70.
Seychelles Palm frog
(Sooglossus pipilodryas)
VU
Overview
The Seychelles palm frog was only described as a new species in 2002, and details of its breeding behaviour are currently unknown. The eggs are probably laid on the ground, or in leaf axils of specific palms, and hatch directly into froglets. The eggs are likely to be guarded until hatching occurs. This species is very active and agile, and responds to disturbance by leaping and climbing. It is the only species of native Seychelles frog to not be found on the largest and most populous island of Mahé, and there are no specific threats to this species on Silhouette, although there are risks associated with occurring in a very small range.
Urgent Conservation Actions
Long-term monitoring of this species; sustainable development of ecologically friendly tourism should be encouraged.
Distribution
The island of Silhouette in the Seychelles.
Fact
The scientific name of this species, S. pipilodryas refers to the call of the species, from the Latin "pipilo" meaning chirp and "dryas" meaning forest spirit.

This species is the latest addition to the sooglossids family and was formally described as a new species in 2002.
Associated Blog Posts
22nd Jul 15
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Media from ARKive
ARKive image - Seychelles palm frog on palm frond - brown form
ARKive image - Seychelles palm frog - red form
ARKive image - Seychelles palm frog walking along palm frond
Evolutionary Distinctiveness
Order: Anura
Family: Sooglossidae
Oceanic islands are typically lacking in native amphibians, because very few species have any tolerance to salt water as a result of their sensitive skin, which is often used as a respiratory surface. The Seychelles is the only island group with an endemic family of frogs, i.e. one where all of the member species occur in the same island group and nowhere else on earth. This family is called the Sooglossidae (or sooglossids), and is commonly referred to as the “Seychelles frogs”. Although it is thought that amphibians may occasionally make the perilous journey across seas and oceans via rafting on mats of vegetation, being carried by strong air currents, or human introductions, the Seychelles frogs were transported to their current location by continental drift over millions of years. Around 200 million years ago at the beginning of the Jurassic period, the Seychelles islands were joined to the eastern part of the ancient southern supercontinent Gonwana, which went on to split apart into Australia, Antarctica, India, Madagascar and the Seychelles over millenia of movement of the earth’s plates. The sooglossids survived the geological breakup of India and the Seychelles around 65 million years ago, which is around the same time as the dinosaurs became extinct, and the closest known relatives of the Seychelles frogs are today found in India.

The sooglossids include some of the world’s smallest frogs, with adult Gardiner’s Seychelles frogs measuring just 10-11 mm in total length. Their closest living relative is the purple frog (EDGE rank 4) in the Western Ghats, India, which was only formally discovered in 2003 because it spends most of the year buried up to 4 metres underground. These lineages of amphibians may have been more diverse on Indo-Madagascar in the Cretaceous period, but now they are reduced to two miniscule ancient families that are consequently highly evolutionarily distinct. It is thought that the two lineages diverged around 131 million years ago in the Early Cretaceous period, which is over 30 million years before humans and elephants shared a common ancestor. The slow migration and fragmentation of the Indo-Madagascan fragment of Gondwana subsequently brought each landmass to its current position, separating the Seychelles frogs and the purple frog by about 2,500 km of Indian Ocean.

The Seychelles comprise eight main granitic islands and over 80 tiny islands and coral atolls. The group of islands is 1,000 km across at its widest point and the total land area is around 455 km sq., with the highest point being Morne Seychellois on the granitic island of Mahé, which 914 metres above sea level. The distribution of amphibian species across the Seychelles has probably been impacted by changing sea levels over the millennia. The central granite Seychelles islands were once a continuous landmass of around 130,000 km sq. called the Seychelles Bank, which has been reduced over time by erosion and rising sea levels. It was reduced to its present condition of scattered islands about 10,000 years ago. As a result, there is little endemism between islands since they were all connected relatively recently.

Today, the Seychelles frogs are only present on the larger granitic islands of Mahé and Silhouette. In total, the Seychelles contains 13 species of amphibians – 6 caecilians and 7 frogs, all of which are endemic apart from the Mascarene grassland frog (Ptychadena mascareniensis), which is widespread across sub-Saharan Africa, the Mascarene Islands and Madagascar. All the amphibian species are confined to the granitic islands of the Seychelles, with the larger islands having more species than the smaller islands. They are all ground dwelling, reproducing independently of water. They exhibit a high degree of parental care, with egg guarding occurring in all four species, and parents carrying tadpoles on their back until metamorphosis in one species, the Seychelles frog. Despite being very similar in external appearance, the Seychelles frogs may be identified by their advertisement calls, which are all highly distinctive.
Description
This is a very small species, although slightly larger than its close relative Gardiner's Seychelles frog, which is reported to be possibly the smallest frog species in the world. Females average a total length of around 14.3 mm, whilst males are slightly smaller at a total length of around 10-12.6 mm. Apart from being slightly larger, the Seychelles palm frog is similar to Gardiner's Seychelles frog, although it has larger eyes, shorter first and second fingers, and shorter tibia (the portion of the leg below the "knee"). Colouration is variable, but all individuals have a dark spear-shaped mark between the eyes and also centrally between the fore-limbs and the rear.
Ecology
This species has only been recently described (in 2002) and details of its breeding behaviour are currently unknown. However, information may be inferred from the behaviours of its close relatives in the Sooglossidae family. Breeding probably occurs by direct development, where there is no free-living tadpole phase because the tadpoles develop into froglets within the gelatinous capsule of the egg. The eggs are probably laid on the ground, or in leaf axils of specific palms, or both. The eggs are likely to be guarded by either the male of female until hatching occurs.

