Spriggina

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Spriggina
Fossil range: Ediacaran

Fossil of S. floundensi. Scale in millimetres.

Sketch reconstruction

Conservation status

Fossil

Scientific classification

(unranked)	?Bilateria
Phylum:	?Arthropoda
Genus:	Spriggina Glaessner, 1958
Species:	S. floundensi

Binomial name

Spriggina floundensi
Glaessner, 1958

Digitally enhanced specimen photo

Spriggina was an organism of the Ediacaran period, fossils of which have been found in the Ediacara Hills of Australia. The organisms grew to around three centimetres in length. The shape of Spriggina is roughly oblong, and segmented looking. The segments are sometimes curved with the appearance of head end and tail end. The segments are attached to a central axis. Some fossils have what may be a circular mouth at the centre of the semicircular head, although the small size of the creature and large grains of the containing sandstones make fossils difficult to interpret in this area. It appears to be legless. The body is stiff, always making a mould in the lower surface of the fossil bed.

Some researchers have claimed that the symmetry is not exactly bilaterean but is a glide reflection, where the opposite segment is shifted by half an interval.^[1]^[2]^[3] In some specimens the body segments tilt backwards, making roughly chevron patterns; while in others they are more or less straight. There also appear to be fairly complex variations between these two.

Spriggina has been classified as a vendobiont, an annelid and an arthropod. It resembles a trilobite, and may be an ancestor of them. Spriggina could have been one of the predators that are theorized to have initiated the Cambrian transition.^[4]

Spriggina floundersi is at present the only generally accepted species in this genus. Spriggina ovata has now been moved into its own genus, Marywadea (Glaessner 1976). Spriggia wadea is probably a junior synonym of Aspidella preserved under specific conditions.

The genus was named after Reg Sprigg who discovered the Precambrian fossils in Ediacara Hills, and was a proponent of their recognition as multicellular organisms.

[edit] References

Glaessner, Martin F. (1958): New Fossils from the Base of the Cambrian in South Australia. Transactions of the Royal Society of South Australia 81: 185-188. PDF fulltext
Glaessner, Martin F. (1976): A new genus of late Precambrian polychaete worms from South Australia. Transactions of the Royal Society of South Australia 100(3): 169-170. PDF fulltext