EPOW - Ecology Picture of the Week

Indian Cricket Frog in the Burrow

Indian Cricket Frog (Fejervarya aff. limnocharis), Family Dicroglossidae
Kaziranga National Park, Assam, northeast India

Explanation:  This attractive little amphibian has a big story to tell.

This is an Indian cricket frog.  I discovered it while exploring one of the countless islands in the mighty Brahmaputra River in northeast India adjacent to Kaziranga National Park.  

Indian cricket frogs are small, growing on average only to about 35mm (1.4 inches) long.  They breed with the monsoon rains and moist conditions, and are named after their castanet-clattering call, sounding somewhat like a cricket.  

This species seems wonderfully camouflaged to blend right in with its sandy soil background.  But why the bold stripe down the back?  It might serve at least a couple of functions:  (1) it breaks up the body outline with what is called disruptive coloration, so the frog is not so readily seen by a predator such as storks, snakes, and small cats; and (2) it might serve as a visual species-recognition signal which could be important for territoriality or especially when it comes time for breeding.  

This cricket frog was out sunning itself, or maybe waiting in ambush for a passing bug, but when it found that it was the subject of photography, it quickly dashed into its burrow ... backwards.  

Why backwards?  Perhaps so it can poke its nose out and watch for further approaching predators or prey.  Or ... maybe it also serves a similar function as with wart hogs in Africa, which also often enter their burrows backwards, so if they encounter a predator that is already within its burrow, it can quickly dash out to safety.  I think some experiments on this diminutive frog could answer that question.  

So what's the big story with this little herp?

Well, what species is it, exactly?  In the past, it was called Rana limnocharis, because the suite of Asian cricket frogs were included in the family Ranidae.  In fact, this species is very similar to the ranid species Rana tigrina (which I have caught and photographed in the Russian Far East, but that's another story).   

Then, they were split out into their own family of Dicroglossidae, and the genus name Rana was changed to Limnonectes ... so the species was then called Limnonectes limnocharis.  Thereafter, though, came another change:  the name was altered to Fejervarya limnocharis, under a new genus name.

But wait, there's more.

In 2001, the herpetologist S.B. Biju published a study suggesting that frogs that go by Fejervarya limnocharis are actually a species restricted to Indonesia and Malaysia, and are not the one found in India; the Indian form is likely another, undescribed species of genus Fejervarya.  Moreover, recent molecular studies published in 2008 suggest that Fejervarya limnocharis might constitute a multiple species complex. 

Well, so what?  

Consider this.  To best conserve biological diversity, you first need to know what is out there.  If this frog turns out to be a locally restricted, or even endemic, species of India, that could call for a higher degree of conservation attention than if it was a single species widely distributed in Asia.  Conservation of species depends on knowing what species are in the first place -- their taxonomy.  Whether this frog is something common, or something wholly new and as yet undescribed, is not an uncommon quandary in the world of herpetology ... or many other areas as well.

The problem is that the world is losing experienced taxonomists as they grow old and retire, and fewer students are aspiring to enter the field of systematics and taxonomy.  It is an irony that taxonomists themselves may be entering threatened status.  And along with them, the promise for even knowing what species there might be in the world around us, and thus which might be in trouble and needing our conservation attention.

Information:
     Biju, SB.  2001.  A synopsis to the frog fauna of Western Ghats, India.  Occasional Publication, Indian Society for Conservation Biology, Thiruvananthapuram, India.
     Kotaki, M, A Kurabayashi, M Matsui, W Khonsue, TH Djong, M Tandon, and M Sumida.  2008.  Genetic divergences and phylogenetic relationships among the Fejervarya limnocharis complex in Thailand and neighboring countries revealed by mitochondrial and nuclear genes. Zoological Science 25:381-90.
     Islam, MM, MMR Khan, DH Tjong, MS Alam, and M Sumida.  2008.  Genetic differentiation of the Fejervarya limnocharis complex from Bangladesh and other Asian countries elucidated by allozyme analyses.  Zoological Science 25:261-72.