Cheloniellida: Difference between revisions

Cheloniellida; Temporal range: Upper Ordovician–Early Devonian PreꞒ Ꞓ O S D C P T J K Pg N
	Restoration of Cheloniellon
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
(unranked):	†Artiopoda
(unranked):	†Vicissicaudata
(unranked):	†Cheloniellida; Broili, 1932
Genera
	Cheloniellon Broili, 1932; Duslia Jahn, 1893; Eoduslia Van Roy, 2006; Neostrabops Caster & Macke, 1952; Paraduslia Dunlop, 2002; Pseudarthron Selden & White, 1984; Triopus Barrande, 1872;

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Cheloniellida is a taxon (usually referred to as an order^[1]^[2]) of extinct Paleozoic arthropods. As of 2018,^[2] 7 monotypic genera of cheloniellids had been formally described, whose fossils are found in marine strata ranging from Ordovician to Devonian in age. Cheloniellida has a controversial phylogenetic position, with previous studies associated it as either a member or relative of various fossil and extant arthropod taxa.^[2] It was later accepted as a member of Vicissicaudata within Artiopoda.^[3]^[4]^[5]

Morphology

The flattened, ovoid body of cheloniellid comprises an eye-bearing cephalon (head) and segmented trunk region, dorsally divided by a series of tergites (dorsal exoskeleton). The cephalon could be divided into procephalon and gnathocephalon.^[2] Compared to other members of Artiopoda, the head shield (dorsal exoskeleton of cephalon) of cheloniellid is relatively reduced.^[2]^[3] The trunk is wider than the cephalon and is made up of 8-13 tergites.^[2] The pleural (lateral) tips of first few tergites are directed anterolaterally, becoming increasingly posterolaterally directed rearward, giving the segmental boundaries between tergites a radiated appearance.^[3]^[2] The last trunk segment, also known as postabdomen,^[4] is tiny and laterally encompassed by the pleural regions of previous tergite.^[2]

Based on available materials, the cephalon comprises a pair of antennae and 5 pairs of uniramus appendages, with the posterior 4 pairs bore gnathobases.^[6] There are evidences that the non-gnathobasic second cephalic appendages are specialized or even raptorial in some species.^[6]^[2] Each of the trunk segments (except the last one) has a pair of biramous appendages each consisting of a leg-like endopod and a shorter exopod.^[2] The last trunk segment has a pair of spine/whip-like appendages referred as furcae^[3] or cerci,^[6] some species bore a medial spine between it which may or may not be a telson.^[2]

Classification

Phylogenetic position

While Boudreaux (1979) regarded Cheloniellida as a class,^[8] further studies usually treat Cheloniellida as an order.^[1]^[2] Cheloniellida has a controversial phylogenetic position within arthropod higher classifications, with studies mainly around 20th century suggested it as a relative/member of either Crustacea, Trilobita, Chelicerata or Aglaspidida.^[2] Some species even had been misidentified as polyplacophoran mollusks (chiton) when being first described.^[9] Originally, the iconic cheloniellid Cheloniellon was believed to be a crustacean similar to trilobites.^[10]^[11] Subsequent authors suggests that it occupied a position intermediate between trilobitomorphs and chelicerates,^[6]^[7] while some also interpreted it as a sister group of crustaceans^[12] or chelicerates^[13]^[14] as well. The suggested close relationship between cheloniellids and chelicerates was inferred by the gnathobasic appendages similar to those of merostomes (e.g. Xiphosurans and Eurypterids), and the hypothesis that the chelicerates arose from trilobitomorphs through the loss of deutocerebral antennae (i.e. first antennae) and specialization of tritocerebral appendages into chelicerae (comparable to the cheloniellid antennae and specialized 2nd appendages),^[6]^[7] a scenario which is not supported by gene expression,^[15]^[16]^[17]^[18]^[19] neuroanatomical^[20]^[21] and developmental^[22] evidences (suggests that chelicerae are in fact deutocerebral).

	Phytophylaspis

	Trilobita

Cheloniellida

	Triopus

	Duslia

Emeraldella

Kodymirus

	Eozetetes

	Aglaspidida

Summarized phylogeny of Artiopoda with focus on Cheloniellida, based on Lerosey-Aubril et al. (2017).^[4]

As of 21st century, Cheloniellida was mostly found to form a clade with Aglaspidida and Xenopoda (e.g. Sidneyia and Emeraldella).^[23]^[3]^[24]^[25]^[4] The clade was formally named Vicissicaudata in 2013,^[3] united by a differentiated terminal trunk area (postabdomen) that bears a pair of non-leg-like appendages.^[3]^[4] Numerous phylogenetic analyses also retrieved Vicissicaudata within Artiopoda,^[4] a diverse arthropod taxon comprising trilobites and similar fossil taxa that may^[26]^[24] or may not^[3]^[25]^[4] be closely related to chelicerates.

Included genera and species

The unambiguous members of cheloniellids shown as follows:

Cheloniellon Broili, 1932
- Cheloniellon calmani Broili, 1932—Lower Devonian, Germany
Duslia Jahn, 1893
- Duslia insignis Jahn, 1893—Upper Ordovician, Czech Republic, Morocco
Eoduslia Van Roy, 2006 (unpublished?)
- Eoduslia brahimtahiri Van Roy, 2006—Upper Ordovician, Morocco (unpublished?)
Neostrabops Caster & Macke, 1952
- Neostrabops martini Caster & Macke, 1952—Upper Ordovician, United States
Paraduslia Dunlop, 2002
- Paraduslia talimaae Dunlop, 2002—Lower Devonian, Russia
Pseudarthron Selden & White, 1984
- Pseudarthron whittingtoni Selden & White, 1984—Upper Silurian
Triopus Barrande, 1872
- Triopus drabowiensis Barrande, 1872—Upper Ordovician, Czech Republic, Morocco

In 2018, a new species (informally named "Latromirus" in an unpublished thesis from 2016^[27]) was described in a preprint by Wendruff et al.^[2] According to Braddy & Dunlop 2021, the enigmatic Parioscorpio may have cheloniellid affinities,^[28] however that interpretation is denied by Van Roy et al. 2022, only remaining specimen UWGM 2439 (holotype specimen of "Latromirus") as possible cheloniellid.^[29]

