Fish and aquatic news » William http://www.aquaticcommunity.com/news The latest news from below the surface Wed, 23 Oct 2013 11:30:17 +0000 en-US hourly 1 http://wordpress.org/?v=3.6.1 New Arapaima species -Arapaima leptosoma – Slender Arapaima http://www.aquaticcommunity.com/news/lib/1478 http://www.aquaticcommunity.com/news/lib/1478#comments Wed, 23 Oct 2013 11:25:48 +0000 William http://www.aquaticcommunity.com/news/?p=1478 A new species of arapaima, Arapaima leptosoma, has been described by Dr. Donald Stewart of the SUNY College of Environmental Science and Forestry (ESF) at Syracuse University. The new species has been described from specimen that were collected in 2001 near the confluence of the Solimões and Purus rivers in Amazonas State, Brazil. Stewarts discovery brings the total number of […]

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arapaima leptosoma New Arapaima species  Arapaima leptosoma   Slender ArapaimaA new species of arapaima, Arapaima leptosoma, has been described by Dr. Donald Stewart of the SUNY College of Environmental Science and Forestry (ESF) at Syracuse University. The new species has been described from specimen that were collected in 2001 near the confluence of the Solimões and Purus rivers in Amazonas State, Brazil. Stewarts discovery brings the total number of Arapaima species up to five .

donald stewart New Arapaima species  Arapaima leptosoma   Slender Arapaima

Dr Donald Stewart with two A. leptosoma

Four species of Arapaima were recognized in the mid-1800s, but in 1868, Albert Günther, a scientist at the British Museum of Natural History, published that those were all one species, Arapaima gigas. Over time, Günther’s view became the prevailing wisdom. Stewart did however look into these four species and it turns out that all four species are distinct different species.

Stewart believes that their might be more species of Arapaima out there. The fish is an appreciated food fish and has become increasingly rare. This combined with the fish large size means that there are few reference specimens out there which makes it easy to overlook a species or two. Stewart made his discovery when he examined preserved arapaima at the Instituto Nacional de Pesquisas da Amazônia in Manaus, Brazil.

The new species differ from the other species in several ways including the shape of sensory cavities on the head, a sheath that covers part of the dorsal fin and a distinctive color pattern. Its scientific name, A. leptosoma, is in reference to its slender body.

The Arapaima is becoming a more and more important species in aquaculture and this makes it very important to identify all different species and there natural range. If not, different species might be spread to new areas through aquaculture. Once in a new area fish might escape and what is an endangered species in one area might become an invasive species in another. Threatening the local Arapaima species in the area.

The wild populations of Arapaima is very low in many areas as a result of overfishing. Overfishing of Arapaima has been a problem for almost a century and conservation efforts as well as aquaculture of the fish is likely necessary to save these once common species. The conservation effort will however not be as effective as we might want it to be until all species has been identified.

The new species is most likely already cultured and exported into the aquarium trade but under the name Arapaima gigas. It can be mentioned that the new species already is on display in Europe in the Sevastopol Aquarium, Ukraine. The species has been on display there for a long time as A. gigas but is according to Stewart in fact Arapaima leptosoma.

arapaima leptosoma1 New Arapaima species  Arapaima leptosoma   Slender Arapaima

arapaima leptosoma

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Squeaker catfish evolved from single ancestor http://www.aquaticcommunity.com/news/lib/245 http://www.aquaticcommunity.com/news/lib/245#comments Thu, 30 Apr 2009 01:34:41 +0000 William http://www.aquaticcommunity.com/news/?p=245 The members of the genus Synodontis, commonly known as the squeaker catfishes of Lake Tanganyika, evolved from a single common ancestor according to a paper* published in a recent issue of the Journal of Evolutionary Biology.

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The members of the genus Synodontis, commonly known as the squeaker catfishes of Lake Tanganyika, evolved from a single common ancestor according to a paper* published in a recent issue of the Journal of Evolutionary Biology.

synodontis catfish Squeaker catfish evolved from single ancestor
synodontis catfish

Researchers Day, Bills and Friel** analysed 1697 base-pair sequences consisting of nuclear (ribosomal protein-codin gene S7), mitochondrial (cytochrome b) and transfer RNA gene fragments in 65 samples (representing about 40 species) of squeaker catfishes to study the evolutionary relationships of the group.

Through their research, the authors were able to track down a single origin for the Lake Tanganyika species flock. The members of the genus Synodontis all evolved within the last 5.5 million years which makes them a comparatively new addition to this Great Rift Valley Lake which is believed to be at least 9 million, perhaps even 12 million, years old.

Day, Bills and Friel also recovered a monophyletic group of southern African riverine species which seems to have diversified very rapidly (during the last 890,000 years). This group was believed to have been formed due to adaptive radiation within Lake Makgadikgadi; a lake which is now extinct.

* Day, JJ, R Bills & JP Friel (2009) Lacustrine radiations in African Synodontis catfish. Journal of Evolutionary Biology 22, pp. 805–817.

**Julia Day, Roger Bills and John Friel

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