Microderoceras

Microderoceras is a flat sided, evolute, radially ribbed Lower Jurassic ammonite belonging to the ammonitid family Eoderoceratidae and superfamily Eoderoceratoidea. Its whorls are subquadrangular in section; venter on the outer rim, rounded; sides with two rows if distinct spines, tubercles on internal molds, formed at either end of the ribs. The lateral surface of the ribcage is concave toward both sides, the lateral side of the dorsal and the lateral side of the ventral surface. The ribs are divided into six pairs (1-3) of the following types: 2-3 is the only type. In the first type, the ribs on the ventral face are fused to the ribs on the ventral sides; the ribs on the dorsal face are fused to the ribs on the dorsal sides. The second type represents the ribbed body, the ribs are in the same arrangement as in the first type and the rib cage does not fuse to the dorsal surface.

Microderoceras

Ghedoghedo · 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
EoderoceratinaePBDB
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 16 million years on record.

Every occurrence read is dated to somewhere between 199.5 Mya and 184.2 Mya, and nothing in the dating separates them, so that window is what the record shows rather than a span.

Early Jurassic — about 17 of 17 occurrencesEarly Jurassic200–199 Mya — about 0.1 occurrences199–199 Mya — about 1 occurrence199–198 Mya — about 1 occurrence198–198 Mya — about 1 occurrence198–197 Mya — about 1 occurrence197–197 Mya — about 1 occurrence197–196 Mya — about 1 occurrence196–196 Mya — about 1 occurrence196–195 Mya — about 1 occurrence195–195 Mya — about 1 occurrence195–194 Mya — about 1 occurrence194–193 Mya — about 1 occurrence193–193 Mya — about 1 occurrence193–192 Mya — about 0.3 occurrences192–192 Mya — about 0.3 occurrences192–191 Mya — about 0.3 occurrences191–191 Mya — about 0.3 occurrences191–190 Mya — about 0.3 occurrences190–190 Mya — about 0.3 occurrences190–189 Mya — about 0.3 occurrences189–189 Mya — about 0.3 occurrences189–188 Mya — about 0.3 occurrences188–188 Mya — about 0.3 occurrences188–187 Mya — about 0.3 occurrences187–186 Mya — about 0.3 occurrences186–186 Mya — about 0.3 occurrences186–185 Mya — about 0.3 occurrences185–185 Mya — about 0.3 occurrences185–184 Mya — about 0.3 occurrences184–184 Mya — about 0.0 occurrences200 Mya183.7 Mya

17 occurrences of Microderoceras 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

17 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

5 formations

Calcaires à Gryphées — 47.06°N, 4.74°ELower Lias — 51.80°N, 1.88°WAberdouz — 32.01°N, 4.95°WAllgäu — 47.15°N, 10.10°EAsientos — 25.98°S, 69.17°W

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The named rock units Microderoceras has been recovered from, largest first. Drawn where the rock is now, not where it formed. 9 occurrences have no formation on record, which is common for older literature.

Microderoceras and its relatives

Early Jurassic

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

Found in the same rock

109 taxa

The Paleobiology Database records 14 sites for Microderoceras, 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

12 references

Each of the 17 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 content1

Picture of Microderoceras

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

No 3D scan of Microderoceras 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 itEoderoceratinae through timeFormations of the Early JurassicThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Hyatt 1871