Need help to identify symbol on coin

[Mey]

Hi to all
This is obverse of 1931 Iran 10 dinars, this coin plus some other Iran's coins dies engraved at Berlin mint in 1930 and all of them have a swan like symbol under wreath. Do anyone know about this symbol ?
Have you seen that on other coins ?
Thank you

[shanxi]

On colnect it is described as mintmark snake (Tehran).

http://colnect.com/en/coins/coin/19252- ... ~1320-Iran