Protopterus

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African lungfish
Temporal range: 83.6–0  Ma [1]
Gotehal-2.jpg
Protopterus annectens
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Sarcopterygii
Class: Dipnoi
Order: Ceratodontiformes
Family: Protopteridae
Peters, 1855
Genus: Protopterus
Owen, 1839
Species
Protopterus map.jpg
Synonyms [2] [3] [4]
  • ProtomelusHogg 1841
  • RhinocryptisPeters 1844

Protopterus is the genus of four species of lungfish found in Africa. Protopterus is considered the sole genus in the family Protopteridae, which is grouped with Lepidosiren in the order Lepidosireniformes. [5] [6] [7] [8]

Contents

Taxonomy

The earliest fossils of the Protopteridae come from the Late Cretaceous (Campanian-Maastrichtian) of Sudan, [9] but phylogenetic evidence indicates that it and Lepidosirenidae split at the very beginning of the Early Cretaceous, around 145 Ma. [8] Together, their common ancestor diverged from the only other extant lungfishes in Neoceratodontidae during the Late Jurassic. [10]

Some papers suggest grouping Protopterus and Lepidosiren together in the family Lepidosirenidae, as their Cretaceous divergence is relatively recent compared to the Carboniferous origins of other lungfish families. However, most taxonomic authorities retain them as distinct families. [6] [7] [8]

Description

African lungfish are elongated, eel-like fishes with thread-like pectoral and pelvic fins. They have soft scales, and the dorsal and tail fins are fused into a single structure. They can either swim like eels or crawl along the bottom using their pectoral and pelvic fins. [11] The largest species can reach about 200 cm (6.6 ft) in length. [4]

African lungfish generally inhabit shallow waters, such as swamps and marshes. They are also found in larger lakes such as Lake Victoria. They can survive out of water for many months by burrowing into hardened mud beneath a dried stream bed. They are carnivorous, feeding on crustaceans, aquatic insect larvae, and molluscs. [11]

Biology

Lateral view of lungs of a dissected Protopterus dolloi Lungs of Protopterus dolloi.JPG
Lateral view of lungs of a dissected Protopterus dolloi
Clod of mud containing the cocoon of lung fish PSM V63 D037 Clod of earth containing cocoon of lung fish.png
Clod of mud containing the cocoon of lung fish

The African lungfish is an example of how the evolutionary transition from breathing water to breathing air can occur. Lungfish are periodically exposed to water with low oxygen content or encounter situations in which their aquatic environment dries up. To cope with these conditions, they have developed an adaptation in the form of an outpocketing of the gut, similar to the swim bladder found in other fishes. This specialized structure functions as a lung. [11] Within the lung, numerous thin-walled blood vessels allow the blood to absorb oxygen from the air that is gulped into the lung.

They are obligate air breathers, with reduced gills in the adults. There are two anterior gill arches that retain gills, though they are too small to function as the sole respiratory apparatus, and may be more important for carbon dioxide elimination. About 90% of their oxygen is acquired via their lungs, and the remaining ~10% via the gills and skin. [12] The lungfish heart has adaptations that partially separate the flow of blood into its pulmonary and systemic circuits. The atrium is partially divided, so that the left side receives oxygenated blood and the right side receives deoxygenated blood from the other tissues. These two blood streams remain mostly separate as they flow through the ventricle leading to the gill arches. As a result, oxygenated blood mostly goes to the anterior gill arches and the deoxygenated blood mostly goes to the posterior arches.

African lungfishes breed at the beginning of the rainy season. They construct nests or burrows in the mud to hold their eggs, which they then guard against predators. When they hatch, the young resemble tadpoles, with external gills, and only later develop lungs and begin to breathe air. [11]

Spotted African lungfish, Protopterus dolloi Protopterus dolloi Boulenger2.jpg
Spotted African lungfish, Protopterus dolloi

As food

Until the introduction of the Nile perch to the region, lungfish typically comprised a small proportion of a fisherman's catch. Transportation to market from catching sites in Lake Victoria was often done with fish sun-dried for better preservation. Human consumption of the lungfish varies by population; the Luo peoples occasionally do so but the Sukuma avoid eating lungfish due to a taste which is "locally either highly appreciated or strongly disliked." [13] As technology advancements such as longlines and gillnets have been increasingly applied over the past 50 years, the lungfish populations there are believed to be decreasing.

Species and subspecies

Marbled or leopard African lungfish, Protopterus aethiopicus Leopard lungfish (Protopterus aethiopicus) close - GRB.JPG
Marbled or leopard African lungfish, Protopterus aethiopicus

The family Protopteridae and genus Protopterus contain four extant (living) species: [4]

Other extinct species are known from fossil remains:

Related Research Articles

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<span class="mw-page-title-main">Climbing gourami</span> Family of fishes

The Anabantidae are a family of ray-finned fish within the order Anabantiformes commonly called the climbing gouramies or climbing perches. The family includes about 34 species. As labyrinth fishes, they possess a labyrinth organ, a structure in the fish's head which allows it to breathe atmospheric oxygen. Fish of this family are commonly seen gulping at air at the surface of the water. The air is held in a structure called the suprabranchial chamber, where oxygen diffuses into the bloodstream via the respiratory epithelium covering the labyrinth organ. This therefore allows the fish to move small distances across land.

