Australian lungfish
| Australian lungfish | ||||||||||||
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Australian lungfish ( Neoceratodus forsteri ) |
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| Systematics | ||||||||||||
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| Scientific name of the family | ||||||||||||
| Neoceratodontidae | ||||||||||||
| Miles , 1977 | ||||||||||||
| Scientific name of the genus | ||||||||||||
| Neoceratodus | ||||||||||||
| Krefft , 1870 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Neoceratodus forsteri | ||||||||||||
| ( Krefft , 1870) |
The Australian lungfish ( Neoceratodus forsteri ), also known as Djelleh , Barramunda , Burnett Salmon or Queensland lungfish , is the only Australian representative of the subclass of lungfish comprising only six recent species . It is considered to be the most original species of all lung fish occurring today. The lungfish are well known in fossil history from 400 to around 230 million years ago with a great diversity of species. Therefore, the species of the three recent genera are also known as living fossils . The Australian lungfish wasn't discovered until 1870.
Occurrence
The Australian lungfish were originally found only in the Burnett and Mary River river systems in south-eastern Queensland , Australia. However, it was later successfully settled in several neighboring rivers, such as the Brisbane , Albert, Coomera and Stanley Rivers and the Enoggera Reservoir.
In contrast to other species, this lungfish lives in slow-flowing, stagnant waters that do not dry out completely. Here his lungs help him to survive the low-oxygen conditions that result from the partial evaporation of the water. During increased activity or in dry times, when the oxygen supply via the gills is no longer sufficient, it rises to the surface twice an hour to breathe. The sound when you exhale is reminiscent of a small bellows.
description
The brown-olive on the top and light-colored fish on the underside with the elongated trunk is usually up to 90 cm long, occasionally 1.75 m long and weighs up to 43 kg. There are small eyes in the flattened head. It has muscular pectoral and pelvic arms that allow it to move slowly over the mud on the bottom of the water. The beginning of the dorsal fin is in the middle of the back; it is fused with the tail and anal fins like a seam. In contrast to the South American and African lungfish, it has very large, bony scales .
Like all lungfish, the Australian lungfish can breathe with one lung in addition to gills . The separation of the blood circulation into a pulmonary and a body circulation has taken place in this species to a far greater extent than in other lung fish. Unlike the species of the Lepidosireniformes , which develop a two-part lung, it only develops one. As with the other species of lungfish, this one is also divided into small, breathable chambers with an elaborate system of partitions. In addition to breathing, the individual lungs also serve to generate buoyancy in this species. Correspondingly, the lungs of the Australian lungfish are not as efficient at taking up oxygen, and as an optional air breathers they inhabit habitats with a much lower need for air breathing than the obligatory air breathers of the African and South American lungfish. With this, this species has taken a small step towards an adjustable buoyancy device.
Living fossil
Lungfish tooth plate fossils, indistinguishable from those of recent Neoceratodus , have been excavated from Lower Cretaceous sediments in northern New South Wales . This species has survived practically unchanged for more than 100 million years and is therefore probably the oldest vertebrate species living today . According to the available data, the genus Neoceratodes is a sister group to a common clade from the African Protopterus and the South American Lepidosiren , so the age of the stem line can be at least 110 million, but probably (taking fossil taxa) even 250 million years, at the beginning of the Triassic be traced.
Woodcut from 1898, British Museum
Scales at the level of the sideline
Preserved pelvic girdle with pelvic fins
nutrition
The fish is predominantly nocturnal and feeds on frogs, tadpoles, fish, invertebrates and aquatic plants. With the help of his tooth plates in both jaws he can crack hard clams and snails.
Multiplication
Spawning time in running waters is from August to December before the summer rains, when water temperatures rise above 20 ° C. After extensive courtship behavior , they spawn in pairs between aquatic plants. The spawn consists of gelatinous clumps with large eggs and resembles frog spawn . The fry that hatch after 3 to 4 weeks are reminiscent of tadpoles and only breathe through their gills. The fry often lie on their sides on the bottom. Under optimal conditions they can reach 25 cm in length in the first six months, but they are usually significantly smaller.
use
The fish was a popular food fish, but is now a protected species.
threat
Although the species does not appear to be acutely endangered due to its current range, it is strictly protected.
By decree of May 6, 2006, the government of the Australian state of Queensland decided to build a dam on the Mary River. This dam would have destroyed important spawning grounds for the species and endangered the remaining population. At the end of 2009, the project was abandoned due to such considerations.
literature
- G. Allen, S. Midgley, M. Allen: Field Guide to the Freshwater Fishes of Australia . 2nd Edition. Western Australian Museum, Perth 2003, ISBN 0-7307-5486-3 .
- Edwin Stephen Goodrich : Studies on the Structure and Development of Vertebrates . MacMillan & Co, London 1930.
- Alfred Romer : The Vertebrate Body . 1964.
- G. Lauder, K. Liem: The evolution and interrelationships of the actinopterygian fishes . In: Bulletin of The Museum of Comparative Zoology . tape 150 , 1983, pp. 95-197 .
- G. Lauder, K. Liem: Patterns of diversity and evolution in ray-finned fishes . In: Fish Neurobiology . tape 1 , 1983, p. 1-14 .
Web links
- Australian lungfish on Fishbase.org (English) (species)
- Australian Lungfish on Fishbase.org (family)
- Ceratodontiformes on Fishbase.org (English)
Single receipts
- ↑ Warren W. Burggren, Kjell Johansen: Circulation and respiration in lung fishes (Dipnoi). In: Journal of Morphology , Vol. 190, No. S1, 1986, pp. 217-236.
- ^ A. Kemp and RE Molnar (1981): Neoceratodus forsteri from the Lower Cretaceous of New South Wales, Australia. Journal of Paleontology 55 (1): 211-217.
- ^ Lionel Cavin and Anne Kemp (2011): The impact of fossils on the Evolutionary Distinctiveness and conservation status of the Australian lungfish. Biological Conservation 144: 3140-3142. doi: 10.1016 / j.biocon.2011.08.014