the time keeper in metachrosis
Posted by rocksea on 20 Jan 2010 | Category: photography, prakriti
The hourglass mark on its dorsum is attractive, and that is why I call it the time keeper. We found this frog while we were cleaning and pruning the area around our fish pond. Sarah was throwing away some rotten twigs and leaves when she felt something cold and creepy leap on to her 
The photos above and below are of the same frog, taken a few minutes apart. It changed its color from an off-white to a brownish tone! This happened when the frog had moved from its previous location into a bunch of dried leaves and twigs. Such an ability of animals to change its color is called metachrosis.
Metachrosis could be due to several reasons: like the light/temperature/moisture play a vital role in changing the colour. Some amphibians exposed to cold temperature and darkness often exhibit a darkening of their skin due to a melanophorotropic hormone (dark brown – black pigments) release. At higher temperature and light their color tend to get pale due to melanophore contraction. This color change is probably done as part of a hydro-thermal regulation (for regulating its moisture and temperature).
We are not sure if this frog exhibited metchrosis for such a regulation. At first sight we felt it was an instance of “crypsis“, where the animal has the ability to avoid getting noticed, through camouflage, mimicry, etc. However, studies shows that crypsis alone may not be the case of frogs like this one, and hydro-thermal regulations also play a major role. So probably a short time between the dried leaves with less light and colder environment let it change the shade from pale to dark.
The frog in the picture is polypedates occidentalis. To my amazement, the species was identified and named only recently, in 2006 
(link provided below). Hence data is deficient to tell if p.occidentalis is a rare species or not. Probably it is a common species for the western ghats region.
A similar frog is the Common Indian Tree Frog, polypedates maculatus, which also has an hourglass like mark on its dorsum. This one is present in central India and neighboring countries.
Date: 26 Oct 2008
Location: @ home, Kottayam, Kerala, India
Camera: Nikon D80 + Tamron SP AF90mm f/2.8 Di Macro Lens
References:
1. Feder M. E., Burggren W. W., 1992: Environmental physiology of the amphibians, University of Chicago Press.
2. Das I., and Dutta S. K., 2006: New Species of Polypedates (Anura: Rhacophoridae) from the Western Ghats, Southwest India, Journal of Herpetology, 40, 2, 214-220 [link].
3. Dr. K. V. Gururaja, Indian Institute of Science, Bangalore.
P.S. It has been a while since I posted the last article. Time has been flying since pratyahara, and work also is getting tight these days. Anyways timekeeper is here to save me for a while
Buon Anno!
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I was about to say that it has been a long time since we saw a post from you. And what beautiful pictures!
As always, great pictures and nice to read about the frog. The hour glass looks nice like a rabbit on the moon.
haha. nice metaphor abhi
I just wonder how you capture such great pictures.
and thanks a lot for educating us on our co-buddies on earth 
Hey Nithya, They seem to be comfortable with me
When I observe them, photograph them, and prepare these articles for the reader, it is a lot of self-education, and I am happy that it works for them as well. I guess you feel the same with your crafts 
seriously both of U have an eye for tiny things or word has spread in the animal world that rocksea.org is the best place for a little publicity stunt, so they come in search of you, in your balcony, in and around the fish pond on the bed
…
Is this the same principle for some people whose eye colour change according to the dress they wear or time of day? I’ve studied abt mimicry n camouflage the stick and leaf insects and the great chameleon… Metachrosis is a new word in my vocabulary. Thank you Rocksea:)))
yes yes, we have a lot of models lining up haha.
The color change with clothese seems due to reflection from the clothes, especially on lighter eye colors. Metachrosis and crypsis are for you
lol, I was guessing why the couple was kept away from blogosphere for such a long time. My guess was right…good girl.. Already has a firm grip on daddy
yaar it is a boy
He is teething now, irritated of that, and getting more and more active!
Oh sorry boss, so its ‘good boy’!!
its a treat to read ur posts! beautiful pictures and information
Hi Roxy,
Nice to see that you are back in the blog-o-sphere!
Hope you had a nice time with ur family…
I have some photos of frogs and reptilia from my farmhouse backyard…But I got no clue about their species or names whatsoever…
How do I identify them? plz help!
I am “still” having a nice time with my family
There are amphibianindia and reptileindia yahoogroups which share information on frogs and reptiles, which you may want to consider. I am not an expert, but if you send me a few, I can try to find out.
LOL @ Pins
But ya even i wonder what fancies the tiny litl creatures to showcase before you and be caught on camera
may be ya they know Rocksea is the best place for showbiz 
Yep my studio is outside, and the models jump around so that I can see them
Beautiful and crisp pictures you really have the art of photography…… unfortunately Bangalore is so much urbanized and populated its almost 10 years we have seen any frogs in the rainy season….
Yes, whenever I come to Bangalore, I miss the beauty and the nature-spread it had in the past. Seems it is not more called a garden city?
shooting a subject this low would have been a really challenging task!
Difficult, yes. But is nice to lie around with my models once a while
Hi!!! long time no see!! i moved my photoblog so update them thar feeds if you have one for me, you can still find me at totallylike.me tho…. i love the froggy pictures!!! such a pretty little creature and you’ve captured it so well!!
But you are still giving out the old url in your comments. How do I reach you in the new one?
Hi there! the old url should work, it’s a redirect, but right now people are having probs because of the DNS not migrating fast enuff, so i gave you the new direct url…
see you there!!
awww you left so many nice comments on the wrong blog
in the locket? home made holy water
i don’t know where that chain is now, at the moment i wear an emf protector around my neck
The hour glass looks like a butterfly to me..butterfly frog
Wow.. Great capture! Looks like the frogs too have the chameleon instincts. Color and the hour glass formation looks really cool, never observed a frog this close!
Great to see you nd the lovely bits of info and photos…
something more enjoyable has kept u away and rightly so
interesting animal, great shots! that’s a weird frog
mridula, sandeep, flyaway, mohan, kitten, laura:
Amazing photography. And quite an information too. Thanks for sharing
Wow really does look like a leaf! Really great shots.
Awesome pictures, as always!
Good to know that the little one is keeping you busy
What do you call him at home?
Wow! U both do hv a keen eye for details! Loved this one