References

^ ^a ^b Hou, Xianguang. (1997). Arthropods of the Lower Cambrian Chengjiang fauna, southwest China (PDF). Bergström, Jan, 1938-. Oslo: Scandinavian University Press. ISBN 82-00-37693-1. OCLC 38305908.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ Wendruff, Andrew James, et al. "New cheloniellid arthropod with large raptorial appendages from the Silurian of Wisconsin, USA." BioRxiv (2018): 407379. [1]
^ ^a ^b ^c ^d ^e ^f ^g ^h Ortega-Hernández, Javier; Legg, David A.; Braddy, Simon J. (February 2013). "The phylogeny of aglaspidid arthropods and the internal relationships within Artiopoda". Cladistics. 29 (1): 15–45. doi:10.1111/j.1096-0031.2012.00413.x. PMID 34814371. S2CID 85744103.
^ ^a ^b ^c ^d ^e ^f ^g Lerosey-Aubril, Rudy; Zhu, Xuejian; Ortega-Hernández, Javier (2017-09-11). "The Vicissicaudata revisited – insights from a new aglaspidid arthropod with caudal appendages from the Furongian of China". Scientific Reports. 7 (1): 11117. Bibcode:2017NatSR...711117L. doi:10.1038/s41598-017-11610-5. ISSN 2045-2322. PMC 5593897. PMID 28894246.
^ Du, Kun-sheng; Ortega-Hernández, Javier; Yang, Jie; Zhang, Xi-guang (2019). "A soft-bodied euarthropod from the early Cambrian Xiaoshiba Lagerstätte of China supports a new clade of basal artiopodans with dorsal ecdysial sutures". Cladistics. 35 (3): 269–281. doi:10.1111/cla.12344. ISSN 0748-3007. PMID 34622993. S2CID 89985331.
^ ^a ^b ^c ^d ^e ^f Stürmer, Wilhelm; Bergström, Jan (1978). "The arthropod Cheloniellon from the devonian hunsrück shale". Paläontologische Zeitschrift. 52 (1): 57–81. doi:10.1007/BF03006730. S2CID 87725308.
^ ^a ^b ^c STfJRMER, W. t~ BERGSTROM, J. 1981. Weinbergina, a xiphosuran arthropod from the Devonian Hunsriick Slate. - Palaontologische Zeitschrift 55: 237-255.[2] Archived 2020-06-20 at the Wayback Machine
^ Boudreaux H. B., 1979. Significance of intersegmental tendon system in arthropod phylogeny and monophyletic classification of Arthropoda. pp. 551-586. In.: Gupta A.P. [Ed.]. Arthropod Phylogeny. Van Nostrand Reinhold Company, N.Y., 1-762
^ Chlupác I. The enigmatic arthropod Duslia from the Ordovician of Czechoslovakia. Palaeontol. 1988; 31:611–620.[3]
^ BROILI, F. (1932): Ein neuer Crustacee aus dem rheinischen Unterdevon. -- Sitzungsber. bayer. Akad. Wiss.: 27--38; Miinchen.[4]
^ BROILI, F. (1933): Ein zweites Exemplar von Cheloniellon. -- Sitzungsber. bayer. Akad. Wiss.: 11--32; Miinchen.[5]
^ Delle Cave, L. and A.M. Simonetta (1991) Early Palaeozoic arthropods and problems of arthropod phylogeny; with some notes on taxa of doubtful affinities. In The Early Evolution of Metazoa and the Significance of Problematic Taxa, eds. A. M. Simonetta and S. Conway Morris. Cambridge University Press, Cambridge, England. Vol. 189–244.
^ Wills, M. A., Briggs, D. E. G., Fortey, R. A. & Wilkinson, M. 1995. The significance of fossils in understanding arthropod evolution. Verhandlungen der deutschen zoologischen Gesselschaft 88, 203–15.
^ Dunlop, J. A.; Selden, P. A. (1998), Fortey, R. A.; Thomas, R. H. (eds.), "The early history and phylogeny of the chelicerates", Arthropod Relationships, The Systematics Association Special Volume Series, Dordrecht: Springer Netherlands, pp. 221–235, doi:10.1007/978-94-011-4904-4_17, ISBN 978-94-011-4904-4
^ Telford, Maximilian J.; Thomas, Richard H. (1998-09-01). "Expression of homeobox genes shows chelicerate arthropods retain their deutocerebral segment". Proceedings of the National Academy of Sciences. 95 (18): 10671–10675. Bibcode:1998PNAS...9510671T. doi:10.1073/pnas.95.18.10671. ISSN 0027-8424. PMC 27953. PMID 9724762.
^ Damen, Wim G. M. (2002-03-01). "Parasegmental organization of the spider embryo implies that the parasegment is an evolutionary conserved entity in arthropod embryogenesis". Development. 129 (5): 1239–1250. doi:10.1242/dev.129.5.1239. ISSN 0950-1991. PMID 11874919.
^ Jager, Muriel; Murienne, Jérôme; Clabaut, Céline; Deutsch, Jean; Guyader, Hervé Le; Manuel, Michaël (2006). "Homology of arthropod anterior appendages revealed by Hox gene expression in a sea spider". Nature. 441 (7092): 506–508. Bibcode:2006Natur.441..506J. doi:10.1038/nature04591. ISSN 1476-4687. PMID 16724066. S2CID 4307398.
^ Manuel, Michaël; Jager, Muriel; Murienne, Jérôme; Clabaut, Céline; Guyader, Hervé Le (2006-07-01). "Hox genes in sea spiders (Pycnogonida) and the homology of arthropod head segments". Development Genes and Evolution. 216 (7): 481–491. doi:10.1007/s00427-006-0095-2. ISSN 1432-041X. PMID 16820954. S2CID 833103.
^ Brenneis, Georg; Ungerer, Petra; Scholtz, Gerhard (2008). "The chelifores of sea spiders (Arthropoda, Pycnogonida) are the appendages of the deutocerebral segment". Evolution & Development. 10 (6): 717–724. doi:10.1111/j.1525-142X.2008.00285.x. ISSN 1525-142X. PMID 19021742. S2CID 6048195.
^ Mittmann, Beate; Scholtz, Gerhard (2003-02-01). "Development of the nervous system in the "head" of Limulus polyphemus (Chelicerata: Xiphosura): morphological evidence for a correspondence between the segments of the chelicerae and of the (first) antennae of Mandibulata". Development Genes and Evolution. 213 (1): 9–17. doi:10.1007/s00427-002-0285-5. ISSN 1432-041X. PMID 12590348. S2CID 13101102.
^ Harzsch, Steffen; Wildt, Miriam; Battelle, Barbara; Waloszek, Dieter (2005-07-01). "Immunohistochemical localization of neurotransmitters in the nervous system of larval Limulus polyphemus (Chelicerata, Xiphosura): evidence for a conserved protocerebral architecture in Euarthropoda". Arthropod Structure & Development. Arthropod Brain Morphology and Evolution. 34 (3): 327–342. doi:10.1016/j.asd.2005.01.006. ISSN 1467-8039.
^ Mittmann, Beate; Scholtz, Gerhard (2003-02-01). "Development of the nervous system in the "head" of Limulus polyphemus (Chelicerata: Xiphosura): morphological evidence for a correspondence between the segments of the chelicerae and of the (first) antennae of Mandibulata". Development Genes and Evolution. 213 (1): 9–17. doi:10.1007/s00427-002-0285-5. ISSN 1432-041X. PMID 12590348. S2CID 13101102.
^ Edgecombe, Gregory D.; García-Bellido, Diego C.; Paterson, John R. (2011). "A New Leanchoiliid Megacheiran Arthropod from the Lower Cambrian Emu Bay Shale, South Australia". Acta Palaeontologica Polonica. 56 (2): 385–400. doi:10.4202/app.2010.0080. hdl:10261/61352. ISSN 0567-7920.
^ ^a ^b Legg, David A. (2014). "Sanctacaris uncata: the oldest chelicerate (Arthropoda)". Naturwissenschaften. 101 (12): 1065–1073. Bibcode:2014NW....101.1065L. doi:10.1007/s00114-014-1245-4. ISSN 0028-1042. PMID 25296691. S2CID 15290784.
^ ^a ^b Edgecombe, Gregory D.; Paterson, John R.; García-Bellido, Diego C. (2017). "A new aglaspidid-like euarthropod from the lower Cambrian Emu Bay Shale of South Australia". Geological Magazine. 154 (1): 87–95. Bibcode:2017GeoM..154...87E. doi:10.1017/S0016756815001053. ISSN 0016-7568. S2CID 133058010.
^ Legg, David A.; Sutton, Mark D.; Edgecombe, Gregory D. (2013). "Arthropod fossil data increase congruence of morphological and molecular phylogenies". Nature Communications. 4: 2485. Bibcode:2013NatCo...4.2485L. doi:10.1038/ncomms3485. ISSN 2041-1723. PMID 24077329.
^ Wendruff, Andrew J. (2016). Paleobiology and Taphonomy of Exceptionally Preserved Organisms from the Brandon Bridge Formation (Silurian), Wisconsin, USA (Thesis). The Ohio State University.
^ Braddy, S.J.; Dunlop, J.A. (2021). "A sting in the tale of Parioscorpio venator from the Silurian of Wisconsin: is it a cheloniellid arthropod?". Lethaia. 54 (1): 1–7. doi:10.1111/let.12457. S2CID 245285654.
^ Roy, Peter Van; Rak, Štěpán; Budil, Petr; Fatka, Oldřich (2022-06-13). "Redescription of the cheloniellid euarthropod Triopus draboviensis from the Upper Ordovician of Bohemia, with comments on the affinities of Parioscorpio venator". Geological Magazine. 159 (9): 1471–1489. doi:10.1017/S0016756822000292. hdl:1854/LU-8756253. ISSN 0016-7568. S2CID 249652930.

