Pezosiren

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title: "Pezosiren" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["eocene-mammals-of-north-america", "eocene-sirenians", "transitional-fossils", "prehistoric-placental-genera", "fossil-taxa-described-in-2001", "paleogene-jamaica", "fossils-of-jamaica"] description: "Prehistoric amphibious mammal" topic_path: "general/eocene-mammals-of-north-america" source: "https://en.wikipedia.org/wiki/Pezosiren" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Prehistoric amphibious mammal ::

| fossil_range = Early Eocene (Lutetian), | image = Dans l'ombre des dinosaures - Pezosiren - 016.jpg | image_caption = Mounted skeleton | genus = Pezosiren | parent_authority = Domning, 2001 | species = portelli | authority = Domning, 2001

Pezosiren portelli, also known as the "walking manatee", is a basal sirenian from the early Eocene of Jamaica, 50 million years ago. The type specimen is represented by a Jamaican fossil skeleton, described in 2001 by Daryl Domning,{{Cite journal | last = Domning | first = D. P. | title = The earliest known fully quadrupedal sirenians | journal = Nature | volume = 413 | issue = 6856| pages = 625–627 | publisher = Nature Publishing Group | date = 2001-10-11 | doi = 10.1038/35098072 | pmid=11675784| bibcode = 2001Natur.413..625D | s2cid = 22005691

Discovery

::figure[src="https://upload.wikimedia.org/wikipedia/commons/3/3e/Pezosiren_clean.png" caption="''P. portelli'' cast skeleton produced and distributed by [[Triebold Paleontology Incorporated"] ::

In the 1990s, vertebrate fossils were found in lagoon deposits at Seven Rivers in Jamaica by Daryl Domning and colleagues. The site is rich in fossils, and yielded hundreds of bones of mainly aquatic vertebrates, a primitive rhinoceros, and possibly a primate. In 2001, Domning named Pezosiren portelli based on sirenian bones found at Seven Rivers.

The Seven Rivers site is not only one of the very rare examples of a noncave deposit in the West Indies, but also the oldest discovered so far, with an age of late Early or early Middle Eocene, as attributed by Robinson in 1988.{{Cite journal | last = Robinson | first = E. | title = Late Cretaceous and early Tertiary sedimentary rocks of the Central Inlier, Jamaica | journal = Journal of the Geological Society of Jamaica | volume = 24 | pages = 49–67 | date = 1988 }} The presence of Pezosiren in Jamaica can be explained as evidence of an Eocene land bridge connecting North America, the Mexican Arc, the Chortis Block, the Nicaragua Rise, and Jamaica. Whatever might be the origin of this sirenian, it had no further impact in the history of the Antillean mammals, because Jamaica became submerged soon after and with it any terrestrial forms. The rest of the accompanying fossil fauna consists mainly of aquatic vertebrates—fishes, crocodilians, and turtles- and a rhinocerotid species (Hyrachyus).{{Cite journal | last = Domning | first = D. P. |author2=Emry, R. J. |author3=Portell, R. W. |author4=Donovan, S. K. |author5=Schindler, K. S. | title = Oldest West Indian Land Mammal: Rhinocerotoid Ungulate from the Eocene of Jamaica | journal = Journal of Vertebrate Paleontology | volume = 17 | issue = 4 | pages = 638–641 | publisher = Society of Vertebrate Paleontology | date = December 1997 | doi = 10.1080/02724634.1997.10011013 | jstor=4523853| bibcode = 1997JVPal..17..638D }}

Description

::figure[src="https://upload.wikimedia.org/wikipedia/commons/c/c7/Eocene_sirenians_size_comparison.png" caption="Drawing of swimming ''Pezosiren'' (blue) compared to some other Eocene sirenian taxa."] ::

So far, Pezosiren are not known from a single complete skeleton. The original description is based on several partial skeletons and “several hundred” isolated cranial and postcranial elements collected from three different bone beds within the Chapelton Formation. Domning had been looking at sirenian fossils from five different bone beds within a 5 meters thick stratigraphic section of the formation and concluded that remains in the three lower bone beds "appear to represent a single taxon". From these, an almost complete skeleton was composed, only missing most of the feet and the tail. It was the first known quadrupedal sirenian.

The remains of Pezosiren indicate that while it had four limbs adapted to walking on land, the skull, teeth, and heavy ribs are more typical of modern sirenians, such as manatees and dugongs. The living animal is estimated to have been "pig-sized", or roughly 2 meters long (depending on the length of its tail).

Based on the known tail vertebrae, researchers argue that Pezosiren, like its European relative Sobrarbesiren, did not use the tail to propel in the water, but rather used its hind limbs in a mode similar to otters.

References

References

1. Díaz-Berenguer E, Badiola A, Moreno-Azanza M & Canudo J.I., 2018, "First adequately-known quadrupedal sirenian from Eurasia (Eocene, Bay of Biscay, Huesca, northeastern Spain)", ''Scientific Reports'' '''8''': 5127: doi.org/10.1038/s41598-018-23355-w
2. ''Pezosiren'': from [[Greek language. Greek]] {{lang. grc. πεζός (''pezos''), 'on foot', 'walking', and {{lang. grc. Σειρήν (''Seirēn'', Latinized to ''Siren''), 'siren' (Domning 2001, p. 625).
3. Prothero, Donald R. 2007. ''Evolution: What the Fossils Say and Why It Matters''. With original illustrations by Carl Buell. New York, Columbia University Press.
4. Díaz-Berenguer E, Houssaye A, Badiola A & Canudo1 J.I., “The Hind Limbs of ''Sobrarbesiren cardieli'' (Eocene, Northeastern Spain) and New Insights into the Locomotion Capabilities of the Quadrupedal Sirenians”, ''Journal of Mammalian Evolution'' (6/9/2019): doi.org/10.1007/s10914-019-09482-9

::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::