Marsupial mole

{{Automatic taxobox

| name = Marsupial moles{{MSW3 Groves|pages=22}}

| image =A hand-book to the marsupialia and monotremata (Plate XXXI) (cropped).jpg

|image_caption=Southern marsupial mole

| fossil_range = {{Fossil range|20|0}}Miocene to Recent

| taxon = Notoryctes

| authority = Stirling, 1891

| type_species = Psammoryctes typhlops

| type_species_authority = Stirling, 1889

| subdivision_ranks = Species

| subdivision =

Notoryctes typhlops Stirling, 1891

Notoryctes caurinus Thomas, 1920

| range_map = Marsupial mole distribution map.svg

| range_map_caption = Ranges of the two species

}}

Marsupial moles, the Notoryctidae {{IPAc-en|n|ou|t|@|ˈ|r|I|k|t|ᵻ|d|iː}} family, are two species of highly specialized marsupial mammals that are found in the Australian interior.Warburton N. Functional morphology and evolution of marsupial moles (Marsupialia: Notoryctemorphia). 2003. [http://researchrepository.murdoch.edu.au/13863/1/functional_morphology_of_marsupial_moles.pdf PhD Dissertation, University of Western Australia].

They are small burrowing marsupials that anatomically converge on fossorial placental mammals, such as extant golden moles (Chrysochloridae) and extinct epoicotheres. The species are:

Notoryctes typhlops (southern marsupial mole, known as the itjaritjari by the Pitjantjatjara and Yankunytjatjara people in Central Australia){{cite web | access-date = 2006-11-09 | title = Mole Patrol | year = 2004 | work = The Marsupial Society | url = http://www.marsupialsociety.org/members/mole_patrol.html | archive-url = https://web.archive.org/web/20080204172826/http://www.marsupialsociety.org/members/mole_patrol.html | archive-date = 2008-02-04 | url-status = dead }}
Notoryctes caurinus (northern marsupial mole, also known as the kakarratul)

Characteristics

In an example of convergent evolution, notoryctids resemble (and fill the ecological niche of) the talpid or true moles from North America and Eurasia and the Chrysochloridae or golden moles from Southern Africa. Like chrysochlorids and epoicotheres, notoryctids use their forelimbs and enlarged central claws to dig in a parasagittal (i.e., up and down) plane, as opposed to the "lateral scratch" style of digging that characterizes talpid moles.{{cite journal |author=Yalden, D.W. |title=The anatomy of mole locomotion |journal=Journal of Zoology |date=1 May 1966 |volume=149 |issue=1 |pages=55–64 |df=dmy-all|doi=10.1111/j.1469-7998.1966.tb02983.x}}{{cite journal |vauthors=Rose KD, Emry RJ |title=Extraordinary fossorial adaptations in the Oligocene palaeanodonts Epoicotherium and Xenocranium (Mammalia) |journal=Journal of Morphology |date=1 Jan 1983 |volume=175 |issue=1 |pages=33–56 |df=dmy-all|doi=10.1002/jmor.1051750105 |pmid=30053775 |s2cid=51727274}}

Marsupial moles spend most of their time underground, coming to the surface only occasionally, probably mostly after rains. They are functionally blind, their eyes having become reduced to vestigial lenses under the skin that lack a pupil. They have no external ears, just a pair of tiny holes hidden under thick hair. The head is cone-shaped, with a leathery shield over the muzzle, the body is tubular, and the tail is a short, bald stub encased in leathery skin. They are between {{convert|12|and(-)|16|cm}} long, weigh {{convert|40|to(-)|60|g|oz}}, and are uniformly covered in fairly short, very fine pale cream to white hair with an iridescent golden sheen. Their pouch is small but well developed and has evolved to face backwards so it does not fill with sand. It contains just two teats, so the animal cannot support more than two young at a time. They are the only marsupials with a true cloaca.{{cite journal |last1=Gadow |first1=Hans |year=2009 |title=On the Systematic Position of Notoryctes typhlops |journal=Proceedings of the Zoological Society of London |volume=60 |issue=3 |pages=361–433 |doi=10.1111/j.1469-7998.1892.tb06835.x}}

