Marsupial moles, the Notoryctidae , are highly specialized marsupial mammals, known from two species found at the Australian interior. * ''

Notoryctes typhlops The southern marsupial mole (''Notoryctes typhlops''), also known as the itjaritjari () or itjari-itjari, is a mole-like marsupial found in the western central deserts of Australia. It is extremely adapted to a burrowing way of life. It has larg ...

'' (southern marsupial mole, known as the ''itjaritjari'' by the

Pitjantjatjara The Pitjantjatjara (; or ) are an Aboriginal people of the Central Australian desert near Uluru. They are closely related to the Yankunytjatjara and Ngaanyatjarra and their languages are, to a large extent, mutually intelligible (all are vari ...

and

Yankunytjatjara The Yankunytjatjara people, also written Yankuntjatjarra, Jangkundjara, and other variants, are an Aboriginal Australian people of the state of South Australia. Language Yankunytjatjara is a Western Desert language belonging to the Wati la ...

people in Central Australia). * ''

Notoryctes caurinus The northern marsupial mole or kakarratul (''Notoryctes caurinus'') is a marsupial in the family Notoryctidae, an endemic animal of arid regions of Central Australia. It lives in the loose sand of dunes and river plains in the desert, spending n ...

'' (northern marsupial mole, also known as the ''kakarratul'') Notoryctids are small,

fossorial A fossorial () animal is one adapted to digging which lives primarily, but not solely, underground. Some examples are badgers, naked mole-rats, clams, meerkats, and mole salamanders, as well as many beetles, wasps, and bees. Prehistoric evid ...

mammals that anatomically converge on other fossorial (and distantly related) mammals, such as living golden moles (

Chrysochloridae Golden moles are small insectivorous burrowing mammals endemic to Sub-Saharan Africa. They comprise the family Chrysochloridae and as such they are taxonomically distinct from the true moles, family Talpidae, and other mole-like families, all ...

) and extinct epoicotheres (

Pholidota Pangolins, sometimes known as scaly anteaters, are mammals of the order Pholidota (, from Ancient Greek ϕολιδωτός – "clad in scales"). The one extant family, the Manidae, has three genera: ''Manis'', ''Phataginus'', and ''Smutsia'' ...

Characteristics

In an example of

convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...

, notoryctids resemble (and fill the

ecological niche In ecology, a niche is the match of a species to a specific environmental condition. Three variants of ecological niche are described by It describes how an organism or population responds to the distribution of resources and competitors (for ...

of)

moles Moles can refer to: * Moles de Xert, a mountain range in the Baix Maestrat comarca, Valencian Community, Spain *The Moles (Australian band) *The Moles, alter ego of Scottish band Simon Dupree and the Big Sound People * Abraham Moles, French engin ...

from North America and Eurasia and

golden mole Golden moles are small insectivorous burrowing mammals endemic to Sub-Saharan Africa. They comprise the family Chrysochloridae and as such they are taxonomically distinct from the true moles, family Talpidae, and other mole-like families, all ...

s 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. 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 Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. Assessment of the vestigiality must generally rely on co ...

lenses under the skin which 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 long, weigh , 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

teat A teat is the projection from the mammary glands of mammals from which milk flows or is ejected for the purpose of feeding young. In many mammals the teat projects from the udder. The number of teats varies by mammalian species and often corr ...

s, so the animal cannot support more than two young at a time. 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.,

armadillo Armadillos (meaning "little armored ones" in Spanish) are New World placental mammals in the order Cingulata. The Chlamyphoridae and Dasypodidae are the only surviving families in the order, which is part of the superorder Xenarthra, alo ...

s), the last five cervical

vertebra The spinal column, a defining synapomorphy shared by nearly all vertebrates, Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristi ...

e are fused to give the head greater rigidity during digging. The animal swims through the soil and doesn't leave behind any 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 . The upper molar teeth are triangular and zalambdodont, i.e., resembling an inverted Greek letter

lambda Lambda (}, ''lám(b)da'') is the 11th letter of the Greek alphabet, representing the voiced alveolar lateral approximant . In the system of Greek numerals, lambda has a value of 30. Lambda is derived from the Phoenician Lamed . Lambda gave ri ...

in occlusal view, and the lower molars appear to have lost their talonid basins.

Fossil record

Notoryctids are represented by early

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

fossils of ''

Naraboryctes ''Naraboryctes philcreaseri'' is a fossil species of marsupial found at early Miocene deposits of Boodjamulla National Park of Riversleigh area, northwestern Queensland, Australia. Taxonomy It was first named by Michael Archer, Robin Beck, ...

'' from Riversleigh in Queensland, Australia, which document the

mosaic A mosaic is a pattern or image made of small regular or irregular pieces of colored stone, glass or ceramic, held in place by plaster/mortar, and covering a surface. Mosaics are often used as floor and wall decoration, and were particularly pop ...

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''. Regarding the number of teeth in each dental quadrant (or

dental formula Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiolog ...

Archer et al. (2011)
reported that "the dental formula for species of ''Notoryctes'' is controversial because of considerable polymorphism in tooth number, both between specimens and within the same specimen." Nonetheless, reflecting the consensus of older studies
Archer et al. (2011)
report the presence of four molars (typical for marsupials) in each quadrant both in living ''Notoryctes'' and the fossil notoryctid ''Naraboryctes''.

Evolutionary affinities

American paleontologist William King Gregorybr>wrote in 1910 (p. 209)
that "''Notoryctes'' is a true marsupial" and this view has been repeatedly verified by phylogenetic analyses of comparative anatomy,

mitochondrial DNA Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial D ...

, nuclear DNA, rare genomic events, and combined datasets of nuclear and mitochondrial DNA and morphology and DNA. The largest phylogenetic datasets strongly support the placement of ''Notoryctes'' as the sister taxon to a dasyuromorph- peramelian clade, within the

Australidelphia Australidelphia is the superorder that contains roughly three-quarters of all marsupials, including all those native to Australasia and a single species — the monito del monte — from South America. All other American marsupials are members o ...

n radiation.Mitchell KJ, Pratt RC, Watson LN, Gibb GC, Llamas B, Kasper M, Edson J, Hopwood B, Male D, Armstrong KN, Meyer M. Molecular phylogeny, biogeography, and habitat preference evolution of marsupials. Molecular biology and evolution. 2014 Sep 1;31(9):2322-30.

References

University of Western Australia marsupial mole home page

(includes photo)

(includes photo)

* Archer, Hand & Godthelp, ''Australia's lost world: Riversleigh, World Heritage Site'', Reed New Holland, 1991.
External links

*ARKive
images and movies of the marsupial mole ''(Notoryctes typhlops)''
*Australian Geographic
Mole Notoryctidae
Mammals of Western Australia Extant Burdigalian first appearances