Tresus capax

Tresus capax is a species of saltwater clam, commonly named the ‘fat gaper‘, in the family Mactridae. It was originally described as lutraria capax by Augustus Addison Gould. It also shares the common name horse clam with Tresus nuttallii, a species which is similar in both morphology and lifestyle. Both species are somewhat similar to the geoduck, though smaller, with shells up to 8 inches (20 cm) long, weight to 3–4 pounds (1.4–1.8 kg).

Tresus capax

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
Also called
fat gaperPBDB
Sits inside
TresusPBDB
Diet
suspension feederPBDB, for Mactridae
Life habit
infaunalPBDB, for Mactridae
Motility
facultatively mobilePBDB, for Mactridae
Vision
blindPBDB, for Bivalvia

Time the record covers

At most 118 thousand years on record.

Every occurrence read is dated to somewhere between 129 ka and 11.7 ka, and nothing in the dating separates them, so that window is what the record shows rather than a span.

Pleistocene — about 5 of 5 occurrencesPleistoceneHolocene — about 0 of 5 occurrences147 ka–126 ka Mya — about 0.1 occurrences126 ka–105 ka Mya — about 0.9 occurrences105 ka–84 ka Mya — about 0.9 occurrences84 ka–63 ka Mya — about 0.9 occurrences63 ka–42 ka Mya — about 0.9 occurrences42 ka–21 ka Mya — about 0.9 occurrences21 ka–0 Mya — about 0.4 occurrences629 ka0 Mya

5 occurrences of Tresus capax 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

5 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

2 formations

Late Pleistocene terrace — 46.37°N, 123.96°WBattery — 41.76°N, 124.20°W

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The named rock units Tresus capax has been recovered from, largest first. Drawn where the rock is now, not where it formed. 3 occurrences have no formation on record, which is common for older literature.

Tresus capax and its relatives

Pleistocene

Where Tresus capax and its relatives were recorded in the Pleistocene.

Found in the same rock

109 taxa

The Paleobiology Database records 2 sites for Tresus capax, 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

3 references

Each of the 5 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 Tresus capax

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

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

Occurrence data from the Paleobiology Database, CC BY 4.0. (Gould 1850)