Telmatobius culeus

Titicaca giant frog ( Telmatobius culeus )

The Titicaca giant frog ( Telmatobius culeus ), also referred to as Titicacafrosch or Titicacaseefrosch, belongs to the genus of the Andean Pfeiffrösche ( Telmatobius ). He lives endemic only in Lake Titicaca on the high plateau of the Andes in Peru and Bolivia. This type mainly uses their skin for gas exchange. The highly folded skin increases the respiratory surface.

Features

After Jacques- Yves Cousteau in 1973 had explored Lake Titicaca with divers and dive boats, he reported of specimens of this aquatil living frog, which should have been up to 50 cm long and 1 kg. Apparently, however, this biometric information is based on the sum of the head-body length and outstretched hind legs - one in zoology not usual way of measuring. The maximum head -body length itself is likely derived from this information, at least there are more than 20 cm. Other authors even speak of about 12 inches, or just under one foot, which is about 30 centimeters correspond. The Titicaca giant frog is among the largest species among the anurans, even if it does not reach the extent of the West African Goliath frog.

A characteristic feature of the species is their strongly unfolded skin. She looks as if she had come much too big for the frog body. On the back and belly, but also on the legs these baggy folds are very noticeable. The wrinkles on the neck give the frog a look, as if he had a cowl around. The coloring of the skin is variable, ranging from olive green with peach belly over gray with black speckles on the back to black with white marbling. Some specimens are entirely black.

The Titicaca giant frog, like all Andean Pfeiffrösche powerful hind legs and feet with particularly large webbed that allow him a speedy locomotion under water.

Of life in Lake Titicaca

Lake Titicaca is located at an altitude of 3810 m on the Altiplano, a high plateau of the Andes. It covers an area of ​​8288 square kilometers and has a maximum depth of 280 m. At this height, it can come out at night to temperatures below the freezing point during the day prevails intensive sunlight with a high ultraviolet content. These environmental conditions have led to the evolution of living things occurring only here. Conversely, these organisms are more threatened by a change in the environmental factors of extinction than less specialized animals.

For the Titicaca giant frogs especially the low air pressure was at this level, an adjustment factor, as they have to cope with a lower oxygen concentration in the water and on land. To not also suspend the extreme temperature changes on land and the high UV light intensity, the animals were transferred to a fully aquatilen life. The dark to black color on the backs of frogs, which is caused by melanophores in the skin, prevents - as well as the black skin of the polar bear - the penetration of UV radiation.

Oxygen takes Titicaca giant frog from the water almost exclusively through the skin on, one refers to the skin to breathe. The lung has been greatly reduced in the course of evolution. For a greatly enlarged skin surface is formed by a large number of wrinkles and bags that give the frog a very flabby and wrinkled appearance. The ratio of the respiratory volume on the surface of the animal is improved. A movement that is similar to the push-up in sports, means that the water is moved past the wrinkles and the gas exchange works better. There are also special adaptations in the blood of these frogs. Your blood has the smallest red blood cells (erythrocytes ) of all amphibians and simultaneously the highest percentage of hemoglobin. At this hemoglobin, the oxygen is coupled for further transport through the bloodstream.

To feed, the species is not picky and feeds on worms, amphipods of the genus Hyalella, water snails, tadpoles and small fish, such as the Ispi - Andenkärpfling Orestias ISPI. The prey is swallowed whole, with the assistance of the front legs when needed.

Endangering

Jacques -Yves Cousteau looked at his dives in the early 1970s, the ground still covered with dense Titicaca giant frogs. He spoke of millions of individuals who have to live here. Today the frog has almost completely disappeared from many parts of the lake. There is no definitive explanation for this decline in populations. Some researchers suspect the Titicaca giant frog had withdrawn to other parts of the lake where there is more food for him. The reduced frog populations seem to go hand in hand with the decline of a small species of fish mentioned in the Quechua language Ispi. This good 7 cm long fish is the main food source of Titicaca giant frog. He could have followed the migration of schools of fish in other areas of the lake.

On the other hand, the lake also be taken large amounts of smaller fish to be processed as food for the larger fish breeding. The Titicaca giant frog is also often a by-catch in fishing nets. He is of the indigenous population living on the banks of the lake, eaten and used traditionally as a remedy, the frog legs but are also available in restaurants in Peru and Bolivia. An extract of the frogs is sold under the name "Viagra peruano " as an aphrodisiac. This and the pollution of the lake have led to a high risk of Titicacafrosches. The IUCN classified the species now considered " critically endangered " ( critically endangered ) a.

External and internal systematics

The very species-rich family of Südfrösche ( Leptodactylidae broader sense ) is now regarded as paraphyletic and was therefore split into several monophyletic groups. Species of the genus Telmatobius were asked, for example, until 2011, together with the horn frogs ( Ceratophrys ) and five other genera in a family Ceratophryidae.

Former species of the genus Telmatobius are now divided into different taxa, which differ in their distribution, their lifestyle and physique. One widespread in southern South America, especially in Patagonia group, which is now compiled to the genus Atelognathus, includes more smaller species of 25 to 50 mm in size, some of which also live terrestrial. A northern distribution group, which also includes the Titicacafrosch heard consists of much larger species that live aquatil in high altitude lakes and rivers of the Andes. In addition, other former Telmatobius species are found in numerous other genera and other Froschlurchfamilien.

The very different color variants of Titicaca giant frog have led to the suggestion by biologists that up to seven subspecies occur in the lake. According to studies of the Bolivian researcher Edgar Benavides, who first examined the DNA of the various copies in 1997, but all belong to the same species and it involves only a wide range of different coloration ( polymorphism ). Telmatobius albiventris with four subspecies and Telmatobius crawfordi be incorporated by some authors in the way Telmatobius culeus. It has been shown that differences in body size and adaptations to the specific ecological microhabitats are present, but these do not act as crossing barriers, but gradually lead to different forms and patterns of behavior.