The limbs are very short, with reduced digits. The forefeet have two greatly enlarged, spade shaped, flat claws on the third and fourth digits, which are used to excavate soil in front of the animal. The hindfeet are flattened, and bear three small claws; these feet are used to push soil behind the animal as it digs. Epipubic bones are present but small and as in some other fossorial mammals (e.g., armadillos), the last five cervical vertebrae are fused, giving the head greater rigidity during digging. The animal swims through the soil and does not leave behind a permanent burrow.

The teeth of the marsupial moles are degenerate and bear no resemblance to polyprotodont or diprotodont teeth. Their dental formula varies, but is usually somewhere near {{DentalFormula |upper=4–3.1.2.4 |lower=3.1.3.4 |total=42–44}}. The upper molar teeth are triangular and zalambdodont, i.e., resembling an inverted Greek letter lambda in occlusal view, and the lower molars appear to have lost their talonid basins.{{cite web |url=https://animaldiversity.org/accounts/Notoryctes_caurinus/ |title=Notoryctes caurinus |website=animaldiversity.org}}{{cite journal |vauthors=Asher RJ, Horovitz I, Martin T, Sanchez-Villagra MR |title=Neither a rodent nor a platypus: a reexamination of Necrolestes patagonensis Ameghino |journal=American Museum Novitates |date=15 Jan 2007 |issue=3546 |pages=1–40 |doi=10.1206/0003-0082(2007)3546[1:NARNAP]2.0.CO;2 |s2cid=83642532 |url=https://zenodo.org/record/5386468 |df=dmy-all}}{{cite book |editor=Macdonald, D. |author=Gordon, Greg |year=1984 |title=The Encyclopedia of Mammals |publisher=Facts on File |location=New York |page=[https://archive.org/details/encyclopediaofma00mals_0/page/842 842] |isbn=978-0-87196-871-5 |url-access=registration |url=https://archive.org/details/encyclopediaofma00mals_0/page/842 }} Marsupial moles are the only marsupials that are testicond.{{Cite book |last1=Vogelnest |first1=Larry |url=https://books.google.com/books?id=396VDwAAQBAJ&pg=PT143 |title=Current Therapy in Medicine of Australian Mammals |last2=Portas |first2=Timothy |date=2019-05-01 |publisher=Csiro Publishing |isbn=978-1-4863-0753-1 |language=en}}

Fossil record

Notoryctids are represented by early Miocene fossils of Naraboryctes from Riversleigh in Queensland, Australia, which show the mosaic acquisition of dental and skeletal features of the living Notoryctes from a more surface-dwelling ancestor.

The notoryctid fossil record demonstrates that the primary cusp of the molars is the metacone, distinct from the paracone characteristic of zalambdodont tenrecs, golden moles, and Solenodon.{{cite journal |last1=Asher |first1=RJ |last2=Sánchez-Villagra |first2=MR |title=Locking yourself out: diversity among dentally zalambdodont therian mammals |journal=Journal of Mammalian Evolution |year=2005 |volume=12 |issue=1 |pages=265–282|doi=10.1007/s10914-005-5725-3 }} Regarding the number of teeth in each dental quadrant (or dental formula), the fossil record demonstrates polymorphism of tooth number, both between specimens and within the same specimen. Nonetheless, older studies concluded{{cite journal |last1=Thomas |first1=O. |title=XI.—Notoryctes in North-west Australia |journal=Journal of Natural History |year=1920 |volume=6 |issue=31 |pages=111–113|doi=10.1080/00222932008632418 }} there are four molars (typical for marsupials) in each quadrant both in living Notoryctes and the fossil notoryctid Naraboryctes.

