Thursday, July 1, 2010

Fossil of the Week


7/1/10 - Solitary Coral

This is a solitary coral, approximately 3 centimeters (1¼ inches) in diameter. You probably have learned that coral is actually a colony of thousands of soft polyps embedded in a hard calcareous skeleton. Solitary corals are similar but have just one large polyp (so a lot like an anemone), surrounded by a hard skeleton (which anemones lack). This is oversimplified slightly, but you probably get the idea. Although they form single "corallites," solitary corals often aggregate together in large populations. This is in part a product of their most common mode of reproduction - fragmentation - in which breakage results in two or more new polyps, which would naturally "land" not far from the original. The most common living solitary corals to non-specialists are the Mushroom Coral Fungia, sold dried and bleached in curio shops, and the Button Coral Scolymia, which is sold alive for the aquarium trade. The flesh of one common Scolymia species is bright florescent green.

This fossil is a paratype* (PRI 24412) of Cyclomussa concinna, described by John W. Wells** (a student of PRI's founding director, Gilbert Harris) in 1941. It is from the Lower Oligocene, Chira Formation, near Casa Saman, Chira Valley, in northern Peru. It was published in volume 26 of Bulletins of American Paleontology, PRI's monographic series. This and other specimens described in that publication were collected in Peru by another Harris student, Axel Olsson***. Part of Gilbert Harris' original intent in founding PRI was to provide a regional center where young students and professionals could interact and study - it seems that his students did just that! Many of Harris' students ultimately served on PRI's Board of Trustees or otherwise supported the institution through monetary and other donations.

PRI honors the author of this species by its student grant called the John W. Wells Grants-in-Aid of Research Program. This annual award supports collections-based research in any field of paleontology with up to $500 to assist with the student's visit to PRI to use the collections. PRI has one of the largest collections of invertebrate fossils, including corals, in North America.

*For a definition of paratype specimens, see Fossil of the Week 10/14/09 - Atrypa aperanta Crickmay.

**For more about John W. Wells, see Fossil of the Week 12/23/09 - Ichthyodorulite (Fish Spine).

***See Fossil of the Week 11/5/09 - Echinocaris punctata for more about Axel Olsson.

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