Protopterus Annectens
   HOME

TheInfoList



OR:

''Protopterus'' is the
genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
of four
species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
of
lungfish 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, inc ...
found in
Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...
. ''Protopterus'' is considered the sole genus in the family Protopteridae, which is grouped with ''
Lepidosiren The South American lungfish (''Lepidosiren paradoxa''), 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 the order
Lepidosireniformes Lev Berg Lev Semyonovich Berg, also known as Leo S. Berg (; 14 March 1876 – 24 December 1950) was a leading Russian geographer, biologist and ichthyologist who served as President of the Soviet Geographical Society between 1940 and 1950. He i ...
.


Taxonomy

The earliest fossils of the Protopteridae come from the
Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...
(
Campanian The Campanian is the fifth of six ages of the Late Cretaceous epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campa ...
-
Maastrichtian The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ...
) of
Sudan Sudan, officially the Republic of the Sudan, is a country in Northeast Africa. It borders the Central African Republic to the southwest, Chad to the west, Libya to the northwest, Egypt to the north, the Red Sea to the east, Eritrea and Ethiopi ...
, but
phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...
evidence indicates that it and Lepidosirenidae split at the very beginning of the
Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...
, around 145 Ma. Together, their common ancestor diverged from the only other extant lungfishes in
Neoceratodontidae Neoceratodontidae is a Family (biology), family of lungfish containing ''Neoceratodus'' (represented by the extant Australian lungfish) and the extinct ''Mioceratodus''. It, South American lungfish, Lepidosirenidae, and Protopterus, Protopteridae ...
during the
Late Jurassic The Late Jurassic is the third Epoch (geology), epoch of the Jurassic Period, and it spans the geologic time scale, geologic time from 161.5 ± 1.0 to 143.1 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic stratum, strata.Owen ...
. 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.


Description

African lungfish are elongated,
eel Eels are ray-finned fish belonging to the order Anguilliformes (), which consists of eight suborders, 20 families, 164 genera, and about 1000 species. Eels undergo considerable development from the early larval stage to the eventual adult stage ...
-like fishes with thread-like
pectoral Pectoral may refer to: * The chest region and anything relating to it. * Pectoral cross, a cross worn on the chest * a decorative, usually jeweled version of a gorget * Pectoral (Ancient Egypt), a type of jewelry worn in ancient Egypt * Pectora ...
and
pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral (belly) surface of fish, and are the lower of the only two sets of paired fins (the other being the laterally positioned pectoral fins). The pelvic fins are homologous to the hi ...
s. They have soft
scales Scale or scales may refer to: Mathematics * Scale (descriptive set theory), an object defined on a set of points * Scale (ratio), the ratio of a linear dimension of a model to the corresponding dimension of the original * Scale factor, a number ...
, and the
dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage The fus ...
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. The largest species can reach about in length. African lungfish generally inhabit shallow waters, such as swamps and marshes. They are also found in larger lakes such as
Lake Victoria Lake Victoria is one of the African Great Lakes. With a surface area of approximately , Lake Victoria is Africa's largest lake by area, the world's largest tropics, tropical lake, and the world's second-largest fresh water lake by surface are ...
. They can survive out of water for many months by burrowing into hardened mud beneath a dried stream bed. They are carnivorous, feeding on
crustacean Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...
s, aquatic insect larvae, and
mollusc Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...
s.


Biology

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 The swim bladder, gas bladder, fish maw, or air bladder is an internal gas-filled organ (anatomy), organ in bony fish that functions to modulate buoyancy, and thus allowing the fish to stay at desired water depth without having to maintain lift ...
found in other fishes. This specialized structure functions as a lung. 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 arch Branchial arches or gill arches are a series of paired bony/ cartilaginous "loops" behind the throat ( pharyngeal cavity) of fish, which support the fish gills. As chordates, all vertebrate embryos develop pharyngeal arches, though the event ...
es 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. 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
tadpole A tadpole or polliwog (also spelled pollywog) is the Larva, larval stage in the biological life cycle of an amphibian. Most tadpoles are fully Aquatic animal, aquatic, though some species of amphibians have tadpoles that are terrestrial animal, ...
s, with
external gills External gills are the gills of an animal, most typically an amphibian, that are exposed to the environment, rather than set inside the pharynx and covered by gill slits, as they are in most fishes. Instead, the respiratory organs are set on a fri ...
, and only later develop lungs and begin to breathe air.


