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The tuning fork graptoloid, Didymograptus murchisoni (Beck, 1839)
Published online by Cambridge University Press: 03 November 2011
Abstract
The development of D. (Didymograptus) murchisoni (Beck), the type species of the genus, is shown to be unequivocally of anus type, with thl1 dicalyal and a low metasicular origin of thl1. An evolutionary line from the early, Arenig, bifidus group is supported; and clear distinctions are drawn between the subgenera D. (Didymograptus), D. (Didymograptellus) and D. (Jenkinsograptus), the first of these being redefined. The range of variation of biocharacters of D. murchisoni is analysed using exquisitely preserved undeformed material from Saudi Arabia, and comparisons are made with the undeformed type material, and with undeformed (nodule) collections from Abereiddy Bay, Pembrokeshire. The astogenetically late developments of D. murchisoni are described.
Keywords
- Type
- Research Article
- Information
- Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 90 , Issue 3 , 1999 , pp. 173 - 187
- Copyright
- Copyright © Royal Society of Edinburgh 1999
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