The spotted lungfish or slender lungfish (''Protopterus dolloi'') is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

lungfish Lungfish are freshwater vertebrates belonging to the order Dipnoi. Lungfish are best known for retaining ancestral characteristics within the Osteichthyes, including the ability to breathe air, and ancestral structures within Sarcopterygii, i ...

from

Middle Africa Central Africa is a subregion of the African continent comprising various countries according to different definitions. Angola, Burundi, the Central African Republic, Chad, the Democratic Republic of the Congo, the Republic of the Congo, Eq ...

, where found in the

Congo Congo or The Congo may refer to either of two countries that border the Congo River in central Africa: * Democratic Republic of the Congo, the larger country to the southeast, capital Kinshasa, formerly known as Zaire, sometimes referred to a ...

, Kouilou-Niari and Ogowe river basins. It is one of four extant species in the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

Protopterus.

Habitat

The slender lungfish is a freshwater fish and it largely inhabits the middle and lower Congo River basin. It is a primarily

demersal fish Demersal fish, also known as groundfish, live and feed on or near the bottom of seas or lakes (the demersal zone).Walrond Carl . "Coastal fish - Fish of the open sea floor"Te Ara - the Encyclopedia of New Zealand. Updated 2 March 2009 They occ ...

, dwelling in the riverbeds of the above basins and in

Stanley Pool The Pool Malebo, formerly Stanley Pool, also known as Mpumbu, Lake Nkunda or Lake Nkuna by local indigenous people in pre-colonial times, is a lake-like widening in the lower reaches of the Congo River.

. During spawning season, females can be found in open water.

Biology

The slender lungfish has an

anguilliform Fish locomotion is the various types of animal locomotion used by fish, principally by swimming. This is achieved in different groups of fish by a variety of mechanisms of propulsion, most often by wave-like lateral flexions of the fish's body a ...

body, much like an eel. The body of the slender lungfish is generally brown; young of the species oftentimes have black spots throughout the body, however adults generally lose these spots as they age. Like all African lungfish the slender lungfish is an obligate air-breather and is capable of

aestivation Aestivation ( la, aestas (summer); also spelled estivation in American English) is a state of animal dormancy, similar to hibernation, although taking place in the summer rather than the winter. Aestivation is characterized by inactivity and ...

; however, it generally does not aestivate. When it does aestivate, the lungfish creates a dry mucus cocoon on land. As most tropical fish are

ammoniotelic Metabolic wastes or excrements are substances left over from metabolic processes (such as cellular respiration) which cannot be used by the organism (they are surplus or toxic), and must therefore be excreted. This includes nitrogen compounds, w ...

, being on land can induce ammonia toxicity – with negative organismal and cellular level consequences – due to a lack of water to flush excreted ammonia from the gills and other cutaneous surfaces. Studies have shown that the slender lungfish has evolved the ability to reduce endogenous ammonia production, as well as an

ornithine-urea cycle The urea cycle (also known as the ornithine cycle) is a cycle of biochemical reactions that produces urea (NH2)2CO from ammonia (NH3). Animals that use this cycle, mainly amphibians and mammals, are called ureotelic. The urea cycle converts high ...

to increase the conversion rate of ammonia to less toxic

urea Urea, also known as carbamide, is an organic compound with chemical formula . This amide has two amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest amide of carbamic acid. Urea serves an important r ...

, to defend against this toxicity.

Reproduction

Spotted lungfish nests are generally found in June through October. During this time period the male makes a nest and buries it in mud, not unlike the

marbled lungfish The marbled lungfish (''Protopterus aethiopicus'') 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 ...

mating behavior. He guards both eggs and larvae during this time. The female does not take care of the young but rather during this time can be found open water in rivers within its range.

Habitat

Biology

Reproduction

References

Further reading