''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 (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or w ...

, freshwater fish from the herring family

Clupeidae Clupeidae is a family of ray-finned fishes, comprising, for instance, the herrings, shads, sardines, hilsa, and menhadens. The clupeoids include many of the most important food fishes in the world, and are also commonly caught for production ...

which is found in the

Congo River The Congo River ( kg, Nzâdi Kôngo, french: Fleuve Congo, pt, Rio Congo), formerly also known as the Zaire River, is the second longest river in Africa, shorter only than the Nile, as well as the second largest river in the world by discharge ...

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

Belgian Belgian may refer to: * Something of, or related to, Belgium * Belgians, people from Belgium or of Belgian descent * Languages of Belgium, languages spoken in Belgium, such as Dutch, French, and German *Ancient Belgian language, an extinct language ...

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

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 ...

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 botan ...

. 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: Greece 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 ...

word 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 ...

. 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 specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralizes the ...

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 sprats in the herring family, Clupeidae, which is endemic to Africa. There are five recognized species in the genus. Species * '' Microthrissa congica'' (Regan The family name Regan, along with its cognates ...

''.

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 distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as ...

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 (french: République démocratique du Congo (RDC), colloquially "La RDC" ), informally Congo-Kinshasa, DR Congo, the DRC, the DROC, or the Congo, and formerly and also colloquially Zaire, is a country in ...

, Congo,

Central African Republic The Central African Republic (CAR; ; , RCA; , or , ) is a landlocked country in Central Africa. It is bordered by Chad to the north, Sudan to the northeast, South Sudan to the southeast, the DR Congo to the south, the Republic of the C ...

and

Cameroon Cameroon (; french: Cameroun, ff, Kamerun), officially the Republic of Cameroon (french: République du Cameroun, links=no), is a country in west- central Africa. It is bordered by Nigeria to the west and north; Chad to the northeast; th ...

. 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 Democratic Republic of the Congo. It provides the greatest streamflow to the Congo River, while the source of the Congo is recognized as the Chambeshi. The Lualaba is long. Its headwaters are i ...

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 Pellonulinae is a subfamily of freshwater herrings belonging to the family Clupeidae Clupeidae is a family of ray-finned fishes, comprising, for instance, the herrings, shads, sardines, hilsa, and menhadens. The clupeoids include many of t ...

, are common in southern and western Africa, for example '' Limnothrissa miodon'' in

Lake Tanganyika Lake Tanganyika () is an African Great Lake. It is the second-oldest freshwater lake in the world, the second-largest by volume, and the second-deepest, in all cases after Lake Baikal in Siberia. It is the world's longest freshwater lake. T ...

and ''

Potamothrissa acuitirostris ''Potamothrissa'' is a genus of fish in the herring family, Clupeidae, which is native to Africa. It currently contains three species. Species * ''Potamothrissa acutirostris'' (Boulenger, 1899) (Sharpnosed sawtooth pellonuline) * ''Potamothri ...

'' in the

Congo Basin The Congo Basin (french: Bassin du Congo) 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 c ...

. 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