Wooster’s Fossil of the Week: A low-spired, battle-worn trochid gastropod from the Pliocene of Cyprus

1 Gibbula Risso, 1826 apexThis shell looks like a cinnamon roll. It is another product of the 1996 Wooster-Keck expedition to Cyprus with Steve Dornbos (’97) and me. Like the rest of the Cypriot specimens on this blog, it is from the Nicosia Formation (Pliocene) exposed on the Mesaoria Plain in the center of the island. This specimen comes from the Coral Reef locality described in Dornbos and Wilson (1999). We are looking at a well-preserved specimen of the herbivorous gastropod Gibbula Risso, 1826. (I can’t fit it into any known species within the genus.)
2 Gibbula Risso, 1826 sideIn this side view the growth lines are evident (they are parallel to the aperture; the thin ribs following the whorls are ornamentation), as are a couple of shallow, circular pits drilled by some unsuccessful predator. That predator could have been another gastropod or even an octopus. The pits are known by the trace fossil name Oichnus.

Those growth lines are interesting in  this genus. Schöne et al. (2007) studied a species of modern Gibbula and determined that they formed “microgrowth lines” in association with tidal cycles, forming “distinct fortnight bundles of microgrowth increments and lines”. We would need to section this shell and examine it microscopically to see such patterns.

3 Gibbula Risso, 1826 baseHere is the basal view of our Gibbula specimen.

4 RissoThe genus Gibbula was named and described by Giuseppe Antonio Risso (1777-1845), called Antoine Risso, was a productive Italian (more or less; he later can be considered French) naturalist. He was born in the city of Nice, then in the Duchy of Savoy. In 1792, soon after the French Army occupied Nice, Risso became a pharmacist’s apprentice, which encouraged his interest in medicinal botany. Risso was also a pioneering mountaineer in the Alps and other European ranges. He published several books on invertebrates, fish and plants. The work most relevant to us is his 1826 tome entitled: Histoire naturelle des principales productions de l’Europe Méridionale et particulièrement de celles des environs de Nice et des Alpes Maritimes. Risso’s Dolphin is named after him.


Donnarumma, L., Bruno, R., Terlizzi, A. and Russo, G.F. 2015. Population ecology of Gibbula umbilicaris and Gibbula ardens (Gastropoda: Trochidae) in a Posidonia oceanica seagrass bed. Italian Journal of Zoology, DOI: 10.1080/11250003.2015.1073377

Dornbos, S.Q. and Wilson, M.A. 1999. Paleoecology of a Pliocene coral reef in Cyprus: Recovery of a marine community from the Messinian Salinity Crisis. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 213: 103-118.

Risso, A. 1826. Histoire naturelle des principales productions de l’Europe Méridionale et particulièrement de celles des environs de Nice et des Alpes Maritimes. Paris: F.G. Levrault. Vol. 4: IV, 1-439, 12 pls.

Schöne, B.R., Rodland, D.L., Wehrmann, A., Heidel, B., Oschmann, W., Zhang, Z., Fiebig, J. and Beck, L. 2007. Combined sclerochronologic and oxygen isotope analysis of gastropod shells (Gibbula cineraria, North Sea): life-history traits and utility as a high-resolution environmental archive for kelp forests. Marine Biology 150: 1237-1252.

Williams, E.E. 1964. The growth and distribution of Gibbula umbilicalis (da Costa) on a rocky shore in Wales. The Journal of Animal Ecology 33: 433-442.

About Mark Wilson

Mark Wilson is a Professor of Geology at The College of Wooster. He specializes in invertebrate paleontology, carbonate sedimentology, and stratigraphy. He also is an expert on pseudoscience, especially creationism.
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