As food

Until the introduction of the
Nile perch The Nile perch (''Lates niloticus''), also known as the African snook, Goliath perch, African barramundi, Goliath barramundi, Giant lates or the Victoria perch, is a species of freshwater fish in family Latidae of order Perciformes. It is wides ...
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 The Luo (also spelled Lwo) are several ethnic group, ethnically and language family, linguistically related Nilotic, Nilotic ethnic groups that inhabit an area ranging from Egypt and Sudan to South Sudan and Ethiopia, through Northern Uganda an ...
occasionally do so but the
Sukuma Sukuma may refer to: *the Sukuma people *the Sukuma language *the Swahili name for Colewort **the dish sukuma wiki Sukuma wiki is an East African dish made with collard greens, known as , cooked with onions and spices. It is often served and ea ...
avoid eating lungfish due to a taste which is "locally either highly appreciated or strongly disliked."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 As technology advancements such as longlines and
gillnet Gillnetting is a fishing method that uses gillnets: vertical panels of netting that hang from a line with regularly spaced floaters that hold the line on the surface of the water. The floats are sometimes called "corks" and the line with corks is ...
s have been increasingly applied over the past 50 years, the lungfish populations there are believed to be decreasing.


Species and subspecies

The family Protopteridae and genus ''Protopterus'' contain four extant (living) species: * '' Protopterus aethiopicus'' Heckel, 1851 — marbled lungfish ** ''P. a. aethiopicus'' Heckel, 1851 ** ''P. a. congicus''
Poll Poll, polled, or polling may refer to: Forms of voting and counting * Poll, a formal election ** Election verification exit poll, a survey taken to verify election counts ** Polling, voting to make decisions or determine opinions ** Polling pla ...
, 1961
** ''P. a. mesmaekersi''
Poll Poll, polled, or polling may refer to: Forms of voting and counting * Poll, a formal election ** Election verification exit poll, a survey taken to verify election counts ** Polling, voting to make decisions or determine opinions ** Polling pla ...
, 1961
* '' Protopterus amphibius'' ( W. K. H. Peters, 1844) — gilled African lungfish or East African lungfish * '' Protopterus annectens'' (
Owen Owen may refer to: People and fictional characters * Owen (name), including a list of people and fictional characters with the given name or surname Places United States * Owen, Missouri, a ghost town * Owen, Wisconsin * Owen County, Indiana ...
, 1839)
— West African lungfish ** ''P. a. annectens'' (Owen, 1839) ** ''P. a. brieni''
Poll Poll, polled, or polling may refer to: Forms of voting and counting * Poll, a formal election ** Election verification exit poll, a survey taken to verify election counts ** Polling, voting to make decisions or determine opinions ** Polling pla ...
, 1961
— southern lungfish * '' Protopterus dolloi'' Boulenger, 1900 — slender lungfish or spotted African lungfish Other extinct species are known from fossil remains: * †'' Protopterus crassidens'' Churcher & de Iuliis 2001 * †'' Protopterus elongus'' Martin 1995 *†'' Protopterus libycus'' Stromer 1910 * †'' Protopterus nigeriensis'' Martin 1997 * †'' Protopterus polli'' Dartevelle & Casier 1949 *†'' Protopterus protopteroides'' Tabaste 1962 * †'' Protopterus regulatus'' Schall 1984


References

* Purves, Sadava, Orians, Heller, "Life: The Science of Biology" 7th ed. pg. 943. Courier Companies Inc: USA, 2004. {{Authority control Lobe-finned fish genera Taxa named by Richard Owen Freshwater fish genera