''Liyamayi dayi'' is a mammal species of the

Thylacomyidae ''Macrotis'' is a genus of desert-dwelling marsupial omnivores known as bilbies or rabbit-bandicoots; Unabridged they are members of the order Peramelemorphia. At the time of European colonisation of Australia, there were two species. The ...

family known from fossils located at the Riversleigh World Heritage Area in northeast Australia. The discovery of the specimens was identified as deposited around fifteen million years ago, revising the earliest record of this peramelemorphian lineage from those of species that existed around ten million years later.

Taxonomy

A fossil species assigned to a new genus, ''Liyamayi'', in a description by researchers at the Riversleigh fossil area, K. J. Travouillon, S. J. Hand , M. Archer and K. H. Black, who identified distinctions in the dentition from other named genera, for a new species of Riversleigh fauna was published in 2014, the authors proposing the specific epithet for Robert Day in gratitude for support toward the research project. The gender of the genus name ''Liyamayi'' is stated to be masculine, and combines two terms from the Waanyi language, spoken by peoples of the Riversleigh region, ''liya'' and ''mayi'', in reference to the "round tooth" that distinguishes the genus.

Description

A genus known by a single species, ''Liyamayi dayi'' is recognised as an early representative of a thylacomyid lineage that is separated from the

Chaeropodidae ''Chaeropus'', known as the pig-footed bandicoots, is a genus of small mammals that became extinct during the 20th century. They were unique marsupials, of the order Peramelemorphia (bandicoots and bilbies), with unusually thin legs, yet were abl ...

, a family represented by the modern pig-footed bandicoots ''

Chaeropus ''Chaeropus'', known as the pig-footed bandicoots, is a genus of small mammals that became extinct during the 20th century. They were unique marsupials, of the order Peramelemorphia (bandicoots and bilbies), with unusually thin legs, yet were ab ...

'', and the

Peramelidae The marsupial family Peramelidae contains all of the extant bandicoots. They are found throughout Australia and New Guinea, with at least some species living in every available habitat, from rainforest to desert. Four fossil peramelids are descri ...

family of extant bandicooots. The estimates of body mass are from around 650 grams to less than one kilogram. The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

and only known specimen is a section of the animal's right maxillary with remaining evidence of intact molars M1–M3 and

alveoli Alveolus (; pl. alveoli, adj. alveolar) is a general anatomical term for a concave cavity or pit. Uses in anatomy and zoology * Pulmonary alveolus, an air sac in the lungs ** Alveolar cell or pneumocyte ** Alveolar duct ** Alveolar macrophage * ...

of the fourth molar.

Distribution and habitat

The distribution of ''Liyamayi dayi'' is restricted to Riversleigh, an area rich in series of well preserved fossil mammals. The only known location of specimens is Rick's Sausage Site at Riversleigh, a poorly studied site which is probably middle Miocene, Riversleigh Faunal Zone C approximately 15

mya Mya may refer to: Brands and product names * Mya (program), an intelligent personal assistant created by Motorola * Mya (TV channel), an Italian Television channel * Midwest Young Artists, a comprehensive youth music program Codes * Burmese ...

, at that time part of the wet rainforest that dominated the Riversleigh area. The fauna discovered at the same site support the evidence of a local wet rainforest environment. Finding evidence of the lineage, known from other sites and thought to have diversified in other regions, implies they were establishing themselves in the region as the local ecology responded to a drier climate.

References

{{taxobar, from=Q66001997, from2=Q66002153 Riversleigh fauna Peramelemorphs Mammals described in 2014 Prehistoric marsupial genera Fossil taxa described in 2014