Explore this animal in Size of Extinct Animals ↗
517 / Paleozoic
Helmetia
Helmetia expansa
A broad flat shield with marginal spines and a leaf-like tail formed an unusual outline.
View original image · 1600 × 1067- Time range
- About 508 million years ago
- Final stage
- Middle Cambrian
- Geographic range
- Continental-slope seafloor · Canada
01 / DEFINITION & ECOLOGY
What was Helmetia?
Helmetia (Helmetia expansa) was an extinct organism known from About 508 million years ago, with a range in Continental-slope seafloor · Canada.
Life and ecology
It swam close to the bottom or crawled while taking detritus and small animals.
02 / DISAPPEARANCE
Why did Helmetia disappear?
Cambrian arthropod turnover is possible context; the cause of the genus's disappearance is not established.
03 / EVIDENCE
How do scientists know about Helmetia?
Few complete fossils preserve the shield and tail; ventral limbs remain poorly known.
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