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{{Short description|Extinct genus of marsupials}}
{{Taxobox
{{Automatic taxobox
| name = Thingodonts
| fossil_range = {{fossil_range|34|7|[[Oligocene]] - [[Miocene]]}}
| fossil_range = {{fossil_range|34|7|[[Oligocene]] - [[Miocene]]}}
| image =
| regnum = [[Animal]]ia
| image_caption = Life reconstruction of Yalkaparidon coheni by Filipe Martinho
| phylum = [[Chordate|Chordata]]
| grandparent_authority = Archer, Hand & Godthelp, 1988
| classis = [[Mammal]]ia
| parent_authority = Archer, Hand & Godthelp, 1988
| infraclassis = [[Marsupial]]ia
| taxon = Yalkaparidon
| ordo = †'''Yalkaparidontia'''
| ordo_authority = Archer, Hand & Godthelp, 1988
| authority = Archer, Hand & Godthelp, 1988
| subdivision_ranks = Species
| familia = †'''Yalkaparidontidae'''
| subdivision = * †''Yalkaparidon coheni''
| familia_authority = Archer, Hand & Godthelp, 1988
| genus = [[extinction|]]'''''Yalkaparidon'''''
* †''Yalkaparidon jonesi''
| genus_authority = Archer, Hand & Godthelp, 1988
| subdivision_ranks = [[Paleospecies]]
| subdivision =
†''[[Yalkaparidon coheni]]''<br/>
†''[[Yalkaparidon jonesi]]''
}}
}}
'''Thingodonta''' is the colloquial name given to a bizarre order of [[extinct]] [[Australia]]n [[marsupial]]s, first described in 1988 and known only from the [[Oligocene|Oligo]]-[[Miocene]] deposits of [[Riversleigh]], northwestern [[Queensland]], Australia.<ref>Archer M; Hand, Suzanne J. & Godthelp H. [1991] 2000. ''Australia's lost world: Riversleigh, World Heritage Site''. Reed, Sydney. p94 "Thingodonta: off the scale of the unexpected".</ref>


'''''Yalkaparidon''''' is an [[extinct]] genus of [[Australia]]n [[marsupial]]s, first described in 1988 and known only from the [[Oligocene|Oligo]]-[[Miocene]] deposits of [[Australian Fossil Mammal Sites (Riversleigh)|Riversleigh]], northwestern [[Queensland]], Australia.<ref>Archer M; Hand, Suzanne J. & Godthelp H. [1991] 2000. ''Australia's lost world: Riversleigh, World Heritage Site''. Reed, Sydney. p94 "Thingodonta: off the scale of the unexpected".</ref>
A single [[genus]], '''''Yalkaparidon''''' (from an [[Aboriginal Australian|aboriginal]] word for [[boomerang]], alluding to the boomerang shape of its [[Molar (tooth)|molar]]s when seen in occlusal view, and the Greek word for tooth) and two [[species]], ''[[Yalkaparidon coheni|Y. coheni]]'' and ''[[Yalkaparidon jonesi|Y. jonesi]]'', have so far been described. Numerous isolated teeth and [[jaw]] bones of ''Yalkaparidon'' are known, but only a single [[skull]] (of ''Y. coheni'') has so far been recovered.


==Species==
These specimens of ''Yalkaparidon'' exhibit a melange of characters: the molars are zalambdodont (a distinctive [[tooth]] type also found in the marsupial [[mole (animal)|mole]] ''[[Notoryctes]]'', the living placental '[[insectivore]]s' ''[[Solenodon]]'', [[tenrec]]s and [[golden mole]]s, as well as a number of [[fossil]] groups); the [[incisor]]s are very large and hypselodont (open-rooted and hence ever-growing, similar to those of [[rodent]]s); the basicranial region of the only known skull is very primitive, somewhat similar to those of [[plesiomorphic]] [[bandicoot]]s. The zalambdodont molars appear to link it to notoryctid marsupial moles, but detailed study of the teeth of these two groups suggests that they have evolved independently, and ''Yalkaparidon'' is anatomically otherwise very different from the marsupial moles. The incisors resemble those of diprotodontians, but no other features convincingly support this relationship, and the [[convergent evolution]] of such incisors in South American 'pseudodiprotodont' groups (such as [[caenolestid]]s and polydolopimorphians) suggests that ''Yalkaparidon'' and diprotodontians may have evolved similar incisors independently. Basicranial similarities to bandicoots most likely represent shared plesiomorphic characters, and hence are not indicative of a close relationship.
Two [[species]], ''Y. coheni'' and ''Y. jonesi'', have so far been described. Numerous isolated teeth and [[jaw]] bones of ''Yalkaparidon'' are known, but only a single [[skull]] (of ''Y. coheni'') has so far been recovered.


