The photographs featured below are for C. sp. 'Lingga 6'. The limb is yellow in colour and covered with protuberances, similar to many of the cryptocorynes found on Lingga Island. There is a distinctive red collar present too. My friend also termed this as 'bi-colour', you can see his blog for more photographs of its natural environment.
The front and underside of the leaves:
Is this a new species / varieties or should it be regarded as an existing species / varieties? We shall let the experts decide.