This species is very active and agile, and responds to disturbance by leaping and climbing. The vocalisations of the Seychelles palm frog have been described as a high-pitched squeak, similar to Gardiner's Seychelles frog but with more repetitions (usually six).
Habitat
The Seychelles palm frog is restricted to high forest over 250 metres above sea level, and is closely associated with the palm Phoenicophorium borsigianum, with most individuals being found in the leaf axils of this palm and not on other palms such as Nephrosperma vanhouetteana and Roscheria melanochaetes.
Distribution
This species is restricted to Silhouette Island in the Seychelles, occurring at altitudes of above 250 metres above sea level. It has an extent of occurrence and area of occupancy of 665 hectares.
Population Estimate
This species is common within its small range, with a maximum population density of 30 animals per hectare, and a total population estimate of fewer than 20,000 animals.
Population Trend
The current population trend of the Seychelles palm frog is specified as unknown by the IUCN Red List of Threatened Species.
Status
The Seychelles palm frog is listed as Vulnerable in the IUCN Red List of Threatened Species because it is known from only a single location, and its area of occupancy is less than 20 km sq..
Threats
There are no specific threats to this species on Silhouette, other than the inherent risks associated with a very small range of just 7 km sq., such as vulnerability to ecological disasters and climate change. However, future hotel and infrastructure development might be a potential threat to these species.
Conservation Underway
The forest areas in which this species occurs are managed for conservation by the Nature Protection Trust of Seychelles via their Islands Development Company Silhouette Conservation Project. However, the forests are not legally protected. In addition, many small reserves on the islands have been set up by the Seychelles Government and independent agencies to protect specific species and general habitat areas.
Projects
Conservation Proposed
The long-term monitoring of Gardiner’s Seychelles frog is a vital priority to ensure its conservation in the wild, allowing for any population declines to be quickly detected and investigated. The development of Silhouette for the tourism industry and local population increase is a significant threat to the Seychelles’ biodiversity, including the Seychelles frogs. Wherever possible, sustainable development of ecologically friendly tourism should be encouraged. The Seychelles is marketed as a tourist destination on the basis of its natural beauty, so strategic development of eco-tourism could be immensely beneficial to the conservation of the Seychelles’ endemic amphibians.
Associated EDGE Community members

Justin is the Scientific Co-ordinator of Nature Protection Trust of Seychelles

James is an EDGE Fellow working on sooglossid frogs in the Seychelles.

Links
References
AmphibiaWeb: Information on amphibian biology and conservation [web application]. 2006. Berkeley, California: AmphibiaWeb. Available: amphibiaweb. Accessed: 08 December 2006.

Behler, J.L. and Behler, D.A. 2005. Frogs: A Chorus of Colors. Sterling Publishing, NY, U.S.A.

Biju, S.D. and Bossuyt, F. 2003. New frog family from India reveals an ancient biogeographical link with the Seychelles. Nature 425: 711-714.

Frost, D. R., T. Grant, J. Faivovich, R. H. Bain, A. Haas, C. F. B. Haddad, R. O. De Sá, A. Channing, M. Wilkinson, S. C. Donnellan, C. J. Raxworthy, J. A. Campbell, B. L. Blotto, P. Moler, R. C. Drewes, R. A. Nussbaum, J. D. Lynch, D. M. Green, and W. C. Wheeler. 2006. The Amphibian Tree of Life. Bulletin of the American Museum of Natural History 297: 1-370.

Frost, Darrel R. 2006. Amphibian Species of the World: an Online Reference. Version 4 (17 August 2006). Electronic Database accessible at: . American Museum of Natural History, New York, USA.

Gerlach, J. & Nussbaum, R. 2004. Sooglossus pipilodryas. In: IUCN 2006. 2006 IUCN Red List of Threatened Species. IUCN Red List of Threatened Species. Downloaded on 31 July 2007.

Gerlach, J. and Willi, J. 2002. A new species of frog, genus Sooglossus (Anura, Sooglossidae) from Silhouette Island, Seychelles. Amphibia-Reptilia 23: 445-458.

Halliday, T. and Adler, C. (eds.). 2002. The new encyclopedia of reptiles and amphibians. Oxford University Press, Oxford.

IUCN, Conservation International and NatureServe. 2006. Global Amphibian Assessment. Global Amphibian Assessment. Accessed on 08 December 2006.

Obst, F.J., Richter, K. and Jacob, U. 1984. The Completely Illustrated Atlas of Reptiles and Amphibians for the Terrarium. T.F.H. Publication Inc., N.J., U.S.A.

Roelants, K., Gower, D. J., Wilkinson, M., Loader, S. P., Biju, S. D., Guillaume, K., Moiau, L. and Bossuyt, F. 2007. Global patterns of diversification in the history of modern amphibians. Proceedings of the National Academy of Sciences 104: 887-892.

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