Tresus

Tresus is a genus of saltwater clams, marine bivalve mollusks in the family Mactridae. Many of them are known under the common name the horse clam or as species of gaper clam. They are similar to geoducks.

Tresus

Minette Layne from Seattle, Washington, USA · 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
LutrariinaePBDB
Diet
suspension feederPBDB, for Mactridae
Life habit
infaunalPBDB, for Mactridae
Motility
facultatively mobilePBDB, for Mactridae
Vision
blindPBDB, for Bivalvia

Time the record covers

At least 22 million years on record.

The record covers at least 23.04 Mya to 129 ka. No occurrence read is dated outside 27.3 Mya to 0 Mya.

Oligocene — about 3 of 166 occurrencesOligoceneMiocene — about 22 of 166 occurrencesMiocenePliocene — about 42 of 166 occurrencesPliocenePleistocene — about 99 of 166 occurrencesPleistocene28–27 Mya — about 0.3 occurrences27–26 Mya — about 0.7 occurrences26–25 Mya — about 0.7 occurrences25–24 Mya — about 0.7 occurrences24–23 Mya — about 0.7 occurrences23–22 Mya — about 0.2 occurrences22–21 Mya — about 0.1 occurrences21–20 Mya — about 0.1 occurrences20–19 Mya — about 0.1 occurrences19–19 Mya — about 0.1 occurrences19–18 Mya — about 0.1 occurrences18–17 Mya — about 0.1 occurrences17–16 Mya — about 0.1 occurrences12–11 Mya — about 0.9 occurrences11–10 Mya — about 2 occurrences10–9.3 Mya — about 2 occurrences9.3–8.4 Mya — about 2 occurrences8.4–7.4 Mya — about 2 occurrences7.4–6.5 Mya — about 5 occurrences6.5–5.6 Mya — about 6 occurrences5.6–4.6 Mya — about 10 occurrences4.6–3.7 Mya — about 11 occurrences3.7–2.8 Mya — about 19 occurrences2.8–1.9 Mya — about 33 occurrences1.9–928 ka Mya — about 6 occurrences928 ka–0 Mya — about 64 occurrences23.04 Mya129 ka27.8 Mya0 Mya

166 occurrences of Tresus 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

166 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

29 formations

Careaga Sandstone — 34.88°N, 120.51°WCareaga Sandstone — 34.83°N, 120.38°WCareaga Sandstone — 34.90°N, 120.32°WCareaga Sandstone — 34.74°N, 120.41°WCareaga Sandstone — 34.77°N, 120.48°WPalos Verdes Sand — 33.80°N, 118.16°WPalos Verdes Sand — 33.99°N, 118.45°WPalos Verdes Sand — 33.60°N, 117.88°WPalos Verdes Sand — 33.74°N, 118.28°WPalos Verdes Sand — 33.66°N, 117.94°WPico — 34.36°N, 118.56°WPico — 34.33°N, 118.72°WPico — 34.42°N, 118.70°WPico — 34.35°N, 118.52°WPico — 34.34°N, 118.51°WSisquoc — 34.81°N, 120.22°WSisquoc — 34.90°N, 120.31°WEtchegoin — 36.25°N, 120.31°WEtchegoin — 36.12°N, 120.41°WEtchegoin — 36.23°N, 120.33°WEtchegoin — 36.01°N, 120.31°WEtchegoin — 36.21°N, 120.67°WEtchegoin — 36.15°N, 120.64°WEtchegoin — 36.19°N, 120.64°WJacalitos — 36.08°N, 120.48°WJacalitos — 36.09°N, 120.41°WJacalitos — 36.04°N, 120.39°WJacalitos — 36.01°N, 120.31°WJacalitos — 36.14°N, 120.64°WPancho Rico — 35.99°N, 120.91°WPancho Rico — 36.03°N, 120.80°WPancho Rico — 35.90°N, 120.84°WPancho Rico — 35.89°N, 120.56°WPuerto Madryn — 42.97°S, 64.31°WPuerto Madryn — 42.57°S, 64.28°WPuerto Madryn — 44.50°S, 65.27°WUnnamed — 33.24°N, 119.51°WSan Pedro — 33.85°N, 118.06°WSan Pedro — 33.80°N, 118.16°WMerced — 37.39°N, 122.17°WMerced — 38.37°N, 122.92°WToshima Sand — 34.62°N, 137.22°EFoxen Mudstone — 34.86°N, 120.50°WPoul Creek — 60.07°N, 142.27°WPoul Creek — 60.01°N, 141.45°WSan Pedro Sand — 33.74°N, 118.28°WLate Pleistocene terrace — 46.37°N, 123.96°WSaanich — 47.58°N, 122.42°WEmpire — 43.39°N, 124.28°WBattery — 41.76°N, 124.20°WWildcat — 40.64°N, 124.31°WHookton — 40.98°N, 124.11°WMonterey — 33.59°N, 117.71°WWilson Grove — 38.34°N, 122.84°WTimms Point Silt — 33.73°N, 118.28°W

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The named rock units Tresus has been recovered from, largest first. Drawn where the rock is now, not where it formed. 5 further formations hold fewer occurrences each and are not listed. 41 occurrences have no formation on record, which is common for older literature.

Tresus and its relatives

Pleistocene

Where Tresus and its relatives were recorded in the Pleistocene.

Found in the same rock

1,501 taxa

The Paleobiology Database records 135 sites for Tresus, and this reads all of them. Of that, one read hit the database's own return limit, so every count below is a floor rather than a total. 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

49 references

Each of the 166 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. 37 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 Tresus

Credit
Minette Layne from Seattle, Washington, USA
Licence
CC BY 2.0
Commercial use
the licence allows it

No 3D scan of Tresus 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 itLutrariinae through timeFormations of the PleistoceneThe world it lived on

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