Synodontis polystigma

Synodontis polystigma is a species of upside-down catfish that is native to the upper Congo Basin of the Democratic Republic of the Congo and Zambia.[2] It was first described by George Albert Boulenger in 1915. The original specimens were obtained at Lukonzolwa, in Lake Mweru, in what is now the Democratic Republic of the Congo.[3] The species name polystigma is derived from poly, meaning "many" and stigma, meaning "mark or spot", referring to the numerous black spots on the body and fins of the species.[4]

Synodontis polystigma
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Siluriformes
Family: Mochokidae
Genus: Synodontis
Species:
S. polystigma
Binomial name
Synodontis polystigma
Boulenger, 1915

Description

Like all members of the genus Synodontis, S. polystigma 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.[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.[6] The adipose fin is large and the tail, or caudal fin, is forked.[3]

The front edges of the dorsal fins and the pectoral fins are hardened into stiff spines. These spines can be raised into position at right angles to the body and locked into position for defensive purposes.[7][8] The ability to lock the spines into place comes from several small bones attached to the spine, and once raised, the spines cannot be folded down by exerting pressure on the tip.[8]

The fish has 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. On the lower jaw, or mandible, the teeth are attached to flexible, stalk-like structures and described as "s-shaped" or "hooked".[3][5]

The maximum total length of the species is 24.5 centimeters (9.6 in).[2] Generally, females in the genus Synodontis tend to be slightly larger than males of the same age.[9]

Habitat and behavior

In the wild, the species occurs in the Luapula-Mweru River system.[1] It is harvested for human consumption.[1] The species faces threats from overfishing.[1] As a whole, species of Synodontis are omnivores, consuming insect larvae, algae, gastropods, bivalves, sponges, crustaceans, and the eggs of other fishes.[10] The reproductive habits of most of the species of Synodontis are not known, beyond some instances of obtaining egg counts from gravid females.[10] Spawning likely occurs during the flooding season between July and October, and pairs swim in unison during spawning.[11] The growth rate is rapid in the first year, then slows down as the fish age.[9]

References
  1. Moelants, T. (2010). "Synodontis polystigma". IUCN Red List of Threatened Species. 2010. Retrieved 7 November 2016.CS1 maint: ref=harv (link)
  2. Froese, Rainer and Pauly, Daniel, eds. (2016). "Synodontis polystigma" in FishBase. June 2016 version.
  3. "Synodontis polystigma Poll & Roberts, 1968". Planet Catfish. 19 Jul 2013. Retrieved 7 November 2016.
  4. Scharpf, Christopher & Kenneth Lazara (12 Sep 2016). "Order SILURIFORMES: Families MALAPTERURIDAE, MOCHOKIDAE, SCHILBEIDAE, AUCHENOGLANIDIDAE, CLAROTEIDAE and LACANTUNIIDAE". The ETYFish Project. Retrieved 7 November 2016.
  5. 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. Boulenger, George Albert (1909). Catalogue of the fresh-water fishes of Africa in the British museum (Natural history). London: British Museum. p. 391.
  7. Nelson, Joseph; T. Grande & M. Wilson (2016). Fishes of the World (Fifth ed.). John Wiley and Sons. p. 227.
  8. Scherge, M.; S. Gorb & S. Gorb. Biological Micro- and Nanotribology. Springer Science & Business Media. pp. 97–98.
  9. 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. S2CID 24587047.
  10. Wright, J.J. & L.M. Page (2006). "Taxonomic Revision of Lake Tanganyikan Synodontis (Siluriformes: Mochokidae)". Florida Mus. Nat. Hist. Bull. 46 (4): 99–154.
  11. 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.

Data related to Synodontis polystigma at Wikispecies

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