Heptanema

Heptanema is an extinct genus of prehistoric marine coelacanth from the Triassic of Europe. It contains a single species, H. paradoxa from the Middle Triassic (Ladinian)-aged deposits of Monte San Giorgio, in both northern Italy and southern Switzerland. Its placement has been long uncertain, leading to it being excluded from many fossil phylogenies, but a 2025 study found strong evidence for it being a mawsoniid closely related to the freshwater Diplurus of North America.

Heptanema

Giulio de Alessandri (died in 1921) · 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
ActinistiaPBDB
Motility
actively mobilePBDB, for Osteichthyes

Time the record covers

At most 4.5 million years on record.

Every occurrence read is dated to somewhere between 241.464 Mya and 237 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 TriassicLate Triassic — about 0 of 3 occurrences242–241 Mya — about 0.0 occurrences241–241 Mya — about 0.1 occurrences241–241 Mya — about 0.1 occurrences241–241 Mya — about 0.1 occurrences241–241 Mya — about 0.1 occurrences241–241 Mya — about 0.1 occurrences241–240 Mya — about 0.1 occurrences240–240 Mya — about 0.1 occurrences240–240 Mya — about 0.1 occurrences240–240 Mya — about 0.1 occurrences240–240 Mya — about 0.1 occurrences240–239 Mya — about 0.1 occurrences239–239 Mya — about 0.1 occurrences239–239 Mya — about 0.1 occurrences239–239 Mya — about 0.1 occurrences239–239 Mya — about 0.1 occurrences239–239 Mya — about 0.1 occurrences239–238 Mya — about 0.1 occurrences238–238 Mya — about 0.1 occurrences238–238 Mya — about 0.1 occurrences238–238 Mya — about 0.1 occurrences238–238 Mya — about 0.1 occurrences238–237 Mya — about 0.1 occurrences237–237 Mya — about 0.1 occurrences237–237 Mya — about 0.1 occurrences237–237 Mya — about 0.0 occurrences242 Mya236.5 Mya

3 occurrences of Heptanema 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

Meride — 45.90°N, 8.94°EPerledo-Varenna — 46.02°N, 9.30°E

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

Heptanema and its relatives

Middle Triassic

Where Heptanema and its relatives were recorded in the Middle Triassic.

Found in the same rock

15 taxa

The Paleobiology Database records 3 sites for Heptanema, 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

3 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. 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 Heptanema

Credit
Giulio de Alessandri (died in 1921)
Licence
Public Domain
Commercial use
the licence allows it

No 3D scan of Heptanema 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 itActinistia through timeFormations of the Middle TriassicThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Belloti 1857