title: Kodymirus and the case for convergence of raptorial appendages in Cambrian arthropods.
abstract: Kodymirus vagans Chlupáč and Havlíček in Sb Geol Ved Paleontol 6:7-20, 1965 is redescribed as an aglaspidid-like arthropod bearing a single pair of enlarged raptorial appendages, which are shown to be the second cephalic appendage. A number of early Palaeozoic arthropods, recognized from predominantly Cambrian Konservat-Lagerstätten, are known to have borne single pairs of large raptorial appendages. They are well established for the iconic yet problematic anomalocarids, the common megacheirans, and the ubiquitous bivalved Isoxys. Further taxa, such as fuxianhuiids and Branchiocaris, have been reported to have single pairs of specialized cephalic appendages, i.e., appendages differentiated from a largely homonomous limbs series, members of which act in metachronal motion. The homology of these raptorial appendages across these Cambrian arthropods has often been assumed, despite differences in morphology. Thus, anomalocaridids, for instance, have long multiarticulate "frontal appendages" consisting of many articles bearing an armature of paired serial spines, while megacheirans and Isoxys have short "great appendages" consisting of few articles with well-developed endites or elongate fingers. Homology of these appendages would require them to belong to the same cephalic segment. We argue based on morphological evidence that, to the contrary, the raptorial appendages of some of these taxa can be shown to belong to different cephalic segments and are the result of convergence in life habits. K. vagans is yet another important example for this, representing an instance for this morphology from a marginal marine environment.
authors.affiliation: Paleontological Institute and Department of Geology, University of Kansas, 1475 Jayhawk Boulevard, Lawrence, KS 66045, USA. lamsdell@ku.edu
authors.forename: James C
authors.initials: JC
authors.lastname: Lamsdell
authors.forename: Martin
authors.initials: M
authors.lastname: Stein
authors.forename: Paul A
authors.initials: PA
authors.lastname: Selden
mesh_terms: D000825:Animal Structures / Q000033:anatomy & histology; D000818:Animals; D001181:Arthropods / Q000033:anatomy & histology* / Q000145:classification; D005580:Fossils; D010802:Phylogeny; D013045:Species Specificity
references.citation: Nature. 2013 Feb 28;494(7438):468-71
references.pmid: 23446418
references.citation: BMC Evol Biol. 2012 Aug 30;12:162
references.pmid: 22935076
references.citation: Nat Commun. 2012;3:1261
references.pmid: 23232391
references.citation: Science. 2009 Feb 6;323(5915):771-3
references.pmid: 19197061
references.citation: Nature. 2011 May 26;473(7348):510-3
references.pmid: 21614078
references.citation: Nature. 2002 May 16;417(6886):271-5
references.pmid: 12015599
references.citation: Proc Biol Sci. 2012 Dec 7;279(1748):4699-704
references.pmid: 23055069
references.citation: BMC Evol Biol. 2013 May 11;13:99
references.pmid: 23663519
references.citation: Nature. 2011 Dec 07;480(7376):237-40
references.pmid: 22158247
references.citation: Science. 2009 Mar 20;323(5921):1597-600
references.pmid: 19299617
references.citation: Biol Rev Camb Philos Soc. 2012 May;87(2):480-512
references.pmid: 22385518
references.citation: Dev Genes Evol. 2006 Jul-Aug;216(7-8):395-415
references.pmid: 16816969
references.citation: Dev Genes Evol. 2010 Sep;220(3-4):117-22
references.pmid: 20567844
references.citation: Int J Dev Biol. 2009;53(5-6):733-51
references.pmid: 19557680
references.citation: Arthropod Struct Dev. 2010 Mar-May;39(2-3):74-87
references.pmid: 19854297
references.citation: BMC Evol Biol. 2013 May 10;13:98
references.pmid: 23663507
references.citation: Proc Biol Sci. 2009 Jul 22;276(1667):2567-74
references.pmid: 19403536
references.citation: Dev Genes Evol. 2013 Jul;223(4):247-51
references.pmid: 23423435
references.citation: Naturwissenschaften. 2012 Jun;99(6):501-4
references.pmid: 22476406