The
spider stamps issued on December 7, 2009 have common upright SPM watermark. However, less common inverted watermark has also been recorded. I have in my possesion the inverted one for 30s stamp fighting spider (
Thiania bhamoensis), and a collector told me that he has inverted one for stamp 30s curved spiny spider (
Gasteracantha arcuata). I believe that 50s and RM1 could also have watermark variety.
curved spiny spider; Gasteracantha arcuata fighting spider, Thiania bhamoensis