30 November 2022
Ichnoanalogue
Posted by Callan Bentley
Another glimpse of sand on the beach at Esterillos Oeste, Costa Rica…
This time, I offer you a trace of an organism moving through the wet sediment:
Note the two parallel lines of tracks laid down by little feet, and the central groove that overprints them. It reminded me very much of this similar arrangement, from near St. Andrews in Scotland, but: (1) this is the underside of a bed rather than its upper surface, and (2) it is of a rather more substantial magnitude…
(The same pencil is used for scale in both of these images!)
The Scottish example is interpreted as a eurypterid trackway, but since eurypterids are now extinct, I’m not sure what made my Costa Rican example – a crab hauling a stick?
Callan Bentley is Associate Professor of Geology at Piedmont Virginia Community College in Charlottesville, Virginia. He is a Fellow of the Geological Society of America. For his work on this blog, the National Association of Geoscience Teachers recognized him with the James Shea Award. He has also won the Outstanding Faculty Award from the State Council on Higher Education in Virginia, and the Biggs Award for Excellence in Geoscience Teaching from the Geoscience Education Division of the Geological Society of America. In previous years, Callan served as a contributing editor at EARTH magazine, President of the Geological Society of Washington and President the Geo2YC division of NAGT.
Maybe some little turtle with a long face? 🙂
Or a turtle was interested in where the line leads? 🙂
Fantastic how you are able to relate the present day to the fossil, great observation 🙂
It’s a hermit crab dragging a conical/spiral shell.
Hi Troy!
There certainly were a lot of hermit crabs there. Sounds like a good bet.