Boudreaux, H. Bruce (1979). Arthropod phylogeny with special reference to insects. John Wiley & Sons. ISBN 978-0471042907.
Budd, Graham E. (1997). "Stem Group Arthropods from the Lower Cambrian Sirius Passet Fauna of North Greenland". In Fortey, Richard A. (ed.). Arthropod Relationships. Systematics Association Special Volume Series 55. Richard H. Thomas. Springer. ISBN 978-0412754203.
Dunlop, Jason A.; Selden, Paul A. (1997). "The early history and phylogeny of the chelicerates". In Fortey, Richard A. (ed.). Arthropod Relationships. Systematics Association Special Volume Series 55. Richard H. Thomas. Springer. pp. 237–245. ISBN 978-0412754203.
Hou Xianguang; Bergström, Jan (2006). Arthropods of the Lower Cambrian Chengliang fauna, southwest China. Fossils & Strata Monograph Series. Wiley-Blackwell. ISBN 978-8200376934.

[:2-1] Hou, Xianguang. (1997). Arthropods of the Lower Cambrian Chengjiang fauna, southwest China (PDF). Bergström, Jan, 1938-. Oslo: Scandinavian University Press. ISBN 82-00-37693-1. OCLC 38305908.

[:0-2] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ Wendruff, Andrew James, et al. "New cheloniellid arthropod with large raptorial appendages from the Silurian of Wisconsin, USA." BioRxiv (2018): 407379. [1]

[:1-3] ^ ^a ^b ^c ^d ^e ^f ^g ^h Ortega-Hernández, Javier; Legg, David A.; Braddy, Simon J. (February 2013). "The phylogeny of aglaspidid arthropods and the internal relationships within Artiopoda". Cladistics. 29 (1): 15–45. doi:10.1111/j.1096-0031.2012.00413.x. PMID 34814371. S2CID 85744103.

[:5-4] ^ ^a ^b ^c ^d ^e ^f ^g Lerosey-Aubril, Rudy; Zhu, Xuejian; Ortega-Hernández, Javier (2017-09-11). "The Vicissicaudata revisited – insights from a new aglaspidid arthropod with caudal appendages from the Furongian of China". Scientific Reports. 7 (1): 11117. Bibcode:2017NatSR...711117L. doi:10.1038/s41598-017-11610-5. ISSN 2045-2322. PMC 5593897. PMID 28894246.

[5] Du, Kun-sheng; Ortega-Hernández, Javier; Yang, Jie; Zhang, Xi-guang (2019). "A soft-bodied euarthropod from the early Cambrian Xiaoshiba Lagerstätte of China supports a new clade of basal artiopodans with dorsal ecdysial sutures". Cladistics. 35 (3): 269–281. doi:10.1111/cla.12344. ISSN 0748-3007. PMID 34622993. S2CID 89985331.

[:3-6] ^ ^a ^b ^c ^d ^e ^f Stürmer, Wilhelm; Bergström, Jan (1978). "The arthropod Cheloniellon from the devonian hunsrück shale". Paläontologische Zeitschrift. 52 (1): 57–81. doi:10.1007/BF03006730. S2CID 87725308.

[:4-7] STfJRMER, W. t~ BERGSTROM, J. 1981. Weinbergina, a xiphosuran arthropod from the Devonian Hunsriick Slate. - Palaontologische Zeitschrift 55: 237-255.[2] Archived 2020-06-20 at the Wayback Machine

[8] Boudreaux H. B., 1979. Significance of intersegmental tendon system in arthropod phylogeny and monophyletic classification of Arthropoda. pp. 551-586. In.: Gupta A.P. [Ed.]. Arthropod Phylogeny. Van Nostrand Reinhold Company, N.Y., 1-762

[9] Chlupác I. The enigmatic arthropod Duslia from the Ordovician of Czechoslovakia. Palaeontol. 1988; 31:611–620.[3]

[10] BROILI, F. (1932): Ein neuer Crustacee aus dem rheinischen Unterdevon. -- Sitzungsber. bayer. Akad. Wiss.: 27--38; Miinchen.[4]

[11] BROILI, F. (1933): Ein zweites Exemplar von Cheloniellon. -- Sitzungsber. bayer. Akad. Wiss.: 11--32; Miinchen.[5]

[12] Delle Cave, L. and A.M. Simonetta (1991) Early Palaeozoic arthropods and problems of arthropod phylogeny; with some notes on taxa of doubtful affinities. In The Early Evolution of Metazoa and the Significance of Problematic Taxa, eds. A. M. Simonetta and S. Conway Morris. Cambridge University Press, Cambridge, England. Vol. 189–244.

[13] Wills, M. A., Briggs, D. E. G., Fortey, R. A. & Wilkinson, M. 1995. The significance of fossils in understanding arthropod evolution. Verhandlungen der deutschen zoologischen Gesselschaft 88, 203–15.

[14] Dunlop, J. A.; Selden, P. A. (1998), Fortey, R. A.; Thomas, R. H. (eds.), "The early history and phylogeny of the chelicerates", Arthropod Relationships, The Systematics Association Special Volume Series, Dordrecht: Springer Netherlands, pp. 221–235, doi:10.1007/978-94-011-4904-4_17, ISBN 978-94-011-4904-4

[15] Telford, Maximilian J.; Thomas, Richard H. (1998-09-01). "Expression of homeobox genes shows chelicerate arthropods retain their deutocerebral segment". Proceedings of the National Academy of Sciences. 95 (18): 10671–10675. Bibcode:1998PNAS...9510671T. doi:10.1073/pnas.95.18.10671. ISSN 0027-8424. PMC 27953. PMID 9724762.

[16] Damen, Wim G. M. (2002-03-01). "Parasegmental organization of the spider embryo implies that the parasegment is an evolutionary conserved entity in arthropod embryogenesis". Development. 129 (5): 1239–1250. doi:10.1242/dev.129.5.1239. ISSN 0950-1991. PMID 11874919.

[17] Jager, Muriel; Murienne, Jérôme; Clabaut, Céline; Deutsch, Jean; Guyader, Hervé Le; Manuel, Michaël (2006). "Homology of arthropod anterior appendages revealed by Hox gene expression in a sea spider". Nature. 441 (7092): 506–508. Bibcode:2006Natur.441..506J. doi:10.1038/nature04591. ISSN 1476-4687. PMID 16724066. S2CID 4307398.

[18] Manuel, Michaël; Jager, Muriel; Murienne, Jérôme; Clabaut, Céline; Guyader, Hervé Le (2006-07-01). "Hox genes in sea spiders (Pycnogonida) and the homology of arthropod head segments". Development Genes and Evolution. 216 (7): 481–491. doi:10.1007/s00427-006-0095-2. ISSN 1432-041X. PMID 16820954. S2CID 833103.

[19] Brenneis, Georg; Ungerer, Petra; Scholtz, Gerhard (2008). "The chelifores of sea spiders (Arthropoda, Pycnogonida) are the appendages of the deutocerebral segment". Evolution & Development. 10 (6): 717–724. doi:10.1111/j.1525-142X.2008.00285.x. ISSN 1525-142X. PMID 19021742. S2CID 6048195.

