Ranitomeya amazonica

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Ranitomeya amazonica
Ranitomeya amazonica.jpg

Ranitomeya amazonica

Systematics
Subordination : Neobatrachia
Superfamily : Dendrobatoidea
Family : Poison Dart Frogs (Dendrobatidae)
Subfamily : Dendrobatinae
Genre : Ranitomeya
Type : Ranitomeya amazonica
Scientific name
Ranitomeya amazonica
( Schulte , 1999)

Ranitomeya amazonica ( Syn .: Dendrobates amazonicus ) is a frog from the family ofpoison dart frogs (Dendrobatidae), which are also known as poison dart frogs. The frog, described in 1999, lives in the rainforests on the Amazon in Peru .

features

With a length between 16 and 19 millimeters, Ranitomeya amazonica is a relatively small poison dart frog . The skin of this species is smooth, its basic color is black. However, it has striking orange-red to red colored stripes on the back and on the sides as well as above and below the mouth. These stripes can show a color gradient from light orange to red in the direction of the head and thus resemble the color of flames. They are usually fused into a capital Y in the neck area, rarely are they completely separated, as is the case with the closely related species of the belly patch tree climbers . Most of the time, the frogs also have a black nostril.

The abdomen, flanks and limbs are colored very differently. They show a network in blue-green to gray color, between which the black base color appears in round and oval spots and dots of different sizes. These points are larger on the stomach, and on the flank the network is separated from the orange lateral stripe by a black band.

The nostrils are close to the edge of the short snout. The species has no tooth formations. The tympanum , a membrane-like structure of the hearing organ of the frogs, sits behind the eyes and has the shape of a vertical oval. Its diameter is about half the diameter of the eye.

On the forelimbs, the first finger is shorter than the second, the third finger is the longest. The finger-disk on this finger is 2.6 times as wide as the finger. The finger discs are also widened on the other fingers. The first toe does not have a toe disk on the hind limbs. The other, longer toes have a slightly flared toe disk about 1.6 times as wide as the toe.

distribution and habitat

The location of the type specimen described by Rainer Schulte in 1999 is in the hot, humid lowland rainforests around Iquitos in the Loreto region in Peru . From a morphological point of view, Schulte separated the new species from the group of belly-spot tree climbers ( Ranitomeya ventrimaculata ), which is probably a species of several species. However, it is not certain that all the Erstbeschreiber mentioned populations along the eponymous Amazon in Peru, Ecuador , Colombia , Guyana and French Guiana to Ranitomeya amazonica belong. The distribution area is not contiguous and difficult to distinguish from that of the belly-spot tree climber. Some populations within this area differ from one another in terms of molecular genetics .

Other similar species in the range differ quite clearly from Ranitomeya amazonica , either by their pattern like Ranitomeya variabilis or by their shorter body length like Ranitomeya ignea .

Way of life

The clutches of Ranitomeya amazonica consist of four to six black colored eggs with a diameter of around one millimeter. The eggs are deposited in small phytotelmata , which are parts of plants filled with rainwater. They are mostly water-filled bromeliad funnels of the genus Guzmania , which grow as an epiphyte on trees at a height of around 5 meters in clear areas of the rainforest . The tadpoles are omnivorous and feed cannibalistically on eggs or freshly hatched larvae of their own species if there is not enough food.

The black colored tadpoles hatch after 12 to 16 days and show the first colors after around 70 days at a temperature of 22 ° C. They develop into a finished frog within a total of around 75 days. After six months, the males are sexually mature. They mark their territory and present themselves with their calls. The females can lay their first spawns after eight to ten months . Sometimes several females lay their eggs in the same phytotelma .

The frogs can live three to five years.

Skin toxins

Like most poison dart frogs, the species Ranitomeya amazonicas also secretes toxins via skin glands, which protect them from fungal and bacterial attack. In addition, predators are deterred by the poison. The bright colors of the frog serve as a warning signal. The composition of the skin toxins has not yet been investigated for the populations around Iquitos. For the populations on the Rio Nanay in Peru, which many scientists attribute to the closely related species Ranitomeya ventrimaculata , the main poisons identified were pumiliotoxins and histrionicotoxins . These are also found on the skin of other so-called poison dart frogs, e.g. B. Pumiliotoxins in strawberry frogs ( Dendrobates pumilio ) and histrionicotoxins in Oophaga histrionica . However, only three species of the genus Phyllobates are used in practice for the arrow poison of the indigenous population of the Amazon . The formation of skin toxins in poison dart frogs depends on the food available. In terrariums, for example, no skin toxins are formed due to the lack of certain prey animals in the food spectrum. The assumption that the composition of the poisons can be used to distinguish the species has proven to be incorrect.

