Barbourula
Philippines Barbour frog ( Barbourula busuangensis )
The Barbour frogs ( Barbourula ) form a occurring on Southeast Asian islands and consists of only two types of species of amphibians, the phylogenetically primitive to the "lower" anurans ( Archaeobatrachia ) is counted. It is largely aquatil living, inconspicuous frogs on their biology and ecology is very little white because of their rarity and their hidden life. Fossil records are not known. The genus is named after the American herpetologist Thomas Barbour ( 1884-1946 ).
Characteristics and lifestyle
Barbour frogs are inconspicuous dark ( brownish) in color and have a flattened body, a rounded snout and a feinwarzige skin. Eardrums are not externally visible. The eyes with rounded up reversed teardrop-shaped pupils are directed obliquely forward. The Philippines Barbour frog is described as built quite strong and plump. From Borneo Barbour frog only about eleven individuals have so far been found, with males up to 66 mm, females had up to 77.7 mm snout-vent length. The animals have not only between the toes of the hind feet, but also between the fingers webbed pronounced, indicating their strong aquatile of life (see also: dwarf frogs ). They inhabit fast flowing, oxygen-rich streams and even up to 50 meters wide rivers within tropical rain forests; in danger, they dive off rapidly and hide under rocks at the bottom in about 50 centimeters to 5 meters depth. This locality plays an important role for oviposition.
The males have neither Bruns sealed Wielen still sound bubbles. The mating calls they are unusually produce by inhalation of air. However, at least the frog Borneo Barbour appears to have no lungs, but will - similar to the lung, such as lots Salamander - oxygen only over the skin. Came only a scientific expedition in August 2007, were caught in nine specimens of the species to this realization. The absence of lungs is interpreted as a further adaptation to the Habitat: It occurs as less lift, which facilitates descent or prevents drifting in strong currents. A fairly similar lifestyles have, for example, the North American Tail frogs. Also in the Titicaca giant frog 's lungs are at least greatly reduced. The complete regression of lung appears among the anurans but a unique feature of the Borneo - Barbour frog to be.
About the reproductive biology is little known. One knows that Barbour frogs attach greater, non-pigmented eggs on foundation stones of rivers, but knows their tadpoles previously. This fact and the nature of the eggs could according to some authors even suggest a direct development, ie, a discharge of Kaulquappenstadiums in the open water.
Particularly rare information on the proven and described until 1978 Borneo Barbour frog. After a second, 1995 discovery has been published only in 2007 the catch additional copies.
Dissemination
Barbourula busuangensis lives on several islands of the Philippines, as far as hitherto known to Busuanga, Culion and Palawan. This group of islands located north adjacent to the island of Borneo, the species occurs the second kind Barbourula kalimantanensis (Borneo, Indonesia) has so far been observed only in a less than 500 -acre site in West Kalimantan. There, among other things, two separate localities ( five points ) have been described in the middle Kapuas River Valley and in Melawi River Valley.
System
After anatomical features of the Barbour frogs mediate between the genres of authentics Disc- ( Discoglossus ) and toads (Bombina ), but are closer kinship to the latter asked. The exact family assignment is mixed: While some older literature, the Barbour frogs - as well as the toads - or the Scheibenzünglern ( Discoglossidae ) is one of these two genera are now often treated as a separate family Bombinatoridae. This was in 1993 taxonomically cleaved by the herpetologists Ford and Cannatella from the rest of the genera Scheibenzünglern Alytes and Discoglossus after the disco Glos Siden (including Bombina and Barbourula ) had been postulated in 1985 by one of these authors as paraphyletic in the broader sense.
The genus Barbourula consists of the following two ways:
- Barbourula busuangensis Taylor & Noble, 1924 - "Philippines Barbour Frog"
- Barbourula kalimantanensis Iskandar, 1978 - " Borneo Barbour Frog"
Endangering
Both Barbour frogs are given their limited distribution areas, their apparently small populations and threatened in their existence because of widespread habitat destruction by humans. The rivers are polluted and poisoned by illegal entries mining mines ( for example Quecksilbereinschwemmungen from the gold wash) and other industries, as well as fertilizers and pesticides from agriculture. In addition, the rain forests of Southeast Asia are decimated by deforestation ( tropical timber exploitation, land reclamation ) and on. The IUCN classifies Barbourula busuangensis considered "at risk " ( vulnerable ) and Barbourula kalimantanensis as " critically endangered " ( endangered ) a.