[20] Mittmann, Beate; Scholtz, Gerhard (2003-02-01). "Development of the nervous system in the "head" of Limulus polyphemus (Chelicerata: Xiphosura): morphological evidence for a correspondence between the segments of the chelicerae and of the (first) antennae of Mandibulata". Development Genes and Evolution. 213 (1): 9–17. doi:10.1007/s00427-002-0285-5. ISSN 1432-041X. PMID 12590348. S2CID 13101102.

[21] Harzsch, Steffen; Wildt, Miriam; Battelle, Barbara; Waloszek, Dieter (2005-07-01). "Immunohistochemical localization of neurotransmitters in the nervous system of larval Limulus polyphemus (Chelicerata, Xiphosura): evidence for a conserved protocerebral architecture in Euarthropoda". Arthropod Structure & Development. Arthropod Brain Morphology and Evolution. 34 (3): 327–342. doi:10.1016/j.asd.2005.01.006. ISSN 1467-8039.

[22] Mittmann, Beate; Scholtz, Gerhard (2003-02-01). "Development of the nervous system in the "head" of Limulus polyphemus (Chelicerata: Xiphosura): morphological evidence for a correspondence between the segments of the chelicerae and of the (first) antennae of Mandibulata". Development Genes and Evolution. 213 (1): 9–17. doi:10.1007/s00427-002-0285-5. ISSN 1432-041X. PMID 12590348. S2CID 13101102.

[23] Edgecombe, Gregory D.; García-Bellido, Diego C.; Paterson, John R. (2011). "A New Leanchoiliid Megacheiran Arthropod from the Lower Cambrian Emu Bay Shale, South Australia". Acta Palaeontologica Polonica. 56 (2): 385–400. doi:10.4202/app.2010.0080. hdl:10261/61352. ISSN 0567-7920.

[:6-24] Legg, David A. (2014). "Sanctacaris uncata: the oldest chelicerate (Arthropoda)". Naturwissenschaften. 101 (12): 1065–1073. Bibcode:2014NW....101.1065L. doi:10.1007/s00114-014-1245-4. ISSN 0028-1042. PMID 25296691. S2CID 15290784.

[:7-25] Edgecombe, Gregory D.; Paterson, John R.; García-Bellido, Diego C. (2017). "A new aglaspidid-like euarthropod from the lower Cambrian Emu Bay Shale of South Australia". Geological Magazine. 154 (1): 87–95. Bibcode:2017GeoM..154...87E. doi:10.1017/S0016756815001053. ISSN 0016-7568. S2CID 133058010.

[26] Legg, David A.; Sutton, Mark D.; Edgecombe, Gregory D. (2013). "Arthropod fossil data increase congruence of morphological and molecular phylogenies". Nature Communications. 4: 2485. Bibcode:2013NatCo...4.2485L. doi:10.1038/ncomms3485. ISSN 2041-1723. PMID 24077329.

[27] Wendruff, Andrew J. (2016). Paleobiology and Taphonomy of Exceptionally Preserved Organisms from the Brandon Bridge Formation (Silurian), Wisconsin, USA (Thesis). The Ohio State University.

[Braddy&Dunlop2021-28] Braddy, S.J.; Dunlop, J.A. (2021). "A sting in the tale of Parioscorpio venator from the Silurian of Wisconsin: is it a cheloniellid arthropod?". Lethaia. 54 (1): 1–7. doi:10.1111/let.12457. S2CID 245285654.

[29] Roy, Peter Van; Rak, Štěpán; Budil, Petr; Fatka, Oldřich (2022-06-13). "Redescription of the cheloniellid euarthropod Triopus draboviensis from the Upper Ordovician of Bohemia, with comments on the affinities of Parioscorpio venator". Geological Magazine. 159 (9): 1471–1489. doi:10.1017/S0016756822000292. hdl:1854/LU-8756253. ISSN 0016-7568. S2CID 249652930.

