| P number: | P549517 |
|---|---|
| Caption: | Acropora sp, a fossil coral. |
| Description: | Acropora is a colonial coral that first evolved in the Eocene, about 50 million years ago and is still found living today. It is an important reef builder, and has been so since the Miocene times, about 10-15 million years ago. It is found in the warm waters of Eurasia, the Caribbean and the Indio-Pacific, where it prefers shallow, clear, well-oxygenated water. The porous or spongy aragonite wall of scleractinian corals can be seen in the Holocene specimen illustrated. However, this not so obvious after fossilisation, as the aragonite is replaced by calcite. Acropora is a colonial encrusting coral which varies in form, although it generally takes on a branched or a 'stag horn' shape with perforated corallite walls. The corallites are one to two millimetres in diameter and the septa are very thin, inconspicuous, and irregularly formed and may be replaced by spines. At the end of the Permian (248 million years ago), there was a mass extinction event. The rugose and tabulate corals went into extinction, and a new group of corals the Scleractinian corals, evolved. These live in warm shallow waters, where some colonial types form fringing reefs, barrier reefs and atolls, as well as in deeper waters where they form large banks. Others are smaller solitary corals. |
| Photographer: | Unknown |
| Copyright statement: | NERC |
| Orientation: | Portrait |
| Size: | 395.12 KB; 950 x 1001 pixels; 80 x 85 mm (print at 300 DPI); 251 x 265 mm (screen at 96 DPI); |
| Average Rating: | Not yet rated |
| Categories: | Best of BGS Images/ Fossils |
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