Synodontis robbianus

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Synodontis robbianus
Synodontis robbianus.jpg
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Siluriformes
Family: Mochokidae
Genus: Synodontis
Species:
S. robbianus
Binomial name
Synodontis robbianus
Smith, 1875

Synodontis robbianus, known as the russet synodontis, [2] is a species of upside-down catfish that is native to Nigeria where it is found in the Cross and lower Niger Rivers. [3] It was first described by John Alexander Smith in 1875, from specimens collected in the Calabar River, Nigeria. [2] [4] The species name robbianus is named after Rev. Alexander Robb, a Scottish missionary, who collected the original species samples. [2]

Contents

Description

Like all members of the genus Synodontis, S. robbianus has a strong, bony head capsule that extends back as far as the first spine of the dorsal fin. [5] The head contains a distinct narrow, bony, external protrusion called a humeral process. [2] The shape and size of the humeral process helps to identify the species. In S. robbianus, the humeral process is about 1+1⁄2 to 2 times as long as it is broad, rough, and with a ridge on the lower edge. [4]

The fish has three pairs of barbels. The maxillary barbels are on located on the upper jaw, and two pairs of mandibular barbels are on the lower jaw. The maxillary barbel is long and straight without any branches, with a broad membrane at the base. [4] It extends to a length of about 1+1⁄4 to 1+1⁄2 times the length of the head. [4] The outer pair of mandibular barbels is a little under twice the length of the inner pair; and the outer pair with moderately long branches and the inner pair with secondary branches present. [4]

The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. [2] In S. robbianus, the spine of the dorsal fin is about 2⁄3 to 3⁄4 times the length of the head, slightly curved, smooth in the front and serrated on the back. [4] The remaining portion of the dorsal fin is made up of seven branching rays. [4] The spine of the pectoral fin is a little longer than the size of the dorsal spine, and serrated on both sides. [4] The adipose fin is 2+1⁄2 to 3+1⁄2 times as long as it is deep. [4] The anal fin contains three to four unbranched and eight or nine branched rays. [4] The tail, or caudal fin, is deeply forked, with the upper lobe longer. [4]

All members of Syndontis have a structure called a premaxillary toothpad, which is located on the very front of the upper jaw of the mouth. This structure contains several rows of short, chisel-shaped teeth. In S. robbianus, the toothpad forms a short and broad band. [4] On the lower jaw, or mandible, the teeth of Syndontis are attached to flexible, stalk-like structures and described as "s-shaped" or "hooked". [2] [5] The number of teeth on the mandible is used to differentiate between species; in S. robbianus, there are about 15 to 20 teeth on the mandible. [4]

The body color is pale brown, blotched or mottled with darker brown. The ventral and anal fins are dark, the dorsal and caudal fins are lighter. Juveniles show a light streak on each side of the snout, and cross-bars on the dorsal, anal, and caudal fins. [4]

The maximum total length of the species is 13.8 centimetres (5.4 in). [3] Generally, females in the genus Synodontis tend to be slightly larger than males of the same age. [6]

Habitat and behavior

In the wild, the species has only been found in the Cross and lower Niger Rivers. [1] It lives in streams and lakes and eats plankton, detritus, and plants. [1] It is capable of breathing air, and can live in waters with low dissolved oxygen. [1] The reproductive habits of most of the species of Synodontis are not known, beyond some instances of obtaining egg counts from gravid females. [7] Spawning likely occurs during the flooding season between July and October, and pairs swim in unison during spawning. [8] The growth rate is rapid in the first year, then slows down as the fish age. [6]

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<i>Synodontis budgetti</i> Species of fish

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<i>Synodontis caudalis</i> Species of fish

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<i>Synodontis caudovittatus</i> Species of fish

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<i>Synodontis courteti</i> Species of fish

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<i>Synodontis depauwi</i> Species of fish

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<i>Synodontis filamentosus</i> Species of fish

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<i>Synodontis geledensis</i> Species of fish

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<i>Synodontis macrostigma</i> Species of fish

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<i>Synodontis melanopterus</i> Species of fish

Synodontis melanopterus is a species of upside-down catfish that is native to Benin, Niger and Nigeria where it is found at Porto Novo and in the Ouémé, Niger and Ogun River basins. It was first described by Belgian-British zoologist George Albert Boulenger in 1903, from specimens collected at Oguta, Nigeria, in the Niger River delta.

