''Gunggamarandu'' (meaning "river boss" in Barunggam and

Wakka Wakka Wakka Wakka, or Waka Waka, people are an Aboriginal Australian community of the state of Queensland. Name "''Wakka''" was assigned the meaning "no" by Western linguists who documented the Wakawaka language. Ethnonyms based on the duplication of ...

) is 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 ...

monospecific In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

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 ...

tomistomine Tomistominae is a subfamily of crocodylians that includes one living species, the false gharial. Many more extinct species are known, extending the range of the subfamily back to the Eocene epoch. In contrast to the false gharial, which is a fr ...

crocodilia Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period ( Cenomanian stage) and are the closest living ...

n from

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Pleistocene 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 ...

aged deposits in the

Darling Downs The Darling Downs is a farming region on the western slopes of the Great Dividing Range in southern Queensland, Australia. The Downs are to the west of South East Queensland and are one of the major regions of Queensland. The name was generall ...

(possibly the Riversleigh

lagerstätte A Lagerstätte (, from ''Lager'' 'storage, lair' '' Stätte'' 'place'; plural ''Lagerstätten'') is a sedimentary deposit that exhibits extraordinary fossils with exceptional preservation—sometimes including preserved soft tissues. These for ...

) of

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

. ''Gunggamarandu'' represents the first tomistomine known from

Oceania Oceania (, , ) is a region, geographical region that includes Australasia, Melanesia, Micronesia, and Polynesia. Spanning the Eastern Hemisphere, Eastern and Western Hemisphere, Western hemispheres, Oceania is estimated to have a land area of ...

and it is also the southernmost known tomistomine to date. The type, and only known, species is ''Gunggamarandu maunala'' (meaning "head hole", after the Barunggam words for such), which was described by Jorgo Ristevski ''et al.'' in 2021.

Discovery and naming

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 ...

of ''Gunggamarandu'', QMF14.548 (a partial cranium), was discovered no later than the 1870s, probably around 1875, and it was part of the "old collection" at the

Queensland Museum The Queensland Museum is the state museum of Queensland, dedicated to natural history, cultural heritage, science and human achievement. The museum currently operates from its headquarters and general museum in South Brisbane with specialist mu ...

Brisbane Brisbane ( ) is the capital and most populous city of the states and territories of Australia, Australian state of Queensland, and the list of cities in Australia by population, third-most populous city in Australia and Oceania, with a populati ...

and QMF14.548 was later accessioned into the Queensland Museum collection on January 8, 1914. In 1995, Salisbury ''et al.'' suggested that QMF14.548 may have been a

gavialoid Gavialoidea is one of three superfamilies of crocodylians, the other two being Alligatoroidea and Crocodyloidea. Although many extinct species are known, only the gharial ''Gavialis gangeticus'' and the false gharial ''Tomistoma schlegelii'' are ...

.Salisbury, S. W., Molnar, R. E. & Willis, P. M. (1995) A. Fossil gavial from the Pleistocene of Darling Downs, southeastern Queensland. ''Wellington Caves Quaternary Symposium'' QMF14.548 was formally described in 2021 by Jorgo Ristevski ''et al.'' and it was named ''Gunggamarandu maunala''. It was found in a layer of rock in the

in Australia, which dates to the

ages, sometime around 5-2 million years ago. The western Darling Downs is predominantly Pliocene, while the rest is mainly Pleistocene, but since it is unknown exactly where in the Darling Downs the holotype of ''Gunggamarandu'' was discovered, its exact age is unknown.

Description

Upon describing ''Gunggamarandu'', Ristevski ''et al.'' (2021) stated that ''Gunggamarandu'' was a large-sized animal. No size estimates were given, but they did estimate that the skull would have been at least when complete. Some sources outside of Ristevski ''et al.'' (2021) estimate that ''Gunggamarandu'' may have grown up to long when fully grown.

