Isotelus

Isotelus is an extinct genus of large asaphid trilobites from the Middle and Late Ordovician period, fairly common in the northeastern United States into eastern Canada. Isotelus is the state fossil of Ohio, and through multiple specimens from the 1800s into the modern day has held the title of largest trilobite fossil in the world, reaching over 70 centimetres (28 in) long. Isotelus was carnivorous and a burrower which lived in warm shallow seas, feeding on worms and other soft-bodied animals on and below the substrate. As larvae, Isotelus was planktonic, drifting in the water column with a morphology very different from the adult. Their distinctive morphology with a large shovel-like head, prominent eyes, long genal spines, and their enormous size, makes Isotelus one of the most sought after trilobites in North America.

A picture published with the record for Isotelus.

Chris Woodrich · CC BY-SA 4.0 · 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
IsotelinaePBDB
Diet
carnivorePBDB, for Trilobita
Life habit
low-level epifaunalPBDB, for Asaphida
Motility
fast-movingPBDB, for Asaphida
Vision
well-developedPBDB, for Asaphidae
Environment
marinePBDB, for Trilobita

Time the record covers

At least 30 million years on record.

The record covers at least 471.3 Mya to 440.5 Mya. No occurrence read is dated outside 488.9 Mya to 432.9 Mya.

Cambrian — about 0 of 1141 occurrencesOrdovician — about 1140 of 1141 occurrencesOrdovicianSilurian — about 1 of 1141 occurrencesSilurian490–488 Mya — about 0.0 occurrences488–486 Mya — about 0.2 occurrences486–484 Mya — about 0.2 occurrences484–482 Mya — about 0.2 occurrences482–480 Mya — about 0.2 occurrences480–478 Mya — about 0.3 occurrences478–476 Mya — about 0.6 occurrences476–474 Mya — about 0.8 occurrences474–473 Mya — about 0.8 occurrences473–471 Mya — about 8 occurrences471–469 Mya — about 20 occurrences469–467 Mya — about 21 occurrences467–465 Mya — about 21 occurrences465–463 Mya — about 21 occurrences463–461 Mya — about 21 occurrences461–459 Mya — about 21 occurrences459–457 Mya — about 51 occurrences457–455 Mya — about 94 occurrences455–453 Mya — about 109 occurrences453–451 Mya — about 132 occurrences451–449 Mya — about 400 occurrences449–447 Mya — about 107 occurrences447–445 Mya — about 101 occurrences445–443 Mya — about 8 occurrences443–441 Mya — about 1 occurrence441–440 Mya — about 0.1 occurrences440–438 Mya — about 0.3 occurrences438–436 Mya — about 0.3 occurrences436–434 Mya — about 0.3 occurrences434–432 Mya — about 0.1 occurrences471.3 Mya440.5 Mya490 Mya432 Mya

1,141 occurrences of Isotelus on record, most of them in the Ordovician. 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

