Gemma

The amethyst gem clam is species of very small saltwater clam, a marine bivalve mollusk in the family Veneridae, the Venus clams.

Gemma

Smithsonian Environmental Research Center · CC BY 2.0 · 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
VeneridaePBDB
Diet
suspension feederPBDB, for Veneridae
Life habit
infaunalPBDB, for Veneridae
Motility
facultatively mobilePBDB, for Veneridae
Vision
blindPBDB, for Bivalvia

Time the record covers

At least 41 million years on record.

The record covers at least 41.03 Mya to 11.7 ka. No occurrence read is dated outside 48.07 Mya to 0 Mya.

Eocene — about 1 of 67 occurrencesEoceneOligocene — about 1 of 67 occurrencesOligoceneMiocene — about 0 of 67 occurrencesPliocene — about 20 of 67 occurrencesPleistocene — about 43 of 67 occurrences49–47 Mya — about 0.1 occurrences47–46 Mya — about 0.2 occurrences46–44 Mya — about 0.2 occurrences44–42 Mya — about 0.2 occurrences42–41 Mya — about 0.2 occurrences28–26 Mya — about 0.3 occurrences26–25 Mya — about 0.4 occurrences25–23 Mya — about 0.3 occurrences6.5–4.9 Mya — about 1 occurrence4.9–3.3 Mya — about 9 occurrences3.3–1.6 Mya — about 23 occurrences1.6–0 Mya — about 32 occurrences41.03 Mya11.7 ka49 Mya0 Mya

67 occurrences of Gemma 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

67 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

18 formations

Waccamaw — 34.23°N, 77.94°WWaccamaw — 34.29°N, 78.51°WWaccamaw — 34.33°N, 78.20°WWaccamaw — 34.50°N, 79.11°WWaccamaw — 34.63°N, 78.57°WWaccamaw — 34.56°N, 78.49°WWaccamaw — 34.21°N, 81.31°WWaccamaw — 33.63°N, 79.16°WWaccamaw — 33.40°N, 79.25°WYorktown — 35.51°N, 77.62°WYorktown — 35.54°N, 77.67°WYorktown — 37.25°N, 76.50°WYorktown — 34.90°N, 78.05°WDuplin — 34.50°N, 79.11°WDuplin — 34.62°N, 79.01°WDuplin — 34.90°N, 78.05°WCanepatch — 33.83°N, 78.89°WPamlico — 34.78°N, 76.69°WPamlico — 35.50°N, 76.27°WCaloosahatchee — 26.77°N, 81.15°WCaloosahatchee — 26.75°N, 80.93°WCaloosahatchee — 26.93°N, 82.05°WFort Thompson — 26.76°N, 81.44°WFort Thompson — 26.96°N, 81.17°WNew Orleans Barrier Trend — 30.05°N, 89.96°WAcredale — 36.79°N, 76.17°WJames City — 35.28°N, 76.65°WJackson Bluff — 30.39°N, 84.64°WTalbot — 38.07°N, 76.36°WAnastasia — 26.93°N, 80.09°WChowan River — 36.05°N, 76.73°WTamiami — 26.37°N, 80.85°WLisbon — 31.83°N, 88.25°WCharlton — 31.16°N, 81.86°WBelgrade — 34.77°N, 77.18°W

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The named rock units Gemma has been recovered from, largest first. Drawn where the rock is now, not where it formed. 14 occurrences have no formation on record, which is common for older literature.

Gemma and its relatives

Pleistocene

Where Gemma and its relatives were recorded in the Pleistocene.

Found in the same rock

850 taxa

The Paleobiology Database records 38 sites for Gemma, 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

19 references

Each of the 67 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. 7 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 content2

Picture of Gemma

Credit
Smithsonian Environmental Research Center
Licence
CC BY 2.0
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

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 itVeneridae through timeFormations of the PleistoceneThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Deshayes 1853