Didymoceras

Didymoceras is an extinct genus of ammonite cephalopod from the Late Cretaceous epoch. It is one of the most bizarrely shaped genera, with a shell that spirals upwards into a loose, hooked tip. It is thought to have drifted in the water vertically, moving up and down. The genus name comes from Ancient Greek δίδυμος (dídumos), meaning "twin", and κέρας (céras), meaning "horn".

Didymoceras

Mr Fink ( talk ) · CC BY-SA 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
NostoceratidaePBDB
Diet
carnivorePBDB, for Ammonoidea
Life habit
nektonicPBDB, for Ammonoidea
Motility
fast-movingPBDB, for Ammonoidea
Vision
well-developedPBDB, for Cephalopoda
Environment
marinePBDB, for Cephalopoda

Time the record covers

At least 395 million years on record.

The record covers at least 468 Mya to 72.2 Mya. No occurrence read is dated outside 477.1 Mya to 66 Mya.

Ordovician — about 1 of 139 occurrencesOrdovicianSilurian — about 0 of 139 occurrencesDevonian — about 0 of 139 occurrencesCarboniferous — about 0 of 139 occurrencesPermian — about 0 of 139 occurrencesEarly Triassic — about 0 of 139 occurrencesMiddle Triassic — about 0 of 139 occurrencesLate Triassic — about 0 of 139 occurrencesEarly Jurassic — about 0 of 139 occurrencesMiddle Jurassic — about 0 of 139 occurrencesLate Jurassic — about 0 of 139 occurrencesEarly Cretaceous — about 0 of 139 occurrencesLate Cretaceous — about 138 of 139 occurrencesPaleocene — about 0 of 139 occurrences485–471 Mya — about 0.7 occurrences471–457 Mya — about 0.3 occurrences101–86 Mya — about 3 occurrences86–72 Mya — about 115 occurrences72–58 Mya — about 20 occurrences468 Mya72.2 Mya485 Mya58 Mya

139 occurrences of Didymoceras on record, most of them in the Late Cretaceous. 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

139 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

35 formations

Pierre Shale — 43.27°N, 104.27°WPierre Shale — 44.80°N, 105.05°WPierre Shale — 38.83°N, 103.01°WPierre Shale — 38.18°N, 104.48°WPierre Shale — 45.77°N, 105.08°WPierre Shale — 42.72°N, 103.13°WPierre Shale — 40.08°N, 105.35°WPierre Shale — 40.76°N, 105.05°WPierre Shale — 40.65°N, 105.07°WPierre Shale — 40.24°N, 106.40°WPierre Shale — 40.20°N, 105.96°WPierre Shale — 43.23°N, 103.21°WPierre Shale — 43.91°N, 102.91°WAnnona — 33.77°N, 93.92°WAnnona — 33.83°N, 93.81°WAnnona — 33.80°N, 94.06°WKorojon Calcarenite — 22.68°S, 114.35°EBearpaw — 48.13°N, 106.53°WBearpaw — 48.65°N, 106.87°WBearpaw — 48.03°N, 106.32°WSt Lucia — 28.69°S, 32.02°ESt Lucia — 28.45°S, 32.32°ESt Lucia — 27.99°S, 32.41°ESt Lucia — 27.86°S, 32.35°EMarshalltown — 39.55°N, 75.70°WMarshalltown — 39.55°N, 75.65°WMount Laurel Sand — 39.55°N, 75.65°WMount Laurel Sand — 39.79°N, 75.63°WMount Laurel Sand — 39.55°N, 75.65°WRagged Valley Shale — 36.33°N, 120.57°WRagged Valley Shale — 36.21°N, 120.45°WBearpaw Shale — 47.30°N, 106.97°WBearpaw Shale — 48.65°N, 106.87°WBearpaw Shale — 46.33°N, 106.58°WLewis Shale — 36.40°N, 106.84°WLewis Shale — 36.74°N, 106.80°WLewis Shale — 36.61°N, 106.80°WMatanuska — 61.84°N, 148.06°WMatanuska — 61.91°N, 147.46°WMatanuska — 61.95°N, 147.56°WNkporo Shale — 5.20°N, 8.22°ENkporo Shale — 5.83°N, 7.85°EMoreno — 36.64°N, 120.73°WMoreno — 36.22°N, 120.12°WMoreno — 37.47°N, 121.23°WDavutlar — 41.63°N, 33.08°EDavutlar — 40.96°N, 32.08°EDavutlar — 41.15°N, 28.87°EDaralitau — 37.80°N, 68.57°EShinarish — 36.37°N, 41.68°EOzan — 33.77°N, 93.92°WTeba — 13.00°S, 14.00°EPigeon Point — 37.26°N, 122.41°WPigeon Point — 37.19°N, 122.40°WSeidan — 34.28°N, 134.66°EChinomigawa — 42.17°N, 142.82°EKorojon — 23.08°S, 114.07°EKorojon — 22.80°S, 114.14°EHonghuayuan — 33.00°N, 111.00°EMount Laurel — 40.26°N, 74.27°W

Loading coastlines…

The named rock units Didymoceras has been recovered from, largest first. Drawn where the rock is now, not where it formed. 11 further formations hold fewer occurrences each and are not listed. 22 occurrences have no formation on record, which is common for older literature.

Didymoceras and its relatives

Late Cretaceous

Where Didymoceras and its relatives were recorded in the Late Cretaceous.

Found in the same rock

572 taxa

The Paleobiology Database records 116 sites for Didymoceras, 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

42 references

Each of the 139 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. 30 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 content3

Picture of Didymoceras

Credit
Mr Fink ( talk )
Licence
CC BY-SA 3.0
Commercial use
the licence allows it

CT scan

Licence
not stated by the source
Commercial use
cannot be read from the licence given — check the record
Specimen
Didymoceras nebrascense · USNM:PAL:USNM PAL482421

3D model

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

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 itNostoceratidae through timeFormations of the Late CretaceousThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. (Hyatt 1900)