Bumastus
Bumastus is an extinct genus of corynexochid trilobites which existed from the Early Ordovician period to the Late Silurian period. They were relatively large trilobites, reaching a length of 6 in (15 cm). They were distinctive for their highly globular, smooth-surfaced exoskeleton. They possessed well-developed, large compound eyes and were believed to have dwelled in shallow-water sediments in life.

Obsidian Soul · CC BY 3.0 · via Wikipedia/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
- StyginidaePBDB
- Diet
- carnivorePBDB, for Corynexochida
- Life habit
- nektobenthicPBDB, for Corynexochida
- Motility
- actively mobilePBDB, for Corynexochida
- Vision
- well-developedPBDB, for Styginidae
- Environment
- marinePBDB, for Trilobita
Time the record covers
At least 54 million years on record.
The record covers at least 477.1 Mya to 422.7 Mya. No occurrence read is dated outside 486.85 Mya to 419.62 Mya.
226 occurrences of Bumastus on record, most of them in the Silurian. 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
226 occurrences- Ordovician37%
- Silurian63%
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
95 formations
- Racine Dolomite Formation19
- Racine Formation11
- Fukata Formation11
- Rochester Shale Formation · Clinton Group10
- Benbolt Formation8
- Motol Formation7
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The named rock units Bumastus has been recovered from, largest first. Drawn where the rock is now, not where it formed. 71 further formations hold fewer occurrences each and are not listed. 19 occurrences have no formation on record, which is common for older literature.
Bumastus and its relatives
SilurianWhere Bumastus and its relatives were recorded in the Silurian.
Found in the same rock
2,377 taxa- Dalmanites36 sites
- Favosites36 sites
- Atrypa reticularis34 sites
- Leptaena rhomboidalis34 sites
- Bryozoa33 sites
- Calymene33 sites
- Crinoidea29 sites
- Eospirifer radiatus29 sites
- Rafinesquina29 sites
- Strophomena29 sites
- Gastropoda28 sites
- Atrypa26 sites
- Heliolites25 sites
- Stegerhynchus25 sites
- Eucalyptocrinites24 sites
- Whitfieldella24 sites
- Arctinurus23 sites
- Encrinurus23 sites
- Hesperorthis22 sites
- Resserella22 sites
- Sowerbyella22 sites
- Bivalvia21 sites
- Pachydictya20 sites
- Plectatrypa20 sites
The Paleobiology Database records 188 sites for Bumastus, and this reads all 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
82 references- Silurian trilobite associations in North America21
- Caradocian-Gedinnian echinoderm associations of Central and Eastern North America15
- Animal and plant communities of Podolia11
- Silurian Reefs of Gotland9
- Wenlockian fossil communities in New York State and adjacent areas: Paleontology and Paleoecology8
- The Silurian (Wenlockian) reef fauna of Southeastern Wisconsin8
- Silurian trilobites of Japan in comparison with Asian, Pacific and other faunas7
- The Clinton of Western and Central New York7
- Ordovician of the Tungus Basin (Siberian Platform). Field excursion guidebook6
- Oporniih razrez reki Moiero silura Sibirskoi platformih -The Silurian composit section of the Moiero River (Sibirian platform)6
- Palaeozoic geology of the Lake Simcoe Area, Ontario6
- Stratigraphy of the Lower Middle Ordovician of Tazewell County, Virginia6
Each of the 226 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. 70 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 content2
Picture of Bumastus
- Source
- Wikipedia/Commons
- Credit
- Obsidian Soul
- Licence
- CC BY 3.0
- Commercial use
- the licence allows it
3D model
- Source
- Sketchfab
- Licence
- CC Attribution-NonCommercial-NoDerivs
- Commercial use
- the licence does not allow it
Smithsonian Open Access was not reached for this taxon, so this list is what the others held rather than everything there is.
The description on this site
- Source
- Wikipedia, “Bumastus”
- 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 itStyginidae through timeFormations of the SilurianThe world it lived on
Occurrence data from the Paleobiology Database, CC BY 4.0. (Murchison 1839)