People’s contribution to the knowledge of Pycnogonida: citizen science in the case of a “problematic” taxon.

Pycnogonida is a poorly known class of marine arthropods represented by nearly 1350 species described worldwide. We examined data about these organisms available on seven websites for photographs and information sharing among recreational naturalists. We found 384 observations, mainly with data about locality and date. Photos about 65 of them resulted correctly identified to the species level with certainty. The others refer to species whose identification requires a more in-depth analysis under a microscope. Unfortunately, this problem is common to a high percentage of pycnogonids. Therefore it seems unlikely that citizen scientists could contribute significantly to their knowledge. Nevertheless, for some species this would be possible and data on the presence of the taxon could be useful for more general studies at community level.