<span class="mw-page-title-main">Lungfish</span> A type of bony fish

Lungfish are freshwater vertebrates belonging to the class Dipnoi. Lungfish are best known for retaining ancestral characteristics within the Osteichthyes, including the ability to breathe air, and ancestral structures within Sarcopterygii, including the presence of lobed fins with a well-developed internal skeleton. Lungfish represent the closest living relatives of the tetrapods. The mouths of lungfish typically bear tooth plates, which are used to crush hard shelled organisms.

<span class="mw-page-title-main">Sarcopterygii</span> Class of fishes

Sarcopterygii — sometimes considered synonymous with Crossopterygii — is a taxon of the bony fish known as the lobe-finned fish or sarcopterygians, characterised by prominent muscular limb buds (lobes) within the fins, which are supported by articulated appendicular skeletons. This is in contrast to the other clade of bony fish, the Actinopterygii, which have only skin-covered bony spines (lepidotrichia) supporting the fins.

<span class="mw-page-title-main">Bichir</span> Family of archaic-looking ray-finned fishes

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<span class="mw-page-title-main">Swamp eel</span> Family of fishes

The swamp eels are a family (Synbranchidae) of freshwater eel-like fishes of the tropics and subtropics. Most species are able to breathe air and typically live in marshes, ponds and damp places, sometimes burying themselves in the mud if the water source dries up. They have various adaptations to suit this lifestyle; they are long and slender, they lack pectoral and pelvic fins, and their dorsal and anal fins are vestigial, making them limbless vertebrates. They lack scales and a swimbladder, and their gills open on the throat in a slit or pore. Oxygen can be absorbed through the lining of the mouth and pharynx, which is rich in blood vessels and acts as a "lung".

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The Australian lungfish, also known as the Queensland lungfish, Burnett salmon and barramunda, is the only surviving member of the family Neoceratodontidae. It is one of only six extant lungfish species in the world. Endemic to Australia, the Neoceratodontidae are an ancient family belonging to the class Sarcopterygii, or lobe-finned fishes.

<span class="mw-page-title-main">South American lungfish</span> Species of fish

The South American lungfish, also known as the American mud-fish and scaly salamanderfish, is the single species of lungfish found in swamps and slow-moving waters of the Amazon, Paraguay, and lower Paraná River basins in South America. Notable as an obligate air-breather, it is the sole member of its family Lepidosirenidae, although some authors also place Protopterus in the family. In Brazil, it is known by the indigenous language Tupi name piramboia, which means "snake-fish", and synonyms pirarucu-bóia, traíra-bóia, and caramuru.

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The marbled lungfish is a lungfish of the family Protopteridae. Also known as the leopard lungfish, it is found in Eastern and Central Africa, as well as the Nile region. At 133 billion base pairs, it has the largest known genome of any animal and one of the largest of any organism, along with the flowering plant Paris japonica and the protist Polychaos dubium at 150 billion and 670 billion, respectively.

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<span class="mw-page-title-main">West African lungfish</span> Species of fish

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<i>Polypterus palmas</i> Species of fish

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References

  1. "Protopterus". paleobiodb.org. Retrieved 2022-06-03.
  2. "Part 7- Vertebrates". Collection of genus-group names in a systematic arrangement. Archived from the original on 5 October 2016. Retrieved 30 June 2016.
  3. Haaramo, Mikko (2007). "Ceratodiformes – recent lungfishes". Mikko's Phylogeny Archive. Retrieved 3 July 2016.
  4. 1 2 3 Froese, R.; Pauly, D. (2017). "Protopteridae". FishBase version (02/2017). Retrieved 18 May 2017.
  5. "ITIS - Report: Protopteridae". www.itis.gov. Retrieved 2023-03-13.
  6. 1 2 "FAMILY Details for Protopteridae - African lungfishes". www.fishbase.se. Retrieved 2023-03-13.
  7. 1 2 Van Der Laan, Richard; Eschmeyer, William N.; Fricke, Ronald (2014-11-11). "Family-group names of Recent fishes". Zootaxa. 3882 (1): 1–230. doi: 10.11646/zootaxa.3882.1.1 . ISSN   1175-5334. PMID   25543675.
  8. 1 2 3 Kemp, Anne; Cavin, Lionel; Guinot, Guillaume (2017-04-01). "Evolutionary history of lungfishes with a new phylogeny of post-Devonian genera". Palaeogeography, Palaeoclimatology, Palaeoecology. 471: 209–219. Bibcode:2017PPP...471..209K. doi: 10.1016/j.palaeo.2016.12.051 . ISSN   0031-0182.
  9. "Protopterus protopteroides". paleobiodb.org. Retrieved 2022-06-03.
  10. Brownstein, Chase Doran; Harrington, Richard C; Near, Thomas J. (2023-04-12). "The biogeography of extant lungfishes traces the breakup of Gondwana". Journal of Biogeography. doi: 10.1111/jbi.14609 . ISSN   0305-0270.
  11. 1 2 3 4 Bruton, Michael N. (1998). Paxton, J.R.; Eschmeyer, W.N. (eds.). Encyclopedia of Fishes. San Diego: Academic Press. pp. 70–72. ISBN   0-12-547665-5.
  12. A single-cell atlas of West African lungfish respiratory system reveals evolutionary adaptations to terrestrialization
  13. Kees (P. C.) Goudswaard, Frans Witte, Lauren J. Chapman, Decline of the African lungfish (Protopterus aethiopicus) in Lake Victoria (East Africa) East African Wild Life Society, African Journal of Ecology, 40, 42-52, 2002