Acronemus tuberculatus

Acronemus is an extinct genus of euselachian from the Middle Triassic of Switzerland. It is an enigmatic genus with uncertain relations to other groups. Though originally placed within Ctenacanthiformes, it is now considered Euselachii incertae sedis, due to its mixture of features similar to hybodontiforms and neoselachians. Originally, teeth from this genus were attributed to "Acrodus bicarinatus" while fin spines were named "Nemacanthus tuberculatus". Associated material showed they were the same animal, with the older specific epithet (tuberculatus) taking precedence. The euselachian was given the new genus Acrocnemus, containing a single species. Acronemus is found in the Anisian-age Grenzbitumenzone of Monte San Giorgio. It was a small animal measuring 30–35 cm (0.98–1.15 ft) long. A 2018 study considered it to be closely related to the early Carboniferous genus Tristychius as part of the family Tristychiidae as a basal euselachian, with hybodonts more closely related to neoselachians than to Tristychiidae.

Acronemus tuberculatus

Neil Pezzoni · 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
Sits inside
AcronemusPBDB
Diet
carnivorePBDB, for Chondrichthyes
Life habit
nektonicPBDB, for Chondrichthyes
Motility
actively mobilePBDB, for Chondrichthyes

Time the record covers

At most 2 million years on record.

Every occurrence read is dated to somewhere between 243.43 Mya and 241.464 Mya, and nothing in the dating separates them, so that window is what the record shows rather than a span.

Middle Triassic — about 3 of 3 occurrencesMiddle Triassic243–243 Mya — about 0.1 occurrences243–243 Mya — about 0.2 occurrences243–243 Mya — about 0.2 occurrences243–243 Mya — about 0.2 occurrences243–243 Mya — about 0.2 occurrences243–243 Mya — about 0.2 occurrences243–243 Mya — about 0.2 occurrences243–243 Mya — about 0.2 occurrences243–243 Mya — about 0.2 occurrences243–242 Mya — about 0.2 occurrences242–242 Mya — about 0.2 occurrences242–242 Mya — about 0.2 occurrences242–242 Mya — about 0.2 occurrences242–242 Mya — about 0.2 occurrences242–242 Mya — about 0.2 occurrences242–242 Mya — about 0.2 occurrences242–242 Mya — about 0.2 occurrences242–242 Mya — about 0.2 occurrences242–242 Mya — about 0.2 occurrences242–241 Mya — about 0.1 occurrences243.93 Mya240.96 Mya

3 occurrences of Acronemus tuberculatus on record, most of them in the Middle Triassic. 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

3 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

2 formations

Besano — 45.89°N, 8.90°EBesano — 45.91°N, 8.95°E

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The named rock units Acronemus tuberculatus has been recovered from, largest first. Drawn where the rock is now, not where it formed.

Acronemus tuberculatus and its relatives

Middle Triassic

Where Acronemus tuberculatus and its relatives were recorded in the Middle Triassic.

Found in the same rock

23 taxa

The Paleobiology Database records 2 sites for Acronemus tuberculatus, and this reads all of them. The number is how many of those sites it was catalogued from too.

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

2 references

Each of the 3 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. Each entry links to the Paleobiology Database's own record for the work.

Media and terms

Media content1

Picture of Acronemus tuberculatus

Credit
Neil Pezzoni
Licence
CC BY 4.0
Commercial use
the licence allows it

No 3D scan of Acronemus tuberculatus 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 itAcronemus through timeFormations of the Middle TriassicThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. (Bassani 1886)