas of South America towards the end of the Miocene.<ref name="Scarano et al. 2021"/>

==Paleoenvironment==
Fossils of ''Protypotherium'' have been found in various fossiliferous stratigraphic units in South America. Several specimens come from the [[Santa Cruz Formation]] in the [[Austral Basin]] in southern [[Patagonia]], Argentina,<ref name="Cuitiño et al. 2019">{{Cite journal |last1=Cuitiño |first1=José I. |last2=Vizcaíno |first2=Sergio F. |last3=Bargo |first3=M. Susana |last4=Aramendía |first4=Inés |date=2019-05-31 |title=Sedimentology and fossil vertebrates of the Santa Cruz Formation (early Miocene) in Lago Posadas, southwestern Patagonia, Argentina |url=http://www.andeangeology.cl/index.php/revista1/article/view/V46n2-3128 |url-status=live |journal=[[Andean Geology]] |language=en |volume=46 |issue=2 |pages=383–420 |doi=10.5027/andgeoV46n2-3128 |issn=0718-7106 |archive-url=https://web.archive.org/web/20221001040203/http://www.andeangeology.cl/index.php/revista1/article/view/V46n2-3128 |archive-date=2022-10-01 |access-date=2022-11-17 |doi-access=free|hdl=11336/96343 |hdl-access=free }}</ref><ref name="Zurita-Altamirano et al. 2019">{{Cite journal |last1=Zurita-Altamirano |first1=Daniel |last2=Buffetaut |first2=Eric |last3=Forasiepi |first3=Analía M. |last4=Kramarz |first4=Alejandro |last5=Carrillo |first5=Juan D. |last6=Aguirre-Fernández |first6=Gabriel |last7=Carlini |first7=Alfredo A. |last8=Scheyer |first8=Torsten M. |last9=Sánchez-Villagra |first9=Marcelo R. |date=2019 |title=The Allemann collection from the Santa Cruz Formation (late early Miocene), Argentina, in Zurich, Switzerland |journal=[[Swiss Journal of Palaeontology]] |language=en |volume=138 |issue=2 |pages=259–275 |doi=10.1007/s13358-019-00185-5 |issn=1664-2384 |doi-access=free|bibcode=2019SwJP..138..259Z |hdl=11336/120785 |hdl-access=free }}</ref> with other finds from the [[Cerro Azul Formation|Cerro Azul]],<ref name="Montalvo et al. 2019">{{Cite journal |last1=Montalvo |first1=C. I. |last2=Tomassini |first2=R. L. |last3=Sostillo |first3=R. |last4=Cerdeño |first4=E. |last5=Verzi |first5=D. H. |last6=Visconti |first6=G. |last7=Folguera |first7=A. |last8=Schmidt |first8=G. I. |date=2019-11-01 |title=A Chasicoan (late Miocene) vertebrate assemblage from Cerro Azul Formation, central Argentina. Geomorphological and biochronological considerations |url=https://www.sciencedirect.com/science/article/pii/S0895981119301518 |journal=Journal of South American Earth Sciences |language=en |volume=95 |pages=102218 |bibcode=2019JSAES..9502218M |doi=10.1016/j.jsames.2019.102218 |issn=0895-9811 |s2cid=189976661|url-access=subscription }}</ref> [[Cerro Boleadoras Formation|Cerro Boleadoras]],<ref name="Viscainoetal2022" /> [[Ituzaingó Formation|Ituzaingó]],<ref name="Schmidt 2013">{{Cite journal |last=Schmidt |first=Gabriela I. |date=2013 |title=Los ungulados nativos (Litopterna y Notoungulata: Mammalia) del "Mesopotamiense" (Mioceno Tardío) de Entre Ríos, Argentina |url=https://www.peapaleontologica.org.ar/index.php/peapa/article/view/45 |url-status=live |journal=Publicación Electrónica de la Asociación Paleontológica Argentina |language=en |volume=14 |issue=1 |issn=2469-0228 |archive-url=https://web.archive.org/web/20221115033531/https://www.peapaleontologica.org.ar/index.php/peapa/article/view/45 |archive-date=2022-11-15 |access-date=2022-11-17}}</ref> [[Cerro Bandera Formation|Cerro Bandera]],<ref name="CerroBanderaFmstratigraphy" /><ref name="Kramarzetal2015" /> [[Chichinales Formation|Chichinales]],<ref name="Barrioetal1989" /> [[Collón Curá Formation]]s, and the [[Sarmiento Formation]]s of the [[Colorado Basin, Argentina|Colorado]], Austral, [[Paraná Basin|Paraná]], [[Neuquén Basin|Neuquén]], [[Cañadón Asfalto Basin|Cañadón Asfalto]], and [[Golfo San Jorge Basin]]s, as well as the [[Aisol Formation|Aisol]] and [[Salicas Formation|Salicas Formations]] of the same country.<ref>{{cite journal |last1=Forasiepi |first1=Analía M. |last2=Martinelli |first2=Agustín G. |last3=De la Fuente |first3=Marcelo S. |last4=Dieguez |first4=Sergio |last5=Bond |first5=Mariano |year=2011 |title=Paleontology and stratigraphy of the Aisol Formation (Neogene), San Rafael, Mendoza |url=http://naturalis.fcnym.unlp.edu.ar/repositorio/_documentos/sipcyt/bfa002518.pdf |url-status=live |journal=Cenozoic Geology of the Central Andes of Argentina, SCS Publisher, Salta |pages=135–154 |archive-url=https://web.archive.org/web/20220522170431/http://naturalis.fcnym.unlp.edu.ar/repositorio/_documentos/sipcyt/bfa002518.pdf |archive-date=2022-05-22 |access-date=2022-11-17}}</ref><ref name="Brandoni et al.2012">{{cite journal |last1=Brandoni |first1=Diego |last2=Schmidt |first2=Gabriela I. |last3=Candela |first3=Adriana M. |last4=Noriega |first4=Jorge I. |last5=Brunetto |first5=Ernesto |last6=Fiorelli |first6=Lucas E. |year=2012 |title=Mammals from the Salicas Formation (Late Miocene), La Rioja Province, Northwestern Argentina: Paleobiogeography, age and paleoenvironment |url=http://naturalis.fcnym.unlp.edu.ar/repositorio/_documentos/sipcyt/bfa004294.pdf |url-status=live |journal=[[Ameghiniana]] |volume=49 |issue=3 |pages=1–13 |doi=10.5710/AMGH.v49i3(467) |archive-url=https://web.archive.org/web/20170823131229/http://naturalis.fcnym.unlp.edu.ar/repositorio/_documentos/sipcyt/bfa004294.pdf |archive-date=2017-08-23 |access-date=2019-03-13 |s2cid=55646353}}</ref> Furthermore, fossil finds of ''Protypotherium'' have been found in other countries, such as the [[Fray Bentos Formation]] of [[Uruguay]], also in the