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@@ Line 10: / Line 10: @@
 | subdivision = *''[[Cheloniellon]]'' <small>Broili, 1932</small>
 *''[[Duslia]]'' <small>Jahn, 1893</small>
-*''[[Eoduslia]]'' <small>Vidal, 1998</small>
+*''[[Eoduslia]]'' <small>Van Roy, 2006</small>
 *''[[Neostrabops]]'' <small>Caster & Macke, 1952</small>
 *''[[Paraduslia]]'' <small>Dunlop, 2002</small>
 *''[[Pseudarthron]]'' <small>Selden & White, 1984</small>
 *''[[Triopus]]'' <small>Barrande, 1872</small>
-*''?[[Parioscorpio]]'' <small>Wendruff et al, 2020</small><ref name="Braddy&Dunlop2021">{{cite journal |last1=Braddy |first1=S.J. |last2=Dunlop |first2=J.A. |year=2021 |title=A sting in the tale of Parioscorpio venator from the Silurian of Wisconsin: is it a cheloniellid arthropod? |journal=Lethaia |volume=54 |issue=1 |pages=1-7 |doi=10.1111/let.12457}}</ref>
 }}
-'''Cheloniellida''' is a taxon (usually referred to as an order<ref name=":2">{{Cite book|last=Hou, Xianguang.|url=https://foreninger.uio.no/ngf/FOS/pdfs/F&S_45.pdf|title=Arthropods of the Lower Cambrian Chengjiang fauna, southwest China|date=1997|publisher=Scandinavian University Press|others=Bergström, Jan, 1938-|isbn=82-00-37693-1|location=Oslo|oclc=38305908}}</ref><ref name=":0" />) of extinct [[Paleozoic]] [[arthropod]]s. As of 2018,<ref name=":0">Wendruff, Andrew James, et al. "New cheloniellid arthropod with large raptorial appendages from the Silurian of Wisconsin, USA." BioRxiv (2018): 407379. [https://www.biorxiv.org/content/biorxiv/early/2018/09/07/407379.full.pdf]</ref> 7 [[monotypic]] genera of '''cheloniellids''' had been formally described, whose fossils are found in marine strata ranging from [[Ordovician]] to [[Devonian]] in age. Cheloniellida has a controversial [[phylogenetic]] position, with previous studies associated it as either a member or relative of various fossil and extant arthropod taxa.<ref name=":0" /> It was later accepted as a member of [[Vicissicaudata]] within [[Artiopoda]].<ref name=":1">{{Cite journal|last1=Ortega-Hernández|first1=Javier|last2=Legg|first2=David A.|last3=Braddy|first3=Simon J.|date=February 2013|title=The phylogeny of aglaspidid arthropods and the internal relationships within Artiopoda|journal=Cladistics|language=en|volume=29|issue=1|pages=15–45|doi=10.1111/j.1096-0031.2012.00413.x|s2cid=85744103}}</ref><ref name=":5">{{Cite journal|last1=Lerosey-Aubril|first1=Rudy|last2=Zhu|first2=Xuejian|last3=Ortega-Hernández|first3=Javier|date=2017-09-11|title=The Vicissicaudata revisited – insights from a new aglaspidid arthropod with caudal appendages from the Furongian of China|journal=Scientific Reports|language=en|volume=7|issue=1|page=11117|doi=10.1038/s41598-017-11610-5|pmid=28894246|pmc=5593897|issn=2045-2322|doi-access=free}}</ref><ref>{{Cite journal|last1=Du|first1=Kun-sheng|last2=Ortega-Hernández|first2=Javier|last3=Yang|first3=Jie|last4=Zhang|first4=Xi-guang|date=2019|title=A soft-bodied euarthropod from the early Cambrian Xiaoshiba Lagerstätte of China supports a new clade of basal artiopodans with dorsal ecdysial sutures|journal=Cladistics|language=en|volume=35|issue=3|pages=269–281|doi=10.1111/cla.12344|s2cid=89985331|issn=0748-3007}}</ref>
+'''Cheloniellida''' is a taxon (usually referred to as an order<ref name=":2">{{Cite book|last=Hou, Xianguang.|url=https://foreninger.uio.no/ngf/FOS/pdfs/F&S_45.pdf|title=Arthropods of the Lower Cambrian Chengjiang fauna, southwest China|date=1997|publisher=Scandinavian University Press|others=Bergström, Jan, 1938-|isbn=82-00-37693-1|location=Oslo|oclc=38305908}}</ref><ref name=":0" />) of extinct [[Paleozoic]] [[arthropod]]s. As of 2018,<ref name=":0">Wendruff, Andrew James, et al. "New cheloniellid arthropod with large raptorial appendages from the Silurian of Wisconsin, USA." BioRxiv (2018): 407379. [https://www.biorxiv.org/content/biorxiv/early/2018/09/07/407379.full.pdf]</ref> 7 [[monotypic]] genera of '''cheloniellids''' had been formally described, whose fossils are found in marine strata ranging from [[Ordovician]] to [[Devonian]] in age. Cheloniellida has a controversial [[phylogenetic]] position, with previous studies associated it as either a member or relative of various fossil and extant arthropod taxa.<ref name=":0" /> It was later accepted as a member of [[Vicissicaudata]] within [[Artiopoda]].<ref name=":1">{{Cite journal|last1=Ortega-Hernández|first1=Javier|last2=Legg|first2=David A.|last3=Braddy|first3=Simon J.|date=February 2013|title=The phylogeny of aglaspidid arthropods and the internal relationships within Artiopoda|journal=Cladistics|language=en|volume=29|issue=1|pages=15–45|doi=10.1111/j.1096-0031.2012.00413.x|pmid=34814371 |s2cid=85744103}}</ref><ref name=":5">{{Cite journal|last1=Lerosey-Aubril|first1=Rudy|last2=Zhu|first2=Xuejian|last3=Ortega-Hernández|first3=Javier|date=2017-09-11|title=The Vicissicaudata revisited – insights from a new aglaspidid arthropod with caudal appendages from the Furongian of China|journal=Scientific Reports|language=en|volume=7|issue=1|page=11117|doi=10.1038/s41598-017-11610-5|pmid=28894246|pmc=5593897|bibcode=2017NatSR...711117L |issn=2045-2322|doi-access=free}}</ref><ref>{{Cite journal|last1=Du|first1=Kun-sheng|last2=Ortega-Hernández|first2=Javier|last3=Yang|first3=Jie|last4=Zhang|first4=Xi-guang|date=2019|title=A soft-bodied euarthropod from the early Cambrian Xiaoshiba Lagerstätte of China supports a new clade of basal artiopodans with dorsal ecdysial sutures|journal=Cladistics|language=en|volume=35|issue=3|pages=269–281|doi=10.1111/cla.12344|pmid=34622993 |s2cid=89985331|issn=0748-3007|doi-access=free}}</ref>
 == Morphology ==
@@ Line 30: / Line 29: @@
 ===Phylogenetic position===
 [[File:20200615 Cheloniellon calmani anterior ventral abbreviation.png|300px|thumb|The specialized second appendages (Pap, green) and gnathobasic appendages (Gap, cyan) of ''[[Cheloniellon]]'' had been compared to [[chelicerate]] prosomal appendages by some studies.<ref name=":3" /><ref name=":4" />]]
-While Boudreaux (1979) regarded Cheloniellida as a class,<ref>Boudreaux H. B., 1979. Significance of intersegmental tendon system in arthropod phylogeny and monophyletic classification of Arthropoda. pp. 551-586. In.: Gupta A.P. [Ed.]. Arthropod Phylogeny. Van Nostrand Reinhold Company, N.Y., 1-762</ref> further studies usually treat Cheloniellida as an order.<ref name=":2" /><ref name=":0" /> Cheloniellida has a controversial [[phylogenetic]] position within arthropod higher classifications, with studies mainly around 20th century suggested it as a relative/member of either [[Crustacea]], [[Trilobita]], [[Chelicerata]] or [[Aglaspidida]].<ref name=":0" /> Some species even had been misidentified as [[polyplacophoran]] [[mollusks]] ([[chiton]]) when being first described.<ref>Chlupác I. The enigmatic arthropod Duslia from the Ordovician of Czechoslovakia. Palaeontol. 1988; 31:611–620.[https://www.palass.org/sites/default/files/media/publications/palaeontology/volume_31/vol31_part3_pp611-620.pdf]</ref> Originally, the iconic cheloniellid ''[[Cheloniellon]]'' was believed to be a crustacean similar to trilobites.<ref>BROILI, F. (1932): Ein neuer Crustacee aus dem rheinischen Unterdevon. -- Sitzungsber. bayer. Akad. Wiss.: 27--38; Miinchen.[https://www.zobodat.at/pdf/Sitz-Ber-Akad-Muenchen-math-Kl_1932_0027-0038.pdf]</ref><ref>BROILI, F. (1933): Ein zweites Exemplar von Cheloniellon. -- Sitzungsber. bayer. Akad. Wiss.: 11--32; Miinchen.