Squalus

Squalus is a genus of dogfish sharks in the family Squalidae. Commonly known as spurdogs, these sharks are characterized by smooth dorsal fin spines, teeth in upper and lower jaws similar in size, caudal peduncle with lateral keels; upper precaudal pit usually present, and caudal fin without subterminal notch. In spurdogs, the hyomandibula is oriented at a right angle to the neurocranium, while in other sharks, the hyomandibula runs more parallel to the body. This led some to think that the upper jaw of Squalus would not be as protractile as the jaws of other sharks. However, a study that compared different jaw suspension types in sharks showed that this is not the case and that Squalus is quite capable of protruding its upper jaw during feeding.

A picture published with the record for Squalus.

Uncredited · Public Domain · via Wikidata/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
SqualidaePBDB
Diet
carnivorePBDB, for Squaliformes
Life habit
nektonicPBDB, for Squaliformes
Motility
actively mobilePBDB, for Squaliformes

Time the record covers

At least 161 million years on record.

The record covers at least 161.5 Mya to 11.7 ka. No occurrence read is dated outside 165.3 Mya to 0 Mya.

Middle Jurassic — about 1 of 333 occurrencesLate Jurassic — about 0 of 333 occurrencesEarly Cretaceous — about 0 of 333 occurrencesLate Cretaceous — about 67 of 333 occurrencesLate CretaceousPaleocene — about 43 of 333 occurrencesEocene — about 58 of 333 occurrencesEoceneOligocene — about 90 of 333 occurrencesMiocene — about 59 of 333 occurrencesMiocenePliocene — about 9 of 333 occurrencesPleistocene — about 5 of 333 occurrences169–163 Mya — about 0.6 occurrences163–157 Mya — about 0.4 occurrences101–96 Mya — about 2 occurrences96–90 Mya — about 2 occurrences90–84 Mya — about 1 occurrence84–79 Mya — about 11 occurrences79–73 Mya — about 12 occurrences73–67 Mya — about 30 occurrences67–62 Mya — about 25 occurrences62–56 Mya — about 25 occurrences56–51 Mya — about 12 occurrences51–45 Mya — about 11 occurrences45–39 Mya — about 19 occurrences39–34 Mya — about 19 occurrences34–28 Mya — about 71 occurrences28–22 Mya — about 18 occurrences22–17 Mya — about 14 occurrences17–11 Mya — about 30 occurrences11–5.6 Mya — about 14 occurrences5.6–0 Mya — about 16 occurrences161.5 Mya11.7 ka169 Mya0 Mya

333 occurrences of Squalus on record, most of them in the Oligocene. The Paleobiology Database records this as a living group. 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

333 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

106 formations

Boom Clay — 51.13°N, 4.26°EBoom Clay — 51.12°N, 4.35°EBoom Clay — 51.19°N, 4.32°EBoom Clay — 51.16°N, 4.13°ELa Meseta — 64.24°S, 56.60°WLa Meseta — 64.24°S, 56.66°WMesaverde — 44.08°N, 107.74°WMesaverde — 44.10°N, 107.75°WMesaverde — 44.17°N, 107.81°WFox Hills — 46.47°N, 99.58°WFox Hills — 46.38°N, 100.85°WSables de Bracheux — 49.58°N, 2.65°ESables de Bracheux — 49.53°N, 2.75°EDongen — 52.73°N, 6.30°EDongen — 53.16°N, 6.22°ETuffeau de St-Omer — 50.53°N, 3.15°ETuffeau de St-Omer — 50.44°N, 3.07°ELondon Clay — 51.40°N, 0.83°ELondon Clay — 51.51°N, 0.24°ELondon Clay — 51.38°N, 0.24°WLondon Clay — 50.78°N, 0.65°WBerchem — 51.20°N, 4.44°ENorthumberland — 49.55°N, 124.70°WNorthumberland — 49.54°N, 124.71°WGerhartsreit — 47.80°N, 12.62°EHornerstown — 40.10°N, 73.00°WHornerstown — 39.76°N, 75.13°WYamaga — 33.99°N, 130.82°EBreda — 51.97°N, 6.73°EBreda — 52.15°N, 6.61°EBreda — 51.47°N, 5.80°EOiching — 47.94°N, 13.01°EHannut — 50.71°N, 5.00°EHeers — 50.71°N, 4.99°EHeers — 50.10°N, 5.00°ENavidad — 33.91°S, 71.85°WByala — 42.88°N, 27.90°ESubmeseta — 64.23°S, 56.60°WEarnley — 51.08°N, 1.17°WElmore — 50.80°N, 1.20°WSelsey — 50.80°N, 1.21°WEntre Rios — 33.72°S, 59.25°W

Loading coastlines…

The named rock units Squalus has been recovered from, largest first. Drawn where the rock is now, not where it formed. 82 further formations hold fewer occurrences each and are not listed. 57 occurrences have no formation on record, which is common for older literature.

Squalus and its relatives

Oligocene

Where Squalus and its relatives were recorded in the Oligocene.

Found in the same rock

2,886 taxa

The Paleobiology Database records 294 sites for Squalus, and this reads 240 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

129 references

Each of the 333 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. 117 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 Squalus

Credit
nobody named on the record
Licence
Public Domain
Commercial use
the licence allows it

CT scan

Licence
In Copyright
Commercial use
cannot be read from the licence given — check the record
Specimen
Squalus acanthias · 3DAS:00003

3D model

Source
Sketchfab
Licence
CC Attribution
Commercial use
cannot be read from the licence given — check the record

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 itSqualidae through timeFormations of the OligoceneThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Linnaeus 1758