Paraná Basin, the [[Muyu Huasi Formation]] of the [[Muyu Huasi Basin]] in [[Bolivia]], the [[Nazareno Formation]] in the same country, of the [[Tupiza Basin]],<ref name="Croft et al. 2009">{{Cite journal |last1=Croft |first1=Darin Andrew |last2=Anaya |first2=Federico |last3=Auerbach |first3=David |last4=Garzione |first4=Carmala |last5=MacFadden |first5=Bruce J. |date=2009-09-01 |title=New Data on Miocene Neotropical Provinciality from Cerdas, Bolivia |url=https://doi.org/10.1007/s10914-009-9115-0 |url-status=live |journal=Journal of Mammalian Evolution |language=en |volume=16 |issue=3 |pages=175–198 |doi=10.1007/s10914-009-9115-0 |issn=1573-7055 |archive-url=https://web.archive.org/web/20230206215116/https://link.springer.com/article/10.1007/s10914-009-9115-0 |archive-date=2023-02-06 |access-date=2022-11-17 |s2cid=16210582|url-access=subscription }}</ref> and the [[Cura-Mallín Group|Cura-Mallín Formation]] of the Cura Mallín Basin of Argentina and Chile and the [[Río Frías Formation]] of the [[Magallanes Basin]] in Chile.<ref name="Bostelmann et al. 2012">{{cite journal |last1=Bostelmann |first1=J.E. |last2=Bobe |first2=René |last3=Carrasco |first3=G. |last4=Alloway |first4=Brent V. |last5=Malnis |first5=Paula Santi |last6=Mancuso |first6=Adriana Cecilia |last7=Agüero |first7=B. |last8=Zeresenay |first8=Alemseged |last9=Godoy |first9=Y. |year=2012 |title=The Alto Río Cisnes Fossil Fauna (Río Frías Formation, Early-Middle Miocene, Friasian SALMA): A keystone and paradigmatic vertebrate assemblage of the South American Fossil Record |url=https://www.researchgate.net/publication/306123402 |publisher=III Simposio Paleontología en Chile |pages=44–45 |accessdate=2019-03-13}}</ref>

In the Chichinales Formation, which is known for its local mammal fauna, ''Protypotherium'' would have coexisted with [[astrapotheres]], the notoungulates ''[[Cochilius|Cochilius volvens]]'', ''[[Colpodon]]'', ''[[Hegetotheriopsis|Hegetotheriopsis sulcatus]]'' and ''[[Hegetotherium]]'',<ref name="Kramarzetal2013">{{Cite journal |last1=Kramarz |first1=Alejandro Gustavo |last2=Paz |first2=Ernesto Rodrigo |date=2013 |title=Un Hegetotheriidae (Mammalia, Notoungulata) basal del Mioceno temprano de Patagonia |url=http://www.scielo.org.mx/scielo.php?script=sci_abstract&pid=S1026-87742013000100013&lng=es&nrm=iso&tlng=es |journal=Revista Mexicana de Ciencias Geológicas |language=es |volume=30 |issue=1 |pages=186–195 |issn=1026-8774 |access-date=2022-11-17 |archive-date=2022-10-29 |archive-url=https://web.archive.org/web/20221029041100/https://www.scielo.org.mx/scielo.php?script=sci_abstract&pid=S1026-87742013000100013&lng=es&nrm=iso&tlng=es |url-status=live }}</ref> the [[litoptern]] ''[[Cramauchenia]]'', the [[rodents]] ''[[Australoprocta]]'', ''[[Caviocricetus]]'', ''[[Eoviscaccia]]'', and ''[[Willidewu|Willidewu esteparius]]'',<ref name="Vucetichetal2010">{{Cite book |last1=Madden |first1=Richard H. |chapter-url=https://books.google.com/books?id=oY7wkK6lV4cC&q=Colhuehuapian+rodents+from+Gran+Barranca+and+other+Patagonian+localities%3A+the+state+of+the+art.&pg=PA206 |chapter=Colhuehuapian rodents from Gran Barranca and other Patagonian localities: the state of the art. |title=The Paleontology of Gran Barranca: Evolution and Environmental Change Through the Middle Cenozoic of Patagonia |last2=Carlini |first2=Alfredo A. |last3=Vucetich |first3=Maria Guiomar |last4=Kay |first4=Richard F. |date=2010-06-17 |publisher=Cambridge University Press |isbn=978-0-521-87241-6 |language=en |access-date=2022-11-17 |archive-date=2022-10-02 |archive-url=https://web.archive.org/web/20221002174237/https://books.google.com/books?id=oY7wkK6lV4cC&q=Colhuehuapian+rodents+from+Gran+Barranca+and+other+Patagonian+localities:+the+state+of+the+art.&pg=PA206 |url-status=live }}</ref> the [[armadillo]]s ''[[Proeutatus]]'' and ''[[Stenotatus]]'', and the [[sparassodont]] ''[[Cladosictis]]''. Bird remains from the formation are comparatively poor. A part of a [[tibiotarsus]] has previously been classified as an undetermined species of [[Psilopterinae|psilopterine]] phorusrhacid. Other birds include an undetermined [[wading bird]], ''[[Opisthodactylus|Opisthodactylus horacioperezi]]'', a species of [[Rheidae|rhea]], and ''[[Patagorhacos]]'', a phorusrhacid. During the Miocene the area likely consisted of open but wooded environment with temperate climate and a proximity to freshwater.<ref name="Barrioetal1989"/>

The Sarmiento Formation has provided a wide assemblage of mammals, consisting of pyroclastic deposits in an arid desert environment.<ref name="LoessicandfluvialsedimentationinSarmientoFormationpyroclastics">{{Cite book |last=Madden |first=Richard H. |url=http://worldcat.org/oclc/499130096 |title=The paleontology of Gran Barranca : evolution and environmental change through the middle Cenozoic of Patagonia |date=2010 |publisher=Cambridge University Press |isbn=978-0-521-87241-6 |chapter=Loessic and fluvial sedimentation in Sarmiento Formation pyroclastics, middle Cenozoic of central Patagonia |oclc=499130096}}</ref> Among these mammals were the astrapotheres ''[[Astrapotherium]]'' and ''[[Parastrapotherium]]'',<ref name="Maddenetal2010">{{Cite book |last1=Madden |first1=Richard H. |chapter-url=https://books.google.com/books?id=oY7wkK6lV4cC&dq=Colhuehuapian+Astrapotheriidae+%28Mammalia%29+from+Gran+Barranca+south+of+Lake+Colhue+Huapi.