THIRUVANANTHAPURAM: In biology, crypsis is defined as the ability of an organism to avoid observation or detection by other organisms. Some animals make use of night travel, some make use of camouflage and some even mimic other animals as a survival tactic.
Many insects and animals become nocturnal just to avoid predators of the day. Even among nocturnal animals, survival can become a challenge. The night moths escape the predators of the night such as the bat, by putting them on a false trail, by creating sounds that mimic echoes from other locations or objects.
Many animals have evolved so that they visually resemble their surroundings, using some sort of natural camouflage that may match the colour of the surroundings. Some crabs, including the hermit crabs, attach other plants and animals to their bodies to escape attention.
This perpetual conflict between the prey and the predator leads to evolution, with the predator improving its skills to identify the prey and the prey continuously looking for ways to escape the attention of the predator.
While crypsis is part of evolution and biology, so are cryptic species. Cryptic species are two or more distinct but morphologically similar species that were classified as a single species. They look the same on the outside but are genetically different. During the past two decades Science has observed an exponential growth of publications on cryptic species.
This is especially so in the case of little-studied group of animals such as amphibians and fishes. Recently-published reviews have demonstrated that cryptic species have profound consequences on many biological disciplines.
In the latest issue of the journal ‘Animal Conservation’, published by the Zoological Society of London, a group of scientists from the Rajiv Gandhi Centre for Biotechnology, University of Helsinki and the University of Exeter reported a high cryptic diversity of endemic Indirana frogs in the Western Ghats.
The scientists, Abhilash Nair, S V Gopalan, Sanil George, K S Kumar, A G F Teacher and J Merila argue that there is an urgent need for efforts to identify cryptic species, especially given the increasing number of reported amphibian extinctions.
"Amphibians are rapidly declining worldwide, but recent studies have shown that their diversity may be heavily underestimated, and many new species have been recently reported from biodiversity hotspots. For successful conservation and management strategies to be implemented within such hotspots, a better understanding of the species diversity and their evolutionary relationships is required,’’ said the scientists in the paper.
The mountain chains of the Western Ghats in Southern India are a biodiversity hotspot, with an especially high diversity of amphibians, including many endemic families and genera.
The families Nasikabatrachidae, Micrixalidae and Ranixalidae are endemic to the area, and about 132 amphibian species are unique to the Western Ghats.
The study zeroed in on the genus Indirana in endemic family Ranixalidae, which at present is thought to comprise 10 described species. The scientific team used different gene fragments to investigate the genetic diversity within the endemic Indirana genus from the Western Ghats biodiversity hotspot. The species diversity within Indirana was found to be much higher than previously anticipated.
The team also reported a new candidate species within the genus from Vellarimala in Kerala, which is yet to be described. ‘’Our results suggest the existence of multiple unrecognised cryptic lineages within Indirana. Hence, the International Union for Conservation of Nature (IUCN) Red List statuses of Indirana frogs are in need of substantial revision, and we believe detailed genetic studies across the Western Ghats might uncover additional new candidate species from this poorly studied endemic genus,’’ said Sanil George, scientist at RGCB.
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