''Microthrissa royauxi'', the royal sprat, is a species of

pelagic The pelagic zone consists of the water column of the open ocean and can be further divided into regions by depth. The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or water column between the sur ...

, freshwater fish from the herring family

Clupeidae Clupeidae is a family of clupeiform ray-finned fishes, comprising, for instance, the herrings and sprats. Many members of the family have a body protected with shiny cycloid (very smooth and uniform) scales, a single dorsal fin, and a fusiform ...

which is found in the

Congo River The Congo River, formerly also known as the Zaire River, is the second-longest river in Africa, shorter only than the Nile, as well as the third-largest river in the world list of rivers by discharge, by discharge volume, following the Amazon Ri ...

basin in west Africa. It was described in 1902 by the Belgian-

British British may refer to: Peoples, culture, and language * British people, nationals or natives of the United Kingdom, British Overseas Territories and Crown Dependencies. * British national identity, the characteristics of British people and culture ...

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 ...

George Albert Boulenger George Albert Boulenger (19 October 1858 – 23 November 1937) was a Belgian-British zoologist who described and gave scientific names to over 2,000 new animal species, chiefly fish, reptiles, and amphibians. Boulenger was also an active botani ...

. It is of limited importance as a food fish in subsistence fisheries and its conservation status is Least Concern.

Naming and taxonomy

''Microthrissa royauxi'' was named by George Albert Boulenger in 1902 from specimens taken in the Ubangi. Its name is from ''micro'' small and ''thrissa'' from the

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

word 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 ...

. The specific name ''royauxi'' is in honor of Capitaine Louis Joseph Royaux (1866–1936), who led the expedition that collected the

type specimen In biology, a type is a particular wikt:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to ancho ...

and supplied indigenous names of many of the species the expedition collected. It is the type species of the genus ''

Microthrissa ''Microthrissa'' is a genus of freshwater ray-finned fishes belonging to the family Dorosomatidae, which also includes the gizzard shads and sardinellas. The species in this genus are endemic to Africa. Species ''Microthrissa contains the follo ...

''.

Description

''Microthrissa royauxi'' is a small fish with a rather deep body, the height of the body being roughly a third of the length with a fairly pointed snout, lacking a projecting lower jaw. It has strongly keeled scutes 1 or 2 rows before the base of the first

pectoral fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish aquatic locomotion, swim. Apart from the tail or caudal fin, fish fins have no direct connection with the vertebral column ...

ray. In this and other species of West African freshwater clupeid the jaw anatomy is important in identification and this species has rather narrow jaws compared to its relatives. The maximum length is 9.9 cm,. although 8 cm appears to be the average length.

Distribution

''Microthrissa royauxi'' is found in the middle Congo River basin, including the Ubangi system but not the Kasai, it has been recorded from the

Democratic Republic of the Congo The Democratic Republic of the Congo (DRC), also known as the DR Congo, Congo-Kinshasa, or simply the Congo (the last ambiguously also referring to the neighbouring Republic of the Congo), is a country in Central Africa. By land area, it is t ...

, Congo,

Central African Republic The Central African Republic (CAR) is a landlocked country in Central Africa. It is bordered by Chad to Central African Republic–Chad border, the north, Sudan to Central African Republic–Sudan border, the northeast, South Sudan to Central ...

and

Cameroon Cameroon, officially the Republic of Cameroon, is a country in Central Africa. It shares boundaries with Nigeria to the west and north, Chad to the northeast, the Central African Republic to the east, and Equatorial Guinea, Gabon, and the R ...

. This species has been recorded from

Pool Malebo The Pool Malebo, formerly Stanley Pool, also known as Mpumbu, Lake Nkunda or Lake Nkuna by local indigenous people in pre-colonial times, is a lake-like widening in the lower reaches of the Congo River.

(Stanley Pool) and the central Congo River basin, as well as the

Lualaba River The Lualaba River (, , ) flows entirely within the eastern part of Democratic Republic of the Congo. It provides the greatest streamflow to the Congo River, while the River source, source of the Congo is recognized as the Chambeshi River, Chambeshi ...

Kindu Kindu is a city in the Democratic Republic of Congo, the capital of Maniema province. It has a population of about 200,000 and is situated on the Lualaba River at an altitude of about 500 metres, and is about 400 km west of Bukavu. Kindu is ...

Evolution

The clupeids are largely marine, the sub-family that ''Microthrissa royauxi'' is a member of, the Pellonulinae, are common in southern and western Africa, for example ''

Limnothrissa miodon ''Polemon'' is a genus of rear-fanged mildly venomous snakes in the family Atractaspididae. The genus is endemic to Africa. Fifteen species are recognized as being valid. ''Miodon'' is a synonym. The mollusc genus of family Carditidae invalidl ...

'' in

Lake Tanganyika Lake Tanganyika ( ; ) is an African Great Lakes, African Great Lake. It is the world's List of lakes by volume, second-largest freshwater lake by volume and the List of lakes by depth, second deepest, in both cases after Lake Baikal in Siberia. ...

and '' Potamothrissa acuitirostris'' in the

Congo Basin The Congo Basin () is the sedimentary basin of the Congo River. The Congo Basin is located in Central Africa, in a region known as west equatorial Africa. The Congo Basin region is sometimes known simply as the Congo. It contains some of the larg ...

. Molecular phylogenetic reconstructions indicate that the ancestors of these freshwater Pellonulines colonised West Africa 25–50 million years ago, at the end of a major marine incursion in the region. Pellonuline herring subsequently speciated in an evolutionary radiation in West Africa, and spread across the continent and colonising its freshwater bodies.

Habitat

''Microthrissa royauxi'' is a pelagic fish of large rivers.

Fisheries

''Microthrissa royauxi'' makes a small contribution to the catches of local fishermen, it is caught mainly by subsistence fishermen.

References

{{Taxonbar, from=Q5525242 Microthrissa Freshwater fish of Africa Fish described in 1902