&pg=PA182 |title=The Paleontology of Gran Barranca: Evolution and Environmental Change Through the Middle Cenozoic of Patagonia |last2=Carlini |first2=Alfredo A. |last3=Vucetich |first3=Maria Guiomar |last4=Kay |first4=Richard F. |date=2010-06-17 |publisher=Cambridge University Press |isbn=978-0-521-87241-6 |language=en |chapter=Colhuehuapian Astrapotheriidae (Mammalia) from Gran Barranca south of Lake Colhue Huapi. |access-date=2022-11-17 |archive-date=2022-11-10 |archive-url=https://web.archive.org/web/20221110225518/https://books.google.com/books?id=oY7wkK6lV4cC&dq=Colhuehuapian+Astrapotheriidae+(Mammalia)+from+Gran+Barranca+south+of+Lake+Colhue+Huapi.&pg=PA182 |url-status=live }}</ref> the fellow notoungulates ''[[Argyrohippus]]'',<ref name="NotohippidaefromGranBarranca">{{Cite book |last1=G.M López |chapter-url=https://books.google.com/books?id=oY7wkK6lV4cC&pg=PA143 |title=The Paleontology of Gran Barranca. Evolution and Environmental Change Through the Middle Cenozoic of Patagonia |last2=A.M. Ribeiro |last3=M. Bond |publisher=Cambridge University Press |year=2010 |isbn=978-0-521-87241-6 |editor-last=Richard H. Madden |pages=143–151 |chapter=The Notohippidae (Mammalia, Notoungulata) from Gran Barranca: preliminary considerations |editor-last2=Alfredo A. Carlini |editor-last3=Maria Guiomar Vucetich |editor-last4=Richard F. Kay |access-date=2022-11-17 |archive-date=2022-11-10 |archive-url=https://web.archive.org/web/20221110225317/https://books.google.com/books?id=oY7wkK6lV4cC&pg=PA143 |url-status=live }}</ref> ''[[Cochilius]]'', ''[[Colpodon]]'',<ref name="LeontiniidaeSarmientoFormation">{{Cite book |last1=Madden |first1=Richard H. |chapter-url=https://books.google.com/books?id=oY7wkK6lV4cC&dq=The+Leontiniidae+%28Mammalia%2C+Notoungulata%29+from+the+Sarmiento+Formation+at+Gran+Barranca%2C+Chubut+Province%2C+Argentina.&pg=PR5 |title=The Paleontology of Gran Barranca: Evolution and Environmental Change Through the Middle Cenozoic of Patagonia |last2=Carlini |first2=Alfredo A. |last3=Vucetich |first3=Maria Guiomar |last4=Kay |first4=Richard F. |date=2010-06-17 |publisher=Cambridge University Press |isbn=978-0-521-87241-6 |language=en |chapter=The Leontiniidae (Mammalia, Notoungulata) from the Sarmiento Formation at Gran Barranca, Chubut Province, Argentina. |access-date=2022-11-17 |archive-date=2022-11-10 |archive-url=https://web.archive.org/web/20221110225243/https://books.google.com/books?id=oY7wkK6lV4cC&dq=The+Leontiniidae+(Mammalia,+Notoungulata)+from+the+Sarmiento+Formation+at+Gran+Barranca,+Chubut+Province,+Argentina.&pg=PR5 |url-status=live }}</ref> ''[[Interatherium]]'' and ''[[Pachyrukhos]]'',<ref name="NewmammalfaunaatthetopofGranBarranca"/> the litopterns ''[[Cramauchenia]]'',<ref name=Dozo2010>{{cite journal |author1=Dozo, M.T.  |author2=Vera, B. | year = 2010 | title = First skull and associated postcranial bones of Macraucheniidae (Mammalia, Litopterna) from the Deseadan SALMA (late Oligocene) of Cabeza Blanca (Chubut, Argentina) | journal = Journal of Vertebrate Paleontology | volume = 30 | issue = 6 | pages = 1818–1826 |url=https://www.researchgate.net/publication/233015768| doi=10.1080/02724634.2010.521534|bibcode=2010JVPal..30.1818D |s2cid=86291795 | hdl = 11336/93665 | hdl-access = free }}</ref> ''[[Lambdaconus]]'', ''[[Paramacrauchenia]]'', ''[[Proheptaconus]]'',<ref name="Adianthidaesystematics">{{Cite journal |last1=Cifelli |first1=Richard |last2=Soria |first2=Miguel Fernando |date=1983 |title=Systematics of the Adianthidae (Litopterna, Mammalia). |url=https://digitallibrary.amnh.org/handle/2246/5255 |journal=[[American Museum Novitates]] |language=en-US |issue=2771 |pages=1–25 |hdl=2246/5255 |access-date=2022-11-17 |archive-date=2022-10-01 |archive-url=https://web.archive.org/web/20221001074728/https://digitallibrary.amnh.org/handle/2246/5255 |url-status=live }}</ref> ''[[Prolicaphrium]]'',<ref name="Veraetal2015">{{Cite journal |last1=Vera |first1=Bárbara Soledad |last2=Fornasiero |first2=Mariagabriella |last3=Del Favero |first3=Letizia |date=December 2015 |title=The Egidio Feruglio's collection in the Museum of Geology and Palaeontology of the University of Padova: its importance to the knowledge of Cenozoic mammals from South America |url=https://www.researchgate.net/publication/290430697 |journal=Museologia Scientifica |volume=9 |pages=35–44 |issn=1123-265X}}</ref> ''[[Pternoconius]]'',<ref name="NotesonDeseadanMacraucheniidae">{{Cite journal |last1=Cifelli |first1=Richard L. |last2=Soria |first2=Miguel F. |date=1983 |title=Notes on Deseadan Macraucheniidae |journal=Ameghiniana |url=https://ameghiniana.org.ar/index.php/ameghiniana/article/view/1799 |language=es |volume=20 |issue=1–2 |pages=141–153 |issn=1851-8044 |access-date=2022-11-17 |archive-date=2022-09-29 |archive-url=https://web.archive.org/web/20220929232212/https://ameghiniana.org.ar/index.php/ameghiniana/article/view/1799 |url-status=live }}</ref><ref name="Pternoconiustournoueri">{{Cite journal |last1=Soria (h) |first1=Miguel Fernando |last2=Hoffstetter |first2=Robert |date=1985 |title=Pternoconius tournoueri, nueva especie de Macraucheniidae (Mammalia; Litopterna) de edad Colhuehuapense (Oligoceno Tardio); Pcia. Del Chubut, República Argentina |journal=Ameghiniana |url=https://ameghiniana.org.ar/index.php/ameghiniana/article/view/1758 |language=es |volume=22 |issue=3–4 |pages=149–158 |issn=1851-8044 |access-date=2022-11-17 |archive-date=2022-10-04 |archive-url=https://web.archive.org/web/20221004213516/https://ameghiniana.org.ar/index.php/ameghiniana/article/view/1758 |url-status=live }}</ref><ref name="Cheme-Arriagaetal2016">{{Cite journal |last1=Cheme-Arriaga |first1=Lucas |last2=Dozo |first2=MarÍa Teresa |last3=Gelfo |first3=Javier N. |date=2016-11-01 |title=A new Cramaucheniinae (Litopterna, Macraucheniidae) from the early Miocene of Patagonia, Argentina |url=https://doi.org/10.1080/02724634.2017.1229672 |journal=Journal of Vertebrate Paleontology |volume=36 |issue=6 |pages=e1229672 |doi=10.1080/02724634.2017.1229672 |bibcode=2016JVPal..36E9672C |s2cid=88586687 |issn=0272-4634|hdl=11336/30386 |hdl-access=free }}</ref> ''[[Tetramerorhinus]]''<ref name="NewmammalfaunaatthetopofGranBarranca"/>
