# Thulaspis
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{{Short description|Extinct genus of artiopodan}}
{{automatic taxobox
| fossil_range = Cambrian Stage 3
| image = M862361.tif
| image_caption = Holotype specimen
| image2 = Thulaspis diagram.jpg
| image2_caption = Reconstruction
| taxon = Thulaspis
| authority = Berks, et al. 2023
| type_species = Thulaspis tholops
| type_species_authority = Berks, et al. 2023
}}
'''''Thulaspis''''' is an extinct genus of [artiopoda](/source/artiopoda)n arthropod from the [Cambrian Stage 3](/source/Cambrian_Stage_3) aged [Sirius Passet](/source/Sirius_Passet) site in Greenland. It is thought to be a close relative of ''[Squamacula](/source/Squamacula)'', and is possibly one of the most basal members of Artiopoda.
== Description ==
''Thulaspsis'' was relatively large-sized. The largest specimen is about {{Convert|8.7|cm|in}} wide and {{Convert|12|cm|in}} long. The carapace is overall oval-shaped was convex and likely stiff in life, with a raised central axis. The head is broad and bears a pair of [antennae](/source/Antenna_(zoology)), which have at least 20 rectangular segments, and likely two pairs of [biramous](/source/biramous) (two branched) limbs.The body has 15 thoracic segments, which curve forwards in the first few segments, before becoming straight in the fourth and fifth segments, then increasingly posteriorly curved in subsequent segments. At least the first 11 thoracic segments are associated with pairs of biramous limbs. The biramous limbs have robust [endopods](/source/Endopod) (lower, leg-like branches), and flap-shaped [exopod](/source/exopod)s (upper branches). The body terminates with a [pygidium](/source/pygidium).[{{Cite journal |last1=Berks |first1=H. O. |last2=Nielsen |first2=M. L. |last3=Flannery-Sutherland |first3=J. |last4=Nielsen |first4=A. T. |last5=Park |first5=T.-Y. S. |last6=Vinther |first6=J. |year=2023 |title=A possibly deep branching artiopodan arthropod from the lower Cambrian Sirius Passet Lagerstätte (North Greenland) |journal=Papers in Palaeontology |volume=9 |issue=3 |at=e1495 |doi=10.1002/spp2.1495 |s2cid=259253098|doi-access=free |bibcode=2023PPal....9E1495B }}]
== Taxonomy ==
''Thulaspsis'' has been consistently recovered as more closely related to the genus ''[Squamacula](/source/Squamacula)'' that to other artiopods. However, their relationships to other artiopodans are unresolved, though analyses often recover the pair as close to the base of the group. Implied weights parsimony phylogeny after Berks et al. 2023.