The dwarf flathead gudgeon (''Philypnodon macrostomus'') is a

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 sleeper goby

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to eastern

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 ...

Taxonomy

The existence of a second smaller species related to the flathead gudgeon (''

Philypnodon grandiceps The flathead gudgeon (''Philypnodon grandiceps'') is a species of fish in the family Eleotridae endemic to eastern Australia. Taxonomy Gerard Krefft described the flathead gudgeon in 1864 as ''Eleotris grandiceps'', recording it from the Upper ...

'') had been strongly suspected since 1980. ''P. macrostomus'' was described in 2006 by

Douglass Fielding Hoese Douglass may refer to: Surname * Douglass (surname) * Douglass family, family of Frederick Douglass ** Frederick Douglass (1818–1895), noted abolitionist Given name *Douglass Dumbrille (1889–1974), Canadian actor in early Hollywood *Douglas ...

and Sally Reader; the type specimen was collected in

Glenreagh, New South Wales Glenreagh is a small town in the Clarence Valley in the Northern Rivers region of north-eastern New South Wales, Australia. At the 2016 census, Glenreagh had a population of 900 people. It is on the North Coast railway line, completed to Gl ...

. Its species name derived from the

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic peri ...

''makro'' "large" and ''stoma'' "mouth". Genetic analysis of the species from the different river drainages across its range showed that populations from the

Lang Lang River The Lang Lang River is a perennial river of the Western Port catchment, located in the West Gippsland region of the Australian state of Victoria. Location and features The Lang Lang River rises in the Strzelecki Ranges in the East Poowong vall ...

in Victoria had diverged much earlier and most likely represent a separate, as yet undescribed species.

Description

Predominantly dark brown, the dwarf flathead gudgeon has paler brown or orange belly and reaches in length, though more regularly is around . It has dark brown lips. It can be distinguished from the flathead gudgeon, which is larger, has a wider gill opening, and has vertical stripes on the sides of the belly.

Distribution and habitat

The dwarf flathead gudgeon is found in estuaries and freshwater rivers from

Baffle Creek The Baffle Creek is a creek in Central Queensland, Australia. Course and features The Baffle Creek rises near Arthurs Seat in the Eurimbula State Forest and just south of the Eurimbula National Park in the Great Dividing Range. The creek fl ...

in central Queensland through New South Wales and eastern Victoria to

Wilsons Promontory Wilsons Promontory, is a peninsula that forms the southernmost part of the Australian mainland, located in the state of Victoria. South Point at is the southernmost tip of Wilsons Promontory and hence of mainland Australia. Located at nearb ...

. Inland the range extends westward along the

Murray River The Murray River (in South Australia: River Murray) (Ngarrindjeri: ''Millewa'', Yorta Yorta: ''Tongala'') is a river in Southeastern Australia. It is Australia's longest river at extent. Its tributaries include five of the next six longest r ...

into South Australia. In the southern parts of its range, it is more restricted to estuarine habitats, and is found further upstream in more northerly river drainages. The dwarf flathead gudgeon is commonly found alongside its larger relative, and often near some form of cover such as submerged vegetation or rocks.

Feeding

Carnivorous, the dwarf flathead gudgeon eats insects and minute crustaceans.

Breeding

The male guards the eggs after they are laid. The dwarf flathead gudgeon is mature by one year of age, though its longevity is unknown.

References

{{Taxonbar, from=Q2260751 Eleotridae Taxa named by Douglass F. Hoese Taxa named by Sally Reader Fish described in 2006