Sunday, April 14, 2013

Into the world of frogs in Sarawak

THE mysterious worlds of frogs opened up recently thanks to Dr Indreneil Das – an internationally respected herpetologist – who is a professor of herpetology at the Institute of Biodiversity and Environmental Conservation, Universiti Malaysia Sarawak (Unimas).

Ironically, during a time when about a third of the approximate 7,000 known species of frogs are threatened, Das, who is leading the search for unidentified species, has identified several new ones, including the smallest, a pea-sized frog from the Microphylla family that in habitats the liquid in the pitcher plant Nepenthes ampullaria’s cups.

During the talk, Das said that one new species is identified each week. This bloom in species has several sources, including formally inaccessible places, such as mountaintops, suddenly becoming reachable; micro-species are identified; and sub-division of species due to genetic analysis.

Frogs and toads, members of the Anura order, as well as other amphibians, including temperate salamanders, which superficially resemble lizards, and legless tropical ceaecillians – often mistaken for earthworms or snakes – are facing a mass extinction on the same scale as the one that wiped out dinosaurs.

Several factors have been identified as contributing to their demise including pollution, pesticides, habitat loss, climate change, hunting, predators, pet trade but the most deadly is the chytrid fungus disease (Batrachochytrium dendrobactidis). It is fatal because the fungus coats the delicate amphibian skin blocking the pores, which are used for water and moisture transfer, thus killing the frog from dehydration and heart failure.

Frogs and toads are a diverse group filling a vast array of ecological niches ranging from streams, to pools in the forests and even in liquid-filled pitcher plant cups. Amphibians have a water phase and a land phase.

The egg masses like sago pudding are generally laid in water including ponds and streams.

The herbivorous tadpoles, which hatch from the eggs, go through metamorphosis. Gills develop into lungs, limbs develop, as does the nervous system. It is a dramatic transformation.

Most adults are carnivores eating smaller creatures, including insects and snails, however, there is one Indian species that is herbivorous. In Central and South America, where the frog populations have been decimated, mosquito populations and thus the diseases they carry are likely to increase. We are only now beginning to understand the complexities of parental care. In the past it was thought that once the eggs were laid, the young were left to fend for themselves. This is not the case. Frogs which lay their eggs on land carry water to the tadpoles and eggs to ensure that they do not dry out.

Continue reading (Incl. Pics) at: Into the world of frogs in Sarawak