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

Wakka Wakka Wakka Wakka, or Waka Waka, people are an Aboriginal Australian people 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 t ...

) is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce 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 "unispe ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of tomistomine

crocodilia Crocodilia () is an order of semiaquatic, predatory reptiles that are known as crocodilians. They first appeared during the Late Cretaceous and are the closest living relatives of birds. Crocodilians are a type of crocodylomorph pseudosuchia ...

n from

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

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 generally ...

(possibly the Riversleigh

lagerstätte A Fossil-Lagerstätte (, from ''Lager'' 'storage, lair' '' Stätte'' 'place'; plural ''Lagerstätten'') is a sedimentary deposit that preserves an exceptionally high amount of palaeontological information. ''Konzentrat-Lagerstätten'' preserv ...

) of

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

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

Oceania Oceania ( , ) is a region, geographical region including Australasia, Melanesia, Micronesia, and Polynesia. Outside of the English-speaking world, Oceania is generally considered a continent, while Mainland Australia is regarded as its co ...

and it is also the southernmost known tomistomine to date. The

type Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type, collection of values used for computations. * File type * TYPE (DOS command), a command to display contents of a file. * ...

, 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 (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

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 Kurilpa is the state museum of Queensland, funded by the government, and dedicated to natural history, cultural heritage, science and human achievement. The museum currently operates from its headquarters and general museu ...

Brisbane Brisbane ( ; ) is the List of Australian capital cities, capital and largest city of the States and territories of Australia, state of Queensland and the list of cities in Australia by population, third-most populous city in Australia, with a ...

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 fres ...

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 ...

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 Brussels Formatio ...

'', 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 () is an Order (biology), order of semiaquatic, predatory reptiles that are known as crocodilians. They first appeared during the Late Cretaceous and are the closest living relatives of birds. Crocodilians are a type of crocodylomorp ...

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

Mekosuchinae Mekosuchinae is an extinct clade of crocodilians from the Cenozoic of Australasia. They represented the dominant group of crocodilians in the region during most of the Cenozoic, first appearing in the fossil record in the Eocene of Australia, and ...

or even closely related to ''

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

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

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

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 Archipela ...

s (

Peramelidae The marsupial family Peramelidae contains 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 described. O ...

), the

marsupial Marsupials are a diverse group of mammals belonging to the infraclass Marsupialia. They are natively found in Australasia, Wallacea, and the Americas. One of marsupials' unique features is their reproductive strategy: the young are born in a r ...

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 Australia, officially the Commonwealth of Australia, is a country comprising ma ...

'', ''

Palorchestes ''Palorchestes'' ("ancient leaper") is an extinct genus of large terrestrial, herbivorous Australian marsupial of the family Palorchestidae, living from the Miocene through to the Late Pleistocene. Like other palorchestids, it had highly retract ...

'' and ''

Thylacoleo ''Thylacoleo'' ("pouch lion") is an extinct genus of carnivorous marsupials that lived in Australia from the late Pliocene to the Late Pleistocene (until around 40,000 years ago), often known as marsupial lions. They were the largest and last mem ...

'', 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 Resource (biology), resources an ...

, to the

mekosuchine Mekosuchinae is an extinct clade of crocodilians from the Cenozoic of Australasia. They represented the dominant group of crocodilians in the region during most of the Cenozoic, first appearing in the fossil record in the Eocene of Australia, and ...

crocodylian Crocodilia () is an order of semiaquatic, predatory reptiles that are known as crocodilians. They first appeared during the Late Cretaceous and are the closest living relatives of birds. Crocodilians are a type of crocodylomorph pseudosuchian ...

Paludirex ''Paludirex'' (meaning "swamp king") is an extinct genus of mekosuchine crocodylian from the Pliocene and Pleistocene of Australia. A large and robust semi-aquatic ambush hunter capable of attaining lengths of up to , it was likely the top predat ...

'' 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