Asaphiscus
{{Short description|Genus of trilobites}}
{{Italic title}}
{{Automatic taxobox
| image = Asaphiscus wheeleri red CRF.jpeg
| image_caption = Asaphiscus wheeleri, Cambrian shale, Utah
| fossil_range = {{fossilrange|516|498}}Middle Cambrian
| taxon = Asaphiscus
| authority = Meek, 1873
| synonyms = Eteraspis Resser, 1935
| type_species = Asaphiscus wheeleri
| type_species_authority = Meek, 1873
| subdivision_ranks = Species
| subdivision =
- A. wheeleri Meek, 1873
- A. laeviceps Walcott, 1884
Synonyms: Ptychoparia laeviceps, Eteraspis laeviceps
}}
Asaphiscus is a genus of trilobite that lived in the Cambrian. Its remains have been found in Australia and North America, especially in Utah.
Distribution
A. wheeleri occurs in the Middle Cambrian of the United States (Delamaran, Lower Wheeler Shale, Millard County, Utah, 40.0°N, 113.0°W;{{cite journal|first1= S.|last1= Conway Morris|first2= R.A.|last2= Robison|year= 1986|title= Middle Cambrian priapulids and other soft-bodied fossils from Utah and Spain|journal= University of Kansas Paleontological Contributions|volume= 117|pages= 1–22}} cited on {{cite web|website= Fossilworks|title= Lower Wheeler Shale|author= Paul Hearn|url= https://paleobiodb.org/classic/displayCollResults?collection_no=77219|access-date= 17 December 2021}} and Menevian, Wheeler Formation, House Range, Utah, 39.2° N, 113.3° W).{{cite journal|first= R.A.|last= Robison|year= 1971|title= Additional Middle Cambrian trilobites from the Wheeler Shale of Utah|journal= Journal of Paleontology|volume= 45|issue= 5|pages= 796–804}} cited on {{cite web|website= Fossilworks|title= Wheeler Formation, House Range, Utah|author= Shenan Peeters|url= https://paleobiodb.org/classic/displayCollResults?collection_no=56144|access-date= 17 December 2021}}
Description
File:Asaphiscus wheeleri grey CRF.jpeg
Asaphiscus are average size trilobites of (up to {{convert|8|cm|in|disp=or}}) with a rather flat calcified dorsal exoskeleton of inverted egg-shaped outline, about {{frac|1|1|2}}× longer than wide, with the widest point near the back of the headshield (or cephalon). The cephalon is about 40% of the body length, is semi-circular in shape, has wide rounded genal angles, and a well defined border of about {{frac|1|8}}× the length of the cephalon. The central raised area of the cephalon (or glabella) is conical in outline with a wide rounded front and is separated from the border by a preglabellar field of about {{frac|1|8}}× the length of the cephalon, and has 3 sets of furrows that may be clear or inconspicuous. The articulated middle part of the body (or thorax) has 7-11 segments (9 in A. wheeleri), with rounded tips. The tailshield (or pygidium) is about 30% of the body length, is semi-circular in shape, with a wide flat border, and an entire margin.{{cite book|last= Moore|first= R.C.|year= 1959|title= Arthropoda I - Arthropoda General Features, Proarthropoda, Euarthropoda General Features, Trilobitomorpha|publisher= Geological Society of America/University of Kansas Press|series= Treatise on Invertebrate Paleontology|volume= Part O.|pages= O290–O291|location= Boulder, Colorado/Lawrence, Kansas|isbn= 0-8137-3015-5}}
Reassigned species
Some species originally described as belonging to Asaphiscus have later been reassigned to other genera.{{cite book|title=Unpublished PhD dissertation|publisher=University of Chicago|year=2003|last= Peters|first= S.E.|chapter= Paleontology and taphonomy of the Upper Weeks Formation (Cambrian, Upper Marjuman, Cedaria Zone) of western Utah|chapter-url= http://www.geology.wisc.edu/~peters/pdfs/Weeks.pdf|archive-url=https://web.archive.org/web/20140226140032/http://www.geology.wisc.edu/~peters/pdfs/Weeks.pdf|archive-date=February 26, 2014|url-status=dead}}
- A. capella = Glyphaspis capella
- A. granulatus = Genevievella granulata
- A. gregarius = Blainia gregarius
- A. minor = Cedaria minor
- A. unispinus = Weeksina unispina
Sources
- A Pictorial Guide to Fossils by Gerard Ramon Case
References
{{Reflist}}
External links
- [https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=20310 Asaphiscus] in the Paleobiology Database
{{Taxonbar|from=Q4803579}}
Category:Cambrian trilobites of Australia
Category:Cambrian trilobites of North America