Explore this animal in Size of Extinct Animals ↗
252 / Paleozoic
Sidneyia
Sidneyia inexpectans
Robust leg bases formed crushing jaws for small trilobites and other shelled prey.
View original image · 1536 × 1024- Time range
- About 508 million years ago
- Final stage
- Middle Cambrian
- Geographic range
- Offshore shelf · Burgess Shale, Canada
01 / DEFINITION & ECOLOGY
What was Sidneyia?
Sidneyia (Sidneyia inexpectans) was an extinct organism known from About 508 million years ago, with a range in Offshore shelf · Burgess Shale, Canada.
Life and ecology
Sidneyia was a large bottom-dwelling arthropod with a semicircular head shield, broad trunk and tail fan. It probably scavenged and hunted on muddy seafloors.
02 / DISAPPEARANCE
Why did Sidneyia disappear?
Cambrian marine communities changed, but that turnover alone does not explain why this predatory lineage disappeared.
03 / EVIDENCE
How do scientists know about Sidneyia?
Soft-body impressions preserve legs, gills, gut and food fragments inside the digestive tract.
04 / SOURCES & FURTHER READING
Check the source record
Use the scientific name to compare taxonomy, occurrence records and the fossil record. Database coverage and classifications may differ.
05 / REVISION HISTORY
How has this record changed?
- Rewrote an extinction cause that presented environmental or faunal turnover as established; it is now given as context the record does not prove.
- Verified authoritative entity sources and added three responsive reconstruction sizes.
- Initial bilingual species record published.
06 / CORRECTIONS & ADDITIONS