Aglaspidida

Aglaspidida
Temporal range: Cambrian –Ordovician
Aglaspis spinifer
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Stem-group: Chelicerata
Order: Aglaspidida
Walcott, 1911
Families
  • Aglaspididae
  • Lemoneitidae
  • Beckwithiidae
  • ?Strabopidae
Strabops thatcheri, Upper Cambrian. Holotype specimen at Peabody Museum of Natural History.

Aglaspidida, sometimes incorrectly termed "Aglaspida," is an extinct taxon of small, superficially horseshoe crab-like arthropods that were once regarded as basal or ancestral horseshoe crabs. However, anatomical comparisons demonstrate that the aglaspidids cannot be accommodated within the chelicerates.[1] Now, though, they are regarded as a distinct group, possibly being close to the trilobites. An older hypothesis suggesting that they link trilobites with Chelicerata has fallen out of favour.
Aglaspid fossils are found throughout the world, including North America (upper Mississippi valley, Missouri and Utah), Europe, and Australia.

As of 1997, Hou & Bergström split off Strabopidae (which were once regarded as being primitive eurypterids), including the genera Strabops, Paleomerus, Parapaleomerus, and Neostrabops, as its own distinct order/taxon, "Strabopida."

List of Genera

References

  1. ↑ Ortega-Hernández, J.; Braddy, S. J.; Jago, J. B.; Baillie, P. W. (2010). "A new aglaspidid arthropod from the Upper Cambrian of Tasmania". Palaeontology. 53 (5): 1065–1076. doi:10.1111/j.1475-4983.2010.00974.x.

External links

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