Mahenge Formation
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Mahenge Formation
The Mahenge Formation is a Eocene, Middle Eocene-aged geological formation and ''Konservat-Lagerstätte'' from Tanzania. It contains a high variety of exceptionally-preserved fossils, including many of the earliest fossil records of dominant freshwater fish groups found in Africa today. It represents one of the most comprehensive Paleogene-aged African fossil deposits south of the Sahara. Based on fossil plant remains found in the formation, the Mahenge lake was situated within legume-dominated woodlands reminiscent of modern ''miombo'' forests. It was deposited within a former Maar, maar lake formed from a volcanic intrusion into the Precambrian bedrock via a kimberlite pipe. It has been dated to the Lutetian, roughly 46.0 million years ago. Unusually, relatively few fossil insect remains are known from the lake, unlike with other maar deposits. It is thought that the high diversity of fish in the lake may have led to most insects being consumed before they could be fossilized. P ...
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Eocene
The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes from the Ancient Greek (''Ēṓs'', 'Eos, Dawn') and (''kainós'', "new") and refers to the "dawn" of modern ('new') fauna that appeared during the epoch.See: *Letter from William Whewell to Charles Lyell dated 31 January 1831 in: * From p. 55: "The period next antecedent we shall call Eocene, from ήως, aurora, and χαινος, recens, because the extremely small proportion of living species contained in these strata, indicates what may be considered the first commencement, or ''dawn'', of the existing state of the animate creation." The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a brief period in which the concentration of the carbon isoto ...
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Osteoglossidae
Osteoglossidae is a family of large-sized freshwater fish, which includes the arowanas. They are commonly known as bonytongues. The family has been regarded as containing two extant subfamilies Arapaiminae and Osteoglossinae, with a total of five living genera, but these are regarded as valid families in '' Eschmeyer's Catalog of Fishes'' The extinct Phareodontinae are known from worldwide during the Late Cretaceous and Paleogene; they are generally considered to be crown group osteoglossids that are more closely related to one of the extant osteoglossid subfamilies than the other, though their exact position varies. Evolution Osteoglossids are basal teleosts that originated during the Cretaceous, and are placed in the actinopterygian order Osteoglossiformes. The traditionally defined wider family includes several extant species from South America, one from Africa, two from Asia, and two from Australia. The earliest known osteoglossid is '' Cretophareodus'' from the mi ...
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Species Complex
In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each other, further blurring any distinctions. Terms that are sometimes used synonymously but have more precise meanings are cryptic species for two or more species hidden under one species name, sibling species for two (or more) species that are each other's closest relative, and species flock for a group of closely related species that live in the same habitat. As informal taxonomic ranks, species group, species aggregate, macrospecies, and superspecies are also in use. Two or more taxa that were once considered conspecific (of the same species) may later be subdivided into infraspecific taxa (taxa within a species, such as plant variety (botany), varieties), which may be a complex ranking but it is not a species complex. In most cases, a specie ...
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Cichlid
Cichlids () are a large, diverse, and widespread family of percomorph fish in the family Cichlidae, order Cichliformes. At least 1,760 species have been scientifically described, making it one of the largest vertebrate families, with only the Cyprinidae being more speciose. New species are discovered annually, and many species remain undescribed. The actual number of species is therefore unknown, with estimates varying between 2,000 and 3,000. They are native to the Neotropics, Africa (including Madagascar), the Middle East, and the Indian subcontinent, although some species have been introduced worldwide. Many cichlids, particularly tilapia, are important food fishes, while others, such as the '' Cichla'' species, are valued game fish. The family also includes many popular freshwater aquarium fish kept by hobbyists, including the angelfish, oscars, and discus. Cichlids have the largest number of endangered species among vertebrate families, most in the haplochrom ...