==Etymology==
For these reasons, ''Yalkaparidon'' is currently placed in its own [[family (biology)|family]], '''Yalkaparidontidae''', and [[order (biology)|order]], '''Yalkaparidontia'''; this placement would make this the only order of Australian marsupials known to have gone extinct. However, Frederick Szalay suggested in his 1994 book 'Evolutionary History of the Marsupials and an Analysis of Osteological Characters' that ''Yalkaparidon'' is indeed a diprotodontian (as evinced by its incisors), albeit one that retains a highly primitive basicranium.
The generic name ''Yalkaparidon'' comes from an [[Aboriginal Australian|aboriginal]] word for [[boomerang]], alluding to the boomerang-like shape of its [[Molar (tooth)|molar]]s when seen in occlusal view, and the Greek word for tooth.


==Characteristics and classification==
The exact function of its unusual [[dentition]] remains obscure, and suggestions that it may have fed on [[worm]]s (based on the similarities of its molars to those of worm-eating tenrecs), [[caterpillar]]s or [[Egg (biology)|egg]]s are tenuous. However, its source of food presumably had a hard outer covering (necessitating use of the large incisors) but relatively soft interior, as zalambdodont molars cannot crush food items. The possibility that it was a "mammalian woodpecker" similar to the [[Aye-aye]] and [[Striped possum]] has been raised.<ref name = "woodpecker">{{Cite journal | last = Beck | first = R. M. D. | authorlink =
These specimens of ''Yalkaparidon'' exhibit a melange of characters: the molars are [[zalambdodont]] (a distinctive [[tooth]] type also found in the marsupial mole ''[[Notoryctes]]'', the living placental '[[insectivore]]s' ''[[Solenodon]]'', [[tenrec]]s and [[golden mole]]s, as well as a number of [[fossil]] groups); the [[incisor]]s are very large and hypselodont (open-rooted and hence ever-growing, similar to those of [[rodent]]s); the basicranial region of the only known skull is very primitive, somewhat similar to those of [[plesiomorphic]] [[bandicoot]]s. The zalambdodont molars appear to link it to notoryctid marsupial moles, but detailed study of the teeth of these two groups suggests that they have evolved independently, and ''Yalkaparidon'' is anatomically otherwise very different from the marsupial moles. The incisors resemble those of diprotodontians, but no other features convincingly support this relationship, and the [[convergent evolution]] of such incisors in South American 'pseudodiprotodont' groups (such as [[caenolestid]]s and polydolopimorphians) suggests that ''Yalkaparidon'' and diprotodontians may have evolved similar incisors independently. Basicranial similarities to bandicoots most likely represent shared plesiomorphic characters, and hence are not indicative of a close relationship.
| title = Was the Oligo-Miocene Australian metatherian ''Yalkaparidon'' a ‘mammalian woodpecker’?

| journal = [[Biological Journal of the Linnean Society]] | volume = 97 | issue =
For these reasons, ''Yalkaparidon'' is currently placed in its own [[family (biology)|family]], '''Yalkaparidontidae''', and [[order (biology)|order]], '''Yalkaparidontia'''; this placement would make this the only order of Australian marsupials known to have gone extinct. However, Frederick Szalay suggested in his 1994 book 'Evolutionary History of the Marsupials and an Analysis of Osteological Characters' that ''Yalkaparidon'' is indeed a [[diprotodontian]] (as evinced by its incisors), albeit one that retains a highly primitive [[basicranium]].