Evolutionary affinities

American paleontologist William King Gregory wrote that "Notoryctes is a true marsupial"{{cite web |year=1910 |hdl=2246/313 |url=http://digitallibrary.amnh.org/handle/2246/313 |title=The orders of mammals. Bulletin of the AMNH ; v. 27. }}{{rp|209}} and this view has been repeatedly verified by phylogenetic analyses of comparative anatomy,{{cite journal |last1=Horovitz |first1=I |last2=Sánchez-Villagra |first2=MR |title=A morphological analysis of marsupial mammal higher-level phylogenetic relationships |journal=Cladistics |year=2003 |volume=19 |issue=3 |pages=181–212}}{{cite journal |last1=Beck |first1=RM |last2=Warburton |first2=NM |last3=Archer |first3=MI |last4=Hand |first4=SJ |last5=Aplin |first5=KP |title=Going underground: postcranial morphology of the early Miocene marsupial mole Naraboryctes philcreaseri and the evolution of fossoriality in notoryctemorphians |journal=Memoirs of Museum Victoria |year=2016 |volume=74 |pages=151–171|doi=10.24199/j.mmv.2016.74.14 |doi-access=free }} mitochondrial DNA,{{cite journal |last1=Springer |first1=MS |first2=Westerman |last2=M |last3=Kavanagh |first3=JR |last4=Burk |first4=A |last5=Woodburne |first5=MO |last6=Kao |first6=DJ |last7=Krajewski |first7=C |title=The origin of the Australasian marsupial fauna and the phylogenetic affinities of the enigmatic monito del monte and marsupial mole |journal=Proceedings of the Royal Society of London B: Biological Sciences |year=1998 |volume=265 |issue=1413 |pages=2381–2386|doi=10.1098/rspb.1998.0587 |pmid=9921677 |pmc=1689543 }}{{cite journal |last1=Burk |first1=A |last2=Westerman |first2=M |last3=Kao |first3=DJ |last4=Kavanagh |first4=JR |last5=Springer |first5=MS |title=An analysis of marsupial interordinal relationships based on 12S rRNA, tRNA valine, 16S rRNA, and cytochrome b sequences |journal=Journal of Mammalian Evolution |year=1999 |volume=6 |issue=4 |pages=317–334|doi=10.1023/A:1027305910621 }}{{cite journal |last1=Kjer |first1=KM |last2=Honeycutt |first2=RL |title=Site specific rates of mitochondrial genomes and the phylogeny of eutheria |journal=BMC Evolutionary Biology |year=2007 |volume=7 |issue=1 |pages=8|doi=10.1186/1471-2148-7-8 |doi-access=free |pmid=17254354 |pmc=1796853 }} nuclear DNA,{{cite journal |last1=Amrine-Madsen |first1=H |last2=Scally |first2=M |last3=Westerman |first3=M |last4=Stanhope |first4=MJ |last5=Krajewski |first5=C |last6=Springer |first6=MS |title=Nuclear gene sequences provide evidence for the monophyly of australidelphian marsupials |journal=Molecular Phylogenetics and Evolution |year=2003 |volume=28 |issue=2 |pages=186–196|doi=10.1016/S1055-7903(03)00122-2 |pmid=12878458 }}{{cite journal |last1=Meredith |first1=RW |last2=Janečka |first2=JE |last3=Gatesy |first3=J |last4=Ryder |first4=OA |last5=Fisher |first5=CA |last6=Teeling |first6=EC |last7=Goodbla |first7=A |last8=Eizirik |first8=E |last9=Simão |first9=TL |last10=Stadler |first10=T |last11=Rabosky |first11=DL |title=Impacts of the Cretaceous Terrestrial Revolution and KPg extinction on mammal diversification |journal=Science |year=2011 |volume=334 |issue=6055 |pages=521–524|doi=10.1126/science.1211028 |pmid=21940861 }} rare genomic events,{{Cite journal | last = Nilsson | first = M. A. |author2=Churakov, G.|author3=Sommer, M.|author4=Van Tran, N.|author5=Zemann, A.|author6=Brosius, J.