Dissepiments in the graptolite Monograptus turriculatus
Article first published online: 9 OCT 2007
Volume 26, Issue 3, pages 203–205, December 1993
How to Cite
ZALASIEWICZ, J. (1993), Dissepiments in the graptolite Monograptus turriculatus. Lethaia, 26: 203–205. doi: 10.1111/j.1502-3931.1993.tb01519.x
- Issue published online: 9 OCT 2007
- Article first published online: 9 OCT 2007
- received 17th March, 1992; revised manuscript received 15th September, 1992.
An example of the graptolite Monograptus turriculatus (Barrande, 1850) from the crispus Biozone (Silurian, Llandovery) of the Girvan district, Scotland, shows the first recorded instance of dissepiment formation in graptoloid graptolites. The dissepiments are formed by the fusion of thecal spines with the dorsal wall of the adjacent part of the succeeding whorl of this spiral graptolite. The formation of these structures appears easiest to envisage using models of the graptolite colony that do not involve extrathecal tissue. □Graptolithina, Monograptus, morphology, functional morphology, Silurian, Llandovery.