Lunataspis

Lunataspis Temporal range: 455-445 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓ Latest Sandbian to Earliest Hirnantian
Reconstruction of Lunataspis aurora (bottom left) and Lunataspis borealis (top right)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Chelicerata
Order:	Xiphosura
Suborder:	Xiphosurida
Genus:	†Lunataspis Rudkin, Young & Nowlan, 2008
Type species
†Lunataspis aurora Rudkin, Young & Nowlan, 2008
Species
†L. aurora Rudkin, Young & Nowlan, 2008 †L. borealis Lamsdell et. al., 2022

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).

Discovery and species

Holotype of Lunataspis aurora

Holotype of Lunataspis borealis

The type species, L. aurora, was described from remains found in the Konservat-Lagerstätten deposits of the Stony Mountain Formation, central Manitoba by David Rudkin, Graham Young and Godfrey Nolan, from fossils found in northern Manitoba, Canada in 2005. [1][2] The specific name aurora is Latin for 'dawn' and is also eponymous with the mythological Roman goddess.[1] The deposit dates from the Late Ordovician, earliest Hirnantian c. 445 million years ago.

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.

See also

• 2005 in paleontology
• 2008 in paleontology
• List of xiphosurans

References

1. David M. Rudkin, Graham A. Young & Godfrey S. Nowlan (2008). "The oldest horseshoe crab: a new xiphosurid from Late Ordovician Konservat-Lagerstätten deposits, Manitoba, Canada". Palaeontology. 51 (1): 1–9. doi:10.1111/j.1475-4983.2007.00746.x.
2. Dunlop, J.A.; Penney, D.; Jekel, D. (2015). "A summary list of fossil spiders and their relatives" (PDF). World Spider Catalog. Bern, CH. Natural History Museum Bern. Archived (PDF) from the original on 2023-12-16.
3. Lamsdell, James C.; Isotalo, Phillip A.; Rudkin, David M.; Martin, Markus J. (October 2022). "A new species of the Ordovician horseshoe crab Lunataspis". Geological Magazine: 1–5. doi:10.1017/S0016756822000875. ISSN 0016-7568.