Data for: Variation in eye lenses of two new Late Devonian phacopid trilobites from western Junggar, NW China

The Suborder Phacopina, characterized by schizochroal eyes, is among the most common groups of trilobites in Devonian strata. The marine sediments of the Famennian in western Junggar, Xinjiang, contain abundant low-disparity phacopids, which have previously been designated to Omegops accipitrinus mobilis, Phacops circumspectans tuberculosus, and Omegops cornelius, based on small numbers of poorly preserved specimens. In this study, these phacopids were identified as two new species of Omegops, O. honggulelengensis sp. nov. and O. xiangi sp. nov., based on nearly 200 well-preserved specimens. The intraspecific variations of eye-lenses of these specimens were quantitatively analyzed. Based on differences in the total number, number of dorso-ventral files, and arrangement of the eye lenses, the absence of lenses in the middle part of the visual surface, and asymmetry of the number and/or arrangement of lenses in the two eyes, it was concluded that the reasons for intraspecific variation in..., ,