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Characiformes
Characiformes is an order of ray-finned fish, comprising the characins and their allies. Grouped in 18 recognized families, more than 2000 different species are described, including the well-known piranha and tetras.; Buckup P.A.: "Relationships of the Characidiinae and phylogeny of characiform fishes (Teleostei: Ostariophysi)", ''Phylogeny and Classification of Neotropical Fishes'', L.R. Malabarba, R.E. Reis, R.P. Vari, Z.M. Lucena, eds. (Porto Alegre: Edipucr) 1998:123-144. Taxonomy The Characiformes form part of a series called the Otophysi within the superorder Ostariophysi. The Otophysi contain three other orders, Cypriniformes, Siluriformes, and Gymnotiformes. The Characiformes form a group known as the Characiphysi with the Siluriformes and Gymnotiformes. The order Characiformes is the sister group to the orders Siluriformes and Gymnotiformes, though this has been debated in light of recent molecular evidence. Originally, the characins were all grouped within a sin ...
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Alestidae
African tetras (family (biology), family Alestidae, formerly spelled Alestiidae) are a group of Characiformes, characiform fish found exclusively in Africa. This family contains about 18 genera and 119 species. Among the best known members are the Congo tetra, and Hydrocynus, African tigerfish. Although presently found only in Africa, fossil evidence suggests that during the Paleogene, they ranged as far north as southern Europe and as far east as the Arabian subcontinent. Fossil remains date back to potentially the Late Paleocene with ''Hydrocynus'' remains known from Algeria. Alestid-like teeth are also known from the Late Cretaceous (Maastrichtian) of France, and phylogenetic evidence also suggests they diverged around this time. Taxonomy Taxonomy based on Van der Laan 2017 and ''Eschmeyer's Catalog of Fishes'' (2025): * Family Alestidae Cockerell, 1910 ** Genus ''Alestes'' Johannes Peter Müller, Müller & Franz Hermann Troschel, Troschel, 1844 ** Genus ''Alestion'' Tyson R ...
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Citharinidae
The Citharinidae, the lutefishes, are a small family of characiform fish. They are freshwater fish native to Africa, and are sufficiently abundant to be significant food fishes. They are deep-bodied, silvery fish, measuring up to in length and weighing up to . They are filter feeders. Genera The family contains three genera: *'' Citharidium'' Boulenger, 1902 (monotypic) *'' Citharinops'' Daget, 1962 (monotypic) *'' Citharinus'' Cuvier, 1817 (6 species) References * Characiformes families Taxa named by Albert Günther {{characiformes-stub ...
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Chrysichthys Auratus
The golden Nile catfish (''Chrysichthys auratus'') is a species of fish belonging to the family Claroteidae The Claroteidae are a family of catfish (order Siluriformes) found in Africa. This family was separated from Bagridae. However, the monophyly of the family is sometimes contested. The 9 genera contain 65 known species of claroteids. The family .... The species is found in Africa. The fish is widespread and is known from most of the West African hydrographic basins, except in the coastal areas between Gambia and Liberia, where it is replaced by '' Chrysichthys maurus''.Risch, L.M., 1992. Bagridae. p. 395-431. In C. Lévêque, D. Paugy and G.G. Teugels (eds.) Faune des poissons d'eaux douces et saumâtres d'Afrique de l'Ouest. Tome 2. Coll. Faune Tropicale N° XXVIII. Musée Royal de l'Afrique Centrale, Tervuren, Belgique and O.R.S.T.O.M., Paris, France. It is also present from southern Liberia to Cabinda in Angola, and widespread throughout Lower Guinea. It is also rep ...
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Catfish
Catfish (or catfishes; order (biology), order Siluriformes or Nematognathi) are a diverse group of ray-finned fish. Catfish are common name, named for their prominent barbel (anatomy), barbels, which resemble a cat's whiskers, though not all catfish have prominent barbels or "whiskers", with some seemingly not having them. Siluriformes as a whole are Fish scale, scale-less, with neither the Armoured catfish, armour-plated nor the naked species having scales. This order of fish are Autapomorphy, defined by features of the skull and swimbladder. Catfish range in size and behavior from the three List of largest fish, largest species alive, the Mekong giant catfish from Southeast Asia, the wels catfish of Eurasia, and the piraíba of South America, to detritivorous and scavenging bottom feeders, down to tiny ectoparasitic species known as the Candiru (fish), candirus. In the Southern United States, catfish species may be known by a variety of slang names, such as "mud cat", " ...
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