Diplocraterion
Diplocraterion is an ichnogenus describing vertical U-shaped burrows having a spreite (weblike construction) between the two limbs of the U. The spreite of an individual Diplocraterion trace can be either protrusive (between the paired tubes) or retrusive (below the paired tubes). Some ichnospecies have both types (e.g., Diplocraterion yoyo). The presence/absence of funnel-shaped openings should not be used as an ichnotaxobase due to the high probability that the upper portions of the trace may have been eroded away. Observation of the orientation of Diplocraterion in the field is frequently used to determine the way up of rock strata at outcrop.
| Diplocraterion | |
|---|---|
| Diplocraterion burrow (at left) from the Silurian-age Tuscarora Formation at Bald Eagle Mountain, Centre County, Pennsylvania. Specimen is ~22cm high. | |
| Trace fossil classification | |
| Ichnogenus: | †Diplocraterion |
There are several ichnospecies of Diplocraterion.
| Some Ichnospecies of Diplocraterion | |
|---|---|
| Ichnospecies | Diagnosis |
| D. parallelum | Parallel burrow walls and unidirectional spreite |
| D. helmerseni | U-tubes expand laterally at the base |
| D. biclavatum | Arms of the U-tube extend below the curved base and form blind pouches |
| D. habichi | Arms of the U-tube diverge upward |
| D. polyupsilon | Bidirectional spreite that constrict upward |
| D. yoyo | U-tubes with both retrusive and protrusive spreiten |
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