[https://www.zobodat.at/pdf/Sitz-Ber-Akad-Muenchen-math-Kl_1933_0011-0032.pdf]</ref> Subsequent authors suggests that it occupied a position intermediate between trilobitomorphs and chelicerates,<ref name=":3" /><ref name=":4">STfJRMER, W. t~ BERGSTROM, J. 1981. Weinbergina, a xiphosuran arthropod from the Devonian Hunsriick Slate. - Palaontologische Zeitschrift 55: 237-255.[http://www.museunacional.ufrj.br/mndi/Aracnologia/Xiphosura/St%FCrmer_&_Bergstr%F6m%201981_Weinbergina.pdf]</ref> while some also interpreted it as a [[sister group]] of crustaceans<ref>Delle Cave, L. and A.M. Simonetta (1991) Early Palaeozoic arthropods and problems of arthropod phylogeny; with some notes on taxa of doubtful affinities. In The Early Evolution of Metazoa and the Significance of Problematic Taxa, eds. A. M. Simonetta and S. Conway Morris. Cambridge University Press, Cambridge, England. Vol. 189–244.</ref> or chelicerates<ref>Wills, M. A., Briggs, D. E. G., Fortey, R. A. & Wilkinson, M. 1995. The significance of fossils in understanding arthropod evolution. Verhandlungen der deutschen zoologischen Gesselschaft 88, 203–15.</ref><ref>{{Citation|last1=Dunlop|first1=J. A.|title=The early history and phylogeny of the chelicerates|date=1998|work=Arthropod Relationships|pages=221–235|editor-last=Fortey|editor-first=R. A.|series=The Systematics Association Special Volume Series|place=Dordrecht|publisher=Springer Netherlands|language=en|doi=10.1007/978-94-011-4904-4_17|isbn=978-94-011-4904-4|last2=Selden|first2=P. A.|editor2-last=Thomas|editor2-first=R. H.}}</ref> as well. The suggested close relationship between cheloniellids and chelicerates was inferred by the gnathobasic appendages similar to those of merostomes (e.g. [[Xiphosuran]]s and [[Eurypterid]]s), and the hypothesis that the chelicerates arose from trilobitomorphs through the loss of deutocerebral [[Antenna (biology)|antennae]] (i.e. first antennae) and specialization of tritocerebral appendages into [[chelicerae]] (comparable to the cheloniellid antennae and specialized 2nd appendages),<ref name=":3" /><ref name=":4" /> a scenario which is not supported by [[gene expression]],<ref>{{Cite journal|last1=Telford|first1=Maximilian J.|last2=Thomas|first2=Richard H.|date=1998-09-01|title=Expression of homeobox genes shows chelicerate arthropods retain their deutocerebral segment|journal=Proceedings of the National Academy of Sciences|language=en|volume=95|issue=18|pages=10671–10675|doi=10.1073/pnas.95.18.10671|issn=0027-8424|pmid=9724762|pmc=27953|doi-access=free}}</ref><ref>{{Cite journal|last=Damen|first=Wim G. M.|date=2002-03-01|title=Parasegmental organization of the spider embryo implies that the parasegment is an evolutionary conserved entity in arthropod embryogenesis|url=https://dev.biologists.org/content/129/5/1239|journal=Development|language=en|volume=129|issue=5|pages=1239–1250|doi=10.1242/dev.129.5.1239|issn=0950-1991|pmid=11874919}}</ref><ref>{{Cite journal|last1=Jager|first1=Muriel|last2=Murienne|first2=Jérôme|last3=Clabaut|first3=Céline|last4=Deutsch|first4=Jean|last5=Guyader|first5=Hervé Le|last6=Manuel|first6=Michaël|date=2006|title=Homology of arthropod anterior appendages revealed by Hox gene expression in a sea spider|url=https://www.nature.com/articles/nature04591|journal=Nature|language=en|volume=441|issue=7092|pages=506–508|doi=10.1038/nature04591|pmid=16724066|s2cid=4307398|issn=1476-4687}}</ref><ref>{{Cite journal|last1=Manuel|first1=Michaël|last2=Jager|first2=Muriel|last3=Murienne|first3=Jérôme|last4=Clabaut|first4=Céline|last5=Guyader|first5=Hervé Le|date=2006-07-01|title=Hox genes in sea spiders (Pycnogonida) and the homology of arthropod head segments|journal=Development Genes and Evolution|language=en|volume=216|issue=7|pages=481–491|doi=10.1007/s00427-006-0095-2|pmid=16820954|s2cid=833103|issn=1432-041X}}</ref><ref>{{Cite journal|last1=Brenneis|first1=Georg|last2=Ungerer|first2=Petra|last3=Scholtz|first3=Gerhard|date=2008|title=The chelifores of sea spiders (Arthropoda, Pycnogonida) are the appendages of the deutocerebral segment|journal=Evolution & Development|volume=10|issue=6|pages=717–724|doi=10.1111/j.1525-142X.2008.00285.x|issn=1525-142X|pmid=19021742|s2cid=6048195}}</ref> [[neuroanatomical]]<ref>{{Cite journal|last1=Mittmann|first1=Beate|last2=Scholtz|first2=Gerhard|date=2003-02-01|title=Development of the nervous system in the "head" of Limulus polyphemus (Chelicerata: Xiphosura): morphological evidence for a correspondence between the segments of the chelicerae and of the (first) antennae of Mandibulata|url=https://www.researchgate.net/publication/10897784|journal=Development Genes and Evolution|language=en|volume=213|issue=1|pages=9–17|doi=10.1007/s00427-002-0285-5|pmid=12590348|s2cid=13101102|issn=1432-041X}}</ref><ref>{{Cite journal|last1=Harzsch|first1=Steffen|last2=Wildt|first2=Miriam|last3=Battelle|first3=Barbara|last4=Waloszek|first4=Dieter|date=2005-07-01|title=Immunohistochemical localization of neurotransmitters in the nervous system of larval Limulus polyphemus (Chelicerata, Xiphosura): evidence for a conserved protocerebral architecture in Euarthropoda|url=http://www.sciencedirect.com/science/article/pii/S1467803905000186|journal=Arthropod Structure & Development|series=Arthropod Brain Morphology and Evolution|language=en|volume=34|issue=3|pages=327–342|doi=10.1016/j.asd.2005.01.006|issn=1467-8039}}</ref> and [[Developmental biology|developmental]]<ref>{{Cite journal|last1=Mittmann|first1=Beate|last2=Scholtz|first2=Gerhard|date=2003-02-01|title=Development of the nervous system in the "head" of Limulus polyphemus (Chelicerata: Xiphosura): morphological evidence for a correspondence between the segments of the chelicerae and of the (first) antennae of Mandibulata|journal=Development Genes and Evolution|language=en|volume=213|issue=1|pages=9–17|doi=10.1007/s00427-002-0285-5|pmid=12590348|s2cid=13101102|issn=1432-041X}}</ref> evidences (suggests that chelicerae are in fact deutocerebral).
+While Boudreaux (1979) regarded Cheloniellida as a class,<ref>Boudreaux H. B., 1979. Significance of intersegmental tendon system in arthropod phylogeny and monophyletic classification of Arthropoda. pp. 551-586. In.: Gupta A.P. [Ed.]. Arthropod Phylogeny. Van Nostrand Reinhold Company, N.Y., 1-762</ref> further studies usually treat Cheloniellida as an order.<ref name=":2" /><ref name=":0" /> Cheloniellida has a controversial [[phylogenetic]] position within arthropod higher classifications, with studies mainly around 20th century suggested it as a relative/member of either [[Crustacea]], [[Trilobita]], [[Chelicerata]] or [[Aglaspidida]].<ref name=":0" /> Some species even had been misidentified as [[polyplacophoran]] [[mollusks]] ([[chiton]]) when being first described.<ref>Chlupác I. The enigmatic arthropod Duslia from the Ordovician of Czechoslovakia. Palaeontol. 1988; 31:611–620.[https://www.palass.org/sites/default/files/media/publications/palaeontology/volume_31/vol31_part3_pp611-620.pdf]</ref> Originally, the iconic cheloniellid ''[[Cheloniellon]]'' was believed to be a crustacean similar to trilobites.<ref>BROILI, F. (1932): Ein neuer Crustacee aus dem rheinischen Unterdevon. -- Sitzungsber. bayer. Akad. Wiss.: 27--38; Miinchen.