Unknown species?

This two specimens was taken near Skrova, Nordland, Norway on 1. december 2015. Fluorecent in calcofluor. Size arond 50 my. What can it be?

Nice picture and interesting question.
I have never seen one alike.
Could it be a Dinophysis sp. pictured from the side?
Look at the picture at page 29 at http://images.algaebase.org/algaebase/pdf/5964B9370591d2CDB8jqx16A773A/2...

But the striae are not typical Dinophysis.

I am also thinking in the line of benthic Dionophysis (or similar genera).

I am also into Amphisolenia sp - maybe a specimen in very early stage (and hence much smaller). Look into Okolodokov at the Gulf of Mexico (an SEM picture of Amphisolenia has the same posterior structure as your specimen - two parallel horns)
Plate 7_2 and PLate 10
http://www1.inecol.edu.mx/abm/verhtml/106/Acta106(9-71).html

I stop here since I am feeling that I am trying to avoid my must-do analysis at the moment;-)

Let us know if you solve the problem