Didymoceras nebrascense

Didymoceras nebrascense was an extinct species of heteromorph ammonite from the upper Campanian age. It was sexually dimorphic, with two adult sizes averaging at 270 mm (11 in) and 180 mm (7.1 in) high for females and males respectively. It exhibited three distinct growth stages. The first growth stage was composed of one or two straight sharply bending sections and a gently curved third. The second growth stage is composed of around three and a half loosely coiling whorls. The last (adult) growth stage is composed of a U-shaped bend facing upwards.

Didymoceras nebrascense

Ghedoghedo · 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
DidymocerasPBDB
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 most 12 million years on record.

Every occurrence read is dated to somewhere between 83.6 Mya and 72.2 Mya, and nothing in the dating separates them, so that window is what the record shows rather than a span.

Late Cretaceous — about 10 of 10 occurrencesLate Cretaceous84–83 Mya — about 0.3 occurrences83–83 Mya — about 0.4 occurrences83–82 Mya — about 0.4 occurrences82–82 Mya — about 0.4 occurrences82–82 Mya — about 0.4 occurrences82–81 Mya — about 0.4 occurrences81–81 Mya — about 0.4 occurrences81–80 Mya — about 0.4 occurrences80–80 Mya — about 0.4 occurrences80–80 Mya — about 0.4 occurrences80–79 Mya — about 0.4 occurrences79–79 Mya — about 0.4 occurrences79–78 Mya — about 0.4 occurrences78–78 Mya — about 0.4 occurrences78–77 Mya — about 0.4 occurrences77–77 Mya — about 0.4 occurrences77–77 Mya — about 0.4 occurrences77–76 Mya — about 0.4 occurrences76–76 Mya — about 0.4 occurrences76–75 Mya — about 0.4 occurrences75–75 Mya — about 0.4 occurrences75–75 Mya — about 0.4 occurrences75–74 Mya — about 0.4 occurrences74–74 Mya — about 0.4 occurrences74–73 Mya — about 0.4 occurrences73–73 Mya — about 0.4 occurrences73–73 Mya — about 0.4 occurrences73–72 Mya — about 0.3 occurrences84.1 Mya71.7 Mya

10 occurrences of Didymoceras nebrascense 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

10 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

4 formations

Pierre Shale — 43.27°N, 104.27°WPierre Shale — 43.23°N, 103.21°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°WBearpaw — 48.13°N, 106.53°W

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The named rock units Didymoceras nebrascense has been recovered from, largest first. Drawn where the rock is now, not where it formed. 1 occurrence has no formation on record, which is common for older literature.

Didymoceras nebrascense and its relatives

Late Cretaceous

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

Found in the same rock

16 taxa

The Paleobiology Database records 10 sites for Didymoceras nebrascense, and this reads all of them. The number is how many of those sites it was catalogued from too.

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

6 references

Each of the 10 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. 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 Didymoceras nebrascense

Credit
Ghedoghedo
Licence
CC BY-SA 3.0
Commercial use
the licence allows it

3D model

Source
Sketchfab
Licence
CC Attribution
Commercial use
cannot be read from the licence given — check the record

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 itDidymoceras through timeFormations of the Late CretaceousThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. (Meek and Hayden 1856)