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{{Short description|Extinct species of marsupial}}
<code>''Content in this edit is translated from the [http://ru.wikipedia.org/enwiki/w/index.php?title=Nimiokoala_greystanesi existing Russian Wikipedia article]; see its history for attribution.''</code>{{Taxobox
{{use dmy dates|date=May 2023}}
| name = Riversleigh rainforest koala
{{Speciesbox
| image = Nimiokoala greystanesi.JPG
| fossil_range = Early-middle [[Miocene]]
| image =
| image_caption =
| image_caption =
| regnum = [[Animal]]ia
| genus = Nimiokoala
| species = greystanesi
| phylum = [[Chordate|Chordata]]
| parent_authority = Black and Archer, 1997
| classis = [[Mammal]]ia
| authority = Black and Archer, 1997{{sfn|Black|Archer|1997}}
| ordo = [[Diprotodontia]]
| familia = [[Phascolarctidae]]
| genus = '''''Nimiokoala'''''
| species = '''''N. greystanesi'''''
| binomial = ''Nimiokoala greystanesi''
| binomial_authority = Black and Archer, 1997<ref>{{cite journal|last=Black|first=K.|last2=Archer|first2=M.|title=Nimiokoala gen. nov. (Marsupialia, Phascolarctidae) from Riversleigh, northwestern Queensland, with a revision of Litokoala|url=https://archive.org/details/MemoirsQueensla41Quee|journal=Memoirs of the Queensland Museum|language=en|volume=41|issn=0079-8835|pages=209–228}}</ref>
| fossil_range = early-middle [[Miocene]]
| infraclassis = [[Marsupial]]ia
| image caption = Restoration of N. greystanesi.
}}
}}
'''''Nimiokoala greystanesi''''' is an [[extinct]] [[marsupial]], closely related to the [[Neontology|extant]] [[koala]], that inhabited northwestern [[Queensland]] in the early-middle [[Miocene]] (23–16&nbsp;million years ago).{{sfn|Black|Price|Archer|Hand|2014|pp=1193–1194}} It is the only species assigned to the genus '''''Nimiokoala'''''. Along with [[species]] of [[Sister group|sister]] [[genus]] ''[[Litokoala]]'', it is the smallest representative of [[Family (biology)|family]] [[Phascolarctidae]].{{sfn|Black|Price|Archer|Hand|2014|p=1192}} Based on [[Cladistics|cladistic]] analysis, ''Nimiokoala'' is one of the more [[Basal (phylogenetics)|basal]] genera of Phascolarctide. It died out due to [[Climate change (general concept)|climate change]] rendering the environment more arid.{{sfn|Black|Price|Archer|Hand|2014|p=1195}} It probably had a more generalized diet than that of the modern species, but its exact food preferences are unknown.{{sfn|Musser|2009}}

The '''Riversleigh rainforest koala''' ('''''Nimiokoala greystanesi''''') is an [[extinct]] [[marsupial]], closely related to the [[Neontology|extant]] [[koala]], that inhabited northwestern [[Queensland]] in the early-middle [[Miocene]] (23–16&nbsp;million years ago).<ref name=":0">{{Cite journal|last=K.|first=Black|last2=J.|first2=Price, Gilbert|last3=Michael|first3=Archer,|last4=J.|first4=Hand, Suzanne|title=Bearing up well? Understanding the past, present and future of Australia&#39;s koalas|url=http://www.academia.edu/5610674/Bearing_up_well_Understanding_the_past_present_and_future_of_Australias_koalas._Black_K.H._Price_G.J._Archer_M._Hand_S.J._2014|journal=Gondwana Research|language=en|volume=25|issn=1342-937X}}</ref> Along with [[species]] of [[Sister group|sister]] [[genus]] ''[[Litokoala]]'', the Riversleigh rainforest koala is the smallest representative of [[Family (biology)|family]] ''[[Phascolarctidae|Phascolarctide]]''.<ref name=":0" /> Based on [[Cladistics|cladistic]] analysis, ''Nimiokoala'' is one of the more [[Basal (phylogenetics)|basal]] genera of ''Phascolarctide''. It died out due to [[climate change]] rendering the environment more arid.<ref name=":0" /> It probably had a more generalized diet than that of the modern species, but its exact food preferences are unknown.<ref name="Australian Museum">''Musser, A.'' [https://australianmuseum.net.au/nimiokoala-greystanesi Riversleigh Rainforest koala]. Australian Museum (July 15, 2009). Verified September 8, 2016.</ref>


