| Glossogobius ankaranensis | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Gobiiformes |
| Family: | Gobiidae |
| Genus: | Glossogobius |
| Species: | G. ankaranensis |
| Binomial name | |
| Glossogobius ankaranensis Banister, 1994 | |
Glossogobius ankaranensis is a species of fish in the family Gobiidae. This cavefish is endemic to the Ankarana Reserve in Madagascar. Its natural habitat is inland karsts.
The Ankarana Mountain Range, formed by middle Jurassic sedimentary rock, is located in northern Madagascar, and its highest mountain is about 300 m (980 ft) above sea level. [2] Several trees grow in the mountains' canyons and downfallen caves. Evergreen trees especially have an advantage due to the waters from a system of rivers that flows through the caves. [2] Two important rivers enter the mountain range, the Andranotsisiloha and the Besaboba. These rivers are perennial and provide essential nutrients and habitat for an immense amount of organisms such as G. ankaranensis. [2] This species was found in the Second River Cave. The only approachable section of the Second Cave River is 150 m (490 ft) long and the deepest point is 2 m (6.6 ft) with a width of 5 m (16 ft). The water temperature benefits all organisms it houses because it oscillates around 21 °C (70 °F). [2]
Several physical characteristics distinguish this species from others that live in the region. The lack of pigmentation causes this fish to look pink in color; its blood and internal organs are visible through the scales. [2] Several rows of teeth are accommodated by a big mouth and thick lips. Another factor that helps accommodate the quantity of teeth is the fact that the lower jaws protrude further than the upper jaws. [2] G. ankaranensis is not light sensitive because little to no sunlight reaches the waters in which this species lives. [2] The lengths of these fish typically vary from about 4 to 7 cm (1.6–2.8 in), and they move around slowly with their mouths closed. [2]
Food is very abundant in these caves, which apparently keeps the population of these fishes stable. [2] Some of the species that serve as food for G. ankaranensis are shrimps, insects, and wastes from other animals and the environment. [2]
The discovery of G. ankaranensis was purely accidental. Two trips were performed by several scientists to the Ankarana Mountain Range. [2] The first trip was in 1981 and its mission was to explore the wild life of the Ankarana mountains and rivers. [2] During this trip, several new species of cave-adapted shrimps stood out to scientists and they decided to come back again. In 1986, much more attention was devoted to cave-adapted species. The new species G. ankaranensis, a white and blind fish, was found in the Second River Cave. [2]
These fish are blind; no ocular tissue is found in their eye sockets except for a little black spot in each of the eyes. [2] An increase in predation when G. ankaranensis is exposed to UV light might be due to the lack of eyes and pigments. [3] Pigments are necessary when G. ankaranensis is exposed to UV light because they deflect UV light. [3]
Neuromasts (sensory papillae or pit organs) are interesting adaptations that this species of fish have developed to deal with reduced vision. [4] These structures are not clustered in only one section of the individual's body but widely distributed. Six rows of neuromasts are located on the cheeks as well as the trunk of Glossogobius . Other rows of neuromasts can be found on the dorsolateral and ventrolateral series. [4] G. ankaranensis dark-adapted lifestyle can be supported by the widespread presence of neuromasts along the species body. [4]
Despite its small range, G. ankaranensis is not considered threatened, as it lives entirely within the Ankarana Reserve in an isolated region that is not subjected to human changes (in part because of a local fady ) and its population is relatively stable. [1] Annual floods can be important because much food can be derived from them, but floods can drastically diminish the fish population living in the caves of the Ankarana Reserve. [2] Though G. ankaranensis is generally dispersed among the caves of the Ankarana Mountain Range, the mountain range is very small (28 X 8 km at its widest region). [2]
The Mexican tetra, also known as the blind cave fish, blind cave characin or the blind cave tetra, is a freshwater fish in the Characidae family of the order Characiformes. The type species of its genus, it is native to the Nearctic realm, originating in the lower Rio Grande, and the Neueces and Pecos Rivers in Texas, into the Central Plateau and eastern states of Mexico.
The Amblyopsidae are a fish family commonly referred to as cavefish, blindfish, or swampfish. They are small freshwater fish found in the dark environments of caves, springs and swamps in the eastern half of the United States. Like other troglobites, most amblyopsids exhibit adaptations to these dark environments, including the lack of functional eyes and the absence of pigmentation. More than 200 species of cavefishes are known, but only six of these are in the family Amblyopsidae. One of these, Forbesichthys agassizii, spends time both underground and aboveground. A seventh species in this family, Chologaster cornuta, is not a cave-dweller but lives in aboveground swamps.
