Fossil evidence for chemoautotrophic bacterial symbiosis in the Thyasirid Bivalve Thyasira michelottii from the middle miocene (badenium) of Austria
- Author(s)
- Martin Zuschin, Oleg Mandic, Mathias Harzhauser, Peter Pervesler
- Abstract
Many modern thyasirid bivalves are known to engage with chemoautotrophic bacteria in symbiosis, which can be inferred from the specialized feeding and digestive systems of these bivalves, as well as from stable carbon isotope ratios of their soft tissues. Fossil evidence for this life habit consists largely of facies criteria and bio-geochemical markers. Further evidence for chemosymbiosis is found in the characteristic burrow-systems of these bivalves, by which sulfide is obtained to sustain the symbiotic bacteria. These burrows were previously known only from observations made in aquaria. Such a burrow is described here for the first time in a fossil thyasirid bivalve. Thyasira michelottii (R. Hošrnes, 1875) burrowed in sandy sediment in an anterior-up position, approximately 5-10 cm below the surface, to which it was connected by an inhalant tube. It also produced a prominent posterio-ventral tunnel, extending up to 300mm into the sediment. Like modern thyasirids, this animal lacked an exhalant tube. By comparison with the ecology of modern thyasirid bivalves, we suppose that oxygen was obtained by active ventilation through the inhalant tube and that the prominent posterio-ventral tunnel reflects search by the probing, vermiform foot for short-lived pockets of sulfidic material in an otherwise low-sulfide environment. The monospecific occurrence of Thyasira and the paleogeographic setting indicate dysaerobic, warm water conditions. A short distance to the coast and the occurrence of proximal tempestites suggest an inner shelf setting, prone to occasional disturbance by storms. Œ 2001 OPA (Overseas Publishers Association) N.V.
- Organisation(s)
- Department of Palaeontology
- External organisation(s)
- Naturhistorisches Museum Wien (NHM)
- Journal
- Historical Biology
- Volume
- 15
- Pages
- 223-234
- No. of pages
- 12
- ISSN
- 0891-2963
- Publication date
- 2001
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 105118 Palaeontology
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/fossil-evidence-for-chemoautotrophic-bacterial-symbiosis-in-the-thyasirid-bivalve-thyasira-michelottii-from-the-middle-miocene-badenium-of-austria(c6e326ee-d08d-4625-a82c-0963da7fe83e).html