| P number: | P550283 |
|---|---|
| Caption: | Filholia elliptica, a gastropod that lays giant eggs? |
| Description: | Filholia elliptica lived during Oligocene times, about 23-33 million years ago. Some huge oval gastropod eggs, which are up to 30 mm. long and have a calcareous shell, have been found in rocks of this age in southern England. It is believed that Filholia elliptica may have laid these eggs. Filholia elliptica is a pulmonate caenogastropod that has an elongated shell. The specimen illustrated has six whorls each covered by fine ribs and growth lines. It has a simple aperture, but the shell wall is thickened (resulting in the addition of ribs as the animal 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: | 334.81 KB; 1000 x 464 pixels; 85 x 39 mm (print at 300 DPI); 265 x 123 mm (screen at 96 DPI); |
| Average Rating: | Not yet rated |
| Categories: | Best of BGS Images/ Fossils |
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