The exact function of its unusual [[dentition]] remains obscure, and suggestions that it may have fed on [[worm]]s (based on the similarities of its molars to those of worm-eating tenrecs), [[caterpillar]]s or [[Egg (biology)|egg]]s are tenuous. However, its source of food presumably had a hard outer covering (necessitating use of the large incisors) but relatively soft interior, as zalambdodont molars cannot crush food items. The possibility that it was a "mammalian woodpecker" similar to the [[aye-aye]] and [[striped possum]] has been raised.<ref name = "woodpecker">{{Cite journal | last = Beck | first = R. M. D.
| title = Was the Oligo-Miocene Australian metatherian ''Yalkaparidon'' a 'mammalian woodpecker'?
| journal = [[Biological Journal of the Linnean Society]] | volume = 97
| pages = 1–17 | publisher = [[The Linnean Society of London]] | date = 2009
| pages = 1–17 | publisher = [[The Linnean Society of London]] | date = 2009
| doi = 10.1111/j.1095-8312.2009.01171.x| doi-access = free}}</ref>
| url = http://www3.interscience.wiley.com/journal/122341804/abstract

| doi = | id = | accessdate = 2010-04-20}}</ref>
==Morphology==

Future insights into the evolutionary relationships, functional [[morphology (biology)|morphology]] and lifestyle of ''Yalkaparidon'' must await more detailed study. It remains one of the most enigmatic members of Australia's unique mammalian [[fauna]].
A detailed study on its morphology, including newly referred tarsal material published in 2014 found that it was likely a crown group marsupial, and probably an [[australidelphia]]n, but its unusual morphology made its precise placement uncertain.<ref>{{Cite journal|last1=Beck|first1=Robin M. D.|last2=Travouillon|first2=Kenny J.|last3=Aplin|first3=Ken P.|last4=Godthelp|first4=Henk|last5=Archer|first5=Michael|date=June 2014|title=The Osteology and Systematics of the Enigmatic Australian Oligo-Miocene Metatherian Yalkaparidon (Yalkaparidontidae; Yalkaparidontia; ?Australidelphia; Marsupialia)|url=http://link.springer.com/10.1007/s10914-013-9236-3|journal=Journal of Mammalian Evolution|language=en|volume=21|issue=2|pages=127–172|doi=10.1007/s10914-013-9236-3|s2cid=18490996|issn=1064-7554}}</ref>


==References==
==References==
{{reflist}}
{{Reflist}}

*[http://www.fmnh.helsinki.fi/users/haaramo/Metazoa/Deuterostoma/Chordata/Synapsida/Metatheria/Notometatheria/Australidelphia.htm#Diprotodontia Mikko's Phylogeny Archive - Australidelphia - Australian marsupials]
==External links==
==External links==
*[http://www.lostkingdoms.com/facts/factsheet21.htm Yalkaparidon coheni from the lost kingdoms.com.]
*[http://www.lostkingdoms.com/facts/factsheet21.htm Yalkaparidon coheni from the lost kingdoms.com]
*[https://web.archive.org/web/20070827000052/http://www.fmnh.helsinki.fi/users/haaramo/Metazoa/Deuterostoma/Chordata/Synapsida/Metatheria/Notometatheria/australidelphia.htm#Diprotodontia Mikko's Phylogeny Archive - Australidelphia - Australian marsupials]

{{Taxonbar|from1=Q142875|from2=Q12902672|from3=Q19776311}}


[[Category:Prehistoric mammals of Australia]]
[[Category:Prehistoric marsupial genera]]
[[Category:Prehistoric marsupials]]
[[Category:Oligocene mammals of Australia]]
[[Category:Miocene mammals of Australia]]
[[Category:Riversleigh fauna]]
[[Category:Fossil taxa described in 1988]]

Latest revision as of 09:41, 13 September 2024

Yalkaparidon
Temporal range: Oligocene - Miocene
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Infraclass: Marsupialia
Order: Yalkaparidontia
Archer, Hand & Godthelp, 1988
Family: Yalkaparidontidae
Archer, Hand & Godthelp, 1988
Genus: Yalkaparidon
Archer, Hand & Godthelp, 1988
Species
  • Yalkaparidon coheni
  • Yalkaparidon jonesi

Yalkaparidon is an extinct genus of Australian marsupials, first described in 1988 and known only from the Oligo-Miocene deposits of Riversleigh, northwestern Queensland, Australia.[1]

Species

[edit]

Two species, Y. coheni and Y. jonesi, have so far been described. Numerous isolated teeth and jaw bones of Yalkaparidon are known, but only a single skull (of Y. coheni) has so far been recovered.

