Megalonyx

Megalonyx is an extinct genus of ground sloths of the family Megalonychidae, native to North America. It evolved during the Pliocene Epoch and became extinct at the end of the Late Pleistocene, living from ~5 million to ~13,000 years ago. The type species, M. jeffersonii, the youngest and largest known species, measured about 3 m (9.8 ft) in length and weighed up to nearly 1,300 kg (2,900 lb).

Megalonyx

Jonathan Chen · CC BY-SA 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
MegalonychinaePBDB
Diet
herbivorePBDB, for Megalonychidae
Life habit
ground dwellingPBDB, for Megalonychidae
Motility
actively mobilePBDB, for Osteichthyes
Environment
terrestrialPBDB, for Eutheria

Time the record covers

At least 4.5 million years on record.

The record covers at least 4.7 Mya to 129 ka. No occurrence read is dated outside 9.4 Mya to 0 Mya.

Miocene — about 20 of 168 occurrencesMiocenePliocene — about 30 of 168 occurrencesPliocenePleistocene — about 118 of 168 occurrencesPleistoceneHolocene — about 0 of 168 occurrences9.6–9.2 Mya — about 0.8 occurrences9.2–8.9 Mya — about 2 occurrences8.9–8.6 Mya — about 2 occurrences8.6–8.3 Mya — about 2 occurrences8.3–7.9 Mya — about 2 occurrences7.9–7.6 Mya — about 2 occurrences7.6–7.3 Mya — about 2 occurrences7.3–6.9 Mya — about 2 occurrences6.9–6.6 Mya — about 2 occurrences6.6–6.3 Mya — about 2 occurrences6.3–5.9 Mya — about 2 occurrences5.9–5.6 Mya — about 2 occurrences5.6–5.3 Mya — about 2 occurrences5.3–5.0 Mya — about 2 occurrences5.0–4.6 Mya — about 2 occurrences4.6–4.3 Mya — about 4 occurrences4.3–4.0 Mya — about 4 occurrences4.0–3.6 Mya — about 4 occurrences3.6–3.3 Mya — about 5 occurrences3.3–3.0 Mya — about 5 occurrences3.0–2.6 Mya — about 5 occurrences2.6–2.3 Mya — about 7 occurrences2.3–2.0 Mya — about 7 occurrences2.0–1.6 Mya — about 7 occurrences1.6–1.3 Mya — about 7 occurrences1.3–990 ka Mya — about 11 occurrences990 ka–660 ka Mya — about 12 occurrences660 ka–330 ka Mya — about 13 occurrences330 ka–0 Mya — about 55 occurrences4.7 Mya129 ka9.9 Mya0 Mya

168 occurrences of Megalonyx on record, most of them in the Pleistocene. 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

168 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

43 formations

Palm Spring — 32.90°N, 117.10°WSnake Creek — 42.40°N, 103.80°WSan Timoteo — 33.90°N, 117.00°WTamiami — 27.37°N, 82.45°WTamiami — 27.30°N, 80.80°WTamiami — 27.78°N, 82.68°WBlanco — 33.81°N, 101.21°WBlanco — 33.70°N, 101.10°WPalos Verdes Sand — 34.00°N, 118.20°WPalos Verdes Sand — 33.60°N, 117.80°WAsh Hollow — 42.70°N, 100.00°WAsh Hollow — 41.30°N, 101.89°WGila Conglomerate — 32.90°N, 109.10°WGila Conglomerate — 32.70°N, 109.00°WRexroad — 37.20°N, 100.30°WCrooked Creek — 37.20°N, 100.30°WRingold — 47.00°N, 118.50°WRingold — 46.30°N, 119.10°WMcPherson — 38.30°N, 97.60°WSan Pedro — 33.75°N, 118.28°WLadson — 32.98°N, 80.04°WLadson — 32.02°N, 80.04°WOgallala — 36.70°N, 101.40°WRancho Viejo Beds — 21.08°N, 100.67°WRattlesnake — 44.50°N, 119.30°WAlkali Canyon — 45.84°N, 119.29°WMehrten — 37.30°N, 120.60°WPinole Tuff — 37.97°N, 122.25°WSan Diego — 32.90°N, 117.10°WTemecula Arkose — 33.90°N, 117.00°WGlenns Ferry — 42.82°N, 114.94°WLong Pine — 42.38°N, 98.23°W

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The named rock units Megalonyx has been recovered from, largest first. Drawn where the rock is now, not where it formed. 19 further formations hold fewer occurrences each and are not listed. 100 occurrences have no formation on record, which is common for older literature.

Megalonyx and its relatives

Pleistocene

Where Megalonyx and its relatives were recorded in the Pleistocene.

Found in the same rock

1,422 taxa

The Paleobiology Database records 162 sites for Megalonyx, 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

112 references

Each of the 168 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. 100 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 Megalonyx

Credit
Jonathan Chen
Licence
CC BY-SA 4.0
Commercial use
the licence allows it

Laser scan

Licence
In Copyright
Commercial use
cannot be read from the licence given — check the record
Specimen
Megalonyx jeffersoni · ansp:vp:12507

3D model

Source
Sketchfab
Licence
CC0 Public Domain
Commercial use
the licence allows 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 itMegalonychinae through timeFormations of the PleistoceneThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Jefferson 1799