and ''[[Theosodon]]'',<ref name="Picturotherium">{{Cite journal |last1=Kramarz |first1=Alejandro G. |last2=Bond |first2=Mariano |date=2005 |title=Los Litopterna (Mammalia) de la Formación Pinturas, Mioceno Temprano-Medio de Patagonia |url=https://www.ameghiniana.org.ar/index.php/ameghiniana/article/view/928 |language=es |volume=42 |issue=3 |pages=611–625 |issn=1851-8044 |access-date=2022-11-17 |archive-date=2022-09-26 |archive-url=https://web.archive.org/web/20220926214926/https://www.ameghiniana.org.ar/index.php/ameghiniana/article/view/928 |url-status=live }}</ref> the [[xenarthra]]ns ''[[Hapaloides]]'', ''[[Holomegalonyx]]'', ''[[Nematherium]]'', ''[[Peltephilus]]'', ''[[Proeutatus]]'', ''[[Proschismotherium]]'', ''[[Prozaedyus]]'', ''[[Stegotherium]]'', and ''[[Stenotatus]]'',<ref name="Carlinietal2010">{{Cite book |last1=Carlini |first1=Alfredo Armando |url=https://www.researchgate.net/publication/233955405 |title=The Paleontology of Gran Barranca. Evolution and Environmental Change Through the Middle Cenozoic of Patagonia |last2=Ciancio |first2=Martin R. |last3=Scillato-Yané |first3=G. J. |publisher=Cambridge University Press |year=2010 |isbn=978-0-521-87241-6 |pages=143–151 |chapter=Middle Eocene-early Miocene Dasypodidae (Xenarthra) of Southern South America, successive faunas in Gran Barranca; Biostratigraphy and Palaeoecology}}</ref> the [[metatheria]]ns ''[[Acyon]]'', ''[[Acrocyon]]'', ''[[Arctodictis]]'', ''[[Borhyaena]]'', ''[[Cladosictis]]'', ''[[Palaeothentes]]'', and ''[[Sipalocyon]]'',<ref name="Goinetal2013"/> the rodents ''[[Acarechimys]]''<ref name="Vucetichetal2010" /> ''[[Acaremys]],''<ref name="Vucetichetal2015">{{Cite journal |last1=Vucetich |first1=M.G. |last2=Dozo |first2=M.T. |last3=Arnal |first3=M. |last4=Pérez |first4=M.E. |date=2015-02-17 |title=New rodents (Mammalia) from the late Oligocene of Cabeza Blanca (Chubut) and the first rodent radiation in Patagonia |url=https://doi.org/10.1080/08912963.2014.883506 |journal=[[Historical Biology]] |volume=27 |issue=2 |pages=236–257 |doi=10.1080/08912963.2014.883506 |bibcode=2015HBio...27..236V |s2cid=84157246 |issn=0891-2963|hdl=11336/17958 |hdl-access=free }}</ref> ''[[Caviocricetus]]'',<ref name="ArnalandVucetich2015" /> ''[[Eosteiromys]]'', ''[[Eoviscaccia]]'',<ref name="VucetichandKramarz2003">{{Cite journal |last1=Vucetich |first1=María Guiomar |last2=Kramarz |first2=Alejandro G. |date=2003-06-17 |title=New Miocene rodents from Patagonia (Argentina) and their bearing on the early radiation of the octodontoids (Hystricognathi) |url=https://doi.org/10.1671/0272-4634(2003)023&#91;0435:NMRFPA&#93;2.0.CO;2 |journal=Journal of Vertebrate Paleontology |volume=23 |issue=2 |pages=435–444 |doi=10.1671/0272-4634(2003)023[0435:NMRFPA]2.0.CO;2 |s2cid=85705842 |issn=0272-4634 |access-date=2022-11-17 |archive-date=2023-02-06 |archive-url=https://web.archive.org/web/20230206215126/https://www.tandfonline.com/doi/abs/10.1671/0272-4634%282003%29023%5B0435%3ANMRFPA%5D2.0.CO%3B2 |url-status=live |url-access=subscription }}</ref> ''[[Hypsosteiromys]]'', ''[[Neoreomys]]'',<ref name="VucetichandVerzi1996">{{Cite journal |last1=Vucetich |first1=M. G. |last2=Verzi |first2=D. 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|pages=519–533 |doi=10.1007/s10914-015-9291-z |s2cid=16937577 |issn=1573-7055 |access-date=2022-11-17 |archive-date=2023-02-06 |archive-url=https://web.archive.org/web/20230206215128/https://link.springer.com/article/10.1007/s10914-015-9291-z |url-status=live |hdl=11336/19056 |hdl-access=free }}</ref><ref name="Buskeretal2019">{{Cite journal |last1=Busker |first1=Felipe |last2=Pérez |first2=María E. |last3=Dozo |first3=María T. |date=2019-07-01 |title=A new chinchilloid (Rodentia, Hystricognathi) from the early Miocene of the localities of Bryn Gwyn and Gran Barranca (Patagonia, Argentina) |journal=Comptes Rendus Palevol |language=en |volume=18 |issue=5 |pages=525–540 |doi=10.1016/j.crpv.2019.05.003 |s2cid=202185808 |issn=1631-0683|doi-access=free |bibcode=2019CRPal..18..525B }}</ref> and the [[primate]]s ''[[Homunculus (genus)|Homunculus]]'', ''[[Mazzonicebus]]'' and ''[[Tremacebus]]''.<ref name="Hershkovitz1981">{{Cite journal |last=Hershkovitz |first=Philip |date=1981-01-31 |title=Comparative Anatomy of Platyrrhine Mandibular Cheek Teeth dpm4, pm4, m1 with Particular Reference to Those of Homunculus (Cebidae), and Comments on Platyrrhine Origins |url=https://brill.com/view/journals/ijfp/35/2-3/article-p179_5.xml |journal=Folia Primatologica |volume=35 |issue=2–3 |pages=179–217 |doi=10.1159/000155972 |pmid=7021372 |issn=0015-5713 |access-date=2022-11-17 |archive-date=2022-10-05 |archive-url=https://web.archive.org/web/20221005070016/https://brill.com/view/journals/ijfp/35/2-3/article-p179_5.xml |url-status=live |url-access=subscription }}</ref><ref name="Novoetal2018">{{Cite journal |last1=Novo |first1=Nelson M. |last2=Tejedor |first2=Marcelo F. |last3=Ruiz |first3=Laureano R. González |date=2018-11-08 |title=Previously unknown fossil platyrrhines (Primates) of Patagonia from the Tournouër collection at the Muséum national d'Histoire naturelle, Paris |journal=Geodiversitas |volume=40 |issue=4 |pages=529–535 |doi=10.5252/geodiversitas2018v40a22 |issn=1280-9659 |doi-access=free|hdl=11336/82708 |hdl-access=free }}</ref><ref name="Hershkovitz1974">{{Cite journal |last=Hershkovitz |first=Philip |date=1974 |title=A New Genus of Late Oligocene Monkey (Cebidae, Platyrrhini) with Notes on Postorbital Closure and Platyrrhine Evolution |url=https://www.karger.com/Article/FullText/155594 |journal=[[Folia Primatologica]] |language=english |volume=21 |issue=1 |pages=1–35 |doi=10.1159/000155594 |issn=0015-5713 |pmid=4210697 |access-date=2022-11-17 |archive-date=2023-02-06 |archive-url=https://web.archive.org/web/20230206215141/https://www.karger.com/Article/Abstract/155594 |url-status=live |url-access=subscription }}</ref> The late-surviving [[meridiolestida]]n ''[[Necrolestes]]'' was also present.<ref name="Goinetal2013">{{Cite journal |last1=Goin |first1=Francisco J. |last2=Abello |first2=María Alejandra |date=February 2013 |title=Los Metatheria Sudamericanos de Comienzos Del Neógeno (Mioceno Temprano, Edad MamÍFero Colhuehuapense): Microbiotheria y Polydolopimorphia |journal=Ameghiniana |volume=50 |issue=1 |pages=51–78 |doi=10.5710/AMGH.9.11.2012.570 |issn=0002-7014 |doi-access=free|hdl=11336/76812 |hdl-access=free }}</ref>

Multiple species of ''Protypotherium'' lived during the [[Early Miocene]] in the Santa Cruz Formation of Argentina, which preserves mostly a coastal environment, but also forested and grassland regions.<ref name="Croft 2016">Croft, D. A. (2016). ''Horned armadillos and rafting monkeys: the fascinating fossil mammals of South America''. Indiana University Press.</ref> The area had little rainfall, so forests developed around lakes and rivers, giving Santa Cruz a diverse environment. During the Miocene, the climate was similar to those of the coasts of [[Chile]] with semi-[[Temperate rainforest|temperate]] forests and oceanic winds. Grasslands began spreading into Argentina during the Miocene, though much of inner [[Patagonia]] was still arid with small rainforests in between. Large, herbivorous, [[South American native ungulates|South American ungulates]] such as the [[Astrapotheria|astrapothere]] ''[[Astrapotherium]]'', the [[Toxodontia|toxodont]] [[Notoungulata|notoungulates]] ''[[Adinotherium]], [[Homalodotherium]]'' and ''[[Nesodon]]'' shared the niche of low browsers, along with the litopterns ''[[Adianthus]]'',<ref name="Adianthidaesystematics"/> ''[[Anisolophus]]'', ''[[Diadiaphorus]]'', ''[[Tetramerorhinus]]'', ''[[Theosodon]]'', and ''[[Thoatherium]]'',<ref name=schmidt>{{cite journal|last1=Schmidt|first1=Gabriela I.|last2=Ferrero|first2=Brenda S.|date=September 2014|title=Taxonomic Reinterpretation of ''Theosodon hystatus'' Cabrera and Kraglievich, 1931 (Litopterna, Macraucheniidae) and Phylogenetic Relationships of the Family|journal=Journal of Vertebrate Paleontology|url=https://www.tandfonline.com/doi/abs/10.1080/02724634.2014.837393|volume=34|issue=5|pages=1231–1238|doi=10.1080/02724634.2014.837393|bibcode=2014JVPal..34.1231S |s2cid=86091386|access-date=2022-11-22|archive-date=2022-10-06|archive-url=https://web.archive.org/web/20221006040309/https://www.tandfonline.com/doi/abs/10.1080/02724634.2014.837393|url-status=live|hdl=11336/18953|hdl-access=free}}</ref><ref name="Schmidt et al. 2019">{{Cite journal |last1=Schmidt |first1=Gabriela Ines |last2=Pino |first2=Santiago Hernández Del |last3=Muñoz |first3=Nahuel Antú |last4=Fernández |first4=Mercedes |date=2019-12-20 |title=Litopterna (Mammalia) From the Santa Cruz Formation (Early-Middle Miocene) At the Río Santa Cruz, Southern Argentina. |url=https://www.peapaleontologica.org.ar/index.php/peapa/article/view/290 |journal=Publicación Electrónica de la Asociación Paleontológica Argentina |language=en |volume=19 |issue=2 |doi=10.5710/PEAPA.13.08.2019.290 |issn=2469-0228 |doi-access=free |access-date=2022-11-22 |archive-date=2022-11-22 |archive-url=https://web.archive.org/web/20221122001101/https://www.peapaleontologica.org.ar/index.php/peapa/article/view/290 |url-status=live |hdl=11336/121536 |hdl-access=free }}</ref><ref name="Fernández et al. 2019">{{Cite journal |last1=Fernández |first1=Mercedes |last2=Muñoz |first2=Nahuel Antu |date=2019-12-20 |title=Notoungulata and Astrapotheria (Mammalia, Meridiungulata) of the Santa Cruz Formation (Early-Middle Miocene) along the Río Santa Cruz, Argentine Patagonia. |url=https://www.peapaleontologica.org.ar/index.php/peapa/article/view/288 |journal=Publicación Electrónica de la Asociación Paleontológica Argentina |language=en |volume=19 |issue=2 |doi=10.5710/PEAPA.19.09.2019.288 |issn=2469-0228 |doi-access=free |access-date=2022-11-17 |archive-date=2022-11-17 |archive-url=https://web.archive.org/web/20221117002220/https://www.peapaleontologica.org.ar/index.php/peapa/article/view/288 |url-status=live |hdl=11336/120862 |hdl-access=free }}</ref><ref name="Cuitiño et al. 2019" /><ref name="Chimento and Agnolin 2020">{{Cite journal |last1=Chimento |first1=Nicolás R. |last2=Agnolin |first2=Federico L. |year=2020 |title=Phylogenetic tree of Litopterna and Perissodactyla indicates a complex early history of hoofed mammals |journal=Scientific Reports |volume=10 |issue=1 |pages=13280 |doi=10.1038/s41598-020-70287-5 |issn=2045-2322 |pmc=7413542 |pmid=32764723 |bibcode=2020NatSR..1013280C |hdl-access=free |hdl=11336/135739|doi-access=free}}</ref><ref name="MacPheeetal2021">{{Cite journal |last1=MacPhee |first1=R. D. E. |last2=Pino |first2=Santiago Hernández Del |last3=Kramarz |first3=Alejandro |last4=Forasiepi |first4=Analía M. |last5=Bond |first5=Mariano |last6=Sulser |first6=R. Benjamin |date=2021-04-19 |title=Cranial Morphology and Phylogenetic Relationships of Trigonostylops wortmani, an Eocene South American Native Ungulate |journal=Bulletin of the American Museum of Natural History |volume=449 |issue=1 |pages=1–183 |doi=10.1206/0003-0090.449.1.1 |issn=0003-0090 |doi-access=free|hdl=11336/152049 |hdl-access=free }}</ref> with the rabbit-like [[Interatheriidae|interatheres]] such as ''[[Interatherium]]'' and the [[Hegetotheriidae|hegetotheres]] ''[[Hegetotherium]]'' and ''[[Pachyrukhos]]'' being [[Frugivore|frugivorous]].