Obamus

Obamus Temporal range: Ediacaran ~ 555 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Artist's reconstruction
Scientific classification
Domain:	incertae sedis
Genus:	†Obamus Dzaugis et al., 2020
Species:	†O. coronatus
Binomial name
†Obamus coronatus Dzaugis et al., 2020

Obamus is an extinct enigmatic organism from the late Ediacaran of Australia, 555 Ma. It is torus in shape, and is a monotypic genus, containing only Obamus coronatus.

Discovery and naming

Fossil specimens of Obamus were found in the Ediacara Member of the Rawnsley Quartzite, in Nilpena Ediacara National Park, Flinders Ranges of South Australia in 2017, and were formally described and named in 2020.^[1]

The generic name Obamus is in honour of former President Barack Obama, due to his passion for the sciences, and the morphology of the organisms bearing similarities to his ears. The specific name coronatus derives directly from the Latin word of the same spelling, to mean "Wreath", due to the torus-like appearance of the organisms.^[1][2]

Description

Obamus coronatus is a torus-shaped organism, getting up to 20 mm (0.8 in) in diameter. The body has six, overlapping arched grooves set into it, giving it a distinct wreath-like patterning. The arches are consistent, in that they all arch in the same clockwise direction. At one of the joins of a groove, there is a notable tuck, not only resulting in an asymmetric form, and also an ear-like morphology.^[1]

The fossils are all preserved in negative hyporelief, where they are impressions on the rock surface, and smaller specimens are less well defined and more compacted, appearing only as small pits in the rock. The outer margins of all Obamus specimens are very poorly defined, and sometimes features a small moat-like feature around the organism.^[1]

Palaeoecology

The general lifestyle of Obamus has been inferred from its preservation, with it being noted that it was most likely a sessile benthic organism, being slightly embedded within the microbial mat-ground of the Rawnsley Quartzite. It also had some environmental tolerances, being found in beds that were estuarine to coastal during deposition. Meanwhile, they are also not found in areas with thin mat-grounds, suggesting the organisms may have preferred areas with thicker and mature mat-grounds.^[1][3]

A later study noted this to be the first example of substrate-selective dispersal in the Ediacaran, inferred from the large distances between even the closest specimens, discounting any probable use of stolons or budding, and instead possible sexual reproduction, as no specimens have been found entirely on their own either.^[4]

See also

• List of things named after Barack Obama
• List of organisms named after famous people (born 1950–present)

References

1. Dzaugis, P. W.; Evans, S. D.; Droser, M. L.; Gehling, J. G.; Hughes, I. V. (2020). "Stuck in the mat: Obamus coronatus, a new benthic organism from the Ediacara Member, Rawnsley Quartzite, South Australia". Australian Journal of Earth Sciences. 67 (6): 897–903. Bibcode:2020AuJES..67..897D. doi:10.1080/08120099.2018.1479306.
2. "Obama's Ears Inspired the Name of this 550-Million-Year-Old Critter". Live Science. 21 June 2018.
3. Droser, Mary L.; Evans, Scott D.; Tarhan, Lidya G.; Surprenant, Rachel L.; Hughes, Ian V.; Hughes, Emmy B.; Gehling, James G. (23 February 2022). "What Happens Between Depositional Events, Stays Between Depositional Events: The Significance of Organic Mat Surfaces in the Capture of Ediacara Communities and the Sedimentary Rocks That Preserve Them". Frontiers in Earth Science. 10 826353. Bibcode:2022FrEaS..10.6353D. doi:10.3389/feart.2022.826353.
4. Boan, Phillip C.; Evans, Scott D.; Hall, Christine M. S.; Droser, Mary L. (2023-03-13). "Spatial distributions of Tribrachidium, Rugoconites, and Obamus from the Ediacara Member (Rawnsley Quartzite), South Australia". Paleobiology. 49 (4): 601–620. Bibcode:2023Pbio...49..601B. doi:10.1017/pab.2023.9. ISSN 0094-8373. S2CID 257521294.