Lunataspis is the oldest known xiphosuran, with two known species both dating from the late Ordovician (latest Sandbien for L. borealis to earliest Hirnantian for L. aurora).
A second species, L. borealis, was described in 2022 based on three specimens, including an adult (ROM IP 64616) and two juveniles or subadults (ROM IP 64617 and ROM IP 64618). All specimens were found in the upper member of the Gull River Formation in Kingston, Ontario, dating from the latest Sandbian, late Ordovician, c.454 million years ago.[3] This site was a warm-water platform shelf at the time near the paleo-equator.