== Etymology ==
== Etymology ==
The [[Genus|generic name]], ''Nimiokoala,'' is derived from the [[Latin]] word ''Nimio'' "excessive" referring to its complex molar morphology relative to other koala species. The [[Specific name (zoology)|specific name]], ''greystanesi,'' honors Greystanes High School.<ref>{{Cite book|url=http://archive.org/details/MemoirsQueensla41Quee|title=Memoirs of the Queensland Museum|last=Hamlyn-Harris|first=Ronald|date=June 30, 1997|publisher=South Brisbane : Queensland Museum|year=|isbn=|location=|pages=209–228}}</ref>
The [[Genus|generic name]], ''Nimiokoala,'' is derived from the [[Latin]] word ''Nimio'' "excessive" referring to its complex molar morphology relative to other koala species. The [[Specific name (zoology)|specific name]], ''greystanesi,'' honors [[Greystanes High School]].{{sfn|Black|Archer|1997}}


== History of Research ==
== History of research ==
As of 2013, the fossil record of extinct koalas consists of 163 specimens across 58 deposits in [[Riversleigh]]; 55 specimens are attributed to the Riversleigh rainforest koala.<ref name=":0" /> To date, a partial [[skull]] has been found along with several [[Mandible|lower jaws]] and isolated teeth. On the basis of these fossils, the dental apparatus of the animal has been completely restored. The species was named in 1997. Specimen QMF30482 was assigned as a [[holotype]]; it's bones are stored in the [[Queensland Museum]].<ref name="Australian Museum" />
As of 2013, the fossil record of extinct koalas consists of 163 specimens across 58 deposits in [[Australian Fossil Mammal Sites (Riversleigh)|Riversleigh]]; 55 specimens are attributed to ''N. greystanesi''.{{sfn|Black|Price|Archer|Hand|2014|p=1188}} To date, a partial [[skull]] has been found along with several [[Mandible|lower jaws]] and isolated teeth. On the basis of these fossils, the dental apparatus of the animal has been completely restored. The species was named in 1997 with [[Queensland Museum]] specimen "QMF30482" being designated the [[holotype]]; with the specimens used by the type description being part of the Queensland Museum collections.{{sfn|Musser|2009}}


== Description ==
== Description ==
In the absence of postcranial fossils, the dimensions of the Riversleigh rainforest koala were calculated from measurements of its surviving teeth. It is estimated to have body length of about 25–30&nbsp;cm (9.8-11.8&nbsp;in), and a weight of about 3.5&nbsp;kg (7.7&nbsp;lb), one third the size of modern koalas and more than 10 times smaller than the largest known representative of ''Phascolarctide'' (''[[Phascolarctos yorkensis]]''). Its muzzle was more prominent than that of modern koalas,<ref name="Australian Museum" /> resembling the [[Cuscus|possum]] snout.<ref>{{Cite web|url=https://www.science.unsw.edu.au/news/discovery-20-million-year-old-extinct-koala-species|title=Discovery: 20 million year old extinct koala species - UNSW Science for society|website=www.science.unsw.edu.au|language=en|access-date=2017-04-09}}</ref> The teeth of the Riversleigh rainforest koala are selenodontal (crescent-shaped), with a numerous cusps and accessory shearing blades.<ref name=":0" /> The fossilized skull contains large [[Orbit (anatomy)|orbits]] and very large [[Tympanic part of the temporal bone|auditory bulliae]] relative to its size.<ref name=":0" />
In the absence of postcranial fossils, the size of ''Nimiokoala'' has been estimated from measurements of its surviving teeth. It is estimated to have body length of about 25–30&nbsp;cm (9.8-11.8&nbsp;in), and a weight of about 3.5&nbsp;kg (7.7&nbsp;lb), one third the size of modern koalas and more than 10 times smaller than the largest known representative of Phascolarctidae (''[[Phascolarctos yorkensis]]''). Its muzzle was more prominent than that of modern koalas,{{sfn|Musser|2009}} resembling the [[Cuscus|possum]] snout.{{sfn|Smith|2013}}{{sfn|Black|Louys|Price|2014}} The teeth of the Riversleigh rainforest koala are selenodontal (crescent-shaped), with a numerous cusps and accessory shearing blades.{{sfn|Black|Price|Archer|Hand|2014|p=1192}} The fossilized skull contains large [[Orbit (anatomy)|orbits]] and very large [[Tympanic part of the temporal bone|auditory bulliae]] relative to its size.{{sfn|Black|Price|Archer|Hand|2014|pp=1193–1194}}


== Ecology and Behavior ==
== Ecology and behavior ==
In the early-middle Miocene, Riversleigh was covered with [[Tropical and subtropical moist broadleaf forests|tropical forests]]. More open areas, with [[karst]] soil, occurred at forest edges or freshwater streams and lakes.<ref name="Australian Museum" /> As the climate became more arid, with a more pronounced change of seasons, small species of koalas died out, including the Riversleigh rainforest koala.
In the early-middle Miocene, Riversleigh was covered with [[Tropical and subtropical moist broadleaf forests|tropical forests]]. More open areas, with [[karst]] soil, occurred at forest edges or freshwater streams and lakes.{{sfn|Musser|2009}} As the climate became more arid, with a more pronounced change of seasons, small species of koalas died out, including the Riversleigh rainforest koala.


