Seychelles frogs
| Seychelles frogs | ||||||||||||
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| Noble , 1931 |
Seychelles frogs (Sooglossidae) form a small family of the frogs (Anura). Only four species are endemic to the Seychelles archipelago in the Indian Ocean northeast of Madagascar , where they only inhabit the two islands of Mahé (around 150 km²) and Silhouette (just under 20 km²).
Overview
These are very small (maximum 4.5 centimeters long) frogs that are either slender and frog-like graceful or rather stocky and toad-like. The species "Gardiner's Seychelles frog " ( Sechellophryne gardineri , syn. Sooglossus gardineri ) is one of the smallest frogs in the world with a head-trunk length of around 1.1 cm (compare, for example, toads and Monte Iberia frogs ). The ends of the limbs are widened in the shape of a disk and are spotted. The males' mating calls consist of relatively complex, high-frequency tone sequences. In contrast to the other representatives of the "modern frogs" ( Neobatrachia ), the amplexus of the Seychelles frogs is not axillary, but, as in the Archaeobatrachia and Mesobatrachia, in the lumbar region of the females.
The species' habitats are always moist forests on the mountain slopes of the two above-mentioned islands, where they can be found either on the ground between leaf litter and modern plant remains, on rocks near streams or in the leaf axils of certain palm trees. The deposits are mostly at altitudes between 240 and almost 1000 meters above sea level. The animals have adapted to a terrestrial life. This also means that the gelatinous eggs are not deposited in a body of water, but on land, where they are guarded by the male. The hatching tadpoles (around ten to fifteen per clutch) crawl onto the father's back, where they hold on - presumably supported by the male's skin secretions. Until their metamorphosis into lung-breathing, four-legged frogs, they hold out for several weeks without ingesting food. They feed on the yolk supply of the embryonic phase in the eggs. The gas exchange takes place via skin respiration , whereby the tail with its large skin surface probably plays an important role.
Taxonomy
After a subfamily Sooglossinae was previously added to the real frogs (Ranidae), a separate family Sooglossidae is now formed with two genera and four species. The closest recent relative is the species Nasikabatrachus sahyadrensis , which was only newly discovered in India in 2003 . The close relationship between the Indian species and the Sooglossidae refers to the history of the Seychelles' origins: Until the Mesozoic , the Indian subcontinent and Madagascar formed a contiguous land area, including Africa. In this phase the Seychelles were still part of the continental mass of the supercontinent Gondwana . In the course of the earth's history, different parts of the supercontinent were separated from each other by the continental drift , the frog populations were isolated from each other. A separate family Nasikabatrachidae was set up for Nasikabatrachus , but some authors also classify Nasikabatrachus directly in the Sooglossidae family.
Genera and species
There are four species within the Seychelles frog family: (As of April 2, 2016)
- Genus Sechellophryne
Nussbaum & Wu , 2007
- Art Sechellophryne gardineri (Boulenger , 1911)
- Art Sechellophryne pipilodryas ( Gerlach & Willi , 2003)
- Genus Sooglossus Boulenger , 1906
- Species Sooglossus Sechellensis ( Boettger , 1896)
- Species Sooglossus thomasseti ( Boulenger , 1909)
Danger
Because of their extremely isolated and very small-scale occurrence, the Seychelles frogs are considered to be potentially endangered species. According to the IUCN , all species are classified as VU (endangered).
Other amphibian fauna of the Seychelles
In addition to the Sooglossidae family, there are three other amphibian families with a total of eight species in the Seychelles: four representatives of the genus Grandisonia ( G. alternans, G. brevis, G. larvata, G. Sechellensis ) and one each from Hypogeophis ( H. rostratus ) and Praslinia ( P. cooperi; all Caecilian family Caeciliidae ), to a respective Froschlurchart the genus Tachycnemis ( T. seychellensis; family Hyperoliidae ) and the genus Ptychedena ( P. mascareniensis; family Ranidae ).
literature
- Günther E. Freytag, Bernhard Grzimek, Oskar Kuhn & Erich Thenius (eds.): Lurche . In: Grzimeks Tierleben, Vol. 5: Fish 2, Lurche. Licensed edition in dtv, Munich 1980, ISBN 3-423-03204-9
Individual evidence
- ^ A b Ronald A. Nussbaum & Sheng-Hai Wu: Morphological Assessments and Phylogenetic Relationships of the Seychellean Frogs of the Family Sooglossidae (Amphibia: Anura) . Zoological Studies 46, 3, pp. 322–335, 2007 ( PDF online ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. )
Web links
- List of species of the Sooglossidae family at Amphibiaweb
- List of species of amphibians in the Seychelles at Amphibiaweb
- Sooglossidae on the IUCN Red List of Threatened Species 2010.
- AMNH: Amphibian Species of the World