Fin Sucker

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Fin Sucker
Beaufortia k Weichowensis, South China, 7 cm.

Beaufortia k Weichowensis , South China, 7 cm.

Systematics
Cohort : Otomorpha
Sub-cohort : Ostariophysi
without rank: Otophysa
Order : Carp-like (Cypriniformes)
Subordination : Loach- like (Cobitoidei)
Family : Fin Sucker
Scientific name
Gastromyzontidae
Fowler , 1905

The fin suckers (Gastromyzontidae ("belly suckers")) are a family of loach- like (Cobitoidea) widespread in southern China and southeast Asia in clear, fast-flowing waters .

Construction and way of life

In a morphological series, which does not have to represent phylogenesis , one can start from loach-like brook fish (slender, swiveling, tail flattened), whose pectoral and ventral fins are then widened in a characteristic way in order to be more pressed against the sediment by the current and thus to increase the adhesion. The widening of the abdominal surface is already clear in the Balitoridae (with large, square pair fins; they can suck in something with the abdominal surface; the rear part of the pectoral fin can, however, still be used for "rowing" when bent up); the head also becomes wider, the trunk z. Sometimes shorter, higher ( Homaloptera species). In the Gastromyzontidae, the adaptation to fast-flowing water is the most advanced, the abdominal surface is wide, together with the pair of fins it forms a round "suction cup" which (as you can see on glass panes) can actually hold negative pressure for a while, but more in nature acts through friction (pressed by the shape of the fuselage). The fish also "walk" like centipedes on their fin rays (as is also known from flatfish ). The genus with the widest disc is probably Sewellia , whose pelvic fins are as wide as the pectoral fins.

The eyes stand high on the head, but should look to the sides, which is why the eye sockets (orbites; as in Callionymidae ) protrude slightly from the top of the skull. Approx. 30 vertebrae. The small mouth with more or less distinct (6) barbels is part of this disc, sometimes surrounded by other whisker-like skin flaps for scraping, but does not carry the main load of the suction as in other carp (see Mahseer , Gyrinocheilidae ) and catfish ( Loricariidae ) Substrate, but can devote themselves more to breathing and algae "sucking off". Because of the lower negative pressure on the mouth and its lack of teeth, these animals are not real algae "cleaners", they only sweep the algae away and especially eat the microfauna in the They have few prerequisites for cleaning aquarium glass panes (but there are species that scrape off more sharply). The area around the mouth and its mobility is quite different, with some species a typical maxillary apparatus has been developed.

Beaufortia leveretti , underside

In most of the "violin-shaped" Gastromyzontidae, the front (4-6) rays of the paired fins are simple, the rear ones split. The pectoral fin rays are almost doubled (13 → 24), those of the pelvic fins from 7 to 17.

  • Fin formula of Sewellia lineolata : D 11-12, A 1/4, P 22-23, V 18-19, C 11.

In contrast to the Balitoridae , the Gastromyzontidae have only one unbranched fin rays in front in the pectoral and ventral fins (Balitoridae two or more fin rays). The caudal fin is rounded. The side of the torso is unpigmented, scaly and translucent (you can see the gills, heart and liver), while the back is usually patterned with light (dark) dots or spots. The scales are small (about 50 on the sidelines) to very small. The males are sometimes recognizable by pearl organs on the front rays of the pectoral fins. A distribution center of the Gastromyzontidae seems to be Kalimantan .

These fin suckers are small, often lively, sociable animals with a mouse-like scurry (partly crepuscular). But they like to fight among themselves (rank fights, sometimes territoriality as with other "pastures", such as Plecoglossus altivelis ; Wickler 1971). Unlike Gyrinocheilus , they don't grab other fish to grate them. However, they are not very suitable for aquarium maintenance, because you can hardly offer them the strong current of “fresh” (fresh) water (some species are also found in lakes); Offspring have only been successful occasionally so far. They show a remarkable ability to crawl out of unappealing pools.

