I found it!
I met the same palm again like on my trip 4 years ago.
The Bactris route was leading to a dead end, I didn't find any with the silvery undersides of the fronds nor the arrangement of the spines on the trunk.
Then I came upon an Astrocaryum sp somewhere on the web, forgot where
and my guts told me I was on the right track!
The Flora do Brasil only mentions 1 species (fortunately!
)
It is Astrocaryum aculeatissimum!
https://www.google.be/search?q...
