View source for Kiisortoqia

{{Short description|Extinct genus of arthropods}}
{{Speciesbox
| fossil_range = {{fossil range|Sirius Passet}}
| image = Kiisortoqia.png
| image_upright = 1.3
| image_caption = Life restoration
| genus = Kiisortoqia
| parent_authority = Stein, 2010
| species = soperi
| authority = Stein, 2010
}}
'''''Kiisortoqia soperi''''' is an extinct species of [[arthropod]] from the Early Cambrian [[Sirius Passet]] [[Lagerstätte]] in Greenland. While it had a superficially [[trilobite]]-like bodyform, it also possessed large frontal appendages similar to those of [[Radiodonta|radiodonts]].
== Description ==
[[File:Kiisortoqia Size Comparison.svg|left|thumb|Size comparison based on the type specimen]]
The body of ''K.&nbsp;soperi'' consisted of a simple head shield, 16 trunk segments ([[tergite]]s) and a tail plate. In outward appearance the body is almost elliptical, about twice as long as wide, with the widest point in the front third of the body at the 3rd to 5th tergite.<ref name="Stein2010">{{cite journal |author=Martin Stein |year=2010 |title=A new arthropod from the Early Cambrian of North Greenland, with a 'great appendage'-like antennula |journal=[[Zoological Journal of the Linnean Society]] |volume=158 |issue=3 |pages=477–500 |doi=10.1111/j.1096-3642.2009.00562.x}}</ref>
The head plate was simple, convex in shape, wider than long, and represented about 20% of the total body length. The tergites were short, about five times as wide as long, and the rear edge of each tergite overlapped the following by about a fifth of its length. The tergites 1–5 all had about the same width, the following tergites becoming narrower towards the posterior end of the animal. In the middle of the tergites an axis can be clearly seen, which constituted about half the width of a tergite and gave it a three-lobed shape. At the lateral ends of each tergite existed spines which increased in length towards the tail. The tiny tail was semi-circular, about half as long as wide. The front half to two-thirds of the tail shield also has a three-lobed shape.<ref name="Stein2010"/>
The first segment bore a ventral pair of large appeandages, which are about half to two-thirds as long as the body. They consisted of a cylindrical stem and about 15 segments. The segments had a flat outer side and two widely spaced spines.<ref name="Stein2010"/>
The other [[Arthropod leg|limbs]] – three pairs in the head region shield and 16 on the body segments – composed of two branches. The basipod was long, trapezoid-shaped and had two rows with different numbers of spines. The [[Exopod|exopods]] were paddle-like lobes, which were fringed with bristles. The length was little more than two thirds of the length of the endopodite.<ref name="Stein2010"/>
Its gut is occasionally preserved in three dimensions, perhaps [[phosphatization|in phosphate]].
==Ecology==
It is believed that ''Kiisortoqia'' was a [[predator]]y swimmer. The large paddle-like exopods were probably suitable for swimming. With its robust appendages, ''K.&nbsp;soperi'' could capture prey, probably using its prickly basipods to bring them to its mouth.<ref name="Stein2010"/>
== Etymology ==
The name of the genus is derived from the [[Greenlandic language|Greenlandic]] word ''{{lang|kl|kiisortoq}}'', meaning "predator" or "hunter". The specific epithet is in honor of Norman John (Jack) Soper who, together with A. K. Higgins, discovered the Sirius Passet fauna and collected the first fossils from the locality.<ref name="Stein2010"/>
== Distribution ==
More than 170 specimens of the species were recovered in the course of several expeditions between 1985 and 2006 from the Lower Cambrian Sirius Passet Konservat-Lagerstätte, in [[Peary Land]], northern Greenland. The specimens are usually more or less completely preserved: disarticulated fossils were not discovered.<ref name="Stein2010"/>
== Systematic position ==
''Kiisortoqia soperi'' possesses three crown-arthropod homologies: a head shield with three pairs of limbs, plus the appendages; postappendage biramous limbs; and flap-like exopods fringed with setae. An exact position within the arthropods, however, cannot be determined, due to the possible lack of eyes and the ambiguous shape of the tail plate. A possible [[synapomorphy]] of the appendages with the [[Chelicerata|chelicerates]] is purely speculative. A later [[cladistic]] analysis resolved ''Kiisortoqia'' as [[sister taxon|sister]] to the rest of [[crown group|crown-group]] arthropods studied.<ref name=Stein2011>{{cite journal |author=Martin Stein & Paul A. Selden |year=2012 |title=A restudy of the Burgess Shale (Cambrian) arthropod ''Emeraldella brocki'' and reassessment of its affinities |journal=[[Journal of Systematic Palaeontology]] |volume=10 |issue=2 |pages=361–383 |doi=10.1080/14772019.2011.566634}}</ref> A later study also suggested it was closely related to the morphologically similar ''[[Bushizheia]]'' known from the [[Chengjiang Biota]] of China.<ref name=":0">{{Cite journal |last=O’Flynn |first=Robert J. |last2=Audo |first2=Denis |last3=Williams |first3=Mark |last4=Zhai |first4=Dayou |last5=Chen |first5=Hong |last6=Liu |first6=Yu |date=2020-08-05 |title=A new euarthropod with ‘great appendage’-like frontal head limbs from the Chengjiang Lagerstätte, Southwest China |url=https://palaeo-electronica.org/content/2020/3115-a-new-cambrian-euarthropod |journal=Palaeontologia Electronica |language=English |volume=23 |issue=2 |pages=1–23 |doi=10.26879/1069 |issn=1094-8074 |doi-access=free}}</ref> A close relationship with [[Artiopoda]], which includes trilobites and their close relatives, has been suggested by some analyses.<ref name="Berks2023">{{cite journal |last1=Berks |first1=H. O. |last2=Lunde Nielsen |first2=M. |last3=Flannery‐Sutherland |first3=J. |last4=Thorshøj Nielsen |first4=A. |last5=Park |first5=T.‐Y. S. |last6=Vinther |first6=J. |date=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 |doi=10.1002/spp2.1495|doi-access=free }}</ref>
== References ==
{{Reflist}}
{{Taxonbar|from1=Q19842438|from2=Q1575382}}
[[Category:Cambrian arthropods]]
[[Category:Prehistoric arthropod genera]]
[[Category:Fossils of Greenland]]
[[Category:Cambrian genus extinctions]]