Shell adaptation in achrothelid brachiopods to settlement on a soft substrate
Article first published online: 9 OCT 2007
Volume 7, Issue 1, pages 57–61, January 1974
How to Cite
HENDERSON, R. A. (1974), Shell adaptation in achrothelid brachiopods to settlement on a soft substrate. Lethaia, 7: 57–61. doi: 10.1111/j.1502-3931.1974.tb00884.x
- Issue published online: 9 OCT 2007
- Article first published online: 9 OCT 2007
The protegulum of acrothelid inarticulate brachiopods is characterised by slender. elongate, hilaterally arranged spines which are interpreted as adaptations to facilitate settlement on a soft substrate. They provide a mechanism for positioning the gape clear of the substrate and a means of shell eversion to permit recovery from an overturned position. Holoperipheral growth and attainment of a low subconical form by the pedicle valve during later growth stages provide different strategies for solving these problems, and the protegular spines become non-functional and largely worn away. The structures arc illustrated in a species of Orbithele from the Upper Cambrian of Australia.