Classification

Salisbury ''et al.'' (1995) classified the then unnamed ''Gunggamarandu'' as a possible

, while Ristevski ''et al.'' (2021), who formally named and described the animal, placed ''Gunggamarandu'' into the

Tomistominae Tomistominae is a subfamily of crocodylians that includes one living species, the false gharial. Many more extinct species are known, extending the range of the subfamily back to the Eocene epoch. In contrast to the false gharial, which is a fre ...

as the

sister taxon In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and t ...

to ''

Dollosuchoides ''Dollosuchoides'', colloquially known as the Crocodile of Maransart, is an extinct monospecific genus of gavialoid crocodilian, traditionally regarded as a member of the subfamily Tomistominae. Fossils have been found in the Brussel Formation o ...

'', although its precise position in the group is uncertain due to the scant nature of the holotype. The authors also found ''Gunggamarandu'' morphologically distinct from all other known Australian

crocodylia Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period (Cenomanian stage) and are the closest living ...

ns, thus by default making ''Gunggamarandu'' not referable to

Mekosuchinae Mekosuchinae is an extinct clade of crocodilians from the Cenozoic of Australasia. They first appear in the fossil record in the Eocene in Australia, and survived until the arrival of humans: in the Pleistocene in Australia and within the Holocene ...

or even closely related to ''

Crocodylus ''Crocodylus'' is a genus of true crocodiles in the family Crocodylidae. Taxonomy The generic name, ''Crocodylus'', was proposed by Josephus Nicolaus Laurenti in 1768. ''Crocodylus'' contains 13–14 extant (living) species and 5 extinct species ...

''. The results of the analysis can be shown in the

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to d ...

below:

Paleoecology

In the

, where the holotype was discovered, ''Gunggamarandu'' would have shared its habitat with a number of species, such as: several species of

bandicoot Bandicoots are a group of more than 20 species of small to medium-sized, terrestrial, largely nocturnal marsupial omnivores in the order Peramelemorphia. They are endemic to the Australia–New Guinea region, including the Bismarck Archipelago t ...

s (

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 ...

), the

marsupial Marsupials are any members of the mammalian infraclass Marsupialia. All extant marsupials are endemic to Australasia, Wallacea and the Americas. A distinctive characteristic common to most of these species is that the young are carried in a po ...

s ''

Diprotodon ''Diprotodon'' (Ancient Greek: "two protruding front teeth") is an extinct genus of marsupial from the Pleistocene of Australia, containing one species, ''D. optatum''. The earliest finds date to 1.77 million to 780,000 years ago, but most speci ...

'', ''

Euryzygoma ''Euryzygoma'' is an extinct genus of marsupial which inhabited humid eucalyptus forests in Queensland and New South Wales during the Pliocene of Australia. ''Euryzygoma'' is believed to have weighed around 500 kg, and differed from other ...

'', ''

Palorchestes ''Palorchestes'' ("ancient leaper or dancer") is an extinct genus of terrestrial animal, terrestrial, herbivorous marsupials of the family (biology), family Palorchestidae. The genus was endemic to Australia, living from the Miocene through to th ...

'' and ''

Thylacoleo ''Thylacoleo'' ("pouch lion") is an extinct genus of carnivorous marsupials that lived in Australia from the late Pliocene to the late Pleistocene (2 million to 46 thousand years ago). Some of these marsupial lions were the largest mammalian pred ...

'', and it may have competed in the same, or a similar

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 ...

, to the

mekosuchine Mekosuchinae is an extinct clade of Crocodilia, crocodilians from the Cenozoic of Australasia. They first appear in the fossil record in the Eocene in Australia, and survived until the arrival of humans: in the Pleistocene in Australia and within ...

crocodylian Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period (Cenomanian stage) and are the closest living re ...

Paludirex ''Paludirex'' (meaning "swamp king") is an Extinction (biology), extinct genus of mekosuchinae, mekosuchine crocodylians from the Pliocene and Pleistocene of Australia. Remains of this animal have been found in the Australian Fossil Mammal Sites ...

'' and possibly also an unnamed species of ziphodont crocodile, which was the second found in the area in 150 years since around 1860.

References

{{Taxonbar, from=Q107268641, from2=Q112828639 Gavialidae Reptiles described in 2021 Fossil taxa described in 2021 Extinct animals of Australia Crocodiles of Australia Prehistoric pseudosuchian genera Pleistocene crocodylomorphs