''Lunataspis'' is the oldest known

xiphosura Xiphosura () is an order of arthropods related to arachnids. They are more commonly known as horseshoe crabs (a name applied more specifically to the only extant family, Horseshoe crab, Limulidae). They first appeared in the Hirnantian (Late Ordo ...

n. It was first formally described by David Rudkin, Graham Young and Godfrey Nolan, from fossils found in northern

Manitoba Manitoba ( ) is a Provinces and territories of Canada, province of Canada at the Centre of Canada, longitudinal centre of the country. It is Canada's Population of Canada by province and territory, fifth-most populous province, with a population o ...

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

in 2005; the deposit dates from the Late

Ordovician The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start ...

, .Chliboyko, J. ''Crabby Ancestors'', Canadian Geographic Magazine, April 2008, p. 25

Discovery and species

The type species, ''L. aurora'', was described from remains found in the Konservat-Lagerstätten deposits of the Stony Mountain Formation, central

. The specific name ''aurora'' is Latin for 'dawn' and is also eponymous with the mythological Roman goddess. A second species, ''L. borealis'', was described in 2022 based on three specimens, including an adult (

ROM Rom, or ROM may refer to: Biomechanics and medicine * Risk of mortality, a medical classification to estimate the likelihood of death for a patient * Rupture of membranes, a term used during pregnancy to describe a rupture of the amniotic sac * ...

IP 64616) and two juveniles or subadults (

IP 64617 and

IP 64618). All specimens were found in the upper member of the Gull River Formation in

Kingston, Ontario Kingston is a city in Ontario, Canada. It is located on the north-eastern end of Lake Ontario, at the beginning of the St. Lawrence River and at the mouth of the Cataraqui River (south end of the Rideau Canal). The city is midway between Toro ...

References

Xiphosura Late Ordovician arthropods Ordovician animals of North America Ordovician Canada Fossil taxa described in 2008 {{paleo-arthropod-stub

Discovery and species

See also

References