Synodontis polli

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Synodontis polli
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Siluriformes
Family: Mochokidae
Genus: Synodontis
Species:
S. polli
Binomial name
Synodontis polli
Gosse, 1982

Synodontis polli, known as Poll's synodontis, [2] is a species of upside-down catfish endemic to the Democratic Republic of the Congo, Burundi, Zambia, and Tanzania, where it is only known from Lake Tanganyika. [3] [4] It was first described by Belgian ichthyologist Jean-Pierre Gosse in 1982, from specimens collected at multiple points along the shore of Lake Tanganyika. [3]

Contents

Etymology

The species name is in honor in honor of Belgian ichthyologist Max Poll. [5]

Description

Like all members of the genus Synodontis, S. polli has a strong, bony head capsule that extends back as far as the first spine of the dorsal fin. [6] The head is about 3⁄10 of the standard length of the fish. [3] 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. polli, the humeral process is wide, triangular, and rough in appearance, with a poorly-defined ridge on the bottom edge. [3] The top edge is convex and the end is sharply pointed. [3] It is about 1⁄2 of the length of the head. [3] The diameter of the eye is about 1⁄7 of the length of the head. [3]

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 has a narrow membrane attached near the base and is straight without any branches. [3] It extends at least as far as the base of the pectoral fin, about 2⁄3 as long as the head. [3] The outer pair of mandibular barbels extends just short of the pectoral girdle, about 1⁄2 of the length of the head, [3] and contains four to five branches without secondary branches. [3] The inner pair of mandibular barbels is about 1⁄2 to 2⁄3 as long as the outer pair, about 1⁄4 of the length of the head, [3] with three to five branches, with many secondary branches present. [3]

The skin of S. polli has a large number of tiny vertical skin folds. The exact purpose of the skin folds is not known, but is a characteristic of the species of Syndontis that are endemic to Lake Tanganyika. [3] External thin papilla are present but do not extend onto the fins. [3]

The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. [2] In S. polli, the spine of the dorsal fin is short, about 2⁄3 as long as the head, [3] is slightly curved, is smooth on the front and finely serrated on the back, and ends with short, dark filament. [3] The remaining portion of the dorsal fin is made up of seven branching rays. [3] The spine of the pectoral fin is slightly curved, almost as long as the dorsal fin spine, with small serrations on the front and large serrations on the back. [3] The pectoral spine ends in short, black filament. [3] The rest of the pectoral fins are made up of seven to eight branching rays. [3] The adipose fin does not contain any rays, is long and well developed, and has a convex shape. [3] The pelvic fin contains one unbranched and six branched rays. [3] The front edge of the pelvic fin is aligned or slightly forward of the front edge of the adipose fin. [3] The anal fin contains three to five unbranched and seven to nine branched rays; it is vertically aligned with the adipose fin. [3] The tail, or caudal fin, is forked, with rounded lobes, and contains eight rays on the upper lobe, nine rays on the lower lobe. [3]

The mouth of the fish faces downward and has wide lips that contain papilla. [3] 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 some species, this toothpad is made up of a large patch with several rows in a large cluster. In other species of Syndontis, this toothpad is clearly divided into two separate groups, separated by a thin band of skin that divides the toothpad. [3] This character is used as a method of differentiating between two different but similar species of Syndontis. [3] In S. polli, the toothpad is interrupted, with a distinct gap between groups of teeth. [3] 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] [6] The number of teeth on the mandible is used to differentiate between species; in S. polli, there are 40 to 70 teeth on the mandible, arranged in a 6 to 8 rows. [3]

Some of the species of Synodontis have an opening or series of openings called the axillary pore. It is located on the sides of the body below the humeral process and before the pectoral fin spine. The exact function of the port is not known to scientists, although its presence has been observed in seven other catfish genera. Fish in the genus Acrochordonichthys are known to secrete a mucus with toxic properties from their axillary pore, but there is no scientific consensus as to the exact purpose of the secretion or the pore. [3] S. polli does not have an axillary pore. [3]

The body color is olive brown on the back, covered with large, irregularly-shaped black spots. [3] The underside is lighter, with smaller spots. [3] Most of the species of Synodontis of Lake Tanganyika have a recognizable pattern consisting of dark triangles at the bases of all of the rayed fins, present in S. polli, and the back edges of the fins are whiter. [3] The caudal fin has a black bar that runs from the base of each lobe to the top of the fin. [3] The barbels are white. [2] [3]

The maximum standard length of known specimens is 14.5 centimetres (5.7 in) with a total length of 18 centimetres (7.1 in). [3] [4] Generally, females in the genus Synodontis tend to be slightly larger than males of the same age. [7]

