| P number: | P550293 |
|---|---|
| Caption: | Euomphalus pentangulatus, from the Silurian of Ireland. |
| Description: | Euomphalus is an archeogastropod that first evolved in the Silurian times and eventually became extinct in the Permian. Euomphalus pentangulatus lived in the tropical seas in early Carboniferous times, about 340-350 million years ago. The specimen illustrated comes from Ireland. Euomphalus pentangulatus is almost planispiral - it has a very low spire. It has a thick shell, but no ornament. Only fine growth lines may be seen on the outer surface of the shell. The illustrated specimen has what looks like a rib running around the spire, but this is due to an angular channel at the aperture which is retained as the shell grows. Gastropods are molluscs with a muscular foot, eyes, tentacles, and a rasp-like feeding organ (a radula), although only the coiled or conical shell is fossilised. The earliest Cambrian species were marine, but gastropods now colonise fresh water and the land. Classification is based mainly on soft body parts, which are not fossilised, and although there is uncertainty, most fossils appear to fall into one of three groups: 1. Archaeogastropods which have two auricles in the heart, two gills and two kidneys. 2. Caenogastropods which have one gill, auricle and kidney and sometimes a siphon. 3. Pulmonates which have a lung. |
| Photographer: | Unknown |
| Copyright statement: | Unknown |
| Orientation: | Landscape |
| Size: | 441.07 KB; 1001 x 849 pixels; 85 x 72 mm (print at 300 DPI); 265 x 225 mm (screen at 96 DPI); |
| Average Rating: | Not yet rated |
| Categories: | Best of BGS Images/ Fossils |
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