Cassiduloida
Cassiduloida is an order of sea urchins. The group was extremely diverse with many families and species during the Mesozoic, but today, only seven extant species remain.

Didier Descouens · CC BY-SA 4.0 · via Wikidata/Commons. May be a photograph of a specimen, or an artist’s reconstruction — an interpretation of a skeleton, since colour and soft tissue are almost never preserved.
On record
Recorded, not inferred- Sits inside
- NeognathostomataPBDB
- Diet
- detritivorePBDB
- Life habit
- semi-infaunalPBDB
- Motility
- slow-movingPBDB
- Vision
- limitedPBDB, for Echinoidea
- Environment
- marinePBDB, for Echinodermata
Time the record covers
At least 120 million years on record.
The record covers at least 121.4 Mya to 774 ka. No occurrence read is dated outside 125.77 Mya to 129 ka.
456 occurrences of Cassiduloida on record, most of them in the Late Cretaceous. The Paleobiology Database records this as a living group, and the chart stops with its fossils rather than at the present. Bar height is expected occurrences, not a count: each fossil is spread across the span it is dated to, so a tall narrow bar means tight dating and a low wide one means loose.
When
456 occurrences- Early Cretaceous2%
- Late Cretaceous54%
- Paleocene5%
- Eocene25%
- Oligocene8%
- Miocene5%
- Plioceneunder 1%
- Pleistoceneunder 1%
These are dates about fossils, not the animal: the record can only begin after it arose and end before it died out, so either end may reach further. Shares are expected occurrences: a fossil dated to a span is counted partly in each period it straddles. More on what this infers.
Found in
96 formations
- Castle Hayne Formation36
- Santee Limestone Formation22
- Maastricht Formation22
- Suwannee Limestone Formation · Vicksburg Group22
- Providence Formation18
- Ripley Formation16
Loading coastlines…
The named rock units Cassiduloida has been recovered from, largest first. Drawn where the rock is now, not where it formed. 72 further formations hold fewer occurrences each and are not listed. 87 occurrences have no formation on record, which is common for older literature.
Cassiduloida and its relatives
Late CretaceousWhere Cassiduloida and its relatives were recorded in the Late Cretaceous.
Found in the same rock
2,061 taxa- Harduinia41 sites
- Glycymeris36 sites
- Turritella34 sites
- Catopygus33 sites
- Bryozoa31 sites
- Echinogalerus31 sites
- Anomia argentaria30 sites
- Cubitostrea tecticosta28 sites
- Hemiaster28 sites
- Exogyra (Exogyra) costata27 sites
- Granocardium27 sites
- Serpula27 sites
- Ostrea26 sites
- Crassatella vadosa25 sites
- Tetragramma variolare22 sites
- Cardium21 sites
- Chlamys21 sites
- Temnocidaris (Stereocidaris)21 sites
- Cyprimeria20 sites
- Rhyncholampas gouldii20 sites
- Cliona19 sites
- Goniasteridae19 sites
- Nucleopygus19 sites
- Syncyclonema19 sites
The Paleobiology Database records 333 sites for Cassiduloida, and this reads 240 of them. The number is how many of those sites it was catalogued from too. The 24 sharing the most are listed.
This is not a list of everything alive at the time. It is only what has come out of the same ground as this animal and been written down.
Entered from
88 references- American Upper Cretaceous Echinoidea55
- Late Cretaceous-Early Paleocene echinoderms and the K/T boundary in the southeast Netherlands and the northeast Belgium. - part 4: Echinoids44
- The Echinoids of the Middle Eocene Warley Hill Formation, Santee Limestone, and Castle Hayne Limestone of North and South Carolina42
- Paléoécologie et paléobiogéographie des faunes d'échinides du Cénomanien nord-aquitain (Charente-Maritime, France)32
- Upper Cretaceous (Maestrichtian) Mollusca from the Haustator bilira Assemblage Zone in the East Gulf Coastal Plain19
- Molluscs of the Tampa and Suwannee Limestones19
- Upper Cretaceous (Maestrichtian) larger invertebrates from the Haustator bilira Assemblage Zone in the Atlantic Coastal Plain with further data for the East Gulf18
- Stratigraphic Distribution of Paleocene and Eocene Fossils in the Eastern Gulf Coast Region15
- The Mesozoic and Cenozoic Echinodermata of the United States12
- Diversity patterns and biostratigraphy of Cenozoic echinodems from Florida10
- Cenomanian and Lower Turonian echinoderms from Wilmington, south-east Devon, England10
- Late Cretaceous (Maastrichtian) echinoid-mollusc-coral assemblages and palaeoenvironments from a Tethyan carbonate platform succession, northern Oman Mountains9
Each of the 456 occurrences read was entered from one of these publications, ordered by how many each accounts for. This is not a search for papers mentioning the name. 76 further references are not listed. Entries link to doi.org where the Paleobiology Database holds an identifier, and to its own record where it does not. Relayed as the Paleobiology Database holds them, not checked against what they resolve to.
Media and terms
Media content1

Picture of Cassiduloida
- Source
- Wikidata/Commons
- Credit
- Didier Descouens
- Licence
- CC BY-SA 4.0
- Commercial use
- the licence allows it
No 3D scan of Cassiduloida was found in Smithsonian Open Access and Sketchfab.
MorphoSource was not reached for this taxon, so this list is what the others held rather than everything there is.
The description on this site
- Licence
- CC BY-SA 4.0
This is what the site found, which is not the same as what exists.
Keep going
What may have been alongside itNeognathostomata through timeFormations of the Late CretaceousThe world it lived on
Occurrence data from the Paleobiology Database, CC BY 4.0. Agassiz and Desor 1847