however, in 1961, the american paleontologist erik norman kjellesvig-waering split "hughmilleria" in two subgenera, "h." ("hughmilleria") for species with large ovoid marginal eyes and "h." ("nanahughmilleria") for small reniform intramarginal (within the margin) eyes. since "h. patteni" fulfilled this condition, it was referred to "h." ("nanahughmilleria"). it was not until 2008 when during a phylogenetic review of the entire adelophthalmidae family by the norwegian odd erik tetlie and german markus poschmann paleontologists, "n. patteni" was recognized as sufficiently different to represent its own genus due to the anterior position of its eyes, much more exaggerated than in the other adelophthalmid genera. the first part of the generic name is composed of the word "eysysla", the viking name for saaremaa, and the second part by "opterus", a suffix commonly used in eurypterids which means "wing" (and therefore, translated as "wing of "eysysla"").