Amphistegina

Amphistegina is a genus of foraminiferal protists included in the Rotaliida with a stratigraphic range extending from the Eocene to recent and a cosmopolitan distribution. The test is an asymmetrically biconvex trochospiral that may be bi-involute or partially evolute on the spiral side. Chambers are numerous, broad. and low, strongly curved back at the periphery to form chamber prolongations. The umbilical side is stellate, like that of Asterigerina, and has a distinct umbilical plug. The wall is calcareous, optically radial; the surface finely perforate and smooth overall. The periphery angular to carinate (keeled); the aperture an interiomarginal slit on the umbilical side, bordered by a lip.

Amphistegina

Carlos Natário · 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
AmphisteginidaePBDB
Diet
carnivorePBDB
Life habit
semi-infaunalPBDB, for Foraminifera
Motility
stationaryPBDB, for Rotaliina
Environment
outer shelf,marinePBDB, for Rotaliina

Time the record covers

At least 48 million years on record.

The record covers at least 48.07 Mya to 11.7 ka. No occurrence read is dated outside 56 Mya to 0 Mya.

Paleocene — about 0 of 683 occurrencesEocene — about 20 of 683 occurrencesEoceneOligocene — about 118 of 683 occurrencesOligoceneMiocene — about 233 of 683 occurrencesMiocenePliocene — about 41 of 683 occurrencesPleistocene — about 259 of 683 occurrences57–55 Mya — about 0.3 occurrences55–53 Mya — about 0.8 occurrences53–51 Mya — about 0.8 occurrences51–50 Mya — about 0.8 occurrences50–48 Mya — about 1 occurrence48–46 Mya — about 3 occurrences46–44 Mya — about 3 occurrences44–42 Mya — about 3 occurrences42–40 Mya — about 2 occurrences40–38 Mya — about 2 occurrences38–36 Mya — about 2 occurrences36–34 Mya — about 2 occurrences34–32 Mya — about 12 occurrences32–30 Mya — about 14 occurrences30–29 Mya — about 14 occurrences29–27 Mya — about 20 occurrences27–25 Mya — about 31 occurrences25–23 Mya — about 31 occurrences23–21 Mya — about 24 occurrences21–19 Mya — about 19 occurrences19–17 Mya — about 17 occurrences17–15 Mya — about 21 occurrences15–13 Mya — about 35 occurrences13–11 Mya — about 30 occurrences11–9.5 Mya — about 22 occurrences9.5–7.6 Mya — about 26 occurrences7.6–5.7 Mya — about 33 occurrences5.7–3.8 Mya — about 21 occurrences3.8–1.9 Mya — about 55 occurrences1.9–0 Mya — about 238 occurrences48.07 Mya11.7 ka57 Mya0 Mya

683 occurrences of Amphistegina on record, most of them in the Pleistocene. The Paleobiology Database records this as a living group. 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

683 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

50 formations

Qom Formation — 33.51°N, 51.99°EQom Formation — 34.51°N, 50.95°ETortonian Limestone — 34.99°N, 24.75°ELithothamnion limestone — 45.19°N, 16.37°ELower Coralline Limestone — 35.92°N, 14.42°EGuitar Formation — 9.12°N, 92.80°ENummulitic Limestone — 43.78°N, 7.56°ENummulitic Limestone — 44.00°N, 7.74°ENummulitic Limestone — 43.96°N, 6.69°ENummulitic Limestone — 43.38°N, 6.87°EMolare — 44.37°N, 8.20°EMolare — 44.50°N, 8.48°ESedini — 40.82°N, 8.83°EMonte S Angelo — 42.69°N, 9.32°EEl Bosque — 37.90°N, 1.57°WMut — 36.83°N, 33.47°EAntigua — 17.15°N, 61.78°WAntigua — 17.17°N, 61.85°WAntigua — 17.03°N, 61.68°WCalcare Massiccio — 42.93°N, 11.87°EBakhtiari — 32.06°N, 50.81°EPakhna — 34.97°N, 34.08°ESan Juan — 16.67°N, 93.08°WRosignano Limestone — 43.40°N, 10.47°ERosignano Limestone — 43.50°N, 10.43°ECala di Labra — 41.37°N, 9.18°ECalcareniti di Castelgomberto — 45.48°N, 11.58°EQom — 35.50°N, 48.42°EPesco Falcone — 42.17°N, 14.10°ERoaia — 47.59°N, 24.02°ECalcari a Briozoi e Litotamni — 41.42°N, 13.97°ECalcari a Briozoi e Litotamni — 41.49°N, 13.86°ESanya — 16.85°N, 112.35°E

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The named rock units Amphistegina has been recovered from, largest first. Drawn where the rock is now, not where it formed. 26 further formations hold fewer occurrences each and are not listed. 446 occurrences have no formation on record, which is common for older literature.

Amphistegina and its relatives

Pleistocene

Where Amphistegina and its relatives were recorded in the Pleistocene.

Found in the same rock

943 taxa

The Paleobiology Database records 514 sites for Amphistegina, 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

108 references

Each of the 683 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. 96 further references are not listed. Each entry links to doi.org. Relayed as the Paleobiology Database holds them, not checked against what they resolve to.

Media and terms

Media content2

Picture of Amphistegina

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

3D model

Source
Sketchfab
Licence
CC Attribution-NonCommercial
Commercial use
the licence does not allow it

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 itAmphisteginidae through timeFormations of the PleistoceneThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. d'Orbigny 1826