Ditrupa plana
Ditrupa plana
Summary
Ditrupa plana was a serpulid polychaete worm that lived inside a hard calcareous tube. The animal itself was soft-bodied; at the tube opening it carried a crown of tentacles used for suspension feeding and respiration, collecting fine organic particles from seawater.
Unlike many firmly cemented serpulids, Ditrupa-like tubes could lie free on the sediment surface. The fossil record is therefore almost entirely the tube, not the worm, and the repeated occurrence of Ditrupa in London Clay mudstones records a benthic suspension-feeding component of the soft-bottom community.
Quick Identification
Look for: a smooth, narrow, gently curved calcareous tube that tapers toward one end and lacks the tightly coiled disc of Rotularia; broken sections show a hollow tube rather than a solid spine or tusk shell.
Diagnostic Features
- Tube elongate, slender and gently curved.
- One end narrows progressively, producing a tapered tube profile.
- External surface is comparatively smooth, without the broad planispiral coil of Rotularia.
- Cross-section is hollow with a continuous calcareous wall.
- Growth follows the tube axis; irregular broken ends should not be mistaken for natural apertures.
Fossil Details
Similar Species
Recorded Fossil Sites
London Clay Formation
Walton Member
References
- Tracey, S.; Donovan, S. K.; Clements, D.; Jeffery, P.; Cooper, J.; Rye, P.; Hensley, C. (2002). Temporary exposures of the Eocene London Clay Formation at Highgate, north London: rediscovery of a fossiliferous horizon ‘lost’ since the nineteenth century. Proceedings of the Geologists' Association, 113(4), 319–331 View reference
- Wrigley, A. (1951). Some Eocene Serpulids. Proceedings of the Geologists' Association, 62(3), 177–202 View reference