Aglaspidida

Aglaspidida Temporal range: Cambrian PreЄ Є O S D C P T J K Pg N
Aglaspis spinifer
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Stem-group:	Chelicerata
Order:	Aglaspidida Walcott, 1911
Families
Aglaspididae Lemoneitidae Beckwithiidae  ?Strabopidae

The Aglaspida, more correctly termed Aglaspidida, were a group of small, horseshoe crab-like arthropods that were once regarded as basal or ancestral horseshoe crabs. However they cannot be accommodated within the chelicerates. Now, though, they are regarded as a distinct group, possibly being close to the trilobites. The older idea 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

• Aglaspella
• Aglaspis
• Aglaspoides
• Angarocaris
• Beckwithia
• Borchgrevingkium
• Craspedops
• Cyclopites
• Flobertia
• Girardevia
• Glypharthrus
• Kodymirus
• Neostrabops
• Setaspis
• Sinaglaspis
• Strabops
• Triopus
• Tuboculops
• Uarthrus

References

• Hesselbo, SP. 1992. Aglaspidida (Arthropoda) from the Upper Cambrian of Wisconsin. Journal of Paleontology 66(6)885-923.
• Raasch, GO. 1939. Cambrian Merostomata. Geological Society of America Special Paper 19, 146p.

External links

• Mikko's Phylogeny Archive on Aglaspida
• Virtual fossli museum on Aglaspida
• Fossilmall Australian Aglaspida
• Merostomata genera
• Enrico Bonino Aglaspida description page (in Italian)