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The nature and significance of the appendages of Opabinia from the Middle Cambrian Burgess Shale

2007; Wiley; Volume: 40; Issue: 2 Linguagem: Inglês

10.1111/j.1502-3931.2007.00013.x

1502-3931

Xingliang Zhang, Derek E. G. Briggs,

Paleontology and Evolutionary Biology

LethaiaVolume 40, Issue 2 p. 161-173 The nature and significance of the appendages of Opabinia from the Middle Cambrian Burgess Shale XINGLIANG ZHANG, XINGLIANG ZHANGSearch for more papers by this authorDEREK E. G. BRIGGS, DEREK E. G. BRIGGSSearch for more papers by this author XINGLIANG ZHANG, XINGLIANG ZHANGSearch for more papers by this authorDEREK E. G. BRIGGS, DEREK E. G. BRIGGSSearch for more papers by this author First published: 08 April 2007 https://doi.org/10.1111/j.1502-3931.2007.00013.xCitations: 45 Xingliang Zhang [[email protected]], State Key Laboratory for Continental Dynamics and Department of Geology, Northwest University, Xian 710069, China; Derek E. G. Briggs (corresponding author) [[email protected]], Department of Geology and Geophysics, Yale University, PO Box 208109, New Haven, CT 06520-8109, USA. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Abstract Opabinia regalis has long been regarded as a curious animal, with its five eyes, its long flexible anterior process, and gill lamellae carried on the outside of overlapping lateral lobes. More recently, Opabinia has been reconstructed with lobopod limbs lying adaxial but separate from the lateral lobes. This version of Opabinia represented a lobopod–arthropod transition and prompted a hypothesis for the origin of the biramous limb that involved uniting the lobopod limb with a lateral lobe. New evidence of elemental maps is consistent with previous interpretations of the triangular structures in Opabinia as lateral extensions of the gut; there is no convincing evidence for the presence of lobopod limbs. Re-examination of critical specimens reveals that the gill lamellae are not on the outside of the lateral lobes. The limbs of Opabinia resemble the phyllopodous exopod of arthropods; the posterior margin is fringed with blades. Opabinia remains on the stem of euarthropods but not as a part of a paraphyletic Lobopodia. The Lobopodia is a clade of Cambrian armoured lobopods and onychophorans. A new hypothesis for the origin of the arthropod biramous limb from an exopod like that in Opabinia is presented, which involves an endite-bearing phyllopodous limb as an intermediate stage. Citing Literature Volume40, Issue2June 2007Pages 161-173 RelatedInformation