A reconsideration of systematics in the Mollusca (phylogeny and higher classification)
von Salvini-Plawen, L. (1980). A reconsideration of systematics in the Mollusca (phylogeny and higher classification). Malacologia 19(2): 249-278
In: Malacologia: International Journal of Malacology. Institute of Malacology: Ann Arbor. ISSN 0076-2997; e-ISSN 2168-9075, more
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| Abstract |
A reconsideration of phylogenetic interrelations in molluscs with respect to several more recent studies on different groups of various taxa leads to a somewhat revised presentation of presumed molluscan evolution. Taking into consideration not only the quantitatively predominant shelled groups, adequately documented as fossils, but allowing also for the minor, yet comparative-anatomically equivalent aplacophoran molluscs, the synorganizationally relevant characters and organ systems reflect distinct anagenetic pathways. This analysis evidences a homogenous frame of continuous evolution along a phylogenetic main line of archimolluscs (Placophora-Conchifera), and an early sidebranch of Scutopoda. Four essential steps of progressive differentiation are obvious which separate a) the Scutopoda (Caudofoveata) from the Adenopoda (all other molluscs), b) the Solenogastres from the shell-bearing adenopods (Testaria), c) the Placophora from the Conchifera, and d) the conchiferan groups among each other. Herein the Placophora and Solenogastres are synapomorphously tied together in contrast to the merely symplesiomorphous characters in Solenogastres and Caudofoveata ("Aplacophora"). A correspondingly modified higher classification is proposed. |
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