<ref name="Cassini et al. 2013">{{Cite journal |last=Cassini |first=Guillermo H. |date=2013 |title=Skull Geometric Morphometrics and Paleoecology of Santacrucian (Late Early Miocene; Patagonia) Native Ungulates (Astrapotheria, Litopterna, and Notoungulata) |url=https://bioone.org/journals/ameghiniana/volume-50/issue-2/AMGH.7.04.2013.606/Skull-Geometric-Morphometrics-and-Paleoecology-of-Santacrucian-Late-Early-Miocene/10.5710/AMGH.7.04.2013.606.full |journal=Ameghiniana |volume=50 |issue=2 |pages=193–216 |doi=10.5710/AMGH.7.04.2013.606 |s2cid=128999112 |issn=0002-7014 |access-date=2022-11-22 |archive-date=2023-02-06 |archive-url=https://web.archive.org/web/20230206215131/https://bioone.org/journals/ameghiniana/volume-50/issue-2/AMGH.7.04.2013.606/Skull-Geometric-Morphometrics-and-Paleoecology-of-Santacrucian-Late-Early-Miocene/10.5710/AMGH.7.04.2013.606.short |url-status=live |hdl=11336/26393 |hdl-access=free }}</ref><ref name=":9">Townsend, K. B., & Croft, D. A. (2008). Diets of notoungulates from the Santa Cruz Formation, Argentina: new evidence from enamel microwear. ''Journal of Vertebrate Paleontology'', ''28''(1), 217-230.</ref><ref name="Cassini et al. 2017">{{Cite journal |last1=Cassini |first1=Guillermo H. |last2=Pino |first2=Santiago Hernández Del |last3=Muñoz |first3=Nahuel A. |last4=Acosta |first4=M. V. Walter G. |last5=Fernández |first5=Mercedes |last6=Bargo |first6=M. Susana |last7=Vizcaíno |first7=Sergio F. |date=2017 |title=Teeth complexity, hypsodonty and body mass in Santacrucian (Early Miocene) notoungulates (Mammalia) |journal=Earth and Environmental Science Transactions of the Royal Society of Edinburgh |language=en |volume=106 |issue=4 |pages=303–313 |doi=10.1017/S1755691016000153 |issn=1755-6910|doi-access=free|hdl=11336/48917 |hdl-access=free }}</ref> Both mammalian and avian carnivores inhabited the area, the largest being the phorusrhacid ''[[Phorusrhacos]].'' [[Marsupial]]s also lived in the region, including the large carnivorous [[Sparassodonta|sparassodonts]] ''[[Borhyaena]]'' and the smaller sparassodonts ''[[Acyon]]'', ''[[Cladosictis]]'', and ''[[Sipalocyon]]''. [[Xenarthra]]ns in the Santa Cruz Formation were fairly common, such as the [[ground sloth]]s ''[[Analcimorphus]]'', ''[[Analcitherium]]'', ''[[Eucholoeops]]'',<ref name="Iuliis et al. 2014">{{Cite journal |last1=Iuliis |first1=Gerardo De |last2=Pujos |first2=François |last3=Toledo |first3=Nestor |last4=Bargo |first4=M. Susana |last5=Vizcaíno |first5=Sergio F. |date=2014 |title=Eucholoeops Ameghino, 1887 (Xenarthra, Tardigrada, Megalonychidae) from the Santa Cruz Formation, Argentine Patagonia: implications for the systematics of Santacrucian sloths |url=https://sciencepress.mnhn.fr/fr/periodiques/geodiversitas/36/2/eucholoeops-ameghino-1887-xenarthra-tardigrada-megalonychidae-de-la-formation-santa-cruz-de-patagonie-argentine-implications-pour-la-systematique-des-paresseux-santacruziens |journal=Geodiversitas |volume=36 |issue=2 |pages=209–255 |doi=10.5252/g2014n2a2 |hdl=11336/80624 |issn=1280-9659 |doi-access=free |access-date=2022-11-26 |archive-date=2022-06-20 |archive-url=https://web.archive.org/web/20220620012715/https://sciencepress.mnhn.fr/fr/periodiques/geodiversitas/36/2/eucholoeops-ameghino-1887-xenarthra-tardigrada-megalonychidae-de-la-formation-santa-cruz-de-patagonie-argentine-implications-pour-la-systematique-des-paresseux-santacruziens |url-status=live |hdl-access=free }}</ref> ''[[Hapalops]]'', ''[[Hyperleptus]]'', ''[[Nematherium]]'', ''[[Megalonychotherium]]'', ''[[Planops]]'', ''[[Prepotherium]]'', ''[[Schismotherium]]'', ''[[Trematherium]]'', and ''[[Xyophorus]]'',<ref name="Toledo et al. 2014">{{Cite journal |last1=Toledo |first1=Néstor |last2=Cassini |first2=Guillermo Hernán |last3=Vizcaíno |first3=Sergio Fabián |last4=Bargo |first4=M. Susana |date=2014 |title=Mass Estimation of Santacrucian Sloths from the Early Miocene Santa Cruz Formation of Patagonia, Argentina |journal=Acta Palaeontologica Polonica |volume=59 |issue=2 |pages=267–280 |doi=10.4202/app.2012.0009 |issn=0567-7920|doi-access=free|hdl=11336/20506 |hdl-access=free }}</ref><ref name="Bargo et al. 2019">{{Cite journal |last1=Bargo |first1=M. Susana |last2=Iuliis |first2=Gerardo De |last3=Toledo |first3=Néstor |date=2019-12-20 |title=Early Miocene Sloths (Xenarthra, Folivora) From the Río Santa Cruz Valley (Southern Patagonia, Argentina), Ameghino, 1887 Revisited |url=https://www.peapaleontologica.org.ar/index.php/peapa/article/view/297 |journal=Publicación Electrónica de la Asociación Paleontológica Argentina |language=en |volume=19 |issue=2 |doi=10.5710/PEAPA.06.08.2019.297 |issn=2469-0228 |doi-access=free |access-date=2022-11-17 |archive-date=2022-11-17 |archive-url=https://web.archive.org/web/20221117230201/https://www.peapaleontologica.org.ar/index.php/peapa/article/view/297 |url-status=live |hdl=11336/126223 |hdl-access=free }}</ref> and the [[armadillo]]s ''[[Cochlops]]'', ''[[Eucinepeltus]]'', ''[[Proeutatus]]'', ''[[Propalaehoplophorus]]'', ''[[Prozaedyus]]'', ''[[Stegotherium]]'', and ''[[Stenotatus]]''.