|author7= Schmitz, J. | title = Tracking Marsupial Evolution Using Archaic Genomic Retroposon Insertions | journal = PLOS Biology | volume = 8 | issue = 7 | pages = e1000436 | publisher = Public Library of Science | date = 2010 | doi = 10.1371/journal.pbio.1000436 | pmid=20668664 | pmc=2910653 | doi-access = free}} and combined datasets of nuclear and mitochondrial DNA{{cite journal |last1=Phillips |first1=MJ |last2=McLenachan |first2=PA |last3=Down |first3=C |last4=Gibb |first4=GC |last5=Penny |first5=D |title=Combined mitochondrial and nuclear DNA sequences resolve the interrelations of the major Australasian marsupial radiations |journal=Systematic Biology |year=2006 |volume=55 |issue=1 |pages=122–137|doi=10.1080/10635150500481614 |pmid=16507529 }} and morphology and DNA.{{cite journal |last1=Asher |first1=RJ |last2=Horovitz |first2=I |last3=Sánchez-Villagra |first3=MR |year=2004 |title=First Combined Cladistic Analysis of Marsupial Mammal Interrelationships |journal=Molecular Phylogenetics and Evolution |volume=33 |issue=1 |pages=240–250|doi=10.1016/j.ympev.2004.05.004 |pmid=15324852 }}{{cite journal |last1=Beck |first1=RM |last2=Godthelp |first2=H |last3=Weisbecker |first3=V |last4=Archer |first4=M |last5=Hand |first5=SJ |title=Australia's oldest marsupial fossils and their biogeographical implications |journal=PLOS ONE |year=2008 |volume=3 |issue=3 |pages=e1858|doi=10.1371/journal.pone.0001858 |doi-access=free |pmid=18365013 |pmc=2267999 }}{{cite journal |last1=O’Meara |first1=RN |last2=Thompson |first2=RS |title=Were there Miocene meridiolestidans? Assessing the phylogenetic placement of Necrolestes patagonensis and the presence of a 40 million year meridiolestidan ghost lineage |journal=Journal of Mammalian Evolution |year=2014 |volume=21 |issue=3 |pages=271–284|doi=10.1007/s10914-013-9252-3 }} The largest phylogenetic datasets strongly support the placement of Notoryctes as the sister taxon to a dasyuromorph-peramelian clade, within the Australidelphian radiation.{{cite journal |last1=Mitchell |first1=KJ |last2=Pratt |first2=RC |last3=Watson |first3=LN |last4=Gibb |first4=GC |last5=Llamas |first5=B |last6=Kasper |first6=M |last7=Edson |first7=J |last8=Hopwood |first8=B |last9=Male |first9=D |last10=Armstrong |first10=KN |last11=Meyer |first11=M |title=Molecular phylogeny, biogeography, and habitat preference evolution of marsupials |journal=Molecular Biology and Evolution |year=2014 |volume=31 |issue=9 |pages=2322–2330|doi=10.1093/molbev/msu176 |pmid=24881050 }}

References

{{Reflist|refs=

{{cite journal | last1 = Archer | first1 = M. | title = Australia's first fossil marsupial mole (Notoryctemorphia) resolves controversies about their evolution and palaeoenvironmental origins | journal = Proceedings of the Royal Society of London B: Biological Sciences | volume = 278 | issue = 1711 | pages = 1498–1506 | date = 2011-05-22 | doi = 10.1098/rspb.2010.1943 | pmid = 21047857 | pmc = 3081751}}

}}

External links

ARKive - [https://web.archive.org/web/20050103072957/http://www.arkive.org/species/GES/mammals/Notoryctes_typhlops/ images and movies of the marsupial mole (Notoryctes typhlops)]
Australian Geographic - [https://web.archive.org/web/20130607002640/http://www.australiangeographic.com.au/journal/the-marsupial-mole-an-enduring-enigma.htm The marsupial mole: an enduring enigma]

Category:Notoryctidae

Category:Mammals of Western Australia

Category:Extant Burdigalian first appearances

Category:Taxa named by Edward Charles Stirling