| 研究実績の概要 |
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.
|
| 現在までの達成度 (区分) |
現在までの達成度 (区分)
3: やや遅れている
理由
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).
|
| 今後の研究の推進方策 |
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).
|
| 次年度使用額が生じた理由 |
In most cases, COVID travel restrictions either prevented travel to conferences or caused conferences to be postponed. This meant that the parts of the planned budget concerned with domestic and overseas travel could not be spent in its entirety. However, I did manage to attend one domestic conference: PALEO10 (autumn 2022).
|
