Isistius

Isistius is a genus of dogfish sharks in the family Dalatiidae. They are commonly known as cookiecutter sharks. Members of the genus are known for their unusual behaviour and dentition.

Isistius

NOAA Observer Project · 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
DalatiidaePBDB
Diet
carnivorePBDB, for Squaliformes
Life habit
nektonicPBDB, for Squaliformes
Motility
actively mobilePBDB, for Squaliformes

Time the record covers

At least 50 million years on record.

The record covers at least 56 Mya to 5.333 Mya. No occurrence read is dated outside 59.24 Mya to 1.8 Mya.

Paleocene — about 1 of 90 occurrencesEocene — about 53 of 90 occurrencesEoceneOligocene — about 0 of 90 occurrencesMiocene — about 30 of 90 occurrencesMiocenePliocene — about 6 of 90 occurrencesPleistocene — about 0 of 90 occurrences60–58 Mya — about 0.3 occurrences58–56 Mya — about 0.6 occurrences56–54 Mya — about 4 occurrences54–52 Mya — about 5 occurrences52–50 Mya — about 5 occurrences50–48 Mya — about 5 occurrences48–46 Mya — about 7 occurrences46–44 Mya — about 8 occurrences44–42 Mya — about 8 occurrences42–40 Mya — about 6 occurrences40–38 Mya — about 1 occurrence38–36 Mya — about 1 occurrence36–35 Mya — about 1 occurrence35–33 Mya — about 0.3 occurrences25–23 Mya — about 0.1 occurrences23–21 Mya — about 0.3 occurrences21–19 Mya — about 3 occurrences19–17 Mya — about 3 occurrences17–15 Mya — about 5 occurrences15–13 Mya — about 7 occurrences13–11 Mya — about 5 occurrences11–8.6 Mya — about 2 occurrences8.6–6.6 Mya — about 2 occurrences6.6–4.6 Mya — about 4 occurrences4.6–2.6 Mya — about 4 occurrences2.6–651 ka Mya — about 0.3 occurrences56 Mya5.333 Mya60 Mya651 ka

90 occurrences of Isistius on record, most of them in the Eocene. 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

90 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

35 formations

Dongen — 52.73°N, 6.30°EDongen — 53.16°N, 6.22°EDongen — 52.12°N, 6.72°ELondon Clay — 51.51°N, 0.24°ELondon Clay — 51.62°N, 0.07°WLondon Clay — 51.40°N, 0.83°ELondon Clay — 50.78°N, 0.65°WSelsey — 50.80°N, 1.21°WOnzole — 0.63°S, 80.47°WOnzole — 0.60°S, 80.45°WOnzole — 0.97°N, 79.61°WNeuhofen — 48.50°N, 14.28°EJoe's River — 13.22°N, 59.55°WOsinovaya — 48.36°N, 41.85°EOsinovaya — 48.46°N, 41.83°EMarnes de Miretrain — 43.69°N, 1.13°WGatun — 9.35°N, 79.80°WElmore — 50.80°N, 1.21°WFilakovo — 48.31°N, 19.70°ERishtan — 41.65°N, 64.69°EYorktown — 35.36°N, 76.82°WMiretrain Marl — 43.57°N, 1.11°WNanjemoy — 38.28°N, 77.37°WUscari — 9.57°N, 82.57°WChagres Sandstone — 9.28°N, 80.04°WLodo — 36.61°N, 120.68°WSenhata — 35.16°N, 139.86°EAchen — 47.88°N, 12.27°EPétervására — 48.24°N, 19.66°EKuma — 45.10°N, 34.63°EBuchak — 49.53°N, 39.07°EGuayacán — 10.01°N, 83.53°W

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The named rock units Isistius has been recovered from, largest first. Drawn where the rock is now, not where it formed. 11 further formations hold fewer occurrences each and are not listed. 19 occurrences have no formation on record, which is common for older literature.

Isistius and its relatives

Eocene

Where Isistius and its relatives were recorded in the Eocene.

Found in the same rock

1,256 taxa

The Paleobiology Database records 88 sites for Isistius, 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

44 references

Each of the 90 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. 32 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 content3

Picture of Isistius

Credit
NOAA Observer Project
Licence
Public Domain
Commercial use
the licence allows it

CT scan

Licence
not stated by the source
Commercial use
cannot be read from the licence given — check the record
Specimen
Isistius brasiliensis · UF:Fish:79884

3D model

Source
Sketchfab
Licence
CC Attribution-NonCommercial
Commercial use
the licence does not allow it

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 itDalatiidae through timeFormations of the EoceneThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Gill 1864