 The two species were not, however, as closely related to the 270 other species of harvestmen studied.The team determined "H. argus" and "E. sheari" shared three features – two pairs of eyes, an open gonostome (a part of the reproductive system), and external male genitalia – which distinguish them from all other harvestmen.Thus, the two species were classified into a new suborder, Tetrophthalmi.