Editing Lobopodia (section)

== Categories ==

Based on external morphology, lobopdians may fall under different categories — for example the general worm-like taxa as "xenusiid" or "xenusian"; xenusiid with sclerite as "armoured lobopodians"; and taxa with both robust frontal appendages and lateral flaps as "gilled lobopodians". Some of them were originally defined under a taxonomic sense (e.g. class Xenusia), but neither any of them are generally accepted as [[monophyletic]] in further studies.<ref name="ReferenceA" /><ref name=":8" /><ref name=":10" />

=== Armoured lobopodians ===

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| image1 = MICRODICTYON SINICUM.jpg
| caption1 = Fossil of ''[[Microdictyon]] sinicum'', showing pairs of sclerite and trace of trunk and lobopods.
| image2 = 20210429 Diania cactiformis diagrammatic reconstruction.png
| caption2 = ''[[Diania]] cactiformis'', an armoured lobopodian covered by myriad spines.
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Armoured lobopodians referred to [[xenusiid]] lobopodians which bore repeated sclerites such as spine or plates on their trunk (e.g. ''[[Hallucigenia]]'', ''[[Microdictyon]]'', ''[[Luolishania]]'') or lobopods (e.g. ''[[Diania]]''). In contrast, lobopodians without sclerites may be referred to as "unarmoured lobopodians".<ref name=":3" /><ref name=":13" /> Function of the sclerites were interpreted as protective armor and/or muscle attachment points.<ref name=":33" /><ref name="Budd2001" /><ref name=":0" /> In some cases, only the disarticulated sclerites of the animal were preserved, which represented as component of [[small shelly fossils]] (SSF).<ref name=":33" /><ref name=":15" /> Armoured lobopodians were suggest to be onychophoran-related and may even represent a [[clade]] in some previous studies,<ref name="Budd2001" /> but their phylogenetic positions in later studies are controversial. ([[#As stem-group onychophorans|see text]])

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=== Gilled lobopodians ===

[[File:20210730 Gilled lobopodians Pambdelurion Kerygmachela.png|thumb|The gilled lobopodians ''[[Pambdelurion]]'' (top left) and ''[[Kerygmachela]]'' (bottom right).]]

[[dinocaridida|Dinocaridids]] with lobopodian affinities (due to shared features like annulation and lobopods) are referred to as "gilled lobopodians"<ref name=":8" /><ref name=":7" /><ref name=":29" /> or "gilled lobopods".<ref name=":18" /> These forms sport a pair of flaps on each trunk segment, but otherwise no signs of arthropodization, in contrast to more derived dinocaridids like the [[Radiodonta]] that have robust and sclerotized frontal appendages. Gilled lobopodians cover at least four genera: ''[[Pambdelurion]]'', ''[[Kerygmachela]]'', ''[[Utahnax]]'' and ''[[Mobulavermis]]''.<ref name=":13" /><ref>{{Cite journal |last=McCall |first=C. R. A. |year=2023 |title=A large pelagic lobopodian from the Cambrian Pioche Shale of Nevada |journal=Journal of Paleontology |volume=97 |issue=5 |pages=1009–1024 |doi=10.1017/jpa.2023.63|bibcode=2023JPal...97.1009M }}</ref> ''[[Opabinia]]'' may also fall under this category in a broader sense,<ref name=":8">{{Cite journal|last=Ortega-Hernández|first=Javier|date=December 2014|title=Making sense of 'lower' and 'upper' stem-group Euarthropoda, with comments on the strict use of the name Arthropoda von Siebold, 1848|journal=Biological Reviews of the Cambridge Philosophical Society|volume=91|issue=1|pages=255–273|doi=10.1111/brv.12168|issn=1469-185X|pmid=25528950|s2cid=7751936}}</ref><ref name=":17">{{Cite journal|last1=Van Roy|first1=Peter|last2=Daley|first2=Allison C.|last3=Briggs|first3=Derek E. G.|date=2015|title=Anomalocaridid trunk limb homology revealed by a giant filter-feeder with paired flaps|journal=Nature|language=en|volume=522|issue=7554|pages=77–80|doi=10.1038/nature14256|pmid=25762145|issn=1476-4687|bibcode=2015Natur.522...77V|s2cid=205242881}}</ref> although the presence of lobopods in this genus is not definitively proven.<ref>{{Cite journal|last1=Budd|first1=Graham E.|last2=Daley|first2=Allison C.|date=January 2012|title=The lobes and lobopods of Opabinia regalis from the middle Cambrian Burgess Shale: The lobes of Opabinia|url=https://www.academia.edu/483085|journal=Lethaia|language=en|volume=45|issue=1|pages=83–95|doi=10.1111/j.1502-3931.2011.00264.x}}</ref> ''[[Omnidens]]'', a genus known only from ''Pambdelurion''-like mouthparts and distal parts of the frontal appendages, may also be a gilled lobopodian.<ref name=":7" /><ref name="qiongqii">{{cite journal |last1=Li |first1=Wei |last2=Yang |first2=Jie |last3=Yang |first3=Xiaoyu |last4=Dhungana |first4=Alavya |last5=Wang |first5=Yu |last6=Zhang |first6=Xiguang |last7=Smith |first7=Martin R. |date=November 2024 |title=Omnidens appendages and the origin of radiodont mouthparts |url=https://onlinelibrary.wiley.com/doi/10.1002/spp2.1600 |journal=Papers in Palaeontology |language=en |volume=10 |issue=6 |doi=10.1002/spp2.1600 |bibcode=2024PPal...10E1600L |issn=2056-2799}}</ref> The body flaps may have functioned as both swimming appendages and gills,<ref name=":18" /> and are possibly homologous to the dorsal flaps of radiodonts and exites of [[euarthropods|Euarthropoda]].<ref name=":1" /><ref name=":17" /> Whether these genera were true lobopodians is still contested by some.<ref>{{Cite journal|last1=Chen|first1=J.-y|last2=Ramskold|first2=L.|last3=Zhou|first3=G.-q|title=Evidence for Monophyly and Arthropod Affinity of Cambrian Giant Predators|url=https://www.academia.edu/1781228|journal=Science|language=en|volume=264|issue=5163|pages=1304–1308|issn=0036-8075|doi=10.1126/science.264.5163.1304|bibcode=1994Sci...264.1304C|year=1994|pmid=17780848|s2cid=1913482}}</ref> However, they are widely accepted as stem-group [[arthropod]]s just basal to radiodonts.<ref name=":8" /><ref name="ReferenceA" /><ref name=":2" /><ref name=":10" />