The small size of ''Nimiokoala'', which requires a proportionately more intensive diet, and large eye sockets, which indicate good night vision, suggest that this animal was much more mobile than the modern koala.<ref name=":0" /> The structure of the ear of ''Nimikoala'' corresponds to that which can be observed in modern koalas; in conjuction with the large [[Tympanic part of the temporal bone|auditory bulliae]], it can be concluded that the Riversleigh rainforest koala was sensitive to and used low-frequency sounds for communication, including to attract mates.<ref>{{Cite web|url=https://www.science.unsw.edu.au/news/loud-and-lazy-didnt-chew-gum-ancient-koalas|title=Loud and lazy but didn't chew gum: Ancient koalas - UNSW Science for society|website=www.science.unsw.edu.au|language=en|access-date=2017-04-09}}</ref>
The small size of ''Nimiokoala'', which requires a proportionately more intensive diet, and large eye sockets, which indicate good night vision, suggest that this animal was much more mobile than the modern koala. The structure of the ear of ''Nimikoala'' corresponds to that which can be observed in modern koalas; in conjunction with the large [[Tympanic part of the temporal bone|auditory bulliae]], it can be concluded that the Riversleigh rainforest koala was sensitive to and used low-frequency sounds for communication, including to attract mates.{{sfn|Gaffney|2009}}


==References==
==References==
{{reflist}}
{{Reflist|30em}}
==Works cited==

{{refbegin}}
{{portal|Paleontology}}
* {{cite journal |last1=Black |first1=K. |last2=Archer |first2=M. |title=Nimiokoala gen. nov. (Marsupialia, Phascolarctidae) from Riversleigh, northwestern Queensland, with a revision of Litokoala |url=https://archive.org/details/MemoirsQueensla41Quee |journal=Memoirs of the Queensland Museum |year=1997 |language=en |volume=41 |issue=2 |issn=0079-8835 |pages=209–228 |name-list-style=amp}}
* {{cite journal |last1=Black |first1=Karen H. |last2=Louys |first2=Julien |last3=Price |first3=Gilbert J. |title=Understanding morphological variation in the extant koala as a framework for identification of species boundaries in extinct koalas (Phascolarctidae; Marsupialia) |journal=Journal of Systematic Palaeontology |year=2014 |volume=12 |issue=2 |pages=237-264 |doi=10.1080/14772019.2013.768304 |name-list-style=amp}}
* {{cite journal |last1=Black |first1=Karen H. |last2=Price |first2=Gilbert J. |last3=Archer |first3=Michael |last4=Hand |first4=Suzanne J. |date=2014 |title=Bearing up well? Understanding the past, present and future of Australia's koalas |url=https://www.academia.edu/5610674|journal=Gondwana Research |language=en |volume=25 |issue=3 |pages=1186–1201 |doi=10.1016/j.gr.2013.12.008 |bibcode=2014GondR..25.1186B |issn=1342-937X |name-list-style=amp}}
* {{cite web |url=https://www.science.unsw.edu.au/news/loud-and-lazy-didnt-chew-gum-ancient-koalas|title=Loud and lazy but didn't chew gum: Ancient koalas |website=UNSW Science for society |last=Gaffney |first=Dan |date=2009-12-21 |language=en |archive-url=https://web.archive.org/web/20161002172651/https://www.science.unsw.edu.au/news/loud-and-lazy-didnt-chew-gum-ancient-koalas |archive-date=2016-10-02 |access-date=2017-04-09 |url-status=dead}}
* {{cite web |url=https://australianmuseum.net.au/nimiokoala-greystanesi |title=Nimiokoala greystanesi |last=Musser |first=Anne |date=2009-07-15 |website=Australian Museum |language=en |archive-url=https://web.archive.org/web/20170409202217/https://australianmuseum.net.au/nimiokoala-greystanesi |archive-date=2017-04-09 |access-date=2017-05-14}}
* {{cite web |url=https://www.science.unsw.edu.au/news/discovery-20-million-year-old-extinct-koala-species|title=Discovery: 20 million year old extinct koala species |website=UNSW Science for society |last=Smith |first=Deborah |date=2013-05-29 |language=en |archive-url=https://web.archive.org/web/20161002173838/https://www.science.unsw.edu.au/news/discovery-20-million-year-old-extinct-koala-species |archive-date=2016-10-02 |url-status=dead |access-date=2017-04-09 }}
{{refend}}
{{Vombatiformes}}
{{Taxonbar|from1=Q1189148|from2=Q42602605}}


