Stenus

Stenus is a genus of semiaquatic rove beetles in the subfamily Steninae, and one of the largest genera in the kingdom Animalia, with some 3100 known species worldwide. They are predators of Collembola and other small arthropods. Adults have a protrusible labium with a sticky tip used in prey capture. To overcome the rapid escape of Collembola, the labium is protruded at high speed by hemolymph pressure, and immediately withdrawn, pulling the prey within the range of the mandibles. However, the labium tip does not easily stick to prey covered in scales or setae or that have a large body size. Stenus comma is more likely to catch such prey by lunging forward and grabbing them directly with its mandibles rather than using its labium. Stenus species are also known for "skimming" on the water surface using their pygidial gland secretions that act as a surfactant and rapidly propel the beetle fast forward, a phenomenon known as the Marangoni effect. Stenus comma has been seen to achieve a velocity of 0.75 m/s, and to cover a distance of up to 15 m if the secretion is continuous.

Stenus

Udo Schmidt from Deutschland · CC BY-SA 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
SteninaePBDB
Motility
actively mobilePBDB, for Arthropoda
Environment
terrestrialPBDB, for Insecta

Time the record covers

At least 93 million years on record.

The record covers at least 93.9 Mya to 129 ka. No occurrence read is dated outside 100.5 Mya to 11.7 ka.

Early Cretaceous — about 0 of 110 occurrencesLate Cretaceous — about 2 of 110 occurrencesLate CretaceousPaleocene — about 0 of 110 occurrencesEocene — about 22 of 110 occurrencesEoceneOligocene — about 5 of 110 occurrencesOligoceneMiocene — about 2 of 110 occurrencesMiocenePliocene — about 0 of 110 occurrencesPleistocene — about 79 of 110 occurrences103–99 Mya — about 0.2 occurrences99–96 Mya — about 0.5 occurrences96–92 Mya — about 0.3 occurrences85–82 Mya — about 0.1 occurrences82–79 Mya — about 0.3 occurrences79–75 Mya — about 0.3 occurrences75–72 Mya — about 0.3 occurrences41–38 Mya — about 0.6 occurrences38–34 Mya — about 20 occurrences34–31 Mya — about 2 occurrences31–27 Mya — about 0.5 occurrences27–24 Mya — about 3 occurrences24–21 Mya — about 0.8 occurrences14–10 Mya — about 0.2 occurrences10–6.8 Mya — about 0.8 occurrences6.8–3.4 Mya — about 1 occurrence3.4–0 Mya — about 79 occurrences93.9 Mya129 ka103 Mya0 Mya

110 occurrences of Stenus 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

110 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

Kap København — 82.47°N, 23.66°WKap København — 82.45°N, 24.10°WKap København — 82.32°N, 23.85°WHighbury Silts and Sands — 51.56°N, 0.06°WTitusville Till — 41.62°N, 79.64°WFlorissant — 38.92°N, 105.28°WFlorissant — 38.93°N, 105.24°WQuadra Sand — 49.29°N, 122.88°WQuadra Sand — 49.23°N, 122.78°WNiveau du gypse d'Aix — 43.52°N, 5.45°EOlympia beds — 47.66°N, 122.43°WImuruk Volcanics — 65.88°N, 163.13°WOla — 60.17°N, 150.49°ERott — 50.75°N, 7.26°EOler — 69.50°N, 158.50°E

Loading coastlines…

The named rock units Stenus has been recovered from, largest first. Drawn where the rock is now, not where it formed. 54 occurrences have no formation on record, which is common for older literature.

Stenus and its relatives

Pleistocene

Where Stenus and its relatives were recorded in the Pleistocene.

Found in the same rock

2,843 taxa

The Paleobiology Database records 76 sites for Stenus, 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

24 references

Each of the 110 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. 12 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 content2

Picture of Stenus

Credit
Udo Schmidt from Deutschland
Licence
CC BY-SA 2.0
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
Stenus Stenus guttula · ETHZ:ENT:0576222

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 itSteninae through timeFormations of the PleistoceneThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Latreille 1796