#amphibeans

The evolutionary origins of modern amphibians are still a bit murky, but one of the most likely possibilities is that they evolved from a group of temnospondyls known as amphibamiformes. (Or, at least, that frogs-and-salamanders evolved from them. Caecilians might be a different type of temnospondyl.)

And a recent discovery adds a little bit more evidence to that hypothesis.

A new specimen from the 309-million-year-old Late Carboniferous Mazon Creek fossil deposits in Illinois, USA, shows some soft-tissue impressions around the body of a terrestrial amphibamiform* — most notably showing its toes, with chunky rounded fleshy pads at the end like those seen in many modern amphibians.

Fossil trackways already suggested that some terrestrial temnospondyls had chunky toes, but up until now all known soft-tissue impressions only showed the slender tapering toes of aquatic forms. This is the first direct fossil evidence of toe pads, and hints that a lot of modern amphibians' soft-tissue features may have actually had a very ancient origin.

(*A more precise identification couldn't be made, but it shows some similarities to both Doleserpeton and Pasawioops.)

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Madagascar Forest team’s work on surveying reptiles and amphibians has found a new species to Nosy Be and produced the first assessment of Nosy Komba.

Image courtesy of Frontier's Madagascar Wildlife Conservation Adventure project

Two former staff members from the Frontier Madagascar Forest research programme have had their findings published on the Herpetofaunal research carried out on Nosy Be and Nosy Komba. Sam Hyde Roberts and Charlotte Daly found 17 species new to Nosy Komba while conducting a rapid assessment of the reptile and amphibian life on the island (published in last month’sSalamandra) as well as reporting the first sighting of Petter’s chameleon Furcifer petteri on our main research island of Nosy Be (published in last month’s Herpetology Notes).

The male chameleon was discovered during a night survey on the 6th August 2013 in the Lokobe Integral Reserve. The species is classed as “vulnerable” by the IUCN Red list; previously its range was only thought to include the northern tip of Madagascar. It is under threat from human disturbances such as logging and agriculture, which cause populations to become fragmented. This new discovery in the reserve adds to the huge biodiversity on the island and strengthens the need for protection and further research into its density and morphology, as this particular specimen was a particularly large example of the species.

In other news, a rapid biodiversity assessment on Nosy Komba, the small island located 2.7 km south of Nosy Be, has identified 17 species of reptiles and amphibians which had never previously been recorded on the island. These included nocturnal species like Henkel’s Leaf tailed Gecko, the Nosy Be Ground Gecko, the Fish-scale Gecko and the snake species Lycodryas granuliceps; it is thought that no night surveys had previously been conducted on the island, when the survey found greater diversity. This raises the number of recorded herpetofaunal species on the island to 38 (9 amphibian and 29 reptile).

Image of a Leaf Tailed Gecko, courtesy Frontier's Nosy Komba Satellite Camp

Nosy Komba was isolated from the Madagascan mainland by rising sea levels around 8000 years ago; finding out about the composition of the island’s herpetofauna and comparing it to both the mainland and its larger neighbour Nosy Be could be crucial in gaining insight into the causes and mechanisms of extinction. There is more historical logging and deforestation on Nosy Komba than Nosy Be. It also has many tourist resorts and plantations and no protected areas; making this mosaic plantation and secondary forest habitat an interesting place to ascertain which species are thriving here and which may be absent.

On three visits to the island, 26 hours of rapid biodiversity assessments were carried out; 26 reptile and 6 amphibian species were recorded. Two of these are classified as endangered; Seipp’s day gecko and the plated lizard Zonosaurus subunicolor, but the island’s herptile population was dominated by the Blue-nosed Chameleon. The generalist nature of the species found supports historical accounts that the island was entirely deforested during the last two centuries. Being a smaller island, the impact of deforestation, storms and human disturbance would be greater than on Nosy Be and a study of the abundance of these animals over time would be revealing.

The results of the survey showed that proportionally, there were less amphibians than would be expected, based on our findings from Nosy Be. This is probably down to the topography of Nosy Komba, which has much higher altitudes and has greater gradients than the larger island, meaning there are fewer potential aquatic habitats which amphibians need, however the overall herpetofaunal community on Nosy Komba appears to be more adaptable than first expected; the report’s findings indicate that the current assemblage has been heavily influenced by habitat destruction.

A high altitude view from Nosy Komba, courtesy of the Madagascar Wildlife Conservation Adventure project

It is hoped that these findings can be combined with our research on other species towards creating a proposal for a protected area around the remaining natural habitat on the island, as well as some of the diverse secondary re-growth, encouraging the local community to conserve and manage this threatened habitat.

By Alex Caldwell

As well wildlife conservation and research projects that operate in Madagascar, Frontier operates a huge variety of projects dedicated to conservation worldwide that you can join from 2 weeks to 1 year and make your travel meaningful!

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