Taxonomy

At the time of the first description of Ranitomeya amazonica , only morphological features were used to differentiate between species. However, these are very variable both in Ranitomeya amazonica and in the related species in the Amazon region. There were therefore doubts as to whether all the populations living in the range really belonged to the new species. It turned out, however, that Ranitomeya amazonica clearly differs from those groups of frogs, which at that time were often referred to as Ranitomeya ventrimaculata , but are now counted as Ranitomeya variabilis , both in terms of molecular genetics and in the type of calling sounds of the males . In general, one can say that all variants with red or bright orange shades can be counted as Ranitomeya amazonica . To the south of Iquitos, in the area of ​​the Río Tigre , the distribution areas of Ranitomeya amazonica and Ranitomeya variabilis overlap , the two species probably live there sympatric .

Danger

The species is listed in the Washington Convention on the Protection of Species in Appendix II under its former name Dendrobates amazonicus . So export and import permits would have to be issued for this poison dart frog. Although no export permits have been issued, Ranitomeya amazonica is widely available from pet stores in North America and Europe. The IUCN gives the endangered status of the species as “Data Deficient” (insufficient data), as it cannot be clarified which of the commercially available animals come from wild-caught animals and how many come from breeding. In addition, the number of individuals is difficult to estimate because of the difficult species delimitation. The IUCN points out that only a small part of the population lives in a protected area, namely in the Peruvian Reserva Nacional Alpahuayo Mishana . Both the protected area and the unprotected habitats in the rainforest are decreasing due to increasing agricultural activities.

On the occasion of the UN Conference on Species Conservation in Nagoya, Japan, in October 2010, the colorful frog was presented to the international press by the WWF, along with other species newly discovered in the Amazon region between 1999 and 2009 .

Individual evidence

  1. ^ Rainer Schulte: Poison dart frogs - species part Peru. Nikola Verlag, Stuttgart 1999.
  2. ^ JP Caldwell, CW Myers: A new poison frog from Amazonian Brazil, with further revision of the quinquevittatus Group of Dendrobates. In: American Museum Novitates. 2988, 1990, pp. 1-21.
  3. ↑ TD Grant, DR Frost, JP Caldwell, R. Gagliardo, CFB Haddad, PJR Kok, BD Means, BP Noonan, W. Schargel, WC Wheeler .: Phylogenetic systematics of dart-poison frogs and their relatives (Anura: Athesphatanura: Dendrobatidae ). In: Bulletin of the American Museum of Natural History. 299, 2006, pp. 1-262.
  4. ↑ JW Daly, TF Spande, HM Garraffo: Alkaloids from amphibian skin: a tabulation of over eight hundred compounds. In: Journal of Natural Products . 68, 2005, pp. 1556-1575.
  5. ↑ S. Lötters, M. Vences: Comments on the nomenclature and taxonomy of Peruvian poison dart frogs. In: Salamandra. 36, 4, pp. 247-260, 2000.
  6. ↑ Jason Brown, Evan Twomey: A taxonomic revision of the Neotropical poison frog genus Ranitomeya (Amphibia: Dendrobatidae). In: Zootaxa. 3083, pp. 1–120, 2011 ( PDF ( Memento of the original from January 14, 2016 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , English) @1@ 2Template: Webachiv / IABot / www.jasonleebrown.org
  7. ↑ Evan Twomey, Jason Brown: A summary of the taxonomic changes within Ranitomeya. ( Memento of the original from March 10, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. dendrobates.org, 2011 (accessed March 5, 2013) @1@ 2Template: Webachiv / IABot / www.dendrobates.org
  8. ↑ Taxonomic Checklist of CITES listed Amphibians ( Memento of the original from December 25, 2010 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (PDF, p. 2) @1@ 2Template: Webachiv / IABot / www.cites.org
  9. ^ IUCN Red List , accessed October 28, 2010.
  10. ↑ 1200 new species discovered in the Amazon Focus Online from October 26, 2010 (with picture of the frog)

literature

  • Rainer Schulte: Poison dart frogs - species part Peru. Nikola Verlag, Stuttgart 1999, ISBN 3-934300-01-4 .

Web links