1,141 occurrences

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

154 formations

Kope — 38.87°N, 84.46°WKope — 39.00°N, 84.00°WKope — 38.80°N, 84.16°WKope — 39.01°N, 84.45°WKope — 39.06°N, 84.44°WKope — 39.03°N, 84.54°WKope — 38.68°N, 83.79°WKope — 38.43°N, 83.99°WKope — 38.77°N, 84.10°WKope — 38.68°N, 84.04°WWaynesville — 39.45°N, 83.83°WWaynesville — 39.44°N, 84.20°WWaynesville — 39.42°N, 85.01°WWaynesville — 39.00°N, 84.00°WWaynesville — 39.53°N, 84.08°WWaynesville — 39.38°N, 84.08°WWaynesville — 39.35°N, 85.10°WWaynesville — 39.58°N, 84.95°WWaynesville — 39.34°N, 84.95°WWaynesville — 39.48°N, 84.05°WWaynesville — 39.36°N, 84.36°WWaynesville — 39.33°N, 84.07°WWaynesville — 38.77°N, 85.36°WMartinsburg — 38.93°N, 78.20°WMartinsburg — 38.51°N, 78.63°WMartinsburg — 40.48°N, 76.53°WMartinsburg — 37.38°N, 80.86°WMartinsburg — 36.90°N, 81.53°WMartinsburg — 37.35°N, 80.81°WMartinsburg — 38.52°N, 78.89°WMartinsburg — 38.30°N, 78.01°WMartinsburg — 38.25°N, 79.05°WMartinsburg — 41.74°N, 74.18°WLexington Limestone — 38.00°N, 84.67°WLexington Limestone — 38.22°N, 84.86°WLexington Limestone — 38.31°N, 84.85°WLexington Limestone — 37.90°N, 84.27°WLexington Limestone — 38.35°N, 84.86°WLexington Limestone — 37.68°N, 84.76°WLexington Limestone — 37.67°N, 84.94°WLexington Limestone — 37.63°N, 84.73°WLexington Limestone — 37.65°N, 84.95°WFairview — 39.47°N, 87.41°WFairview — 39.00°N, 84.00°WFairview — 39.01°N, 84.45°WFairview — 39.03°N, 84.51°WFairview — 38.68°N, 83.79°WLiberty — 39.00°N, 84.00°WLiberty — 38.20°N, 85.57°WLiberty — 39.49°N, 84.95°WLiberty — 39.34°N, 84.95°WLiberty — 39.48°N, 84.06°WLiberty — 39.48°N, 84.05°WLiberty — 38.78°N, 85.37°WDenley Limestone — 43.21°N, 75.46°WDenley Limestone — 44.00°N, 75.00°WDenley Limestone — 43.28°N, 75.14°WDenley Limestone — 43.00°N, 75.00°WDenley Limestone — 43.88°N, 75.49°WValcour — 44.61°N, 73.42°WValcour — 44.87°N, 73.41°WValcour — 44.86°N, 73.34°WValcour — 44.30°N, 73.31°WValcour — 43.97°N, 73.39°WCorryville — 39.00°N, 84.00°WCorryville — 39.43°N, 84.60°WCorryville — 39.17°N, 84.12°WCorryville — 39.30°N, 84.40°WCorryville — 38.68°N, 83.79°WCorryville — 39.33°N, 84.07°WCrown Point — 44.61°N, 73.42°WCrown Point — 44.58°N, 73.53°WCrown Point — 44.88°N, 73.44°WCrown Point — 43.95°N, 73.44°WSunset — 37.74°N, 84.25°WSunset — 39.33°N, 84.07°WSunset — 38.49°N, 83.76°WSunset — 39.34°N, 84.39°WSunset — 39.37°N, 84.39°WSunset — 39.41°N, 84.50°WSunset — 39.13°N, 84.62°WSunset — 38.61°N, 83.77°WSunset — 39.03°N, 83.85°WTrenton — 36.70°N, 83.29°WVerulam — 44.75°N, 79.33°WVerulam — 44.60°N, 78.97°WVerulam — 44.50°N, 78.58°WVerulam — 44.50°N, 78.67°WVerulam — 44.52°N, 78.97°WVerulam — 44.43°N, 78.78°WVerulam — 44.02°N, 77.15°WVerulam — 44.50°N, 79.17°WDay Point — 44.62°N, 73.44°WDay Point — 44.83°N, 73.35°WDay Point — 44.84°N, 73.36°WDay Point — 44.87°N, 73.48°WWhitewater — 39.42°N, 85.01°WWhitewater — 39.00°N, 84.00°WWhitewater — 38.00°N, 85.50°WWhitewater — 39.49°N, 84.95°WWhitewater — 39.34°N, 84.95°WWhitewater — 39.48°N, 84.06°WWhitewater — 39.39°N, 83.93°WWhitewater — 38.93°N, 83.52°WWhitewater — 38.83°N, 83.51°WOregonia — 39.44°N, 84.98°WOregonia — 39.34°N, 84.95°WOregonia — 39.48°N, 84.06°WOregonia — 39.22°N, 84.08°WOregonia — 39.33°N, 84.07°WOregonia — 38.58°N, 83.70°WOregonia — 39.03°N, 83.85°WCopenhagen — 39.98°N, 116.27°WCopenhagen — 39.44°N, 116.29°WCopenhagen — 39.20°N, 116.25°WCopenhagen — 39.23°N, 116.41°WCopenhagen — 38.82°N, 116.50°WBull Fork — 39.39°N, 83.92°WBull Fork — 38.40°N, 83.72°WBull Fork — 38.60°N, 83.72°WEsbataottine — 62.00°N, 127.00°WEsbataottine — 61.72°N, 125.93°WEsbataottine — 61.63°N, 125.75°WEsbataottine — 61.63°N, 125.73°WCliffield — 37.15°N, 81.49°WCliffield — 37.13°N, 81.41°WCliffield — 37.08°N, 81.33°WCliffield — 37.08°N, 81.71°WCliffield — 37.00°N, 81.00°WCliffield — 37.06°N, 81.75°WEdinburg — 38.00°N, 79.00°WEdinburg — 38.97°N, 78.40°WEdinburg — 36.88°N, 81.68°WEdinburg — 37.74°N, 79.51°WMingan — 50.21°N, 63.45°WMingan — 50.21°N, 63.62°WMingan — 50.21°N, 63.75°WMingan — 50.21°N, 63.90°WMingan — 50.20°N, 63.20°WMingan — 50.20°N, 63.34°WClays Ferry — 38.00°N, 84.67°WClays Ferry — 38.31°N, 84.85°WClays Ferry — 37.88°N, 84.34°WClays Ferry — 37.65°N, 85.07°WClays Ferry — 38.82°N, 84.24°WBobcaygeon — 44.67°N, 78.80°WBobcaygeon — 44.53°N, 78.55°WBobcaygeon — 44.50°N, 79.20°WBobcaygeon — 44.60°N, 79.00°WBobcaygeon — 44.58°N, 79.09°W

Loading coastlines…

The named rock units Isotelus has been recovered from, largest first. Drawn where the rock is now, not where it formed. 130 further formations hold fewer occurrences each and are not listed. 33 occurrences have no formation on record, which is common for older literature.

Isotelus and its relatives

Ordovician

Where Isotelus and its relatives were recorded in the Ordovician.

Found in the same rock

1,422 taxa

The Paleobiology Database records 952 sites for Isotelus, 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

124 references

Each of the 1,141 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. 112 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 Isotelus

Credit
Chris Woodrich
Licence
CC BY-SA 4.0
Commercial use
the licence allows it

3D model

Source
Sketchfab
Licence
CC0 Public Domain
Commercial use
the licence allows it

This entry was cached before the site began recording what Smithsonian Open Access and MorphoSource did, so a search that failed cannot be told from one that found nothing.

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 itIsotelinae through timeFormations of the OrdovicianThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. (Dekay 1824)