<ref name="Vizcaíno 2012">{{Cite book |last1=Vizcaíno |first1=Sergio F. |title=Paleobiology of Santacrucian glyptodonts and armadillos (Xenarthra, Cingulata) |date=2012 |url=https://www.cambridge.org/core/books/early-miocene-paleobiology-in-patagonia/paleobiology-of-santacrucian-glyptodonts-and-armadillos-xenarthra-cingulata/58CB0068C890DBBD5F3E7AA03E423905 |chapter=Early Miocene Paleobiology in Patagonia: High-Latitude Paleocommunities of the Santa Cruz Formation |pages=194–215 |editor-last=Bargo |editor-first=M. Susana |place=Cambridge |publisher=Cambridge University Press |isbn=978-0-521-19461-7 |last2=Fernicola |first2=Juan C. |last3=Bargo |first3=M. Susana |editor2-last=Kay |editor2-first=Richard F. |editor3-last=Vizcaíno |editor3-first=Sergio F. |access-date=2022-11-17 |archive-date=2018-06-05 |archive-url=https://web.archive.org/web/20180605183127/https://www.cambridge.org/core/books/early-miocene-paleobiology-in-patagonia/paleobiology-of-santacrucian-glyptodonts-and-armadillos-xenarthra-cingulata/58CB0068C890DBBD5F3E7AA03E423905 |url-status=live }}</ref><ref name="Cuitiño et al. 2019" /> In addition, fossils of rodents, such as ''[[Acarechimys]]'', ''[[Acaremys]]'', ''[[Adelphomys]]'', ''[[Eocardia]]'', ''[[Neoreomys]]'', ''[[Perimys]]'', ''[[Pliolagostomus]]'', ''[[Prolagostomus]]'',<ref name="Vizcaíno et al. 2021">{{Cite journal |last1=Vizcaíno |first1=Sergio F. |last2=Bargo |first2=M. Susana |last3=Kay |first3=Richard F. |last4=Raigemborn |first4=M. Sol |date=2021-07-07 |title=The record of the typothere Pachyrukhos (Mammalia, Notoungulata) and the Chinchillid Prolagostomus (Mammalia, Rodentia) in the Santa Cruz Formation (early–middle Miocene) south to the Río Coyle, Patagonia, Argentina |url=https://www.peapaleontologica.org.ar/index.php/peapa/article/view/385 |journal=Publicación Electrónica de la Asociación Paleontológica Argentina |language=en |volume=21 |issue=2 |pages=1–15 |doi=10.5710/PEAPA.26.05.2021.385 |issn=2469-0228 |doi-access=free |access-date=2022-11-26 |archive-date=2022-11-22 |archive-url=https://web.archive.org/web/20221122020057/https://www.peapaleontologica.org.ar/index.php/peapa/article/view/385 |url-status=live |hdl=11336/147286 |hdl-access=free }}</ref> ''[[Schistomys]]'', ''[[Scleromys]]'', ''[[Spaniomys]]'', and ''[[Stichomys]]'' are also known.<ref name="Arnal et al. 2019">{{Cite journal |last1=Arnal |first1=Michelle |last2=Pérez |first2=María Encarnación |last3=Deschamps |first3=Cecilia |date=2019-12-20 |title=Revision of the Miocene caviomorph rodents from the Río Santa Cruz (Argentinean Patagonia). |url=https://www.peapaleontologica.org.ar/index.php/peapa/article/view/299 |journal=Publicación Electrónica de la Asociación Paleontológica Argentina |language=en |volume=19 |issue=2 |doi=10.5710/PEAPA.25.09.2019.299 |issn=2469-0228 |doi-access=free |access-date=2022-11-17 |archive-date=2022-11-17 |archive-url=https://web.archive.org/web/20221117222229/https://www.peapaleontologica.org.ar/index.php/peapa/article/view/299 |url-status=live |hdl=11336/175184 |hdl-access=free }}</ref> There were also [[primate]]s found in the formation, such as ''[[Carlocebus]]'' and ''[[Homunculus (genus)|Homunculus]]''.<ref name="Fleagle et al. 2022">{{Cite journal |last1=Fleagle |first1=John G. |last2=Gladman |first2=Justin T. |last3=Kay |first3=Richard F. |date=2022 |title=A New Humerus of Homunculus patagonicus, a Stem Platyrrhine from the Santa Cruz Formation (Late Early Miocene), Santa Cruz Province, Argentina |url=https://bioone.org/journals/ameghiniana/volume-59/issue-1/AMGH.29.09.2021.3447/A-New-Humerus-of-Homunculus-patagonicus-a-Stem-Platyrrhine-from/10.5710/AMGH.29.09.2021.3447.full |journal=Ameghiniana |volume=59 |issue=1 |pages=78–96 |doi=10.5710/AMGH.29.09.2021.3447 |s2cid=244330777 |issn=0002-7014 |access-date=2022-11-17 |archive-date=2023-02-06 |archive-url=https://web.archive.org/web/20230206215133/https://bioone.org/journals/ameghiniana/volume-59/issue-1/AMGH.29.09.2021.3447/A-New-Humerus-of-Homunculus-patagonicus-a-Stem-Platyrrhine-from/10.5710/AMGH.29.09.2021.3447.short |url-status=live |url-access=subscription }}</ref><ref name="Kay et al. 2019">{{Cite journal |last1=Kay |first1=Richard Frederick |last2=Perry |first2=Jonathan Marcus G. |date=2019-12-20 |title=New primates from the Río Santa Cruz and Río Bote (Early-Mid Miocene), Santa Cruz Province, Argentina |url=https://www.peapaleontologica.org.ar/index.php/peapa/article/view/289 |journal=Publicación Electrónica de la Asociación Paleontológica Argentina |language=en |volume=19 |issue=2 |doi=10.5710/PEAPA.24.08.2019.289 |issn=2469-0228 |doi-access=free |access-date=2022-11-17 |archive-date=2022-11-17 |archive-url=https://web.archive.org/web/20221117222229/https://www.peapaleontologica.org.ar/index.php/peapa/article/view/289 |url-status=live }}</ref>

