genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
in the family Tachyglossidae. It contains a single species, ''Murrayglossus hacketti'', the giant echidna, an
extinct
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
of
echidna
Echidnas (), sometimes known as spiny anteaters, are quill-covered monotremes (egg-laying mammals) belonging to the family Tachyglossidae . The four extant species of echidnas and the platypus are the only living mammals that lay eggs and the ...
from
Western Australia
Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...
that is dated to the
Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...
. It is known only from a few bones. It was about long and probably weighed about 30 kg (66 lb). This makes it the largest monotreme known to have ever lived. Historically treated as a species of
long-beaked echidna
The long-beaked echidnas (genus ''Zaglossus'') make up one of the two extant genera of echidnas, spiny monotremes that live in New Guinea; the other being the short-beaked echidna. There are three living species and one extinct species in this ge ...
s, it was separated into its own genus ''Murrayglossus'' in 2022. The generic name combines the last name of paleontologist Peter Murray and ''glossus'', the Greek word for "tongue".
Description
At around long, tall and about , ''M. hacketti'' was the largest monotreme known to have existed. ''M. hacketti'' had longer, straighter legs than any of the modern echidnas. Augee (2006) speculates that this feature made the animal more adept at traversing through thickly wooded forests. The main diagnostic characteristics of genus ''Murrayglossus'' are a set of femoral traits: a low femoral head; the very low position of the
lesser trochanter
The lesser trochanter is a conical posteromedial bony projection of the femoral shaft. it serves as the principal insertion site of the iliopsoas muscle.
Structure
The lesser trochanter is a conical posteromedial projection of the shaft of the fe ...
relative to head (situated directly below the internal margin of the femur); the large
trochanter
A trochanter is a tubercle of the femur near its joint with the hip bone. In humans and most mammals, the trochanters serve as important muscle attachment sites. Humans are known to have three trochanters, though the anatomic "normal" includes ...
that has a high position relative to the head; a flared medial epicondyle; and obliquely oriented
Fossils of ''Murrayglossus hacketti'' were discovered in
Mammoth Cave
Mammoth Cave National Park is an American national park in west-central Kentucky, encompassing portions of Mammoth Cave, the longest cave system known in the world.
Since the 1972 unification of Mammoth Cave with the even-longer system under F ...
,
Western Australia
Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...
, and excavated in 1909. They were found mixed with the remains of other taxa such as '' Sthenurus'' and ''
Macropus
''Macropus'' is a marsupial genus in the family Macropodidae. It has two extant species of large terrestrial kangaroos. The term is derived from the Ancient Greek μάκρος, ''makros'' "long" and πους, ''pous'' "foot". Thirteen known ext ...
''. Australian paleontologist
Ludwig Glauert
Ludwig Glauert MBE (5 May 1879 – 1 February 1963) was a British-born Australian paleontologist, herpetologist and museum curator. He is known for work on Pleistocene mammal fossils, and as a museum curator who played an important role in na ...
described the fossils in a 1914 publication. The specific epithet ''hacketti'' honours
John Winthrop Hackett
Sir John Winthrop Hackett Sr. (4 February 184819 February 1916), generally known as "Winthrop Hackett", was a proprietor and editor of several newspapers in Western Australia, a politician and a university chancellor.
Early life
Hackett was b ...
, "as a slight acknowledgement of his generous support which alone rendered the exploration of these caves possible.". The material is poor, mostly
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 ...
and leg bones, and the cranial material is completely absent, making ''M. hackettis historical classification into the genus ''Zaglossus'' uncertain. Some of the fossils have incisions and burn marks, suggesting that ''M. hacketti'' was at least occasionally hunted by humans.
Aboriginal rock art found in Arnhem Land in the
Northern Territory
The Northern Territory (commonly abbreviated as NT; formally the Northern Territory of Australia) is an states and territories of Australia, Australian territory in the central and central northern regions of Australia. The Northern Territory ...
may represent ''M. hacketti'' or the extant
western long-beaked echidna
The western long-beaked echidna (''Zaglossus bruijnii'') is one of the four extant echidnas and one of three species of '' Zaglossus'' that occurs in New Guinea. Originally described as ''Tachyglossus bruijnii'', this is the type species of ''Zag ...