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Titel |
Lacustrine mollusc radiations in the Lake Malawi Basin: experiments in a natural laboratory for evolution |
VerfasserIn |
D. Damme, A. Gautier |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1726-4170
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Digitales Dokument |
URL |
Erschienen |
In: Biogeosciences ; 10, no. 9 ; Nr. 10, no. 9 (2013-09-03), S.5767-5778 |
Datensatznummer |
250085318
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Publikation (Nr.) |
copernicus.org/bg-10-5767-2013.pdf |
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Zusammenfassung |
In terminal Pliocene–early Pleistocene times, part of the Malawi Basin was
occupied by paleo-lake Chiwondo. Molluscan biostratigraphy situates this
freshwater lake either in the East African wet phase between 2.7–2.4 Ma or
that of 2.0–1.8 Ma. In-lake divergent evolution remained restricted to a
few molluscan taxa and was very modest. The lacustrine Chiwondo fauna went
extinct at the beginning of the Pleistocene. The modern Lake Malawi
malacofauna is depauperate and descends from ubiquistic southeast African
taxa and some Malawi basin endemics that invaded the present lake after the
Late Pleistocene mega-droughts. The Pleistocene aridity crises caused
dramatic changes, affecting the malacofauna of all East African lakes. All
lacustrine endemic faunas that had evolved in the Pliocene rift lakes, such
as paleo-lake Chiwondo, became extinct. In Lake Tanganyika, the freshwater
ecosystem did not crash as in other lakes, but the environmental changes were
sufficiently important to trigger a vast radiation. All African endemic
lacustrine molluscan clades that are the result of in-lake divergence are
hence geologically young, including the vast Lavigeria clade in Lake
Tanganyika (ca. 43 species). |
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