Table of Contents
- Summary & Introduction
- Epifaunal Worm Tubes on Lower Lias Ammonites – Results
- Epifaunal Worm Tubes on Lower Lias Ammonites – Detailed Observations and interpretation
- Epifaunal Worm Tubes on Lower Lias Ammonites – Discussion
- Epifaunal Worm Tubes on Lower Lias Ammonites – Conclusions and References
Over 40 ammonites with worm tubes attached have been considered in detail (Table 1), of which 38 are pyritized Promicroceras (e.g., Figs 2-7). In addition, seven Promicroceras with fragments of worm tubes attached were collected that are too poorly preserved for analysis.
It is significant that, for the ammonites with single (Figs 2-4) or multiple (Figs 5-7) peripheral tubes, not one worm grew counter to the direction of growth of the ammonite to which it was attached. In summary, the most common association among our specimens is of a single, peripheral worm tube (Figs 2-4) growing on the ammonite Promicroceras. In many cases the ammonite eventually grew over the worm tube, clearly indicating that the ammonite was alive while the worm tube was growing. We regard this most common association as the ‘standard pattern’ and discuss its significance below (Section 4.1).