[https://www.zobodat.at/pdf/Sitz-Ber-Akad-Muenchen-math-Kl_1932_0027-0038.pdf]</ref><ref>BROILI, F. (1933): Ein zweites Exemplar von Cheloniellon. -- Sitzungsber. bayer. Akad. Wiss.: 11--32; Miinchen.[https://www.zobodat.at/pdf/Sitz-Ber-Akad-Muenchen-math-Kl_1933_0011-0032.pdf]</ref> Subsequent authors suggests that it occupied a position intermediate between trilobitomorphs and chelicerates,<ref name=":3" /><ref name=":4">STfJRMER, W. t~ BERGSTROM, J. 1981. Weinbergina, a xiphosuran arthropod from the Devonian Hunsriick Slate. - Palaontologische Zeitschrift 55: 237-255.[http://www.museunacional.ufrj.br/mndi/Aracnologia/Xiphosura/St%FCrmer_&_Bergstr%F6m%201981_Weinbergina.pdf] {{Webarchive|url=https://web.archive.org/web/20200620211959/http://www.museunacional.ufrj.br/mndi/Aracnologia/Xiphosura/St%FCrmer_%26_Bergstr%F6m%201981_Weinbergina.pdf |date=2020-06-20 }}</ref> while some also interpreted it as a [[sister group]] of crustaceans<ref>Delle Cave, L. and A.M. Simonetta (1991) Early Palaeozoic arthropods and problems of arthropod phylogeny; with some notes on taxa of doubtful affinities. In The Early Evolution of Metazoa and the Significance of Problematic Taxa, eds. A. M. Simonetta and S. Conway Morris. Cambridge University Press, Cambridge, England. Vol. 189–244.</ref> or chelicerates<ref>Wills, M. A., Briggs, D. E. G., Fortey, R. A. & Wilkinson, M. 1995. The significance of fossils in understanding arthropod evolution. Verhandlungen der deutschen zoologischen Gesselschaft 88, 203–15.</ref><ref>{{Citation|last1=Dunlop|first1=J. A.|title=The early history and phylogeny of the chelicerates|date=1998|work=Arthropod Relationships|pages=221–235|editor-last=Fortey|editor-first=R. A.|series=The Systematics Association Special Volume Series|place=Dordrecht|publisher=Springer Netherlands|language=en|doi=10.1007/978-94-011-4904-4_17|isbn=978-94-011-4904-4|last2=Selden|first2=P. A.|editor2-last=Thomas|editor2-first=R. H.}}</ref> as well. The suggested close relationship between cheloniellids and chelicerates was inferred by the gnathobasic appendages similar to those of merostomes (e.g. [[Xiphosuran]]s and [[Eurypterid]]s), and the hypothesis that the chelicerates arose from trilobitomorphs through the loss of deutocerebral [[Antenna (biology)|antennae]] (i.e. first antennae) and specialization of tritocerebral appendages into [[chelicerae]] (comparable to the cheloniellid antennae and specialized 2nd appendages),<ref name=":3" /><ref name=":4" /> a scenario which is not supported by [[gene expression]],<ref>{{Cite journal|last1=Telford|first1=Maximilian J.|last2=Thomas|first2=Richard H.|date=1998-09-01|title=Expression of homeobox genes shows chelicerate arthropods retain their deutocerebral segment|journal=Proceedings of the National Academy of Sciences|language=en|volume=95|issue=18|pages=10671–10675|doi=10.1073/pnas.95.18.10671|issn=0027-8424|pmid=9724762|pmc=27953|bibcode=1998PNAS...9510671T |doi-access=free}}</ref><ref>{{Cite journal|last=Damen|first=Wim G. M.|date=2002-03-01|title=Parasegmental organization of the spider embryo implies that the parasegment is an evolutionary conserved entity in arthropod embryogenesis|url=https://dev.biologists.org/content/129/5/1239|journal=Development|language=en|volume=129|issue=5|pages=1239–1250|doi=10.1242/dev.129.5.1239|issn=0950-1991|pmid=11874919}}</ref><ref>{{Cite journal|last1=Jager|first1=Muriel|last2=Murienne|first2=Jérôme|last3=Clabaut|first3=Céline|last4=Deutsch|first4=Jean|last5=Guyader|first5=Hervé Le|last6=Manuel|first6=Michaël|date=2006|title=Homology of arthropod anterior appendages revealed by Hox gene expression in a sea spider|url=https://www.nature.com/articles/nature04591|journal=Nature|language=en|volume=441|issue=7092|pages=506–508|doi=10.1038/nature04591|pmid=16724066|bibcode=2006Natur.441..506J |s2cid=4307398|issn=1476-4687}}</ref><ref>{{Cite journal|last1=Manuel|first1=Michaël|last2=Jager|first2=Muriel|last3=Murienne|first3=Jérôme|last4=Clabaut|first4=Céline|last5=Guyader|first5=Hervé Le|date=2006-07-01|title=Hox genes in sea spiders (Pycnogonida) and the homology of arthropod head segments|journal=Development Genes and Evolution|language=en|volume=216|issue=7|pages=481–491|doi=10.1007/s00427-006-0095-2|pmid=16820954|s2cid=833103|issn=1432-041X}}</ref><ref>{{Cite journal|last1=Brenneis|first1=Georg|last2=Ungerer|first2=Petra|last3=Scholtz|first3=Gerhard|date=2008|title=The chelifores of sea spiders (Arthropoda, Pycnogonida) are the appendages of the deutocerebral segment|journal=Evolution & Development|volume=10|issue=6|pages=717–724|doi=10.1111/j.1525-142X.2008.00285.x|issn=1525-142X|pmid=19021742|s2cid=6048195}}</ref> [[neuroanatomical]]<ref>{{Cite journal|last1=Mittmann|first1=Beate|last2=Scholtz|first2=Gerhard|date=2003-02-01|title=Development of the nervous system in the "head" of Limulus polyphemus (Chelicerata: Xiphosura): morphological evidence for a correspondence between the segments of the chelicerae and of the (first) antennae of Mandibulata|url=https://www.researchgate.net/publication/10897784|journal=Development Genes and Evolution|language=en|volume=213|issue=1|pages=9–17|doi=10.1007/s00427-002-0285-5|pmid=12590348|s2cid=13101102|issn=1432-041X}}</ref><ref>{{Cite journal|last1=Harzsch|first1=Steffen|last2=Wildt|first2=Miriam|last3=Battelle|first3=Barbara|last4=Waloszek|first4=Dieter|date=2005-07-01|title=Immunohistochemical localization of neurotransmitters in the nervous system of larval Limulus polyphemus (Chelicerata, Xiphosura): evidence for a conserved protocerebral architecture in Euarthropoda|url=http://www.sciencedirect.com/science/article/pii/S1467803905000186|journal=Arthropod Structure & Development|series=Arthropod Brain Morphology and Evolution|language=en|volume=34|issue=3|pages=327–342|doi=10.1016/j.asd.2005.01.006|issn=1467-8039}}</ref> and [[Developmental biology|developmental]]<ref>{{Cite journal|last1=Mittmann|first1=Beate|last2=Scholtz|first2=Gerhard|date=2003-02-01|title=Development of the nervous system in the "head" of Limulus polyphemus (Chelicerata: Xiphosura): morphological evidence for a correspondence between the segments of the chelicerae and of the (first) antennae of Mandibulata|journal=Development Genes and Evolution|language=en|volume=213|issue=1|pages=9–17|doi=10.1007/s00427-002-0285-5|pmid=12590348|s2cid=13101102|issn=1432-041X}}</ref> evidences (suggests that chelicerae are in fact deutocerebral).
 {{cladogram
@@ Line 45: / Line 44: @@
   |label3=|3=[[Conciliterga]]
   |4={{clade
-    |1=[[Petalopleura]]
+    |1=[[Artiopoda|Petalopleura]]
     |2={{clade
       |1=[[Nektaspidida]]
@@ Line 72: / Line 71: @@
