Tuesday, January 29, 2008

Horseshoe crabs now date back to 445 MYA

"A remarkable new fossil horseshoe crab, Lunataspis aurora gen. et sp. nov., from recently discovered Upper Ordovician (c. 445 Ma) shallow marine Konservat-Lagerst├Ątten deposits in Manitoba (Canada)."

Lunatapsis aurora

See Rudkin, DM, GA Young & GS Nowlan, 2008. The oldest horseshoe crab: a new Xiphosurid from late Ordovician Konservat-Lagerst├Ątten deposits in Manitoba, Canada. Palaeontology, 51(1): 1-9. and "Oldest Horseshoe Crab Fossil Discovered," by Jeanna Bryner. LiveScience.com, 28 Jan 2008.

This pushes back evidence for the mysterious horseshoe crabs by almost 100 million years, from 350 million to 445 million years ago. Having survived multiple extinction events during its geological existence, but habitat loss and marine pollution have seen significant localised loss of population numbers in some countries.

Wikimedia: Phanerozoic Biodiversity

Present day horseshoe crabs appear to be similar to such fossils and we refer to them as "living fossils". In Singapore, Mandai mangroves appear to be a significant refuge for them. Let's hope we can extend their impressive record a little longer.

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