[[Category:Pleistocene mammals of Australia]]
[[Category:Pleistocene mammals of Australia]]

Latest revision as of 17:12, 4 March 2024

Nimiokoala
Temporal range: Early-middle Miocene
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Infraclass: Marsupialia
Order: Diprotodontia
Family: Phascolarctidae
Genus: Nimiokoala
Black and Archer, 1997
Species:
N. greystanesi
Binomial name
Nimiokoala greystanesi
Black and Archer, 1997[1]

Nimiokoala greystanesi is an extinct marsupial, closely related to the extant koala, that inhabited northwestern Queensland in the early-middle Miocene (23–16 million years ago).[2] It is the only species assigned to the genus Nimiokoala. Along with species of sister genus Litokoala, it is the smallest representative of family Phascolarctidae.[3] Based on cladistic analysis, Nimiokoala is one of the more basal genera of Phascolarctide. It died out due to climate change rendering the environment more arid.[4] It probably had a more generalized diet than that of the modern species, but its exact food preferences are unknown.[5]

Etymology

[edit]

The generic name, Nimiokoala, is derived from the Latin word Nimio "excessive" referring to its complex molar morphology relative to other koala species. The specific name, greystanesi, honors Greystanes High School.[1]

History of research

[edit]

As of 2013, the fossil record of extinct koalas consists of 163 specimens across 58 deposits in Riversleigh; 55 specimens are attributed to N. greystanesi.[6] To date, a partial skull has been found along with several lower jaws and isolated teeth. On the basis of these fossils, the dental apparatus of the animal has been completely restored. The species was named in 1997 with Queensland Museum specimen "QMF30482" being designated the holotype; with the specimens used by the type description being part of the Queensland Museum collections.[5]

Description

[edit]

In the absence of postcranial fossils, the size of Nimiokoala has been estimated from measurements of its surviving teeth. It is estimated to have body length of about 25–30 cm (9.8-11.8 in), and a weight of about 3.5 kg (7.7 lb), one third the size of modern koalas and more than 10 times smaller than the largest known representative of Phascolarctidae (Phascolarctos yorkensis). Its muzzle was more prominent than that of modern koalas,[5] resembling the possum snout.[7][8] The teeth of the Riversleigh rainforest koala are selenodontal (crescent-shaped), with a numerous cusps and accessory shearing blades.[3] The fossilized skull contains large orbits and very large auditory bulliae relative to its size.[2]

Ecology and behavior

[edit]

In the early-middle Miocene, Riversleigh was covered with tropical forests. More open areas, with karst soil, occurred at forest edges or freshwater streams and lakes.[5] As the climate became more arid, with a more pronounced change of seasons, small species of koalas died out, including the Riversleigh rainforest koala.

The small size of Nimiokoala, which requires a proportionately more intensive diet, and large eye sockets, which indicate good night vision, suggest that this animal was much more mobile than the modern koala. The structure of the ear of Nimikoala corresponds to that which can be observed in modern koalas; in conjunction with the large auditory bulliae, it can be concluded that the Riversleigh rainforest koala was sensitive to and used low-frequency sounds for communication, including to attract mates.[9]

References

[edit]

Works cited

[edit]
  • Black, K. & Archer, M. (1997). "Nimiokoala gen. nov. (Marsupialia, Phascolarctidae) from Riversleigh, northwestern Queensland, with a revision of Litokoala". Memoirs of the Queensland Museum. 41 (2): 209–228. ISSN 0079-8835.
  • Black, Karen H.; Louys, Julien & Price, Gilbert J. (2014). "Understanding morphological variation in the extant koala as a framework for identification of species boundaries in extinct koalas (Phascolarctidae; Marsupialia)". Journal of Systematic Palaeontology. 12 (2): 237–264. doi:10.1080/14772019.2013.768304.
  • Black, Karen H.; Price, Gilbert J.; Archer, Michael & Hand, Suzanne J. (2014). "Bearing up well? Understanding the past, present and future of Australia's koalas". Gondwana Research. 25 (3): 1186–1201. Bibcode:2014GondR..25.1186B. doi:10.1016/j.gr.2013.12.008. ISSN 1342-937X.
  • Gaffney, Dan (21 December 2009). "Loud and lazy but didn't chew gum: Ancient koalas". UNSW Science for society. Archived from the original on 2 October 2016. Retrieved 9 April 2017.
  • Musser, Anne (15 July 2009). "Nimiokoala greystanesi". Australian Museum. Archived from the original on 9 April 2017. Retrieved 14 May 2017.
  • Smith, Deborah (29 May 2013). "Discovery: 20 million year old extinct koala species". UNSW Science for society. Archived from the original on 2 October 2016. Retrieved 9 April 2017.