Oar-footed Crab Burrowing

[Abhishek Jamalabad]

Oar-footed Crab Matuta lunaris in the act of burrowing, photographed on Karwar beach.
These crabs are commonly found on tidal sand flats, where they use their oar-shaped feet to burrow into the soft wet sand. I have watched them conceal themselves completely within a few seconds. They remain just below the surface by day, and emerge to feed on worms, shellfish etc. by night.

Canon 500D, Canon 100mm Macro USM
Aperture Priority AE
Av 10.0
Tv 1/320
ISO 400
Very small crop (9%) to remove a distraction from the left edge of the frame.

Thanks, C&C awaited.

[Abhishek Jamalabad]

Here is a record image of the oar-shaped foot. It is used for burrowing and paddling.

[Mrudul Godbole]

Nice environment photograph. Had never seen this species before. The Oar shaped feet does look quite different. The back nicely camouflages with its habitat. Nicely captured. Thanks for sharing the information and the details. Look forward to more.

[Roopak Gangadharan]

Neatly done Abhishek. U caught it displaying a typical behavior. I think i know this kind with a sort of jerky movement of the limbs it disappears under the sand.
Also if Im not wrong some other crab varieties have a similar appendage (Oar shaped) Ive seen it on the mud crabs and also on a couple of varieties found in the sea, mostly caught for the pot.

TFS
Roopak

[Abhishek Jamalabad]

Thanks both.

Roopak: You are right, several marine crabs have these oar-shaped appendages. I believe it is an adaptation for their more aquatic habits as compared to their terrestrial/freshwater counterparts. Matuta lunaris has all 4 pairs of legs modified into the oar-shape, in others such as Scylla serata and genus Portunus crabs (many species of which are fished commercially), only the last pair shows this modification. I have never seen it on mud crabs though...

[Sabyasachi Patra]

Nice documentation. I have seen them vanish fast while I was trying to click with my cellphone. Don't worry, am not ditching cameras. I was just trying to see the capability of the cameras in the phones.


Cheers,
Sabyasachi