The Collón Curá Formation and the Colloncuran age of South America represent a time when more open environments with reduced plant covering predominated, similar to [[semiarid]] and temperate to warm, dry [[woodland]]s or [[bushlands]]. The open environment allowed more [[cursorial]] (adapted for running) and large animals to occur, contrasting with the earlier conditions during the late [[Early Miocene]], with its well-developed forests with tree-dwelling animals. Forests would then have been restricted to valleys of the [[cordillera]] mountain ranges, with few tree-dwelling species. This change happened progressively during the earlier [[Friasian]] stage.<ref name="Neogene">{{cite book |last1=Tonni |first1=Eduardo P. |title=The Late Cenozoic of Patagonia and Tierra del Fuego |last2=Carlini |first2=Alfredo A. |publisher=Elsevier Science |year=2008 |isbn=978-0-08-055889-9 |editor=Rabassa, Jorge |pages=269–278 |chapter=Neogene vertebrates from Argentine Patagonia: their relationship with the most significant climatic changes}}</ref><ref name="Climate">{{cite journal |last1=Genise |first1=Jorge F. |last2=Bellosi |first2=Eduardo S. |last3=Cantil |first3=Liliana F. |last4=González |first4=Mirta G. |last5=Puerta |first5=Pablo |date=2022 |title=Middle Miocene climate transition as reflected by changes in ichnofacies and palaeosols from Patagonia, Argentina |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |volume=594 |pages=110932 |bibcode=2022PPP...59410932G |doi=10.1016/j.palaeo.2022.110932 |s2cid=247423841}}</ref> The transition towards more [[arid]] landscapes would have happened simultaneously with [[climate changes]] that corresponded to the [[Middle Miocene Climate Transition]], a [[global cooling]] event which had a drying effect on continents.<ref name="Climate" />

The Collón Curá Formation of Argentina has provided a wide assemblage of mammals, including at least 24 taxa such as the [[xenarthrans]] ''[[Megathericulus]]'', ''[[Prepotherium]]'', ''[[Prozaedyus]]'', and ''[[Paraeucinepeltus]]'', the [[notoungulate]]s ''[[Hegetotherium]]'', ''[[Interatherium]]'', and ''[[Pachyrukhos]]'', the [[astrapothere]] ''[[Astrapotherium]]'', the [[sparassodonts]] ''[[Patagosmilus]]'' and ''[[Cladosictis]]'', the [[marsupial]] ''[[Abderites (mammal)|Abderites]]'', the [[primate]] ''[[Proteropithecia]]'', and [[rodents]] such as ''[[Maruchito]]'', ''[[Protacaremys]]'', ''[[Neoreomys]]'', and ''[[Prolagostomus]]''.<ref name="Megathericulus">{{cite journal |last1=Brandoni |first1=Diego |last2=Ruiz |first2=Laureano González |last3=Bucher |first3=Joaquín |date=2020 |title=Evolutive implications of ''Megathericulus patagonicus'' (Xenarthra, Megatheriinae) from the Miocene of Patagonia Argentina |url=https://link.springer.com/article/10.1007/s10914-019-09469-6 |journal=Journal of Mammalian Evolution |volume=27 |issue=3 |pages=445–460 |doi=10.1007/s10914-019-09469-6 |s2cid=163164163 |access-date=2022-11-17 |archive-date=2022-05-12 |archive-url=https://web.archive.org/web/20220512011629/https://link.springer.com/article/10.1007/s10914-019-09469-6 |url-status=live |url-access=subscription }}</ref><ref name="Pitheciin">{{cite journal |last1=Kay |first1=Richard Frederick |last2=Johnson |first2=Derek |last3=Meldrum |first3=Don Jeffrey |date=1998 |title=A new pitheciin primate from the middle Miocene of Argentina. |url=https://www.researchgate.net/publication/13583562 |journal=American Journal of Primatology |volume=45 |issue=4 |pages=317–336 |doi=10.1002/(SICI)1098-2345(1998)45:4<317::AID-AJP1>3.0.CO;2-Z |pmid=9702279 |s2cid=22214720}}</ref><ref name="Cladosictis">{{cite journal |last1=Echarri |first1=Sebastian |last2=Ulloa-Guaiquin |first2=Karen S. |last3=Aguirrezabala |first3=Guillermo |last4=Forasiepi |first4=Analia M. |date=2021 |title=''Cladosictis patagonica'' (Metatheria, Sparassodonta) from the Collón Cura Formation (Middle Miocene), Río Negro, Argentina |journal=Ameghiniana |volume=58 |issue=6 |doi=10.5710/AMGH.06.08.2021.3439 |hdl=11336/171288 |s2cid=240529252|hdl-access=free }}</ref><ref name="Astrapotherium">{{cite journal |last1=Kramarz |first1=Alejandro |last2=Garrido |first2=Alberto |last3=Bond |first3=Mariano |date=2019 |title=''Astrapotherium'' from the Middle Miocene Collón Cura Formation and the Decline of Astrapotheres in Southern South America |journal=Ameghiniana |volume=56 |issue=4 |pages=290 |doi=10.5710/AMGH.15.07.2019.3258 |s2cid=199099778}}</ref> In addition to the mammals that characterize sediments of this age, there are also a few fossils of birds, reptiles, [[amphibians]], and fish.<ref name="Neogene" />

== References ==
{{Portal|Paleontology}}
{{Reflist}}

== External links ==

* {{commons category-inline}}
{{Meridiungulata|N.|state=collapsed}}
{{Taxonbar|from=Q1040573}}

[[Category:Typotheres]]
[[Category:Prehistoric placental genera]]
[[Category:Chattian first appearances]]
[[Category:Messinian extinctions]]
[[Category:Oligocene mammals of South America]]
[[Category:Miocene mammals of South America]]
[[Category:Huayquerian]]
[[Category:Chasicoan]]
[[Category:Mayoan]]
[[Category:Laventan]]
[[Category:Colloncuran]]
[[Category:Friasian]]
[[Category:Santacrucian]]
[[Category:Colhuehuapian]]
[[Category:Deseadan]]
[[Category:Neogene Argentina]]
[[Category:Fossils of Argentina]]
[[Category:Neogene Bolivia]]
[[Category:Fossils of Bolivia]]
[[Category:Neogene Chile]]
[[Category:Fossils of Chile]]
[[Category:Oligocene Uruguay]]
[[Category:Fossils of Uruguay]]
[[Category:Fossil taxa described in 1882]]
[[Category:Taxa named by Florentino Ameghino]]
[[Category:Neuquén Basin]]
[[Category:Paraná Basin]]
[[Category:Golfo San Jorge Basin]]
[[Category:Austral or Magallanes Basin]]
[[Category:Cerro Azul Formation]]
[[Category:Cerro Bandera Formation]]
[[Category:Chichinales Formation]]
[[Category:Ituzaingó Formation]]
[[Category:Sarmiento Formation]]
[[Category:Santa Cruz Formation]]
[[Category:Fray Bentos Formation]]