Tridacna

Tridacna is a genus of large saltwater clams, marine bivalve molluscs in the subfamily Tridacninae, the giant clams. Many Tridacna species are threatened. They have heavy shells, fluted with 4 to 6 folds. The mantle is often brightly coloured. They inhabit shallow waters of coral reefs in warm seas of the Indo-Pacific region. These clams are popular in marine aquaria, and in some areas, such as the Philippines, members of the genus are farmed for the marine aquarium trade. They live in symbiosis with photosynthetic algae (zooxanthellae). Some species are eaten by humans.

Tridacna

Charles J. Sharp · 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
TridacninaePBDB
Diet
photosymbiotic, suspension feederPBDB, for Tridacninae
Life habit
epifaunal, solitaryPBDB, for Tridacninae
Motility
stationary, attachedPBDB, for Tridacninae
Vision
limitedPBDB
Environment
marinePBDB, for Tridacninae

Time the record covers

At least 20 million years on record.

The record covers at least 20.45 Mya to 11.7 ka. No occurrence read is dated outside 23.04 Mya to 0 Mya.

Oligocene — about 0 of 83 occurrencesMiocene — about 11 of 83 occurrencesMiocenePliocene — about 2 of 83 occurrencesPliocenePleistocene — about 60 of 83 occurrencesPleistocene24–23 Mya — about 0.1 occurrences23–22 Mya — about 0.4 occurrences22–21 Mya — about 0.4 occurrences21–20 Mya — about 0.4 occurrences20–20 Mya — about 0.2 occurrences20–19 Mya — about 0.2 occurrences19–18 Mya — about 0.2 occurrences18–17 Mya — about 0.2 occurrences17–16 Mya — about 0.2 occurrences16–16 Mya — about 0.2 occurrences16–15 Mya — about 0.1 occurrences15–14 Mya — about 0.1 occurrences14–13 Mya — about 0.0 occurrences12–11 Mya — about 0.8 occurrences11–10 Mya — about 1.0 occurrences10–9.4 Mya — about 1.0 occurrences9.4–8.6 Mya — about 1.0 occurrences8.6–7.8 Mya — about 1.0 occurrences7.8–7.1 Mya — about 1.0 occurrences7.1–6.3 Mya — about 1.0 occurrences6.3–5.5 Mya — about 1.0 occurrences5.5–4.7 Mya — about 0.4 occurrences4.7–3.9 Mya — about 0.3 occurrences3.9–3.1 Mya — about 0.7 occurrences3.1–2.4 Mya — about 2 occurrences2.4–1.6 Mya — about 6 occurrences1.6–785 ka Mya — about 6 occurrences785 ka–0 Mya — about 57 occurrences20.45 Mya11.7 ka23.5 Mya0 Mya

83 occurrences of Tridacna 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

83 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

11 formations

Aldabra Limestone — 9.42°S, 46.45°ECilanang — 7.01°S, 107.33°ECilanang — 7.49°S, 110.00°EAbbas — 16.63°N, 42.00°EAbbas — 16.75°N, 41.73°ELower Gelingseh — 1.50°N, 116.50°ETakamaka Limestone — 9.42°S, 46.45°ERyukyu Limestone — 24.38°N, 124.22°EMandul Marl — 3.75°N, 117.65°ETagpochau — 15.18°N, 145.76°EBundera Calcarenite — 21.89°S, 114.02°EGhubbarah — 19.04°N, 57.75°EKutai Basin — 0.17°N, 117.44°E

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The named rock units Tridacna has been recovered from, largest first. Drawn where the rock is now, not where it formed. 60 occurrences have no formation on record, which is common for older literature.

Tridacna and its relatives

Pleistocene

Where Tridacna and its relatives were recorded in the Pleistocene.

Found in the same rock

719 taxa

The Paleobiology Database records 27 sites for Tridacna, 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

41 references

Each of the 83 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. 29 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 content3

Picture of Tridacna

Credit
Charles J. Sharp
Licence
CC BY-SA 4.0
Commercial use
the licence allows it

Photogrammetry

Licence
not stated by the source
Commercial use
cannot be read from the licence given — check the record
Specimen
Tridacna gigas · MST:PALEO:MST-SP-3741

3D model

Source
Sketchfab
Licence
CC0 Public Domain
Commercial use
the licence allows it

Smithsonian Open Access 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 itTridacninae through timeFormations of the PleistoceneThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Bruguière 1797