Initiation of a species-level fossil diatom image database
| Project/Area Number |
19K06820
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 45030:Biodiversity and systematics-related
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| Research Institution | Yamagata University |
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Principal Investigator |
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| Project Period (FY) |
2019-04-01 – 2024-03-31
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| Project Status |
Granted (Fiscal Year 2022)
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| Budget Amount *help |
¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2021: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2020: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2019: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
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| Keywords | Eocene / Proboscia / diatom / sediments / assemblages / lineage / Pseudopyxilla / fossil / Taxonomy / Morphology / Diatom / Fossil / Diatoms / Images / Database |
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| Outline of Research at the Start |
Cylindrical diatoms are commonly found in marine biosiliceous sediments around the world, with many of the genera having long stratigraphic records. However, due to the lack of good diagnostic features in the light microscope and the paucity of scanning electron microscope studies, diatomists rarely identify them to species level.This study aims to produce an online database of cylindrical fossil marine diatoms using both light and scanning electron microscope images in order to document their true diversity, and improve their identification and use in palaeoenvironmental reconstruction.
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| Outline of Annual Research Achievements |
During 2022, I focused again on the Eocene, particularly Mors (Jutland) which contains a number of dubious Rhizosolenia spp. that appear to belong to Proboscia. One of these species, R. dubia, had a seemingly complicated life cycle - published illustrations of two specimens had shown combination cells involving Pseudopyxilla dubia and an unnamed Rhizosolenia species. Our results demonstrated that the latter was a Proboscia species and despite observing hundreds of specimens, no combination cells were seen. We named this species, Proboscia pinocchioi, due to its unique long middle spinula. Some specimens were also seen with claspers and contiguous areas on the valve base - this is the oldest record of claspers found to date, and proof that some fossil Proboscia were capable of making short chains (Abe & Jordan, 2022). Unlike the ridged forms of the P. cretacea lineage, P. pinocchioi combines characters of the two subsequent lineages, the P. barboi lineage (with large polar spines) and P. alata lineage (with claspers). Other species in Mors (R. clavigera, R. fragilis, R. juetlandica, R. sp. 1, R. sp. 3) will also need transferring to Proboscia. Further research was also conducted on other Eocene sites. Notably, Proboscia spp. with serrated edges were observed in samples from the Central Arctic, California, Barbados, Israel and Oamaru. While another Proboscia sp. in the Central Arctic formed mats. There were also clear differences between the Middle Eocene assemblages of the northern and southern hemispheres, a trend which was also apparent in Early Oligocene assemblages.
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| Current Status of Research Progress |
Current Status of Research Progress
3: Progress in research has been slightly delayed.
Reason
Although many samples have been observed in LM and SEM and many photographs of Proboscia specimens have been taken, the process of writing and submitting manuscripts has taken longer than expected. Also, the COVID crisis has restricted my travel to conferences to promote the results and receive feedback from my peers. In the financial year of 2022, only one paper was published (Abe & Jordan, 2022) and one poster presentation was given (PALEO10 autumn 2022).
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| Strategy for Future Research Activity |
The main aim now is to tidy up some of the unfinished research (particularly, the Neogene), write and submit as many manuscripts as possible (focusing initially on the Cretaceous and Paleogene), and to attend domestic and overseas conferences. With regard to the latter, some of the Proboscia results will be presented at the 26th International Diatom Symposium (summer 2023) and at the PALEO10 meeting (autumn 2023).
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Report
(4 results)
Research Products
(7 results)