Habitat and behavior

In the wild, the species is endemic to Lake Tanganyika, which has an observed temperature range of 22 to 26 °C (72 to 79 °F), an approximate pH of 8.5 – 9, and dH range of 4-15. [4] [8] The fish inhabits rocky coasts in the littoral, and has been found at depths of up to 20 metres (66 ft). [3] The reproductive habits of most of the species of Synodontis are not known, beyond some instances of obtaining egg counts from gravid females. [3] Spawning likely occurs during the flooding season between July and October, and pairs swim in unison during spawning. [9] The diet consists of algae that is scraped from rocks and small invertebrates. [3] The growth rate is rapid in the first year, then slows down as the fish age. [7]

Related Research Articles

Synodontis dhonti is a species of upside-down catfish endemic to the Democratic Republic of the Congo where it is only known from Lake Tanganyika. It was first described by Belgian-British zoologist George Albert Boulenger in 1917, based upon a single specimen collected from Lake Tanganyika at Kilewa Bay, in what is now the Democratic Republic of the Congo. The species is named after M.G. Dhont-De Bie, who accompanied the collector, Dr. L. Stappers, on his expedition. At one point, identified specimens Synodontis irsacae was believed to be juvenile individuals of S. dhonti and the two were considered to be the same species, but further research has identified differences between the two species and they are once again recognized as distinct from each other.

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

Synodontis granulosus is a species of upside-down catfish endemic to the Democratic Republic of the Congo, Burundi, Zambia, and Tanzania, where it is only known from Lake Tanganyika. It was first described by Belgian-British zoologist George Albert Boulenger in 1900, from specimens collected at multiple points along the shore of Lake Tanganyika. The species name comes from the Latin word "granulum", meaning of grain, and refers to the granular papillae present on the skin of the fish's body.

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

Synodontis nigrita, known as the false upside down catfish, is a species of upside-down catfish that occurs widely in northern Africa. It was first described by French zoologist Achille Valenciennes in 1840. The type specimen is in the Muséum National d' Histoire Naturelle de Paris.

Lake Victoria squeaker Species of fish

The Lake Victoria squeaker is a species of upside-down catfish that is native to Kenya, Burundi, Tanzania and Uganda where it is found in Lakes Kioga and Victoria and the Victorian Nile the lower Kagera River and the Malagarasi River drainage. It was first described by British-Belgian zoologist George Albert Boulenger in 1906, from specimens collected in the Lake Victoria at Buganga, Uganda and Entebbe, Uganda by Mr. E. Degen. The species name victoriae is derived from the location where the species was originally discovered, Lake Victoria.

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

Synodontis petricola, known as the cuckoo catfish, or the pygmy leopard catfish, is a species of upside-down catfish endemic to Burundi, Zambia, the Democratic Republic of the Congo, and Tanzania where it is only known from Lake Tanganyika. It was first described by Belgian ichthyologist Hubert Matthes in 1959. The species name "petricola" is derived from a combination of the Latin petra, meaning stone or rock, and the Latin cola, meaning inhabitant. This refers to the rocky environment where this species is found.

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

Synodontis depauwi is a species of upside-down catfish that is endemic to the Democratic Republic of the Congo where it can be found in Stanley Pool. It was first described by British-Belgian zoologist George Albert Boulenger in 1899, from specimens collected in Stanley Pool, in the Democratic Republic of the Congo. The species name depauwi is in honour of the "conservateur des collections de l'Université libre de Bruxelles", Louis De Pauw.

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

Synodontis filamentosus, known as the longfin synodontis, is a species of upside-down catfish that is native to the basins of the Nile, Volta and Niger Rivers as well as the Chad Basin. It was first described by British-Belgian zoologist George Albert Boulenger in 1901, from specimens obtained near the mouth of Lake No, on the White Nile in Sudan. The species name filamentosus comes from the elongated rays of the dorsal and caudal fins.

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

Synodontis frontosus, known as the Sudan squeaker, is a species of upside-down catfish that is widely distributed throughout northern and central Africa. It has been reported in Chad, Democratic Republic of the Congo, Ethiopia, Kenya, Somalia, Sudan, and Uganda. It was first described by French zoologist Léon Vaillant in 1895, from specimens collected in the White Nile in Sudan. The species name frontosus is Latin, and means "broad head".

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

Synodontis grandiops is a species of upside-down catfish endemic to the Democratic Republic of the Congo, Burundi, and Tanzania, where it is only known from Lake Tanganyika. It was first described by Jeremy John Wright and Lawrence M. Page in 2006, from specimens collected at multiple points along the shore of Lake Tanganyika. The species name is a Latinized combination of the Latin "grandi", meaning large or big, and the Greek "ops", meaning eye, a reference to the relatively large eyes of this fish.

Synodontis ilebrevis is a species of upside-down catfish endemic to Zambia, where it is only known from Lake Tanganyika. It was first described by Jeremy John Wright and Lawrence M. Page in 2006, from specimens collected from Lake Tanganyika at Cape Chaitika, Zambia. The species name comes from the Latin word "ile", meaning intestine, and the Latin word "bevis", meaning short, and refers to the relatively short gut of this species.