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Gobiidae or gobies is a family of bony fish in the order Gobiiformes, one of the largest fish families comprising more than 2,000 species in more than 200 genera. Most of gobiid fish are relatively small, typically less than 10 cm (3.9 in) in length, and the family includes some of the smallest vertebrates in the world, such as Trimmatom nanus and Pandaka pygmaea, Trimmatom nanus are under 1 cm long when fully grown, then Pandaka pygmaea standard length are 9 mm (0.35 in), maximum known standard length are 11 mm (0.43 in). Some large gobies can reach over 30 cm (0.98 ft) in length, but that is exceptional. Generally, they are benthic or bottom-dwellers. Although few are important as food fish for humans, they are of great significance as prey species for other commercially important fish such as cod, haddock, sea bass and flatfish. Several gobiids are also of interest as aquarium fish, such as the dartfish of the genus Ptereleotris. Phylogenetic relationships of gobiids have been studied using molecular data.
Tetrachromacy is the condition of possessing four independent channels for conveying color information, or possessing four types of cone cell in the eye. Organisms with tetrachromacy are called tetrachromats.
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Ankarana Special Reserve is a protected area in northern Madagascar created in 1956. It is a small, partially vegetated plateau composed of 150-million-year-old middle Jurassic limestone. With an average annual rainfall of about 2,000 millimetres (79 in), the underlying rocks have been eroded to produce caves and feed subterranean rivers—a karst topography. The rugged relief and the dense vegetation have helped protect the region from human intrusion and exploitation.
The crowned lemur is a lemur that is 31–36 cm (12–14 in) long and weighs 2 kg (4.4 lb). Its tail is about 42–51 cm (17–20 in) long.
The Madagascar dry deciduous forests represent a tropical dry forest ecoregion situated in the western and northern part of Madagascar. The area has high numbers of endemic plant and animal species but has suffered large-scale clearance for agriculture. They are among the world's richest and most distinctive dry forests and included in the Global 200 ecoregions by the World Wide Fund. The area is also home to distinctive limestone karst formations known as tsingy, including the World Heritage Site of Bemaraha.
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Caecobarbus geertsi, the African blind barb or Congo blind barb, is a species of cyprinid fish. This threatened cavefish is only known from Democratic Republic of the Congo, and it is the only member of the monotypic genus Caecobarbus. George Albert Boulenger described this fish in 1921 and it apparently lacks any close relatives in the Congo region.
Glossogobius is a genus of gobies native to fresh, brackish and marine waters from Africa to the coasts of the western Pacific Ocean. They are found in Madagascar, South Africa, Japan, Thailand, Australia, Indonesia, Bangladesh, the Philippines, Taiwan, Papua New Guinea, Singapore, Malawi, Eswatini, Botswana, Kenya, Zimbabwe, Tanzania, Mozambique, the Solomon Islands, Palau, Fiji, New Caledonia, India, Laos, Sri Lanka, Myanmar, Borneo, Nepal, Brunei Darussalam, Micronesia, Cambodia, Vietnam, China, Réunion, the Seychelles, Mauritius, the Caroline Islands, Vanuatu, Malaysia and Russia. The genus also includes a troglobitic species, G. ankaranensis.
Typhleotris is a genus of cavefish that are endemic to caves in southwestern Madagascar. Although traditionally considered to belong to the family Eleotridae, studies show that they represent a distinct and far-separated lineage together with the Milyeringa cavefish from Australia, leading some to move them to their own family, Milyeringidae.
The Gobiiformes are an order of fish that includes the gobies and their relatives. The order, which was previously considered a suborder of Perciformes, is made up of about 2,211 species that are divided between seven families. Phylogenetic relationships of the Gobiiformes have been elucidated using molecular data. Gobiiforms are primarily small species that live in marine water, but roughly 10% of these species inhabit fresh water. This order is composed chiefly of benthic or burrowing species; like many other benthic fishes, most gobiiforms do not have a gas bladder or any other means of controlling their buoyancy in water, so they must spend most of their time on or near the bottom. Gobiiformes means "goby-like".
Cavefish or cave fish is a generic term for fresh and brackish water fish adapted to life in caves and other underground habitats. Related terms are subterranean fish, troglomorphic fish, troglobitic fish, stygobitic fish, phreatic fish, and hypogean fish.
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The Ankarana Special Reserve tufted-tailed rat is a species of rodent in the family Nesomyidae. It was first described in 2009. It is endemic to Madagascar, in the Ankarana Special Reserve.
Jane Wilson-Howarth BSc (hons), CF, MSc (Oxon), BM, DCH, DCCH, DFSRH, FRSTM&H, FFTM RCPS (Glasg) is a British physician, lecturer and author. She has written three travel health guides, two travel narratives, a novel and a series of wildlife adventures for children. She has also contributed to anthologies of travellers tales, has written innumerable health articles for non-specialist readers, and many scientific/academic papers.
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Quietula is a genus of fish in the goby subfamily, Gobionellinae. There are two species, both native to the Gulf of California in Mexico. One is endemic to the Gulf, and the other also occurs along the western coast of Baja California and the coast of California. The fish were first described from Guaymas in Sonora, Mexico. The genus name Quietula is from the Latin quietus, meaning "quiet".
