Didacna

Didacna is a genus of brackish-water bivalve molluscs of the cockle family (Cardiidae) characterized by rounded-triangular, oval or trapezoidal shells with flattened ribs. It includes about 90 accepted species, 9 of which are extant and endemic to the Caspian Sea. The genus presumably originated in the Black Sea and the Caspian Sea basins during the Pleistocene around 900,000 years ago. However, several fossil species from older deposits outside of those basins have also sometimes been classified within this genus. These cockles are sedentary filter feeders that bury into the sediment and feed on suspended detritus, microscopic algae and mollusc larvae. They are a food source for some fish species.

Didacna

Wesselingh FP, Neubauer TA, Anistratenko VV, Vinarski MV, Yanina T, ter Poorten JJ, Kijashko P, Albrecht C, Anistrate… · CC BY 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
DidacninaePBDB
Diet
suspension feederPBDB, for Bivalvia
Life habit
infaunalPBDB, for Bivalvia
Motility
facultatively mobilePBDB, for Bivalvia
Vision
blindPBDB, for Bivalvia

Time the record covers

At least 5.2 million years on record.

The record covers at least 5.333 Mya to 129 ka. No occurrence read is dated outside 11.63 Mya to 11.7 ka.

Miocene — about 2 of 10 occurrencesMiocenePliocene — about 0 of 10 occurrencesPleistocene — about 8 of 10 occurrencesPleistoceneHolocene — about 0 of 10 occurrences12–11 Mya — about 0.0 occurrences11–11 Mya — about 0.1 occurrences11–11 Mya — about 0.1 occurrences11–10 Mya — about 0.1 occurrences10–9.7 Mya — about 0.1 occurrences9.7–9.3 Mya — about 0.1 occurrences9.3–8.9 Mya — about 0.1 occurrences8.9–8.5 Mya — about 0.1 occurrences8.5–8.1 Mya — about 0.1 occurrences8.1–7.7 Mya — about 0.1 occurrences7.7–7.3 Mya — about 0.1 occurrences7.3–6.9 Mya — about 0.3 occurrences6.9–6.5 Mya — about 0.3 occurrences6.5–6.1 Mya — about 0.3 occurrences6.1–5.7 Mya — about 0.3 occurrences5.7–5.3 Mya — about 0.2 occurrences809 ka–404 ka Mya — about 1 occurrence404 ka–0 Mya — about 7 occurrences5.333 Mya129 ka12.1 Mya0 Mya

10 occurrences of Didacna 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

10 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.

Didacna and its relatives

Pleistocene

Where Didacna and its relatives were recorded in the Pleistocene.

Found in the same rock

48 taxa

The Paleobiology Database records 4 sites for Didacna, 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

4 references

Each of the 10 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 Didacna

Credit
Wesselingh FP, Neubauer TA, Anistratenko VV, Vinarski MV, Yanina T, ter Poorten JJ, Kijashko P, Albrecht C, Anistrate…
Licence
CC BY 4.0
Commercial use
the licence allows it

No 3D scan of Didacna 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 itDidacninae through timeFormations of the PleistoceneThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Eichwald 1838