Overview

Brief Summary

Gastromyzon is a genus of fishes found exclusively on the island of Borneo. Species in this genus, known as torrent loaches, are obligate bottom-dwellers and exhibit extreme morphological adaptations for life in torrential waters. They have a streamlined shape, wide head, and tapering body. They are poor swimmers and have lost the ability to hover or swim in mid-water. As a consequence, fishes in this genus have evolved new modes of locomotion, which involve creeping and crawling along the bottom and around submerged rocks. In most species, the ventral side of the fish is flat, made up of fused disks. Torrent loaches orient themselves facing upstream, clinging to rocks to avoid being swept downstream with the moving water. They tend to show coloration patterns that allow them to blend in with their environment.

Torrent loaches generally inhabit small, clear, fast moving waters with a rocky substrate. They range in size from 5 to 10 cm. Their diet consists mainly of algae, which they scrape off the rocks to which they cling.

(Inger and Kong 1961; Tan and Leh 2006; Tan and Sulaiman 2006)

  • Inger, R. F., & C.P. Kong. 1961. The Bornean Cyprinoid Fishes of the Genus Gastromyzon Günther. Copeia 1961(2):166-176.
  • Tan, H.H. and Z.H. Sulaiman. 2006. Three new species of Gastromyzon (Teleostei: Balitoridae) from the Temburong River basin, Brunei Darussalam, Borneo. Zootaxa 1117: 1-19.
  • Tan, H.H., & C.U.M. Leh. 2006. Three new species of Gastromyzon (Teleostei: Balitoridae) from southern Sarawak .Zootaxa 1126: 1–19.
Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© Sara Eckert and Leo Shapiro

Supplier: Sara Eckert

Unreviewed

Article rating from 0 people

Default rating: 2.5 of 5

Comprehensive Description

[[ Gastromyzon ZBK ]]

The genus Gastromyzon ZBK , a unique group of fishes endemic to the island of Borneo, exhibits extreme morphological adaptations for life in torrential waters. The included species, which are obligate bottom dwellers, are poor swimmers that have lost the ability to hover or swim in mid-water. As a consequence, the genus has evolved new modes of locomotion, which involve creeping and crawling along the bottom. Balitorid locomotion had been studied by Wickler (1971) using aquarium stocks of G. ctenocephalus ZBK (misidentified as G. borneensis ZBK ). He found that the horizontally oriented pectoral fins, fused pelvic fins, and depressed head and body collectively form a suction cup that enables the fish to adhere to the submerged rock substrate of fast flowing streams. The genera Gastromyzon ZBK , Hypergastromyzon ZBK and Neogastromyzon ZBK are characterized by fused pelvic fins; and a higher number of branched pectoral and pelvic-fin rays (numbering 20-30 and 16-24 respectively) than are found in the other 250 or more species of cyprinoids in the Sunda Islands, in which the number of branched pectoral rays does not usually exceed 17 and branched pelvic rays does not exceed 12 (and is usually not more than 8; Inger & Chin, 1961). Unicellular horny projections, or unculi, on the ventral surfaces of the fish’s body apparently also serve to increase adhesion on smooth rocky surfaces (Roberts, 1982a, 1982b, 1989).

  • H. H. Tan, Z. H. Sulaiman (2006): Three new species of Gastromyzon (Teleostei: Balitoridae) from the Temburong River basin, Brunei Darussalam, Borneo. Zootaxa 1117, 1-19: 1-1, URL:http://www.zoobank.org/urn:lsid:zoobank.org:pub:EFF4FFDA-A1B8-44EB-ACB4-F4A9623FB4B9
Public Domain

MagnoliaPress via Plazi

Source: Plazi.org

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

[[ Gastromyzon ZBK ]]

The genus Gastromyzon ZBK , which is endemic to Borneo, exhibits extreme external morphological adaptations for life in torrential waters. Obligate bottom dwellers, the included species have lost the ability to hover or swim in the mid-water column, and as a consequence have evolved new modes of locomotion, which involve creeping and crawling over submerged rocks. Locomotion in the genus has been studied by Wickler (1971) using aquarium stocks of G. ctenocephalus ZBK (misidentified as G. borneensis ZBK ). The horizontally oriented pectoral fins, fused pelvic fins, and depressed head and body collectively form a suction cup, which enables the fish to adhere to the submerged rocky substrate of fast-flowing stream habitats. In addition, the genus is characterized by greater numbers of pectoral and pelvic-fin rays, these numbering 20-30 and 16-24 branched rays, respectively. This compares to the other 250 or more species of cyprinoids in the Sunda Islands, in which the number of branched pectoral rays usually does not exceed 17 and the number of branched pelvic rays does not exceed 12 (with the latter usually no more than 8; Inger & Chin, 1961). Unicellular horny projections, or unculi, on the ventral surfaces of the fish apparently also serve to increase adhesion on smooth rock surfaces (Roberts, 1982a, 1982b, 1989). The morphological adaptations described above are shared by the closely related balitorid genera Hypergastromyzon ZBK and Neogastromyzon ZBK , which are also endemic to Borneo.

During the course of a taxonomic revision of Gastromyzon ZBK , collaborations were made with regional scientists to facilitate research and collections, which resulted in discovery of the three new species described in this paper.

  • H. H. Tan, C. U. M. Leh (2006): Three new species of Gastromyzon (Teleostei: Balitoridae) from southern Sarawak. Zootaxa 1126, 1-19: 1-2, URL:http://www.zoobank.org/urn:lsid:zoobank.org:pub:62372BE2-2974-42CF-B88F-0D3CD2B66F6C
Public Domain

MagnoliaPress via Plazi

Source: Plazi.org

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Wikipedia

Gastromyzon

Gastromyzon is a genus of gastromyzontid loaches native to Borneo.

Species

There are currently 36 species recognized in this genus:[1]

References

  1. ^ Kottelat, M. (2012): Conspectus cobitidum: an inventory of the loaches of the world (Teleostei: Cypriniformes: Cobitoidei). The Raffles Bulletin of Zoology, Suppl. No. 26: 1-199.
Creative Commons Attribution Share Alike 3.0 (CC BY-SA 3.0)

Source: Wikipedia

Unreviewed

Article rating from 0 people

Default rating: 2.5 of 5

Disclaimer

EOL content is automatically assembled from many different content providers. As a result, from time to time you may find pages on EOL that are confusing.

To request an improvement, please leave a comment on the page. Thank you!