Hydrozoa

Hydrozoa, also called hydroids, are a taxonomic class of individually very small, predatory animals, some solitary and some colonial, most of which inhabit saline water. The colonies of the colonial species can be large, and in some cases the specialized individual animals cannot survive outside the colony. A few genera within this class live in freshwater habitats. Hydrozoans are related to jellyfish and corals, which also belong to the phylum Cnidaria.

Hydrozoa

Ernst Haeckel · Public Domain · 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
MedusozoaPBDB
Diet
carnivore, suspension feederPBDB
Life habit
epifaunalPBDB
Motility
stationary, attachedPBDB
Vision
blindPBDB

Time the record covers

At least 515 million years on record.

The record covers at least 516 Mya to 11.7 ka. No occurrence read is dated outside 521 Mya to 0 Mya.

Cambrian — about 13 of 777 occurrencesCambrianOrdovician — about 12 of 777 occurrencesOrdovicianSilurian — about 14 of 777 occurrencesDevonian — about 29 of 777 occurrencesDevonianCarboniferous — about 22 of 777 occurrencesCarboniferousPermian — about 116 of 777 occurrencesPermianEarly Triassic — about 8 of 777 occurrencesMiddle Triassic — about 85 of 777 occurrencesLate Triassic — about 219 of 777 occurrencesEarly Jurassic — about 9 of 777 occurrencesMiddle Jurassic — about 12 of 777 occurrencesLate Jurassic — about 48 of 777 occurrencesEarly Cretaceous — about 19 of 777 occurrencesLate Cretaceous — about 11 of 777 occurrencesPaleocene — about 8 of 777 occurrencesEocene — about 27 of 777 occurrencesOligocene — about 16 of 777 occurrencesMiocene — about 25 of 777 occurrencesPliocene — about 10 of 777 occurrencesPleistocene — about 48 of 777 occurrences531–514 Mya — about 1 occurrence514–496 Mya — about 12 occurrences496–478 Mya — about 0.9 occurrences478–461 Mya — about 6 occurrences461–443 Mya — about 6 occurrences443–425 Mya — about 6 occurrences425–407 Mya — about 15 occurrences407–390 Mya — about 3 occurrences390–372 Mya — about 13 occurrences372–354 Mya — about 6 occurrences354–337 Mya — about 1 occurrence337–319 Mya — about 1.0 occurrences319–301 Mya — about 15 occurrences301–283 Mya — about 46 occurrences283–266 Mya — about 35 occurrences266–248 Mya — about 44 occurrences248–230 Mya — about 131 occurrences230–213 Mya — about 97 occurrences213–195 Mya — about 83 occurrences195–177 Mya — about 6 occurrences177–159 Mya — about 15 occurrences159–142 Mya — about 46 occurrences142–124 Mya — about 9 occurrences124–106 Mya — about 9 occurrences106–89 Mya — about 1 occurrence89–71 Mya — about 6 occurrences71–53 Mya — about 14 occurrences53–35 Mya — about 19 occurrences35–18 Mya — about 32 occurrences18–0 Mya — about 99 occurrences516 Mya11.7 ka531 Mya0 Mya

777 occurrences of Hydrozoa on record, most of them in the Late Triassic. 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

777 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

206 formations

Anshun — 26.34°N, 106.72°EChangxing — 29.42°N, 110.90°EChangxing — 25.83°N, 106.08°EChangxing — 31.76°N, 108.46°EChangxing — 30.43°N, 108.53°EChangxing — 30.05°N, 108.93°EChangxing — 30.48°N, 109.05°EChangxing — 29.98°N, 109.08°EChangxing — 30.22°N, 109.05°EChangxing — 32.38°N, 107.11°EChangxing — 25.75°N, 112.82°ELuning — 38.43°N, 118.05°WLuning — 38.43°N, 118.12°WLuning — 38.88°N, 117.59°WLuning — 38.35°N, 117.94°WTataouine — 33.00°N, 10.47°ETataouine — 32.00°N, 10.47°EMartin Bridge — 44.97°N, 117.23°WMartin Bridge — 45.37°N, 117.35°WMartin Bridge — 44.95°N, 117.33°WMartin Bridge — 45.32°N, 117.31°WMartin Bridge — 46.29°N, 116.69°WNayband — 33.12°N, 51.98°ENayband — 32.37°N, 57.47°ENayband — 32.93°N, 52.03°ENayband — 32.95°N, 52.08°ENayband — 33.02°N, 52.25°ENayband — 32.94°N, 51.93°ENayband — 34.06°N, 58.08°EKamishak — 57.72°N, 155.30°WKamishak — 59.78°N, 154.50°WCassian — 46.64°N, 12.20°ECassian — 46.53°N, 12.13°ECassian — 46.57°N, 11.92°ECassian — 46.58°N, 12.25°ECassian — 46.54°N, 11.90°ESchlern 1 — 46.47°N, 13.33°EBrèches rouges de Carboneras — 37.60°N, 1.32°WCathedral Mountain — 30.41°N, 103.12°WDachstein — 47.50°N, 13.50°EDachstein — 47.63°N, 13.17°EDachstein — 47.57°N, 14.52°EDachstein — 47.45°N, 13.69°EDachstein — 48.00°N, 16.42°ESchrattenkalk — 47.43°N, 10.23°ESchrattenkalk — 47.43°N, 10.25°EBeykoz — 41.63°N, 33.28°ESafetdara — 38.76°N, 70.89°ELechkogel — 47.43°N, 13.67°ELechkogel — 47.55°N, 14.52°ELechkogel — 46.77°N, 14.45°ELechkogel — 46.67°N, 14.85°ELechkogel — 48.00°N, 16.23°EMoin — 9.97°N, 83.05°WMoin — 10.00°N, 83.04°WLuolou — 26.34°N, 106.72°ELouisiana Limestone — 39.65°N, 91.73°WLouisiana Limestone — 39.84°N, 91.49°WLouisiana Limestone — 39.45°N, 91.05°WLouisiana Limestone — 39.45°N, 91.43°WNehenta — 55.17°N, 131.80°WNehenta — 55.22°N, 131.98°WAbenaki — 43.69°N, 60.83°WWetterstein — 47.42°N, 11.00°EMisfah — 22.78°N, 57.83°EMisfah — 22.92°N, 57.67°EHeshan — 23.77°N, 108.86°EHeshan — 23.71°N, 109.24°E

Loading coastlines…

The named rock units Hydrozoa has been recovered from, largest first. Drawn where the rock is now, not where it formed. 182 further formations hold fewer occurrences each and are not listed. 289 occurrences have no formation on record, which is common for older literature.

Hydrozoa and its relatives

Late Triassic

Where Hydrozoa and its relatives were recorded in the Late Triassic.

Found in the same rock

3,117 taxa

The Paleobiology Database records 512 sites for Hydrozoa, and this reads 240 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

357 references

Each of the 777 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. 345 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 Hydrozoa

Credit
Ernst Haeckel
Licence
Public Domain
Commercial use
the licence allows it

3D model

Source
Sketchfab
Licence
CC0 Public Domain
Commercial use
the licence allows it

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 itMedusozoa through timeFormations of the Late TriassicThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Owen 1843