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

Synodontis omias is a species of upside-down catfish native to the Niger River basin of Guinea, Mali, Niger and Nigeria. It was first described by German-born British zoologist, ichthyologist, and herpetologist Albert Günther in 1864, from a specimen collected in Jebba, Nigeria, on the Niger River. There have been very few specimens of this species identified, and it may be the same species as S. budgetti from the Upper Niger.

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

Synodontis ornatipinnis, known as the barfin synodontis, is a species of upside-down catfish that is native to the Congo Basin of the Democratic Republic of the Congo and Zambia. It was first described by British-Belgian zoologist George Albert Boulenger in 1899, from specimens collected in Mbandaka, on the Congo River in what is now the Democratic Republic of the Congo. The species name ornatipinnis means "ornate fins".

<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 robbianus</i> Species of fish

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

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

Synodontis soloni, known as the scissortail synodontis, is a species of upside-down catfish that is endemic to the Democratic Republic of the Congo where it is found in the Ubangi River and the rapids just below Stanley Pool. It was first described by British-Belgian zoologist George Albert Boulenger in 1899, from the Congo River in what is now the Democratic Republic of the Congo. The species name soloni is a patronym and in memory of Alexandre Solon, who assisted with the collection of fish.

<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.

Synodontis tanganyicae is a species of upside-down catfish endemic to the Democratic Republic of the Congo, Zambia, and Tanzania, where it is only known from Lake Tanganyika. It was first described by Russian-American ichthyologist Nikolai Andreyevich Borodin in 1936, from specimens collected at Kasaga, in what is now the Democratic Republic of the Congo. The species name tanganyicae comes from the habitat of the species, Lake Tanganyika.

Synodontis lucipinnis is a species of upside-down catfish endemic to Zambia, where it is only known from the Musende Rocks area (Mpulungu) of Lake Tanganyika. It was first described by Jeremy John Wright and Lawrence M. Page in 2006. The species name "lucipinnis" is derived from a combination of the Latin luci, meaning bright or clear, and the Latin pinnis, meaning fin. This refers to the light coloration in a patch on the base of the fins of this species.

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

Synodontis melanostictus is a species of upside-down catfish endemic to Lake Tanganyika and its tributaries. It has been found in Zambia, the Democratic Republic of the Congo, and Burundi. It was first described by British-Belgian zoologist George Albert Boulenger in 1906, based upon a specimen from the Lofubu River. The species name "melanostictus" is derived from a combination of the Greek melano, meaning black, and the Greek stiktos, meaning punctured or spotted. This refers to the black spotted pattern that occurs on the body of this species.

Synodontis irsacae is a species of upside-down catfish endemic to Zambia, the Democratic Republic of the Congo, and Tanzania, where it is only known from Lake Tanganyika. It was first described by Belgian ichthyologist Hubert Matthes in 1959, from specimens collected from Lake Tanganyika at Kalundu, in what is now the Democratic Republic of the Congo. The species name " irsacae" is derived from the abbreviation "I.R.S.A.C.", or Institut pour la Recherche Scientifique en Afrique Centrale. For many years, specimens of the species were considered to be juvenile members of S. dhonti, but in 2006, J.J. Wright and L.M. Page identified unique characteristics of this species that established that they were a unique species.

References

  1. ↑ Ntakimazi, G. (2006). "Synodontis polli". IUCN Red List of Threatened Species . 2006: e.T60819A12413288. doi: 10.2305/IUCN.UK.2006.RLTS.T60819A12413288.en . Retrieved 15 November 2021.
  2. 1 2 3 4 5 "Synodontis polli Gosse, 1982". Planet Catfish. 19 Jul 2013. Retrieved 22 October 2016.
  3. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 Wright, J.J. & L.M. Page (2006). "Taxonomic Revision of Lake Tanganyikan Synodontis (Siluriformes: Mochokidae)". Florida Mus. Nat. Hist. Bull. 46 (4): 99–154.
  4. 1 2 3 Froese, Rainer; Pauly, Daniel (eds.) (2016). "Synodontis polli" in FishBase. June 2016 version.
  5. ↑ Christopher Scharpf & Kenneth J. Lazara (22 September 2018). "Order SILURIFORMES: Families MALAPTERURIDAE, MOCHOKIDAE, SCHILBEIDAE, AUCHENOGLANIDIDAE, CLAROTEIDAE and LACANTUNIIDAE". The ETYFish Project Fish Name Etymology Database. Christopher Scharpf and Kenneth J. Lazara. Retrieved 16 March 2022.
  6. 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.
  7. 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.
  8. ↑ Smith, F. (2001). "A preliminary investigation of some chemical and physical profiles of Lake Tanganyika" (PDF). Retrieved 19 October 2016.
  9. ↑ 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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