<i>Synodontis multimaculatus</i> Species of fish

Synodontis multimaculatus, known as the dotted synodontis, is a species of upside-down catfish that is native to the Democratic Republic of the Congo where it is found in the Ubangi River. It was first described by British-Belgian zoologist George Albert Boulenger in 1902, from a specimen collected in the Ubangi River in Mobayi-Mbongo, the Democratic Republic of the Congo. The species name multimaculatus is derived from the word multi, meaning many, and the Latin word maculatus, meaning spots, referring to the many spots on the fish.

<i>Synodontis nigromaculatus</i> Species of fish

Synodontis nigromaculatus, known as the spotted squeaker, the blackspotted squeaker, or the speckled squeaker, is a species of upside-down catfish that is found widely in southern Africa. It has been identified in Angola, Botswana, the Democratic Republic of the Congo, Mozambique, Namibia, South Africa, Zambia, and Zimbabwe. It was first described by British-Belgian zoologist George Albert Boulenger in 1905, from specimens collected in Lake Bangweulu in Zambia.

<i>Synodontis obesus</i> Species of fish

Synodontis obesus, known as the Coas synodontis, is a species of upside-down catfish that is native to the coastal drainages of Cameroon, Ghana, Nigeria and Togo. It was first described by British-Belgian zoologist George Albert Boulenger in 1898. The species name obesus is derived from the Latin word obesus, meaning "fat".

<i>Synodontis resupinatus</i> Species of fish

Synodontis resupinatus is a species of upside-down catfish that is native to the Niger basin and the Bénoué River of Cameroon, Mali, and Nigeria. It was first described by British-Belgian zoologist George Albert Boulenger in 1904, from specimens obtained near Lokoja, Nigeria.

<i>Synodontis sorex</i> Species of fish

Synodontis sorex is a species of upside-down catfish that is widely distributed in the rivers of northern Africa. It was first described by German zoologist Albert Günther in 1864, from specimens obtained in the upper Nile River, near Khartoum, Sudan. The species name sorex comes from the Latin word for shrew or shrew-mouse, the allusion was not explained. It possibly describes the pointed snout or the long, slender teeth.

<i>Synodontis xiphias</i> Species of fish

Synodontis xiphias is a species of upside-down catfish that is native to the Niger River basin of Nigeria. It was first described by German ichthyologist Albert Günther in 1864, from specimens obtained in the Niger River. The species name xiphias comes from the Greek word xiphos, meaning sword, which refers to the long snout that was observed on the stuffed type specimen.

References

  1. 1 2 3 4 Lalèyè, P.; Olaosebikan, B.D. (2020). "Synodontis robbianus". IUCN Red List of Threatened Species . 2020: e.T181646A134966066. doi: 10.2305/IUCN.UK.2020-2.RLTS.T181646A134966066.en . Retrieved 20 November 2021.
  2. 1 2 3 4 5 6 "Synodontis robbianus Smith, 1875". Planet Catfish. 12 Mar 2015. Retrieved 27 October 2016.
  3. 1 2 Froese, Rainer; Pauly, Daniel (eds.) (2016). "Synodontis robbianus" in FishBase. June 2016 version.
  4. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Boulenger, George Albert (1909). Catalogue of the fresh-water fishes of Africa in the British museum (Natural history). London: British Museum. pp. 435–436.
  5. 1 2 Cuvier, Georges (1934). The Animal Kingdom Arranged in Conformity with its Organization, Volume 10. Translated by Griffith, Edward. London: Whittaker and Co. p. 406.
  6. 1 2 H. M. Bishai & Y. B. Abu Gideiri (1965). "Studies on the biology of genus Synodontis at Khartoum". Hydrobiologia . 26 (1–2): 85–97. doi:10.1007/BF00142257.
  7. ↑ Wright, J.J. & L.M. Page (2006). "Taxonomic Revision of Lake Tanganyikan Synodontis (Siluriformes: Mochokidae)". Florida Mus. Nat. Hist. Bull. 46 (4): 99–154.
  8. ↑ John P. Friel & Thomas R. Vigliotta (March 2, 2009). "Mochokidae Jordan 1923: African squeaker and suckermouth catfishes". Tree of Life Web Project . Retrieved 19 October 2016.

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