Actually, LIBRAS has that very sign. 

We were discussing it 10 years ago in Brazil. The thumb is under the finger supporting it, as you said. It's under the tip, not on the tip. 

Check under the 7s. The number is 01-07-016. 

Charles Butler
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Clear writing moves business forward.

--- On Sun, 1/13/13, Dali balti <[log in to unmask]> wrote:

From: Dali balti <[log in to unmask]>
Subject: New handshape???
To: [log in to unmask]
Date: Sunday, January 13, 2013, 8:24 AM

Hello every one!!!
When I was helping some deaf friends, I realized that there was some kind of handshape which was not available on SW bank!!!
the fingers are spread open, but the ring thumb touches the pharangeal of the ring finger which bends forward a little bit!!!! actually it is a sign which aims at focusing on the RING itself to mean "spouse, husband, wife"

I attached a signwriting handshape to give you an idea, it is of my invention to give you an idea only, please how can I write it???? I attached two handshapes in one!!!

thank you all