Wiwaxia corrugata

Overview

Wiwaxia corrugata is a small marine animal covered in overlapping sclerites and long spines. It evokes a slug crawling along the bottom, but its covering is far more unfamiliar. One hard fragment led to the story of the entire animal’s identity.^[1]

Key facts

The first known fossil was one sclerite rather than a whole body. It was therefore once thought to be a worm-tube-like structure. Later discoveries of better-preserved bodies revealed where the small piece had belonged.^[1]

Time and place

This animal lived in Middle Cambrian seas around 505 million years ago. It is known from localities including the Walcott Quarry and Mount Stephen in the Burgess Shale of present-day Canada. Alongside diverse bottom-dwelling organisms, it reveals an ancient sea.^[1]

The time range describes source context, not the complete duration of this species.

Size, form and skeleton

Large specimens are reported to reach approximately 5.5 cm in body length. Overlapping sclerites cover most of the oval body, while two rows of long spines rise from the back. Its mouth contains a feeding apparatus made of plates bearing small teeth.^[1]

Habitat and reproduction

It has been proposed that the animal scraped microbial mats on the seafloor. Its feeding apparatus is compared with that of Odontogriphus. The hard covering and long spines also suggest other survival strategies of a small bottom-dwelling animal.^[1]

Fossil discovery

Matthew described a fragmentary fossil in 1899. Walcott established the genus Wiwaxia in 1911 using more complete material. The original reference fragment was recognized again in a museum collection in 1977.^[1]

References

1. ROM · Wiwaxia corrugata
2. Royal Ontario Museum — Odontogriphus omalus
3. Anomalocaris canadensis
4. Royal Ontario Museum — Wiwaxia corrugata

Research questions

Do the sclerites and feeding apparatus point to the same relatives? Researchers have compared these structures with molluscs, annelids, and other groups. Considering several regions together rather than one feature is important for investigating the ancestry of unfamiliar fossils.^[1]

Observation

Move your gaze from the overlapping sclerites to the two rows of long spines. Keeping the feeding apparatus beneath the body in mind gives a more complete view of this small seafloor animal.^[1]