Helodus

Helodus is an extinct genus of cartilaginous fish, with fossils belonging to the genus identified from the Late Devonian to the Early Permian periods. While the type species, H. simplex from the Late Carboniferous of England is known from articulated specimens, all other Helodus species are known only from isolated teeth. Over 70 species have been attributed to this genus based on these indistinct bead-like teeth, which likely belong to many different unrelated groups of fish in the subclass Holocephali. This makes Helodus as broadly defined a wastebasket taxon, and only the type species can be confidently attributed to this genus. The genus is the sole member of the family Helodontidae and the order Helodontiformes.

Helodus

Wayne M. Itano and Lance L. Lambert · 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
HelodontidaePBDB
Diet
carnivorePBDB, for Holocephali
Life habit
nektobenthicPBDB, for Holocephali
Motility
actively mobilePBDB, for Holocephali

Time the record covers

At least 70 million years on record.

The record covers at least 330.3 Mya to 259.857 Mya. No occurrence read is dated outside 358.86 Mya to 251.902 Mya.

Devonian — about 0 of 31 occurrencesCarboniferous — about 16 of 31 occurrencesCarboniferousPermian — about 15 of 31 occurrencesPermianEarly Triassic — about 0 of 31 occurrences361–357 Mya — about 0.3 occurrences357–354 Mya — about 0.8 occurrences354–350 Mya — about 0.8 occurrences350–346 Mya — about 0.8 occurrences346–342 Mya — about 0.8 occurrences342–339 Mya — about 0.8 occurrences339–335 Mya — about 0.8 occurrences335–331 Mya — about 1 occurrence331–328 Mya — about 1 occurrence328–324 Mya — about 1 occurrence324–320 Mya — about 0.3 occurrences320–317 Mya — about 1 occurrence317–313 Mya — about 1 occurrence313–309 Mya — about 2 occurrences309–305 Mya — about 2 occurrences305–302 Mya — about 1 occurrence302–298 Mya — about 0.1 occurrences298–294 Mya — about 0.1 occurrences294–291 Mya — about 0.1 occurrences291–287 Mya — about 0.6 occurrences287–283 Mya — about 0.6 occurrences283–279 Mya — about 0.1 occurrences279–276 Mya — about 0.1 occurrences276–272 Mya — about 1 occurrence272–268 Mya — about 2 occurrences268–265 Mya — about 1 occurrence265–261 Mya — about 0.6 occurrences261–257 Mya — about 4 occurrences257–253 Mya — about 4 occurrences253–250 Mya — about 0.2 occurrences330.3 Mya259.857 Mya361 Mya250 Mya

31 occurrences of Helodus on record, most of them in the Carboniferous. 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

31 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

Phosphoria — 43.35°N, 109.40°WPhosphoria — 42.75°N, 108.80°WPhosphoria — 43.19°N, 109.16°WPhosphoria — 43.38°N, 109.45°WPhosphoria — 43.54°N, 108.70°WPark City — 43.54°N, 108.70°WPark City — 43.19°N, 109.16°WTunnel Mountain — 50.48°N, 114.71°WCoolkilya — 23.84°S, 114.46°EGarber Sandstone — 34.58°N, 98.85°WNaujoji Akmenė — 56.33°N, 22.95°EMattoon — 38.44°N, 87.86°WLimestone Coal — 55.92°N, 4.33°WBlack Rock Limestone — 51.46°N, 2.63°WMospyne — 48.24°N, 39.30°E

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The named rock units Helodus has been recovered from, largest first. Drawn where the rock is now, not where it formed. 12 occurrences have no formation on record, which is common for older literature.

Helodus and its relatives

Carboniferous

Where Helodus and its relatives were recorded in the Carboniferous.

Found in the same rock

196 taxa

The Paleobiology Database records 26 sites for Helodus, 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

15 references

Each of the 31 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. 3 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 Helodus

Credit
Wayne M. Itano and Lance L. Lambert
Licence
CC BY 4.0
Commercial use
the licence allows it

No 3D scan of Helodus 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 itHelodontidae through timeFormations of the CarboniferousThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Agassiz 1838