Amphilophus

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Amphilophus
Female of Amphilophus labiatus, the type species

Female of Amphilophus labiatus , the type species

Systematics
Ovalentaria
Order : Cichliformes
Family : Cichlids (Cichlidae)
Subfamily : Cichlinae
Tribe : Heroini
Genre : Amphilophus
Scientific name
Amphilophus
Agassiz , 1859

Amphilophus is a genus of Central American cichlids . The genus occurs from Mexico to Panama in rivers and in the larger lakes and crater lakes of Nicaragua . River-dwelling species are mostly restricted to the Atlantic or the Pacific side of the Central American land bridge or to a river system. The scientific name of the genus comes from the Greek (“amphi” = double-sided; “lophos” = cockscomb) and refers to the thick lips of the Amphilophus labiatus type .

features

Amphilophus species are 13 to over 30 centimeters long. Their shape corresponds to the basic chichlasomine pattern, is high-backed and flattened on the sides. The mouth sits deep and is terminal. The males are significantly larger in old age than the females, appear brawnier and often develop a forehead hump. As with all cichlids, the fifth gill arch in Amphilophus species is transformed into a pharynx . This can be built very differently. There are Amphilophus species with "molariform", i.e. with rounded "molar-like" teeth, which make it possible to crack the shells of snails and mussels, or "papilliform" pharyngeal jaws with small, pointed teeth that are suitable for especially to eat insects or crustaceans .

Reproduction

Amphilophus species are open breeders that form a parent family , i.e. H. Females and males care for the brood together. The clutch is very extensive. Depending on the temperature, the larvae hatch after 3 to 4 days and swim freely another 4 to 5 days later. They are closely guarded and looked after by their parents. In Amphilophus citrinellus it was observed that the fry feed on the body mucus of the parents. Increased concentrations of prolactin , growth hormone and thyroxine were found in the mucus . The body mucus is thus comparable to the colostrum of mammals. The growth accelerated by the hormones reduces the time window of the predator-prey system in the area of ​​distribution. In order to be able to form thyroxine, there must be sufficient iodine in the water; in many fresh waters the concentration is too low. Since the Central American plate was lifted out of the ocean, most of the lakes are actually brackish water lakes today (e.g. Apoyo , Xiloá , Lake Nicaragua ).

species

Today (April 2016) 17 species belong to the genus Amphilophus :

Lemon cichlid ( A. citrinellum ), the best known species of the genus

Monophyletic swarm of species of Lake Apoyo :

Monophyletic swarm of species of Lake Xiloá :

Other species that belonged to Amphilophus until April 2016 are now placed in the genus Cribroheros or in the monotypical genera Astatheros , Darienheros and Wajpamheros . In Amphilophus margaritifer , a form of which only the holotype from the Lake Petén Itzá is known, it is intended to be a hybrid between a Thorichthys act -Art and an undetermined second type.

Sympatric speciation

In the small Nicaraguan crater lakes Apoyo and Xiloá there are several very closely related species of the Amphilophus genus , each descended from an immigrant species. The Amphilophus species of these lakes differ not only in terms of color, but also clearly in their morphology, especially the pharynx, and ecological niche . A. zaliosus from Lake Apoyo usually lives in more open and deeper water than the other Amphilophus species in this lake. The species can be clearly distinguished using genetic markers and must have evolved into independent species in less than 23,000 years, the time since the lake was formed. Lake Xiloá is only 10,000 years old. Since an allopatric speciation in these small crater lakes with their homogeneous habitat can be ruled out, these Amphilophus species are considered to be a prime example of sympatric speciation (the emergence of new species in the area of ​​the original species (s)).

literature

  • Claus Schaefer: Amphilophus. In: Claus Schaefer, Torsten Schröer (Hrsg.): The large lexicon of aquaristics. Eugen Ulmer, Stuttgart 2004, ISBN 3-8001-7497-9 , p. 45 f.
  • Barluenga & Meyer: Phylogeography, colonization and population history of the Midas cichlid species complex (Amphilophus spp.) In the Nicaraguan crater lakes. BMC Evolutionary Biology 2010, 10: 326 doi : 10.1186 / 1471-2148-10-326 .

Individual evidence

  1. ↑ Marcus Schütz & GWBarlow: Young of the Midas cichlid get biologically active nonnutriants by eating mucus from the surface of their parents. Fish Physiology and Biochemestry vol. 16 no.1 pp 11-18 (1997) doi : 10.1007 / BF00004536
  2. ↑ a b Říčan, O., Piálek, L., Dragová, K. & Novák, J. (2016): Diversity and evolution of the Middle American cichlid fishes (Teleostei: Cichlidae) with revised classification . Vertebrate Zoology, 66 (1): 1-102.
  3. ↑ a b Geiger, McCrary & Stauffer: Description of two new species of the Midas cichlid complex (Teleostei: Cichlidae) from Lake Apoyo, Nicaragua. Proceedings of the Biological Society of Washington, 123 (2): 159-173. 2010. PDF
  4. ^ Stauffer, McCrary & Black (2008). Three new species of cichlid fishes (Teleostei: Cichlidae) from Lake Apoyo, Nicaragua. Proceedings of the Biological Society of Washington 121 (1): 117-129. doi: 10.2988 / 06-37.1
  5. ↑ Axel Meyer: Darwin's Secret of Secrets. The - sympatric - emergence of new species. A look back over 150 years. in Elsner, Fritz, Gardstein & Reitner: Evolution, Chance and Inevitability of Creation. Wallstein Verlag, Göttingen 2009, ISBN 978-3-8353-0301-0
  6. ↑ Marta Barluenga, Kai N. Stölting, Walter Salzburger, Moritz Muschick, Axel Meyer: Sympatric speciation in Nicaraguan crater lake cichlid fish Nature 439: 719-723 doi : 10.1038 / nature04325

Web links

Commons : Amphilophus  - collection of images, videos and audio files