Acanthothoraci

Acanthothoraci is an extinct group of chimaera-like placoderms closely related to the rhenanid placoderms. Superficially, the acanthoracids resembled scaly chimaeras and (relatively) heavily armored ptyctodonts. They were distinguished from chimaeras by their large scales and plates, a pair of large spines that emanate from their chests, tooth-like beak plates, and the typical bone-enhanced placoderm eyeball. They were distinguished from other placoderms by differences in skull anatomy and by patterns on the skull plates and thoracic plates that are unique to this order.

Acanthothoraci

Apokryltaros at English Wikipedia · CC BY 2.5 · 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 28 million years on record.

The record covers at least 416.8 Mya to 387.95 Mya. No occurrence read is dated outside 419.62 Mya to 382.31 Mya.

Silurian — about 0 of 19 occurrencesDevonian — about 19 of 19 occurrencesDevonian420–419 Mya — about 1 occurrence419–418 Mya — about 3 occurrences418–416 Mya — about 2 occurrences416–415 Mya — about 1 occurrence415–414 Mya — about 1 occurrence414–413 Mya — about 1 occurrence413–411 Mya — about 0.7 occurrences411–410 Mya — about 0.6 occurrences410–409 Mya — about 0.4 occurrences409–407 Mya — about 0.4 occurrences407–406 Mya — about 0.4 occurrences406–405 Mya — about 0.4 occurrences405–404 Mya — about 0.4 occurrences404–402 Mya — about 0.4 occurrences402–401 Mya — about 0.4 occurrences401–400 Mya — about 0.4 occurrences400–398 Mya — about 0.6 occurrences398–397 Mya — about 0.6 occurrences397–396 Mya — about 0.6 occurrences396–394 Mya — about 0.6 occurrences394–393 Mya — about 0.5 occurrences388–387 Mya — about 0.2 occurrences387–385 Mya — about 0.2 occurrences385–384 Mya — about 0.2 occurrences384–383 Mya — about 0.2 occurrences383–382 Mya — about 0.1 occurrences416.8 Mya387.95 Mya420.4 Mya381.6 Mya

19 occurrences of Acanthothoraci on record, most of them in the Devonian. 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

19 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

10 formations

Radotin Limestone — 49.99°N, 14.34°EDrake Bay — 73.44°N, 101.29°WDrake Bay — 73.50°N, 100.00°WMurrindal — 37.46°S, 148.20°EFukuji — 36.23°N, 137.53°ERoad River — 63.33°N, 126.81°WJauf — 28.38°N, 37.69°EDzhalpak — 40.47°N, 66.13°EVechernin — 63.57°N, 149.36°ETaemas — 34.96°S, 148.81°EDong Tho — 17.65°N, 106.51°E

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The named rock units Acanthothoraci has been recovered from, largest first. Drawn where the rock is now, not where it formed. 3 occurrences have no formation on record, which is common for older literature.

Acanthothoraci and its relatives

Devonian

Where Acanthothoraci and its relatives were recorded in the Devonian.

Found in the same rock

253 taxa

The Paleobiology Database records 15 sites for Acanthothoraci, 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

14 references

Each of the 19 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. 2 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 Acanthothoraci

Credit
Apokryltaros at English Wikipedia
Licence
CC BY 2.5
Commercial use
the licence allows it

No 3D scan of Acanthothoraci 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 itPlacodermi through timeFormations of the DevonianThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Stensiö 1944