The congoli (''Pseudaphritis urvillii''), also known as the freshwater flathead, marble fish, marbled flathead, sand trout, sanding, sandy, sandy whiting or tupong. is a species of marine

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or h ...

and it is the only species of fish in the

monotypic 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 ...

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Pseudaphritidae and the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

''Pseudaphritis''. It was initially classified as a member of the family

Bovichtidae Bovichtidae, the temperate icefishes or thornfishes, is a family of marine ray-finned fishes, classified in the suborder Notothenioidei of the order Perciformes. They are native to coastal waters off Australia, New Zealand, and South America. ...

Taxonomy

The congoli was first formally described as ''Aphritis urvillii'' in 1832 by the French

zoologist Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the animal kingdom, including the structure, embryology, evolution, classification, habits, and d ...

Achille Valenciennes but the name ''Aphritis'' was a junior synonym of the Diptera genus '' Aphritis'' named by

Pierre André Latreille Pierre André Latreille (; 29 November 1762 – 6 February 1833) was a French zoologist, specialising in arthropods. Having trained as a Roman Catholic priest before the French Revolution, Latreille was imprisoned, and only regained his freedom ...

in 1805. The genus ''Pseudaphritis'' was described by the French zoologist Francis de La Porte Castelnau in 1872. The family Pseudaphritidae was first named by the Australian ichthyologist Allan Riverstone McCulloch in 1929. The Pseudaphritidae are the sister family of the

and

Eleginopidae The Patagonian blennie (''Eleginops maclovinus''), also known as the rock cod, is a species of marine ray-finned fish, belonging to the monotypic family Eleginopidae and monotypic genus ''Eleginops''. It is found in coastal and estuarine habitat ...

and these are all sister to the rest of the families in the

Notothenioidei Notothenioidei is one of 19 suborders of the order Perciformes. The group is found mainly in Antarctic and Subantarctic waters, with some species ranging north to southern Australia and southern South America. Notothenioids constitute approx ...

which have been placed in the suggested superfamily Cryonotothenioidea. Pseudaphritidae is one of two families of the suborder Notothenioidei with a primarily non-Antarctic distribution, the other being Bovichtidae. The congoli is the only species in its genus and family. The genus name ''Pseudoaphritis'' is a compound of ''pseudo'' which means “false” and ''aphritis'', a name which dates back to

Aristotle Aristotle (; grc-gre, Ἀριστοτέλης ''Aristotélēs'', ; 384–322 BC) was a Greek philosopher and polymath during the Classical period in Ancient Greece. Taught by Plato, he was the founder of the Peripatetic school of ph ...

, who used it for a type of

anchovy An anchovy is a small, common forage fish of the family Engraulidae. Most species are found in marine waters, but several will enter brackish water, and some in South America are restricted to fresh water. More than 140 species are placed in 1 ...

whitebait Whitebait is a collective term for the immature fry of fish, typically between long. Such young fish often travel together in schools along coasts, and move into estuaries and sometimes up rivers where they can be easily caught using fine- ...

. Valenciennes originally used ''Aphritis'' as the name of the genus but this name was unavailable as

Pierre Andre Latreille Pierre is a masculine given name. It is a French form of the name Peter. Pierre originally meant "rock" or "stone" in French (derived from the Greek word πέτρος (''petros'') meaning "stone, rock", via Latin "petra"). It is a translation ...

had used it for a fly genus '' Aphritis'' in 1804. Lev Berg proposed a replacement name, ''Phricus'' but this was a synonym of Castelnau's earlier ''Pseudaphritis''. the specific name honours the explorer

Jules Dumont d'Urville Jules Sébastien César Dumont d'Urville (; 23 May 1790 – 8 May 1842) was a French explorer and naval officer who explored the south and western Pacific, Australia, New Zealand, and Antarctica. As a botanist and cartographer, he gave his nam ...

, leader of the Astrolabe expedition (1826- 1829), in the course of which type was collected. Gerorges Cuvier's ''Eleginus bursinus'' is a senior synonym of ''Pseudaphritis urvillii'' but has been disregarded due to the prevailing usage of ''P. urvillii''.

Distribution and habitat

The congolli is found in fresh, brackish and marine waters around south-eastern Australia, including

Tasmania ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...

, and is

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 else ...

to Australia. It lives mostly in slow-moving waters of

estuaries An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environmen ...

, rivers and streams. Water temperatures in its habitat range from . This fish will inhabit areas with log snags, overhanging banks, and leaf litter. Between late April and August, it migrates south to estuaries and sea to breed. In 2017, congolli were recorded in five rivers on

Kangaroo Island Kangaroo Island, also known as Karta Pintingga (literally 'Island of the Dead' in the language of the Kaurna people), is Australia's third-largest island, after Tasmania and Melville Island. It lies in the state of South Australia, southwest ...

South Australia South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...

for the first time, thanks to a project conducted by Department of Environment, Water and Natural Resources (DEWNR) and carried out by a number of citizen science volunteers. Tupongs have made a recovery in the Glenelg River in south-western

Victoria Victoria most commonly refers to: * Victoria (Australia), a state of the Commonwealth of Australia * Victoria, British Columbia, provincial capital of British Columbia, Canada * Victoria (mythology), Roman goddess of Victory * Victoria, Seychelle ...

, after years of absence.

Description

The congolli is a slender, mottled fish, with a silvery-white underside. Its head is slightly flattened, with eyes positioned towards the top and the snout is pointed. It has two separate

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through c ...

s. The colour varies according to where it lives: it may be bluish, purplish or reddish-brown, marbled with greenish-brown above, and a yellowish white to silvery colour below. Juvenile fish have black saddles on their dorsal surfaces. The largest adult measured is about long. Usually, adults grow up to long.

Diet

The congolli is a carnivorous ambush

predator Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...

, and feeds on insects (especially in freshwater), fish,

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can ...

s (especially in estuaries), worms,

molluscs Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is estim ...

, and other

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

Behaviour

The congolli is an ambush predator that usually buries itself in the substrate.

Reproduction

Congolli are

catadromous Fish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousan ...

– they live in freshwater habitats as adults, and migrate downstream to estuaries to spawn. Adults migrate south to estuaries reproduce between late April and August. The larvae are carried out to sea, and slowly move upstream as they grow; the larger adults live furthest upstream.

Importance to humans

Aboriginal peoples Indigenous peoples are culturally distinct ethnic groups whose members are directly descended from the earliest known inhabitants of a particular geographic region and, to some extent, maintain the language and culture of those original people ...

living in the area used to eat Congolli, and the flesh is today considered "excellent eating". However the fish are rarely large enough and no longer important in commercial fishing, although once a minor part of lower Murray fisheries.