Yesterday and today |
Obviously, you have a better chance to see a fossil brachiopod - more than 25 000 species - than a living species. Their number dropped considerably. There are rather less species than in the past, not more than 350. |
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YesterdayExample : the fauna of the "Coral Rag of Bourges", France These fossil brachiopods are characteristic of the upper Oxfordian (approx. 160 m. y.) layers surrounding a beginning reef. Nearly ten species populated the carbonated platforms in swallow warm water. This picture shows a sample of faunal association : |
TodayExample : brachiopods of New Zealand
These two specimens were collected in New Zealand. They are among to ten endemic species. - The south of the South Island (Fjordland, Foveaux Strait...) is one of the rare places in the world where significant colonies of brachiopods still exist. - The black shellis a specimen of Notosaria nigricans (Sow.) of the family of Rhynchonellidae. The pinkish one, on the other hand, is a variety of Terebratulidae. Its name is Calloria inconspicua (Sow.) - Although the majority of the recent representatives of these two families live in deep water, sometimes until 1300m deep, some exceptions exist. It is the case of the fauna of Paterson Inlet, which is of great scientific interest : vagile species (Neothyris lenticularis Desh....), shallow water... |
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Lingula of yesterday and todayFor a long time, the species Lingula was regarded as the typical example of a "living fossil", because it was believed that the morphology of its shell had not really evolved since the Cambrian period. However, this conservatism seems to be deceptive. According to certain specialists, notable differences exist between the ancient and the recent species (volume of the lophophorale cavity, length of the ventral channels of the mantle...) (Biernat & Emig, 1993). |
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Glossary
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