Skania is a Cambrian fossil arthropod. The type species, S. fragillis, is known from the Burgess Shale of British Columbia, Canada. A second possible species "S." sundbergi is known from the Kaili Formation of China,[1] but its placement within the genus has been questioned.[2]
Specimens of S. fragillis range in length from 7.5 to 13.5 millimetres (0.30 to 0.53 in) The cordiform dorsal shield/carapace covers the entire body, with its midline having a raised keel. The shield curls around the front to form a doublure, with the posterior edge of the doublure having a pair of lateral spines. A pair of spines is also present on the posterior of the dorsal shield. A hypostome was present on the underside of the head. There are two sets of appendages, the first 5 pairs of appendages are elongate, the first one of which is described as an antenna and has small subquadrate segments/podomeres, while the others have elongate subrectangular segments. These appendages are somewhat curved and extend beyond the shield. In contrast, the trunk appendages are shorter (not extending beyond the shield) and are less curved, and the segments are not preserved. There was a diverticular (digestive) network running through the carapace, along with a central gut tract.[2]
Specimens of "S." sundbergi are on average 7.92 millimetres (0.312 in) in length. The midline keel is more strongly pronounced in "S." sundbergi. The spines present in S. fragillis are either more weakly developed or absent.[1][2]
Taxonomyedit
While previously enigmatic, it is now thought to be a marrellomorph, with both species, regardless of generic placement, belonging to Acercostraca.[2] The resemblance with the EdiacaranorganismParvancorina, to which Skania had previously been suggested to be closely related as part of the proposed clade "Parvancorinomorpha",[1] is superficial and they are probably not related.[2]
Referencesedit
^ abcLin, J. P.; Gon, S. M.; Gehling, J. G.; Babcock, L. E.; Zhao, Y. L.; Zhang, X. L.; Hu, S. X.; Yuan, J. L.; Yu, M. Y.; Peng, J. (2006). "A Parvancorina-like arthropod from the Cambrian of South China". Historical Biology. 18 (1): 33–45. doi:10.1080/08912960500508689. S2CID 85821717.
^ abcdeLegg, D.A. (2015-09-30). "The morphology and affinities of Skania fragilis (Arthropoda) from the middle Cambrian Burgess Shale". Bulletin of Geosciences: 509–518. doi:10.3140/bull.geosci.1532. ISSN 1802-8225.
External linksedit
"Skania fragilis". Burgess Shale Fossil Gallery. Virtual Museum of Canada. 2011. Archived from the original on 2020-11-12.
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skania, swedish, province, scania, cambrian, fossil, arthropod, type, species, fragillis, known, from, burgess, shale, british, columbia, canada, second, possible, species, sundbergi, known, from, kaili, formation, china, placement, within, genus, been, questi. For the Swedish province see Scania Skania is a Cambrian fossil arthropod The type species S fragillis is known from the Burgess Shale of British Columbia Canada A second possible species S sundbergi is known from the Kaili Formation of China 1 but its placement within the genus has been questioned 2 SkaniaTemporal range Cambrian Stage 3 Middle Cambrian PreꞒ Ꞓ O S D C P T J K Pg NIllustration of Skania fragilisScientific classificationDomain EukaryotaKingdom AnimaliaPhylum ArthropodaClass MarrellomorphaOrder AcercostracaGenus SkaniaWalcott 1931SpeciesS fragilis Walcott 1931 S sundbergi Lin et al 2006 Contents 1 Description 2 Taxonomy 3 References 4 External linksDescription edit nbsp Carapace of S sundbergiSpecimens of S fragillis range in length from 7 5 to 13 5 millimetres 0 30 to 0 53 in The cordiform dorsal shield carapace covers the entire body with its midline having a raised keel The shield curls around the front to form a doublure with the posterior edge of the doublure having a pair of lateral spines A pair of spines is also present on the posterior of the dorsal shield A hypostome was present on the underside of the head There are two sets of appendages the first 5 pairs of appendages are elongate the first one of which is described as an antenna and has small subquadrate segments podomeres while the others have elongate subrectangular segments These appendages are somewhat curved and extend beyond the shield In contrast the trunk appendages are shorter not extending beyond the shield and are less curved and the segments are not preserved There was a diverticular digestive network running through the carapace along with a central gut tract 2 Specimens of S sundbergi are on average 7 92 millimetres 0 312 in in length The midline keel is more strongly pronounced in S sundbergi The spines present in S fragillis are either more weakly developed or absent 1 2 Taxonomy editWhile previously enigmatic it is now thought to be a marrellomorph with both species regardless of generic placement belonging to Acercostraca 2 The resemblance with the Ediacaran organism Parvancorina to which Skania had previously been suggested to be closely related as part of the proposed clade Parvancorinomorpha 1 is superficial and they are probably not related 2 References edit a b c Lin J P Gon S M Gehling J G Babcock L E Zhao Y L Zhang X L Hu S X Yuan J L Yu M Y Peng J 2006 A Parvancorina like arthropod from the Cambrian of South China Historical Biology 18 1 33 45 doi 10 1080 08912960500508689 S2CID 85821717 a b c d e Legg D A 2015 09 30 The morphology and affinities of Skania fragilis Arthropoda from the middle Cambrian Burgess Shale Bulletin of Geosciences 509 518 doi 10 3140 bull geosci 1532 ISSN 1802 8225 External links edit Skania fragilis Burgess Shale Fossil Gallery Virtual Museum of Canada 2011 Archived from the original on 2020 11 12 nbsp This prehistoric arthropod related article is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title Skania amp oldid 1193892680, wikipedia, wiki, book, books, library,
