Morphological character evolution and molecular trees in sepiids (Mollusca: Cephalopoda): is the cuttlebone a robust phylogenetic marker? |
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Authors: | LAURE BONNAUD C. C. LU RENATA BOUCHER-RODONI |
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Affiliation: | Muséum National d'Histoire Naturelle, Département Milieux et Peuplements Aquatiques, Biologie des Organismes Marins et Ecosystèmes (UMR 5178 CNRS), 55 rue Buffon, 75005 Paris, France; Department of Life Sciences, National Chung Hsing University, 250 Kuo Kuang Road, Taichung, Taiwan 402–27 |
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Abstract: | The sepiids are characterized by their cuttlebone or sepion, an internal shell resulting from secondary mineralization of a chitinous 'gladius'. The various species are identified using a combination of shell criteria and 'soft-part' characters. Using mitochondrial genes, we established phylogenetic relationships of sepiids including the three accepted genera ( Sepia , Sepiella , Metasepia ) and a species complex of uncertain status ( Doratosepion ). We showed the Sepia genus to be paraphyletic and found no direct correlation between geographical distribution and systematics. We mapped, on the molecular tree, shell characteristics commonly used as reliable diagnostic criteria for taxonomy. Due to the plasticity of the shell, these characters did not appear phylogenetically informative. In an attempt to define systematic categories related to phylogenetic relationships, new clear synapomorphies need to be established for each genus, necessitating a revision of the genus Sepia . © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 89 , 139–150. |
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Keywords: | 12S cephalopod COII gladius mtDNA genes phylogeny sepion shell systematics |
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