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Showing results for tags 'corbicula'.
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From the album: The Mollusca of the Banjaard
A nice example of the freshwater clam. This is a freshwater species, and therefore does not come from the Eemian stage of the Late Pleistocene like most other Banjaard shells (this one might be around 400'000 years old, but it's not sure). Contrarily to the other specimen shown in this album, this shell's shape is much more similar to the extant Corbicula fluminalis, and could possibly be one (and, if the 'tear-drop shape' Corbicula is recognized as a new species, this one will probably be separate from it). Status: still locally alive (in freshwater bodies, not in the sea) Fossil occurrence: rather common© 2019 Max DEREME
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From the album: The Mollusca of the Banjaard
A great specimen of the freshwater clam. This is a freshwater species, and therefore does not come from the Eemian stage of the Late Pleistocene like most other Banjaard shells (this one might be around 400'000 years old, but it's not sure). This one has the typical "tear-drop" shape of the fossil Corbicula's found in Dutch Pleistocene. They are significantly higher, slightly bulkier and more robust than the modern Corbicula fluminalis. Scientists are still debating as to whether it should be a separate species or not. Status: still locally alive (in freshwater bodies, not in the sea) Fossil occurrence: rather common© 2019 Max DEREME
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Hi all, Another very specific bivalve question for you all, this time regarding the freshwater species Corbicula fluminalis. So on the Wikipedia page: LINK, it says that this species is originally from Asia, but was introduced to Europe (and USA). Meaning it was brought here by humans. But, what is weird is that I found 2 fossil specimens of this species (as well as modern ones sometimes) here in the Netherlands! From the late Pleistocene, some 400K years ago. Long before humans had the means to introduce bivalve species like this in new places (and also long before humans came to the Netherlands in the first place). Oh, also, something relevant to take into account is that this species is NOT present in Eemian sediments! (late Pleistocene, 120k years) So how come that this species was "there" 400K years ago, disappeared, and then "came back"? The only thing I would consider as a solution is that the species went locally extinct (while still thriving in Eastern Asia) and was then reintroduced, but what is surprising is that I don't think that one single species could be alive in several different places far away from each other (the distance from Amsterdam to Beijing is nearly 8000 km!)... I don't think a bivalve species could possibly be present in such faraway places. So my question to you all is: what happened? How could it be on/off/on for this species in the Netherlands? Thanks in advance! Max