The bearing of the new Late Cambrian monoplacophoran genus Knightoconus upon the origin of the Cephalopoda
Knightoconus, a new genus of the Hypseloconidae (Mollusca: Monoplacophora) from rocks of early Franconian age in Antarctica, is multiseptate. The multiple septa are a criticàl feature to be expected in a form ancestral to cephalopods. Fossil cephalopods, however, invariably have a siphuncle as well as septa; some gastropods, some hyolithids, and some monoplacophorans also have septa but lack a siphuncle. Therefore, only the siphuncle can be considered a unique and particularly significant feature of the cephalopod shell. Hypothetical reconstructions of molluscan anatomy support the notion that cephalopods may have been derived directly from a hypseloconid having a high, slightly curved, multiseptate, bilaterally symmetrical shell, by the subsequent development of a siphuncle.
Citation Information
Publication Year | 1973 |
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Title | The bearing of the new Late Cambrian monoplacophoran genus Knightoconus upon the origin of the Cephalopoda |
DOI | 10.1111/j.1502-3931.1973.tb01199.x |
Publication Type | Article |
Publication Subtype | Journal Article |
Series Title | Lethaia |
Index ID | 70241914 |
Record Source | USGS Publications Warehouse |