Ecological comparison

Other fish with a suction function do it with a suction cup from the overgrown ventral fins ( gobies , tortoiseshell fish , Cyclopteridae ) - but mainly in the marine surf zone. The Gastromyzontidae are the closest approximation of the Teleostei to the ray form ( Rhinobatidae , Torpedo etc.; albeit with a different ecology. In the case of the rays the tail can be reduced, in the Balitoriden it remains the main driving organ. The narrowed gill openings of some genera serve as support locomotion by squeezing out respiratory water, as in Aspredinidae or Molidae ). Strangely enough, there were even similar "fish" (the Devonian Gemuendina ) among the Placodermi . These had the nose with the eyes on top of the snout like loaches, while the rays have them below, near the mouth (the cypriniforms have a large taste field for this). Despite their flatness, even the Gastromyzontidae are not to be regarded as particularly depressed - the Platycephalidae, for example, clearly tower above them.

Gastromyzon fasciatus , side view and attached to a pane of glass (underside). Borneo. 7 cm.
Sewellia lineolata , Mekong basin , 5.7 cm
Pseudogastromyzon fasciatus

Genera

The fin suckers include 19 genera and around 125 species.

literature

  • GA Boulenger (1899): Descriptions of two new homalopteroid fishes from Borneo. Ann. Mag. Nat. Hist. (Ser. 7) 4: 228-229.
  • PW Fang (1935): Study on the crossostomoid fishes of China. Sinensia 6: 44-97.
  • A. Günther (1874): Descriptions of new species of fishes in the British Museum. Ann. Mag. Nat. Hist. (Ser. 4) 14: 453-455.
  • SL Hora (1931): On a new Homalopterid fish from Annam. Ann. Mag. Nat. Hist. (Ser. 10) 6: 582-586, Pl.15.
  • SL Hora (1932): Classification, bionomics and evolution of homalopterid fishes . Mem. Indian Mus. 12: 263-330, Pls. 10-12.
  • VH Nguyen (2005): Ca Nuoc Ngot Viet Nam. Tap II. [Freshwater fishes of Vietnam]. Ca nuoc ngot Viet Nam. Tap II, v. 2: 760 pp.
  • M. Oshima (1919): Contributions to the study of the fresh water fishes of the island of Formosa. Ann. Carnegie Mus. 12: 169-328, Pls. 48-53.
  • LS Ramaswami (1953): Skeleton of cyprinoid fishes in relation to phylogenetic studies. V. Proc. natl. inst. sci. India 19: 323-347.
  • CT Regan (1911): The classification of the teleostean fishes of the order Ostariophysi. I. Cyprinoidea. Ann. Mag. Nat. Hist. (Ser. 8) 8: 13-32.
  • TR Roberts (1989): The freshwater fishes of western Borneo (Kalimantan Barat, Indonesia) . Memoirs of the California Academy of Sciences 14: i-xii + 1-210.
  • EG Silas (1953): Classification, zoogeography and evolution of the fishes of the cyprinoid families Homalopteridae and Gastromyzonidae. Rec. Indian Mus. (Calcutta) 50: 173-263.
  • HH Tan and ZH Suleiman (2006): Three new species of Gastromyzon (Teleostei: Balitoridae) from the Temburong River basin, Brunei Darussalam, Borneo. Zootaxa 1126: 1-18.
  • W. Wickler (1971): Behavioral studies on a highly specialized demersal, Gastromyzon borneensis (Cyprinoidea, Gastromyzonidae). Journal of Animal Psychology 29: 467-480
  • CY Zheng and YY Chen (1980): The homalopterid fishes from Guangdong Province, China. Acta zootaxon. sin. 5: 89-101.

supporting documents

  1. ^ HW Fowler (1905): Some fishes from Borneo. Proc. Acad. Nat. Sci. Philad. 57: 455-523.
  2. ^ A b Joseph S. Nelson, Terry C. Grande, Mark VH Wilson: Fishes of the World. Wiley, Hoboken, New Jersey, 2016, ISBN 978-1118342336 . Page 192.
  3. ↑ Maurice Kottelat (2012): Conspectus cobitidum: an inventory of the loaches of the world (Teleostei: Cypriniformes: Cobitoidei) . The Raffles Bulletin of Zoology, Suppl. 26: 1-199. PDF
  4. ↑ Maurice Kottelat (2004): On the Bornean and Chinese Protomyzon (Teleostei: Balitoridae), with descriptions of two new genera and two new species from Borneo, Vietnam and China. Ichthyol. Explor. Freshwaters 15: 301-310.

Web links

Commons : Gastromyzontidae  - Collection of images, videos and audio files