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=== ''Siberion'' and similar taxa ===
{{further|Siberiidae}}[[File:20191217 Siberiida Siberion Megadictyon Jianshanopodia.png|thumb|The siberiid lobopodians ''[[Siberion]]'' (upper left), ''[[Megadictyon]]'' (bottom center) and ''[[Jianshanopodia]]'' (upper right).]]

''[[Siberion]]'', ''[[Megadictyon]]'' and ''[[Jianshanopodia]]'' may be grouped as siberiids (order [[Siberiida]]),<ref name=":9">{{Cite journal |last=Dzik |first=Jerzy |date=2011-07-01 |df=dmy-all |title=The xenusian-to-anomalocaridid transition within the lobopodians |url=http://paleoitalia.org/media/u/archives/7.Dzik_-_BollSPI_50-1.pdf |archive-url=https://web.archive.org/web/20170808022647/http://paleoitalia.org/media/u/archives/7.Dzik_-_BollSPI_50-1.pdf |archive-date=2017-08-08 |url-status=usurped |journal=Bollettino della Societa Paleontologica Italiana |volume=50 |pages=65–74}}</ref> jianshanopodians<ref name="ReferenceA" /> or "giant lobopodians"<ref>{{Cite journal|last=Edgecombe|first=Gregory D.|date=2020-11-02|title=Arthropod Origins: Integrating Paleontological and Molecular Evidence|url=https://www.annualreviews.org/doi/10.1146/annurev-ecolsys-011720-124437|journal=Annual Review of Ecology, Evolution, and Systematics|volume=51|issue=1|pages=1–25|doi=10.1146/annurev-ecolsys-011720-124437|s2cid=225478171|issn=1543-592X}}</ref> by some literatures. They are generally large — body length ranging from {{cvt|7|to|22|cm|sigfig=1}}<ref name=":9"/><ref name="Liu2007"/>  — xenusiid lobopodians with widen trunk, stout trunk lobopods without evidence of claws, and most notably a pair of robust frontal appendages.<ref name=":8"/> With the possible exception of ''Siberion'',<ref name=":9" /><ref name="ReferenceA" /> they also have digestive glands like those of a gilled lobopodian and basal euarthropod.<ref name="Liu2006" /><ref name="Liu2007" /><ref name=":8"/><ref name=":5"/> Their anatomy represent transitional forms between typical xenusiids and gilled lobopodians,<ref name=":9"/> eventually placing them under the basalmost position of arthropod stem-group.<ref name="Liu2006"/><ref name="Liu2007"/><ref name=":8"/><ref name=":10"/>
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