Arnioceras

Arnioceras is an extinct genus of large, evolute, discoidal ammonite from the Lower Jurassic. The shell is normally coiled so that all whorls are exposed. Sides bear strong sharp ribs that are straight until reaching the ventrolateral edge where they swing forward and fade. The rim (venter) is keeled and free of grooves.

Arnioceras

Daderot · CC0 · 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
ArietitinaePBDB
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 63 million years on record.

Every occurrence read is dated to somewhere between 237 Mya and 174.7 Mya, and nothing in the dating separates them, so that window is what the record shows rather than a span.

Middle Triassic — about 0 of 368 occurrencesLate Triassic — about 1 of 368 occurrencesLate TriassicEarly Jurassic — about 367 of 368 occurrencesEarly JurassicMiddle Jurassic — about 0 of 368 occurrences238–236 Mya — about 0.0 occurrences236–234 Mya — about 0.0 occurrences234–232 Mya — about 0.0 occurrences232–230 Mya — about 0.0 occurrences230–227 Mya — about 0.0 occurrences227–225 Mya — about 0.0 occurrences225–223 Mya — about 0.0 occurrences223–221 Mya — about 0.0 occurrences221–219 Mya — about 0.0 occurrences219–217 Mya — about 0.0 occurrences217–214 Mya — about 0.0 occurrences214–212 Mya — about 0.0 occurrences212–210 Mya — about 0.0 occurrences210–208 Mya — about 0.0 occurrences208–206 Mya — about 0.0 occurrences206–204 Mya — about 0.0 occurrences204–202 Mya — about 0.0 occurrences202–199 Mya — about 9 occurrences199–197 Mya — about 110 occurrences197–195 Mya — about 110 occurrences195–193 Mya — about 110 occurrences193–191 Mya — about 4 occurrences191–189 Mya — about 4 occurrences189–186 Mya — about 4 occurrences186–184 Mya — about 4 occurrences184–182 Mya — about 3 occurrences182–180 Mya — about 3 occurrences180–178 Mya — about 3 occurrences178–176 Mya — about 3 occurrences176–173 Mya — about 1 occurrence238 Mya173 Mya

368 occurrences of Arnioceras on record, most of them in the Early Jurassic. 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

368 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

31 formations

Inklin — 59.31°N, 133.84°WInklin — 59.32°N, 133.89°WInklin — 59.42°N, 134.00°WSunrise — 38.66°N, 118.19°WSunrise — 38.89°N, 117.87°WLower Lias — 51.80°N, 1.88°WIsztimér Limestone — 47.20°N, 17.90°EIsztimér Limestone — 46.98°N, 17.30°ESierra de Santa Rosa — 30.63°N, 112.57°WBroadford Beds — 57.25°N, 5.87°WIsztimér — 47.18°N, 17.83°ECalcaires à Gryphées — 47.06°N, 4.74°EJinji — 22.16°N, 112.50°EJinji — 24.04°N, 114.20°EJinji — 22.80°N, 112.65°EHuayacocotla — 20.33°N, 98.22°WLast Creek — 51.09°N, 122.97°WMarnes et Calcaires de Strassen — 49.61°N, 6.08°EBlue Lias — 50.00°N, 2.00°WBlue Lias — 51.00°N, 3.00°WTalkeetna — 57.74°N, 155.40°WOust — 36.52°N, 10.06°EAdnet — 47.14°N, 9.84°EAdnet — 47.17°N, 10.03°EHarbledown — 50.58°N, 127.47°WFernie Shale — 49.50°N, 115.00°WTolo Channel — 22.45°N, 114.28°EAntimonio — 30.63°N, 112.57°WLa Negra — 21.67°S, 69.92°WAllgäu — 47.15°N, 10.10°EAin Ouarka — 32.71°N, 0.16°WLantang — 23.42°N, 114.94°E

Loading coastlines…

The named rock units Arnioceras has been recovered from, largest first. Drawn where the rock is now, not where it formed. 7 further formations hold fewer occurrences each and are not listed. 124 occurrences have no formation on record, which is common for older literature.

Arnioceras and its relatives

Early Jurassic

Where Arnioceras and its relatives were recorded in the Early Jurassic.

Found in the same rock

397 taxa

The Paleobiology Database records 99 sites for Arnioceras, 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

46 references

Each of the 368 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. 34 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 Arnioceras

Credit
Daderot
Licence
CC0
Commercial use
the licence allows it

No 3D scan of Arnioceras was found in Sketchfab.

Smithsonian Open Access and MorphoSource were 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 itArietitinae through timeFormations of the Early JurassicThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Hyatt 1867