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-As of 21st century, Cheloniellida was mostly found to form a clade with [[Aglaspidida]] and [[Xenopoda]] (e.g. ''[[Sidneyia]]'' and ''[[Emeraldella]]'').<ref>{{Cite journal|last1=Edgecombe|first1=Gregory D.|last2=García-Bellido|first2=Diego C.|last3=Paterson|first3=John R.|date=2011|title=A New Leanchoiliid Megacheiran Arthropod from the Lower Cambrian Emu Bay Shale, South Australia|url=http://www.app.pan.pl/article/item/app20100080.html|journal=Acta Palaeontologica Polonica|language=en|volume=56|issue=2|pages=385–400|doi=10.4202/app.2010.0080|issn=0567-7920|doi-access=free}}</ref><ref name=":1" /><ref name=":6">{{Cite journal|last=Legg|first=David A.|date=2014|title=Sanctacaris uncata: the oldest chelicerate (Arthropoda)|url=https://www.researchgate.net/publication/266683582|journal=Naturwissenschaften|language=en|volume=101|issue=12|pages=1065–1073|doi=10.1007/s00114-014-1245-4|pmid=25296691|s2cid=15290784|issn=0028-1042}}</ref><ref name=":7">{{Cite journal|last1=Edgecombe|first1=Gregory D.|last2=Paterson|first2=John R.|last3=García-Bellido|first3=Diego C.|date=2017|title=A new aglaspidid-like euarthropod from the lower Cambrian Emu Bay Shale of South Australia|url=https://www.cambridge.org/core/journals/geological-magazine/article/new-aglaspididlike-euarthropod-from-the-lower-cambrian-emu-bay-shale-of-south-australia/6E5897CE0D2D6C7C95274518304D1453|journal=Geological Magazine|language=en|volume=154|issue=1|pages=87–95|doi=10.1017/S0016756815001053|s2cid=133058010|issn=0016-7568}}</ref><ref name=":5" /> The clade was formally named [[Vicissicaudata]] in 2013,<ref name=":1" /> united by a differentiated terminal trunk area (postabdomen) that bears a pair of non-leg-like appendages.<ref name=":1" /><ref name=":5" /> Numerous phylogenetic analyses also retrieved Vicissicaudata within [[Artiopoda]],<ref name=":5" /> a diverse arthropod taxon comprising [[trilobite]]s and similar fossil taxa that may<ref>{{Cite journal|last1=Legg|first1=David A.|last2=Sutton|first2=Mark D.|last3=Edgecombe|first3=Gregory D.|date=2013|title=Arthropod fossil data increase congruence of morphological and molecular phylogenies|url=https://www.researchgate.net/publication/257205419|journal=Nature Communications|volume=4|pages=2485|doi=10.1038/ncomms3485|issn=2041-1723|pmid=24077329|doi-access=free}}</ref><ref name=":6" /> or may not<ref name=":1" /><ref name=":7" /><ref name=":5" /> be closely related to [[chelicerates]].
+As of 21st century, Cheloniellida was mostly found to form a clade with [[Aglaspidida]] and [[Xenopoda]] (e.g. ''[[Sidneyia]]'' and ''[[Emeraldella]]'').<ref>{{Cite journal|last1=Edgecombe|first1=Gregory D.|last2=García-Bellido|first2=Diego C.|last3=Paterson|first3=John R.|date=2011|title=A New Leanchoiliid Megacheiran Arthropod from the Lower Cambrian Emu Bay Shale, South Australia|url=http://www.app.pan.pl/article/item/app20100080.html|journal=Acta Palaeontologica Polonica|language=en|volume=56|issue=2|pages=385–400|doi=10.4202/app.2010.0080|issn=0567-7920|doi-access=free|hdl=10261/61352|hdl-access=free}}</ref><ref name=":1" /><ref name=":6">{{Cite journal|last=Legg|first=David A.|date=2014|title=Sanctacaris uncata: the oldest chelicerate (Arthropoda)|url=https://www.researchgate.net/publication/266683582|journal=Naturwissenschaften|language=en|volume=101|issue=12|pages=1065–1073|doi=10.1007/s00114-014-1245-4|pmid=25296691|bibcode=2014NW....101.1065L |s2cid=15290784|issn=0028-1042}}</ref><ref name=":7">{{Cite journal|last1=Edgecombe|first1=Gregory D.|last2=Paterson|first2=John R.|last3=García-Bellido|first3=Diego C.|date=2017|title=A new aglaspidid-like euarthropod from the lower Cambrian Emu Bay Shale of South Australia|url=https://www.cambridge.org/core/journals/geological-magazine/article/new-aglaspididlike-euarthropod-from-the-lower-cambrian-emu-bay-shale-of-south-australia/6E5897CE0D2D6C7C95274518304D1453|journal=Geological Magazine|language=en|volume=154|issue=1|pages=87–95|doi=10.1017/S0016756815001053|bibcode=2017GeoM..154...87E |s2cid=133058010|issn=0016-7568}}</ref><ref name=":5" /> The clade was formally named [[Vicissicaudata]] in 2013,<ref name=":1" /> united by a differentiated terminal trunk area (postabdomen) that bears a pair of non-leg-like appendages.<ref name=":1" /><ref name=":5" /> Numerous phylogenetic analyses also retrieved Vicissicaudata within [[Artiopoda]],<ref name=":5" /> a diverse arthropod taxon comprising [[trilobite]]s and similar fossil taxa that may<ref>{{Cite journal|last1=Legg|first1=David A.|last2=Sutton|first2=Mark D.|last3=Edgecombe|first3=Gregory D.|date=2013|title=Arthropod fossil data increase congruence of morphological and molecular phylogenies|url=https://www.researchgate.net/publication/257205419|journal=Nature Communications|volume=4|pages=2485|doi=10.1038/ncomms3485|issn=2041-1723|pmid=24077329|bibcode=2013NatCo...4.2485L |doi-access=free}}</ref><ref name=":6" /> or may not<ref name=":1" /><ref name=":7" /><ref name=":5" /> be closely related to [[chelicerates]].
 === Included genera and species ===
+The unambiguous members of cheloniellids shown as follows:
 *''[[Cheloniellon]]'' <small>Broili, 1932</small>
 **''Cheloniellon calmani'' <small>Broili, 1932</small>—Lower [[Devonian]], Germany
 *''[[Duslia]]'' <small>Jahn, 1893</small>
 **''Duslia insignis'' <small>Jahn, 1893</small>—Upper [[Ordovician]], Czech Republic, Morocco
+*''[[Eoduslia]]'' <small>Van Roy, 2006</small> (unpublished?)<!-- nomen nudum and described in an unpublished PhD thesis according to BioLib: https://www.biolib.cz/en/taxon/id1393903/ ; "Vidal, 1998" is an error from Fossilworks/PBDB: https://paleobiodb.org/classic/basicTaxonInfo?taxon_no=348152 -->
-*''[[Eoduslia]]'' <small>Vidal, 1998</small>
-**''Eoduslia brahimtahiri'' <small>Vidal, 1998</small>—Upper Ordovician, Morocco
+**''Eoduslia brahimtahiri'' <small>Van Roy, 2006</small>—Upper Ordovician, Morocco (unpublished?)
 *''[[Neostrabops]]'' <small>Caster & Macke, 1952</small>
 **Neostrabops martini <small>Caster & Macke, 1952</small>—Upper Ordovician, United States
@@ Line 89: / Line 89: @@
 *''[[Triopus]]'' <small>Barrande, 1872</small>
 **''Triopus drabowiensis'' <small>Barrande, 1872</small>—Upper Ordovician, Czech Republic, Morocco
+In 2018, a new species (informally named "''[[Latromirus]]''" in an unpublished thesis from 2016<ref>{{Cite thesis |title=Paleobiology and Taphonomy of Exceptionally Preserved Organisms from the Brandon Bridge Formation (Silurian), Wisconsin, USA |url=https://etd.ohiolink.edu/apexprod/rws_olink/r/1501/10?clear=10&p10_accession_num=osu1468844814#abstract-files |publisher=The Ohio State University |date=2016 |language=en |first=Andrew J. |last=Wendruff}}</ref>) was described in a preprint by Wendruff et al.<ref name=":0" /> According to Braddy & Dunlop 2021, the enigmatic ''[[Parioscorpio]]'' may have cheloniellid affinities,<ref name="Braddy&Dunlop2021">{{cite journal |last1=Braddy |first1=S.J. |last2=Dunlop |first2=J.A. |year=2021 |title=A sting in the tale of Parioscorpio venator from the Silurian of Wisconsin: is it a cheloniellid arthropod? |journal=Lethaia |volume=54 |issue=1 |pages=1–7 |doi=10.1111/let.12457|s2cid=245285654 }}</ref> however that interpretation is denied by Van Roy et al. 2022, only remaining specimen UWGM 2439 (holotype specimen of "''Latromirus''") as possible cheloniellid.<ref>{{Cite journal |last1=Roy |first1=Peter Van |last2=Rak |first2=Štěpán |last3=Budil |first3=Petr |last4=Fatka |first4=Oldřich |date=2022-06-13 |title=Redescription of the cheloniellid euarthropod Triopus draboviensis from the Upper Ordovician of Bohemia, with comments on the affinities of Parioscorpio venator |url=https://www.cambridge.org/core/journals/geological-magazine/article/abs/redescription-of-the-cheloniellid-euarthropod-triopus-draboviensis-from-the-upper-ordovician-of-bohemia-with-comments-on-the-affinities-of-parioscorpio-venator/60A567EA1D28C2A7311BB68CAD427F22 |journal=Geological Magazine |volume=159 |issue=9 |language=en |pages=1471–1489 |doi=10.1017/S0016756822000292 |hdl=1854/LU-8756253 |s2cid=249652930 |issn=0016-7568}}</ref>{{-}}
-{{-}}
 ==References==