Arachnomorpha/Arachnata clade nixed??

Ken Kinman kinman2 at YAHOO.COM
Mon Mar 7 22:24:22 CST 2005

Dear All,
     I have not seen this paper (in Lethaia) yet, but sounds extremely interesting and surprising.  That great-appendaged arthropods are related to Chelicerata is not a surprise at all, BUT anomalocarids closer to Chelicerata than are the trilobites?  YIKES!!!!  I didn't see that one coming at all, and will have to reserve judgment whether I will accept such a conclusion or not.  If true, it would have MAJOR implications for the origins and phylogeny of Arthropoda.
     -----Ken Kinman
Chen Junyuan, Waloszek, D. & Maas, A., 2004?: A new "great appendage" arthropod from the Lower Cambrian of China and the Phylogeny of Chelicerata.  Lethaia 37(1), 3-20.  Based on the descritpion of a new "great-appendages" arthropod, Haikoucaris erkaiensis, which is similar to others of its kind but has a three-forked claw, we re-investigated this set of arthropodas and others to evaluate the early stem lineage of Chelicerata.  Major outcomes: 1) Anomalocaridida are stem-lineage chelicerates, and so are the GAs; 2) Haikoucaris is the latest offshoot = sister taxon to a modern taxa = Chelicerata s. str. (Pycnogonida + Euchelicerata; 3) autapmorphies are presented; 4) Chelicerata started out with a grasping antenna and a predatory life style; 5) a1 was a uniramous, appendage-like structure from scratch; 6) taxa like trilobites and allied cannot be related to Chelicerata, therefore, a taxon Arachnata or Arachnomorpha is not possible.

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