Aglaspida

Taxobox
name = Aglaspida
fossil_range = Cambrian - ?Ordovician


image_caption = "Aglaspis spinifer"
regnum = Animalia
phylum = Arthropoda
subphylum = Chelicerata
superclassis = Aglaspida†
superclassis_authority = Walcott, 1911
subdivision_ranks = Families
subdivision =
* 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. 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 [http://www.fmnh.helsinki.fi/users/haaramo/Metazoa/Protostoma/Arthropoda/Basal_Lamellipedia/Aglaspidida.html Aglaspida]
* [http://www.fossilmuseum.net/fossils/aglaspida.htm Virtual fossli museum on Aglaspida]
* [http://www.fossilmall.com/EDCOPE_Enterprises/invertebrates/invert14/invfossil-14.htm Fossilmall Australian Aglaspida]
* [http://strata.ummp.lsa.umich.edu/jack/showgenera.php?taxon=280&rank=class Merostomata genera]
* [http://www.keyobs.be/fr/ebonino/html/aglaspidi.html Enrico Bonino Aglaspida description page (in Italian)]