Semirostrum ceruttii

Semirostrum ceruttii is an extinct porpoise that lived between 5 and 1.5 million years ago (Ma), during the Pliocene epoch. The species is highly distinctive due to the extremely long symphysis on the lower jaw, reaching lengths of 85 centimeters (33.46 in), while that of a modern porpoise is 1–2 centimeters (0.39–0.79 in) long. The main hypothesis regarding its use is that it probed along the sediment in the murky estuaries and shores of what is now California in search of food, which would easily be scooped up the symphysis and into the jaws. It is the only known species in the genus Semirostrum. The etymology of the name means "half beak", referring to the upper jaw being half the length of the lower.

Semirostrum ceruttii

doryfour · CC BY-SA 2.0 · 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
SemirostrumPBDB
Diet
piscivorePBDB, for Phocoenidae
Life habit
aquatic, depth=surfacePBDB, for Cetacea
Motility
actively mobilePBDB, for Cetacea
Environment
marine,freshwaterPBDB, for Odontoceti

Time the record covers

At most 2.8 million years on record.

Every occurrence read is dated to somewhere between 5.333 Mya and 2.58 Mya, and nothing in the dating separates them, so that window is what the record shows rather than a span.

Miocene — about 0 of 3 occurrencesPliocene — about 3 of 3 occurrencesPliocenePleistocene — about 0 of 3 occurrences5.3–5.2 Mya — about 0.1 occurrences5.2–5.1 Mya — about 0.1 occurrences5.1–5.0 Mya — about 0.1 occurrences5.0–4.8 Mya — about 0.1 occurrences4.8–4.7 Mya — about 0.1 occurrences4.7–4.6 Mya — about 0.1 occurrences4.6–4.5 Mya — about 0.1 occurrences4.5–4.3 Mya — about 0.1 occurrences4.3–4.2 Mya — about 0.1 occurrences4.2–4.1 Mya — about 0.1 occurrences4.1–4.0 Mya — about 0.1 occurrences4.0–3.8 Mya — about 0.1 occurrences3.8–3.7 Mya — about 0.1 occurrences3.7–3.6 Mya — about 0.1 occurrences3.6–3.5 Mya — about 0.2 occurrences3.5–3.3 Mya — about 0.2 occurrences3.3–3.2 Mya — about 0.2 occurrences3.2–3.1 Mya — about 0.2 occurrences3.1–3.0 Mya — about 0.2 occurrences3.0–2.8 Mya — about 0.2 occurrences2.8–2.7 Mya — about 0.2 occurrences2.7–2.6 Mya — about 0.2 occurrences2.6–2.5 Mya — about 0.0 occurrences5.83 Mya2.08 Mya

3 occurrences of Semirostrum ceruttii on record, most of them in the Pliocene. 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

Purisima — 37.29°N, 122.41°WPurisima — 36.98°N, 121.95°WSan Diego — 32.64°N, 117.03°W

Loading coastlines…

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

Semirostrum ceruttii and its relatives

Pliocene

Where Semirostrum ceruttii and its relatives were recorded in the Pliocene.

Found in the same rock

No other named taxon is catalogued from any of those sites.

The Paleobiology Database records 3 sites for Semirostrum ceruttii, and this reads all of them.

Entered from

1 reference

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 doi.org. Relayed as the Paleobiology Database holds them, not checked against what they resolve to.

Media and terms

Media content1

Picture of Semirostrum ceruttii

Credit
doryfour
Licence
CC BY-SA 2.0
Commercial use
the licence allows it

No 3D scan of Semirostrum ceruttii 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 itSemirostrum through timeFormations of the PlioceneThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Racicot et al. 2014