Notoryctes the marsupial mole

Wikipedia reports, “Marsupial moles are a family (Notoryctidae) of cladotherian mammals of the order Notoryctemorphia. They are rare and poorly understood. Once classified as monotremes, they are now thought to be marsupials. Their precise classification was for long a matter for argument.”

Earlier we looked at other mammal moles.

1. Eastern mole – Talpa  (Carnivora, Placentalia)
2. Docofossor (basal Metatheria, Marsupialia)
3. Golden mole – Chrysochloris (Glires, Placentalia)

And some reptilian ‘moles’.

1. Mexican mole lizard – Bipes (Scincomorpha, Squamata)
2. Mermaid skink – Sirenoscincus mobydick (Scincomorpha, Squamata)
3. Texas blind snake – Leptotyphlops dulcis (Serpentes, Squamata)

Today we’ll round out this topic
with the extant marsupial mole (Notoryctes; Stirling 1888, 1891;  Figs. 1-3; 12-16 cm long) which nests with Anebodon at the base of the Marsupialia in the large reptile tree. The two-teat pouch opens backwards to keep dirt out.

Figure 1. Notoryctes skeleton. The hind limbs were not included so the femur and tibia + fibula are added here.

We see burrowing synapsids
all the way back to Thrinaxodon, but moles spend all their time underground.

FIgure 2. Notoryctes in vivo.

Notoryctes typhlops (Stirling 1891; extant; up to 16 cm in length) is the marsupial mole.  This taxon is blind with eyes reduced to vestigial lenses and without external ears. Three molars are present. Several neck vertebrae are fused, as are the sacrals. The tail verts are quite robust, especially for a mole. Tiny epipubes are present. A cloaca is present, a trait otherwise seen in monotremes and tenrecs. The forelimb has transformed to support the two large digging claws.

Figure 3. Notoryctes skull from copyright Digimorph.org, used with permission. Colors added. Although the orbit portion of the confluent lateral temporal fenestra, the eyeball is small and blind.

The claws of the third and fourth digits
are enormous. The canine (orange, Fig. 1) is considered by some as a 4th upper and 3rd lower incisor.

Figure 4. Anebodon luoi subjected to DGS tracing and phylogenetic analysis nests with Notoryctes, the marsupial mole.

 

References
Bi S-D, heng X-T, Meng J, Wang X-L, Robinson N and Davis B 2016. A new symmetrodont mammal (Trechnotheria: Zhangheotheriidae) from the Early Cretaceous of China and trechnotherian character evolution. Nature Scientific Reports 6:26668 DOI: 10.1038/srep26668
Gadow H 1892. On the systematic position of Notoryctes typhlops. Proc. Zool. Soc. London 1892, 361–370.
Stirling EC 1888. Transactions of the Royal Society, South Australia 1888:21
Stirling EC 1891. Transactions of the Royal Society, South Australia 1891:154

wiki/Notoryctes