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 fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of sk ...

. 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 "unisp ...

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Pseudaphritidae and the

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 ...

''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 ( , ) is the scientific study of animals. Its studies include the structure, embryology, classification, habits, and distribution of all animals, both living and extinct, and how they interact with their ecosystems. Zoology is one ...

Achille Valenciennes Achille Valenciennes (9 August 1794 – 13 April 1865) was a French zoology, zoologist. Valenciennes was born in Paris, and studied under Georges Cuvier. His study of parasitic worms in humans made an important contribution to the study of parasi ...

but the name ''Aphritis'' was a junior

synonym A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

of the

Diptera Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advance ...

genus '' Aphritis'' named by

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

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 Ichthyology is the branch of zoology devoted to the study of fish, including bony fish (Osteichthyes), cartilaginous fish (Chondrichthyes), and jawless fish (Agnatha). According to FishBase, 35,800 species of fish had been described as of March 2 ...

Allan Riverstone McCulloch Allan Riverstone McCulloch (20 June 1885 – 1 September 1925) was a prominent Australian ichthyologist. Born in Sydney, Australia, McCulloch began his scientific career at the age of 13 as an unpaid assistant to Edgar Ravenswood Waite in the ...

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 habita ...

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 approximat ...

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 (; 384–322 BC) was an Ancient Greek philosophy, Ancient Greek philosopher and polymath. His writings cover a broad range of subjects spanning the natural sciences, philosophy, linguistics, economics, politics, psychology, a ...

, who used it for a type of

anchovy An anchovy is a small, common forage fish of the Family (biology), 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 speci ...

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-mes ...

. 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 language, French form of the name Peter (given name), Peter. Pierre originally meant "rock" or "stone" in French (derived from the Greek word πέτρος (''petros'') meaning "stone, rock", via ...

had used it for a fly genus '' Aphritis'' in 1804.

Lev Berg Lev Semyonovich Berg, also known as Leo S. Berg (; 14 March 1876 – 24 December 1950) was a leading Russian geographer, biologist and ichthyologist who served as President of the Soviet Geographical Society between 1940 and 1950. He is known f ...

proposed a replacement name, ''Phricus'' but this was a

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 List of explorers, explorer and French Navy, naval officer who explored the south and western Pacific, Australia, New Zealand and Antarctica. As a botanist an ...

, leader of the Astrolabe expedition (1826- 1829), in the course of which

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. * ...

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 Tasmania (; palawa kani: ''Lutruwita'') is an island States and territories of Australia, state of Australia. It is located to the south of the Mainland Australia, Australian mainland, and is separated from it by the Bass Strait. The sta ...

, and is

endemic Endemism is the state of a species being found only 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 foun ...

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 environm ...

, 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 (, ) is Australia's third-largest island, after Tasmania and Melville Island, Northern Territory, Melville Island. It lies in the state of South Australia, southwest of Adelaide. Its closest point to the mainland is Snapper Poi ...

South Australia South Australia (commonly abbreviated as SA) is a States and territories of Australia, state in the southern central part of Australia. With a total land area of , it is the fourth-largest of Australia's states and territories by area, which in ...

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 The term citizen science (synonymous to terms like community science, crowd science, crowd-sourced science, civic science, participatory monitoring, or volunteer monitoring) is research conducted with participation from the general public, or am ...

volunteers. Tupongs have made a recovery in the Glenelg River in south-western Victoria, 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 on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

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 in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common List of feeding behaviours, feeding behaviours that includes parasitism and micropredation ...

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

crustacean Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...

s (especially in estuaries), worms,

molluscs Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

, and other

invertebrate Invertebrates are animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordata, chordate s ...

Behaviour

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

Reproduction

Congolli are

catadromous Fish migration is animal migration, 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 ...

– 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 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.