{{Short description|Extinct genus of arthropods}} {{Automatic taxobox | fossil_range = {{Fossil range|Cambrian Series 2|Burgess Shale}} | image = USNM PAL 57688 Molaria spinifera.jpg | image_caption = ''M. spinifera'' lectotype | image2 = Molaria spinifera.png | image2_caption = Life restoration of ''M. spinifera'' | taxon = Molaria | authority = Walcott, 1912 <ref name=Walcott1912>{{cite journal|author=Walcott, C. D.|year= 1912|title= Middle Cambrian Branchiopoda, Malacostraca, Trilobita and Merostomata|journal= Smithsonian Miscellaneous Collections|volume= 57|pages= 145–228|url=https://books.google.com/books?id=KRwrAAAAYAAJ&dq=Molaria+spinifera&pg=PA200}}</ref> | type_species = '''''Molaria spinifera''''' | type_species_authority = Walcott, 1912 | subdivision_ranks = Other species | subdivision = '''''Molaria steini''''' <small>Peel, 2017</small> }}

'''''Molaria''''' is a genus of Cambrian arthropod, the type species ''M. spinifera'' is known from the Middle Cambrian Burgess Shale. 144 specimens of ''Molaria'' are known from the Greater Phyllopod bed, where they comprise 0.27% of the community.<ref name=Caron2006>{{cite journal|last1=Caron |first1=Jean-Bernard|last2=Jackson |first2=Donald A.|title=Taphonomy of the Greater Phyllopod Bed community, Burgess Shale|journal=PALAIOS |volume=21 |issue=5 |pages=451–65|date=October 2006|doi=10.2110/palo.2003.P05-070R|jstor=20173022|bibcode=2006Palai..21..451C |s2cid=53646959 }}</ref> A second species ''M. steini'' was described from the Sirius Passet in Greenland in 2017.<ref name=":0">{{Cite journal|last=Peel|first=J.S.|date=2017-06-30|title=Molaria (Euarthropoda) from the Sirius Passet Lagerstätte (Cambrian Series 2, Stage 3) of North Greenland|journal=Bulletin of Geosciences|pages=133–142|doi=10.3140/bull.geosci.1658|issn=1802-8225|doi-access=free}}</ref>

== Etymology == The genus name derives from “Molar”, the name of a mountain peak east of the Valley of the Ten Peaks in Alberta, Canada,<ref name=Walcott1912/> which in turn was so named by James Hector in 1859 because the shape of the mountain resembles a molar tooth. The specific name of the type species, ''spinifera'', comes from Latin ''spinifer'' “spine-bearing.”<ref>{{Cite web |title=Molaria spinifera |url=https://burgess-shale.rom.on.ca/fossils/molaria-spinifera/ |website=The Burgess Shale |language=en-US}}</ref>

== Description == <gallery widths="160"> USNM_PAL_272105_Molaria_spinifera.jpg|Specimen of ''M. spinifera'' showing the long telson Molaria size comparison.svg|Size comparison of the two species </gallery>

The body of ''Molaria'' consisted of a head shield (cephalon), a trunk consisting of eight sections (tergites), and a telson, which included a short ventral spine and a long posterior spine. Three pairs of legs were beneath the cephalon and another eight pairs were attached to the trunk. Eyes were lacking, but a pair of short antennae was present on the cephalon. Specimens of ''Molaria'' ranged from 8 to 26&nbsp;mm in length from cephalon to telson, with the posterior spine slightly longer than the body length.<ref name=Whittington>{{cite journal|last=Whittington|first=H. B.|title=Rare Arthropods from the Burgess Shale, Middle Cambrian, British Columbia|journal=Philosophical Transactions of the Royal Society B: Biological Sciences|date=1981|volume=292|issue=1060|pages=329–357|doi=10.1098/rstb.1981.0033|bibcode=1981RSPTB.292..329W|doi-access=free}}</ref>

== Affinity == ''Molaria'' was superficially similar to ''Habelia'', another Burgess Shale arthropod with a long tail spine, but which possessed 12 trunk tergites.<ref name=Whittington/> It is currently considered a member of Artiopoda.<ref name=":0" />

== References == {{Reflist}}

== External links == * {{Cite web|date=2011|title=''Molaria spinifera''|work=Burgess Shale Fossil Gallery|publisher=Virtual Museum of Canada|url=http://burgess-shale.rom.on.ca/en/fossil-gallery/view-species.php?id=83|archive-url=https://web.archive.org/20201112025257/http://burgess-shale.rom.on.ca/en/fossil-gallery/view-species.php?id=83|archive-date=2020-11-12|url-status=dead}}

{{Artiopoda}} {{Taxonbar|from=Q3319449}}

Category:Burgess Shale fossils Category:Artiopoda Category:Cambrian arthropods Category:Fossil taxa described in 1912 Category:Cambrian genus extinctions Category:Artiopod genera

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