Antiarchi

Antiarchi is an order of heavily armored placoderms. The antiarchs form the second-most successful group of placoderms after the arthrodires in terms of numbers of species and range of environments. The order's name was coined by Edward Drinker Cope, who, when examining some fossils that he thought were armored tunicates related to Chelyosoma, mistakenly thought that the orbital fenestra was the opening for the mouth, or oral siphon, and that the opening for the anal siphon was on the other side of the body, as opposed to having both oral and anal siphons together at one end.

Antiarchi

Hectonichus · CC BY-SA 3.0 · 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
PlacodermiPBDB
Diet
carnivorePBDB, for Placodermi
Life habit
nektonicPBDB, for Placodermi
Motility
actively mobilePBDB, for Placodermi

Time the record covers

At least 219 million years on record.

The record covers at least 425 Mya to 205.7 Mya. No occurrence read is dated outside 426.7 Mya to 201.4 Mya.

Silurian — about 2 of 411 occurrencesDevonian — about 405 of 411 occurrencesDevonianCarboniferous — about 3 of 411 occurrencesCarboniferousPermian — about 0 of 411 occurrencesEarly Triassic — about 0 of 411 occurrencesMiddle Triassic — about 0 of 411 occurrencesLate Triassic — about 1 of 411 occurrencesLate TriassicEarly Jurassic — about 0 of 411 occurrences431–423 Mya — about 2 occurrences423–416 Mya — about 16 occurrences416–408 Mya — about 29 occurrences408–400 Mya — about 11 occurrences400–392 Mya — about 29 occurrences392–384 Mya — about 97 occurrences384–377 Mya — about 108 occurrences377–369 Mya — about 49 occurrences369–361 Mya — about 52 occurrences361–353 Mya — about 14 occurrences353–345 Mya — about 0.7 occurrences345–337 Mya — about 0.2 occurrences337–330 Mya — about 0.2 occurrences330–322 Mya — about 0.2 occurrences322–314 Mya — about 0.3 occurrences314–306 Mya — about 0.3 occurrences306–298 Mya — about 0.3 occurrences213–205 Mya — about 0.2 occurrences205–197 Mya — about 0.8 occurrences425 Mya205.7 Mya431 Mya197 Mya

411 occurrences of Antiarchi on record, most of them in the Devonian. The Paleobiology Database records this as a living group, and the chart stops with its fossils rather than at the present. 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

411 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

158 formations

Aztec Siltstone — 78.54°S, 158.43°EAztec Siltstone — 77.88°S, 159.61°EAztec Siltstone — 77.81°S, 160.64°EAztec Siltstone — 78.63°S, 159.45°EAztec Siltstone — 78.58°S, 159.54°EAztec Siltstone — 78.16°S, 159.10°EAztec Siltstone — 78.43°S, 158.68°EAztec Siltstone — 78.53°S, 158.32°EXitun — 25.49°N, 103.80°EZhongning — 37.65°N, 105.99°EZhongning — 37.18°N, 106.05°EZhongning — 37.99°N, 105.70°EZhongning — 37.25°N, 106.07°EZhongning — 33.30°N, 111.48°EOgre — 57.00°N, 22.61°EOgre — 57.03°N, 22.78°EOgre — 57.00°N, 21.62°EOgre — 57.43°N, 25.91°EOgre — 56.36°N, 24.25°EOgre — 56.71°N, 24.84°EOgre — 56.70°N, 24.88°EHunter Siltstone — 33.73°S, 148.35°EHunter Siltstone — 33.74°S, 148.34°EHunter Siltstone — 33.75°S, 148.34°EBindaree — 37.17°S, 146.65°EBindaree — 37.17°S, 146.55°EBindaree — 37.76°S, 147.11°EXishancun — 25.49°N, 103.80°ETaldysai — 48.13°N, 67.77°ETaldysai — 49.31°N, 68.59°ETaldysai — 50.83°N, 75.57°ETaldysai — 49.24°N, 68.48°ERousay — 59.04°N, 2.87°WRousay — 59.07°N, 2.80°WRousay — 58.89°N, 2.82°WRousay — 58.78°N, 2.93°WRousay — 59.25°N, 2.87°WRousay — 59.25°N, 2.88°WRousay — 59.19°N, 2.70°WBurtnieki — 58.10°N, 25.55°ENarva — 57.55°N, 25.29°EXujiachong — 25.59°N, 103.81°EXujiachong — 25.57°N, 103.74°EXujiachong — 25.50°N, 102.43°ECuche — 6.58°N, 75.67°WCuche — 5.14°N, 72.17°WNarva — 59.38°N, 28.19°EAruküla — 59.37°N, 25.08°EAruküla — 57.55°N, 25.28°EDankov-Lebedyan Beds — 52.97°N, 36.07°ETiaomajian — 27.75°N, 111.75°EBac Bun — 21.68°N, 106.56°EJiucheng — 25.53°N, 102.40°ELybster Flagstone — 58.47°N, 3.46°WLybster Flagstone — 57.83°N, 4.18°WLybster Flagstone — 57.68°N, 2.34°WLybster Flagstone — 57.64°N, 3.03°WKetleri — 56.70°N, 22.13°EKetleri — 56.59°N, 22.01°ETonggangling — 22.27°N, 109.97°ELeikutai — 34.00°N, 118.00°E

Loading coastlines…

The named rock units Antiarchi has been recovered from, largest first. Drawn where the rock is now, not where it formed. 134 further formations hold fewer occurrences each and are not listed. 42 occurrences have no formation on record, which is common for older literature.

Antiarchi and its relatives

Devonian

Where Antiarchi and its relatives were recorded in the Devonian.

Found in the same rock

1,252 taxa

The Paleobiology Database records 260 sites for Antiarchi, 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

157 references

Each of the 411 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. 145 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 content1

Picture of Antiarchi

Credit
Hectonichus
Licence
CC BY-SA 3.0
Commercial use
the licence allows it

No 3D scan of Antiarchi was found in MorphoSource and Sketchfab.

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 itPlacodermi through timeFormations of the DevonianThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. (Cope 1885)