Etymology

[edit]

The generic name Yalkaparidon comes from an aboriginal word for boomerang, alluding to the boomerang-like shape of its molars when seen in occlusal view, and the Greek word for tooth.

Characteristics and classification

[edit]

These specimens of Yalkaparidon exhibit a melange of characters: the molars are zalambdodont (a distinctive tooth type also found in the marsupial mole Notoryctes, the living placental 'insectivores' Solenodon, tenrecs and golden moles, as well as a number of fossil groups); the incisors are very large and hypselodont (open-rooted and hence ever-growing, similar to those of rodents); the basicranial region of the only known skull is very primitive, somewhat similar to those of plesiomorphic bandicoots. The zalambdodont molars appear to link it to notoryctid marsupial moles, but detailed study of the teeth of these two groups suggests that they have evolved independently, and Yalkaparidon is anatomically otherwise very different from the marsupial moles. The incisors resemble those of diprotodontians, but no other features convincingly support this relationship, and the convergent evolution of such incisors in South American 'pseudodiprotodont' groups (such as caenolestids and polydolopimorphians) suggests that Yalkaparidon and diprotodontians may have evolved similar incisors independently. Basicranial similarities to bandicoots most likely represent shared plesiomorphic characters, and hence are not indicative of a close relationship.

For these reasons, Yalkaparidon is currently placed in its own family, Yalkaparidontidae, and order, Yalkaparidontia; this placement would make this the only order of Australian marsupials known to have gone extinct. However, Frederick Szalay suggested in his 1994 book 'Evolutionary History of the Marsupials and an Analysis of Osteological Characters' that Yalkaparidon is indeed a diprotodontian (as evinced by its incisors), albeit one that retains a highly primitive basicranium.

The exact function of its unusual dentition remains obscure, and suggestions that it may have fed on worms (based on the similarities of its molars to those of worm-eating tenrecs), caterpillars or eggs are tenuous. However, its source of food presumably had a hard outer covering (necessitating use of the large incisors) but relatively soft interior, as zalambdodont molars cannot crush food items. The possibility that it was a "mammalian woodpecker" similar to the aye-aye and striped possum has been raised.[2]

Morphology

[edit]

A detailed study on its morphology, including newly referred tarsal material published in 2014 found that it was likely a crown group marsupial, and probably an australidelphian, but its unusual morphology made its precise placement uncertain.[3]

References

[edit]
  1. ^ Archer M; Hand, Suzanne J. & Godthelp H. [1991] 2000. Australia's lost world: Riversleigh, World Heritage Site. Reed, Sydney. p94 "Thingodonta: off the scale of the unexpected".
  2. ^ Beck, R. M. D. (2009). "Was the Oligo-Miocene Australian metatherian Yalkaparidon a 'mammalian woodpecker'?". Biological Journal of the Linnean Society. 97. The Linnean Society of London: 1–17. doi:10.1111/j.1095-8312.2009.01171.x.
  3. ^ Beck, Robin M. D.; Travouillon, Kenny J.; Aplin, Ken P.; Godthelp, Henk; Archer, Michael (June 2014). "The Osteology and Systematics of the Enigmatic Australian Oligo-Miocene Metatherian Yalkaparidon (Yalkaparidontidae; Yalkaparidontia; ?Australidelphia; Marsupialia)". Journal of Mammalian Evolution. 21 (2): 127–172. doi:10.1007/s10914-013-9236-3. ISSN 1064-7554. S2CID 18490996.
[edit]