Tags: Arachnid.
Tetrophthalmi is an extinct suborder of Opiliones (commonly known as harvestmen or daddy longlegs) that had four eyes. First described in 2014 it is known from two extinct species. Phylogenetic analysis suggests that four eyes is the ancestral condition for harvestmen placing Tetrophthalmi and Cyphophthalmi at a basal position within Opiliones.
