Hydrodamalis

Hydrodamalis is a genus of extinct herbivorous sirenian marine mammals. It included the Steller's sea cow, the Cuesta sea cow, and the Takikawa sea cow. The fossil genus Dusisiren is regarded as the sister taxon of Hydrodamalis: together, the two genera form the dugong subfamily Hydrodamalinae. They were the largest member of the order Sirenia, whose only extant members are the dugong and the manatees. They reached up to 9 metres (30 ft) in length, making the Steller's sea cow among the largest mammals other than whales to have existed in the Holocene epoch. Steller's sea cow was first described by Georg Wilhelm Steller, Cuesta by Daryl Domning, and Takikawa by Hitoshi Furusawa. The Steller's sea cow was the only member of the genus to survive into modern times, and, although had formerly been abundant throughout the North Pacific, by the mid 1700s, its range had been limited to a single, isolated population surrounding the uninhabited Commander Islands. It was hunted for its meat, skin, and fat by fur traders, and was also hunted by aboriginals of the North Pacific coast, leading to its and the genus' extinction 27 years after discovery. The Cuesta sea cow along with the Takikawa sea cow were probably extinct at the end of the Pliocene due to the onset of the Ice Ages and the subsequent recession of seagrasses—their main food source.

Hydrodamalis

Daderot · CC0 · 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
Also called
Steller's sea cowPBDB
Sits inside
HydrodamalinaePBDB
Diet
herbivorePBDB, for Dugongidae
Life habit
aquaticPBDB, for Sirenia
Motility
actively mobilePBDB, for Osteichthyes
Environment
marinePBDB, for Sirenia

Time the record covers

At least 7.2 million years on record.

The record covers at least 7.246 Mya to 11.7 ka. No occurrence read is dated outside 11.63 Mya to 0 Mya.

Miocene — about 4 of 49 occurrencesMiocenePliocene — about 23 of 49 occurrencesPliocenePleistocene — about 14 of 49 occurrencesPleistoceneHolocene — about 8 of 49 occurrences12–11 Mya — about 0.1 occurrences11–11 Mya — about 0.2 occurrences11–11 Mya — about 0.2 occurrences11–10 Mya — about 0.2 occurrences10–9.7 Mya — about 0.2 occurrences9.7–9.3 Mya — about 0.2 occurrences9.3–8.9 Mya — about 0.3 occurrences8.9–8.5 Mya — about 0.3 occurrences8.5–8.1 Mya — about 0.3 occurrences8.1–7.7 Mya — about 0.3 occurrences7.7–7.3 Mya — about 0.3 occurrences7.3–6.9 Mya — about 0.3 occurrences6.9–6.5 Mya — about 0.3 occurrences6.5–6.1 Mya — about 0.3 occurrences6.1–5.7 Mya — about 0.3 occurrences5.7–5.3 Mya — about 0.6 occurrences5.3–4.9 Mya — about 2 occurrences4.9–4.4 Mya — about 2 occurrences4.4–4.0 Mya — about 2 occurrences4.0–3.6 Mya — about 2 occurrences3.6–3.2 Mya — about 5 occurrences3.2–2.8 Mya — about 6 occurrences2.8–2.4 Mya — about 4 occurrences2.4–2.0 Mya — about 2 occurrences2.0–1.6 Mya — about 2 occurrences1.6–1.2 Mya — about 2 occurrences1.2–809 ka Mya — about 2 occurrences809 ka–404 ka Mya — about 2 occurrences404 ka–0 Mya — about 13 occurrences7.246 Mya11.7 ka12.1 Mya0 Mya

49 occurrences of Hydrodamalis 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

49 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

15 formations

San Mateo — 33.20°N, 117.37°WSan Mateo — 33.26°N, 117.30°WCapistrano — 33.56°N, 117.71°WCapistrano — 33.55°N, 117.71°WSarumaru — 36.67°N, 138.07°EShimonopporo — 43.15°N, 141.51°EShimonopporo — 42.81°N, 141.54°EPismo — 35.17°N, 120.73°WSan Diego — 32.48°N, 117.00°WSouth Bight II — 51.54°N, 178.98°ESan Diego — 32.90°N, 117.10°WHorokaoshirarika — 43.84°N, 141.88°EMandano — 35.34°N, 140.15°EIimuro — 35.62°N, 139.57°EShiroiwa — 37.34°N, 138.83°ETamari — 34.77°N, 138.02°ENakawatari — 38.77°N, 140.15°EToyama — 42.97°N, 141.22°E

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The named rock units Hydrodamalis has been recovered from, largest first. Drawn where the rock is now, not where it formed. 26 occurrences have no formation on record, which is common for older literature.

Hydrodamalis and its relatives

Pliocene

Where Hydrodamalis and its relatives were recorded in the Pliocene.

Found in the same rock

211 taxa

The Paleobiology Database records 48 sites for Hydrodamalis, 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

21 references

Each of the 49 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. 9 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 Hydrodamalis

Credit
Daderot
Licence
CC0
Commercial use
the licence allows it

Laser scan

Licence
In Copyright
Commercial use
cannot be read from the licence given — check the record
Specimen
Hydrodamalis Hydrodamalis gigas · mvz:mammal specimens:107764

3D model

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

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 itHydrodamalinae through timeFormations of the PlioceneThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Retzius 1794