Gehlingia

Gehlingia Temporal range: Ediacaran
Artists reconstruction of Gehlingia dibrachida (note deep groove and tubular structures). Reconstruction from McMenamin and McMenamin, 1994, Hypersea: Life on Land modified by Heather Winkelmann.
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	incertae sedis
Genus:	† Gehlingia McMenamin, 1998
Species:	†G. dibrachida
Binomial name
†Gehlingia dibrachida McMenamin, 1998

Gehlingia dibrachida is a species of enigmatic Ediacaran organism from South Australia described by Mark McMenamin in 1998. Gehlingia has been described as having many characteristics of petalonamids, although it has been classified as a rather close relative of the Tribrachidium . ^[1] The overall shape of Gehlingia contradicts this affinity, however, with its shape being a more bilaterally symmetrical one although the basic structure similar to that of Tribrachidium appears in Gehlingia as separate branches extending into bifurcating minor branches ^[1] along with "thumb structures" that are apparent in Tribrachidium in the form of side bulges on an axis. ^[2]

Etymology

The generic name honours the Australian palaeontologist specialising in Ediacaran fossils, James G. Gehling. ^[2]

Description

Gehlingia dibrachida represents a frond-like bilaterally symmetric organism with two fronds with each half of them having a swollen axis on an inner edge. The organism's axis bifurcated once and bifurcates towards the outer edge of its two fronds. ^[3] Similar deformations occur in both Tribrachidium and Gehlingia, some notable ones being delaying of the bifurcation and tubular structures being visible between the striae. A number of tubular structures emanate from the axis and are often either straight or curved. ^[3] A deep groove separates the two axes. The entire animal is estimated to have been 8 centimeters (3.1 in) in length and 3.1 centimeters (1.2 in) in width. ^[3] The tubular structures of the two "fronds" end abruptly and in turn form a smooth edge to the organism. ^[3]

In Gehlingia (as well as Tribrachidium) there are "thumb" structures that appear to have been positioned on the left and right side of the main branch. ^[1] In Tribrachidium, the thumb structures are visible as side bulges which extend out of an axis. ^[2]

Further reading

• McMenamin, Mark (2000). "The Antiquity of Life: From Life's Origin to the End of the Lipalian Period". In Margulis, Lynn; Matthews, Clifford; Haselton, Aaron (eds.). Environmental Evolution: Effects of the Origin and Evolution of Life on Planet Earth (2nd ed.). Cambridge, Massachusetts and London, England: MIT Press. p. 165. ISBN   9780262631976 . Retrieved 31 March 2025.
• Bechly, Günter (25 March 2021). "Examining Potential Other Trilobozoans". Evolution News and Science Today. Retrieved 31 March 2025.

See also

• List of Ediacaran genera
• Tribrachidium

References

1. McMenamin, Mark A. S. (10 June 2016). Dynamic Paleontology: Using Quantification and Other Tools to Decipher the History of Life. Springer. ISBN   9783319227771.
2. McMenamin, Mark A. S. (1998). The Garden of Ediacara: Discovering the First Complex Life. Columbia University Press. ISBN   9780231105583.
3. Fedonkin, Mikhail A.; Gehling, James G.; Grey, Kathleen; Narbonne, Guy M.; Vickers-Rich, Patricia (Mar 16, 2007). The Rise of Animals: Evolution and Diversification of the Kingdom Animalia. JHU Press. ISBN   9780801886799 . Retrieved May 11, 2022– via Google Books.