Cladocera

Cladocera is a order of aquatic, largely freshwater crustaceans, commonly known as water fleas. Most cladocerans feed on microscopic chunks of organic matter, though some forms are predatory. Over 1000 species have been recognised so far, with many more undescribed. The oldest unequivocal fossils of water fleas date to the Jurassic, though their modern morphology suggests that they originated substantially earlier, during the Paleozoic. Some have also adapted to a life in the ocean, the only members of Branchiopoda to do so, though several anostracans live in hypersaline lakes. Most are 0.2–6.0 mm (0.01–0.24 in) long, with a down-turned head with a single median compound eye, and a carapace covering the apparently unsegmented thorax and abdomen. Most species show cyclical parthenogenesis, where asexual reproduction is occasionally supplemented by sexual reproduction, which produces resting eggs that allow the species to survive harsh conditions and disperse to distant habitats.

Cladocera

Andrei Savitsky · 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
Also called
water fleaPBDB
Sits inside
CladoceromorphaPBDB
Diet
suspension feeder, detritivorePBDB, for Branchiopoda
Life habit
nektobenthicPBDB, for Branchiopoda
Motility
slow-movingPBDB, for Branchiopoda
Vision
well-developedPBDB, for Branchiopoda
Environment
marine,brackish,freshwaterPBDB, for Branchiopoda

Time the record covers

At least 113 million years on record.

The record covers at least 113.2 Mya to 129 ka. No occurrence read is dated outside 119.57 Mya to 11.7 ka.

Early Cretaceous — about 1 of 9 occurrencesEarly CretaceousLate Cretaceous — about 0 of 9 occurrencesPaleocene — about 2 of 9 occurrencesEocene — about 0 of 9 occurrencesOligocene — about 1 of 9 occurrencesOligoceneMiocene — about 2 of 9 occurrencesMiocenePliocene — about 0 of 9 occurrencesPleistocene — about 3 of 9 occurrences122–118 Mya — about 0.3 occurrences118–114 Mya — about 0.6 occurrences114–110 Mya — about 0.1 occurrences69–65 Mya — about 0.4 occurrences65–61 Mya — about 2 occurrences28–24 Mya — about 0.7 occurrences24–20 Mya — about 0.7 occurrences20–16 Mya — about 0.6 occurrences16–12 Mya — about 0.0 occurrences12–8.1 Mya — about 0.8 occurrences8.1–4.1 Mya — about 0.2 occurrences4.1–0 Mya — about 3 occurrences113.2 Mya129 ka122 Mya0 Mya

9 occurrences of Cladocera 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

9 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

3 formations

Sobral — 64.25°S, 56.75°WRott — 50.75°N, 7.26°ESkarðsströnd–Mókollsdalur — 65.51°N, 21.53°W

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The named rock units Cladocera has been recovered from, largest first. Drawn where the rock is now, not where it formed. 5 occurrences have no formation on record, which is common for older literature.

Cladocera and its relatives

Pleistocene

Where Cladocera and its relatives were recorded in the Pleistocene.

Found in the same rock

300 taxa

The Paleobiology Database records 6 sites for Cladocera, 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

7 references

Each of the 9 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 Cladocera

Credit
Andrei Savitsky
Licence
CC BY 4.0
Commercial use
the licence allows it

No 3D scan of Cladocera 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 itCladoceromorpha through timeFormations of the PleistoceneThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Latreille 1829