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Too valuable to lose: Extinct relative reveals rarity of last two remaining monk seal species

By Micaela Jemison

This illustration of the extinct Caribbean Monk seal was done by artist Peter Schouten.

This illustration of the extinct Caribbean monk seal was done by artist Peter Schouten.

A newly released study focusing on an extinct species, the Caribbean monk seal (Monachus tropicalis), has revealed just how evolutionarily unique its only two living relatives, the endangered Mediterranean and Hawaiian monk seals, truly are.

DNA analysis and skull comparisons by Smithsonian scientists and colleagues show the Caribbean and Hawaiian species together represent a new genus, long isolated from other seals. As a result, the Mediterranean and Hawaiian monk seals are the last and only living species of long separated branches on the seal family tree.

This is the first new genus recognized among modern pinnipeds (seals, sea lions, and walruses) in more than 140 years. The team’s findings are published in the scientific journal ZooKeys.

First reported by Christopher Columbus in 1494, the Caribbean monk seal once ranged throughout the Caribbean with an estimated population in the hundreds of thousands. Unrestricted hunting led to its eventual extinction by the 1950s. Monk seals, as a group, are unusual among seals in being adapted for life in warm water.

With the Caribbean species now extinct, the Hawaiian monk seal is the last surviving species of the genus Neomonachus, as the Mediterranean species is in its genus, Monachus. Only about 1,200 Hawaiian seals are left and the Mediterranean monk seal is even more rare with a population of  fewer than 600.

A Hawaiian Monk seal and her pup. (Photo by Tom Elliot)

A Hawaiian monk seal and her pup. (Photo by Tom Elliot)

Specimens of the Caribbean monk seal are today found only in museum collections, the largest sample residing in the Smithsonian’s National Museum of Natural History. Studying the remains of these seals and their relatives led to this new discovery by several Smithsonian scientists, including Kris Helgen, curator of mammals; Graham Slater, Peter Buck post doctoral fellow;, Charley Potter, collection manager of Marine Mammals; and their colleagues..

“The DNA extracted from the century-old monk seal skins in the museum’s collection showed us that the Caribbean species was more closely related to the Hawaiian rather than the Mediterranean monk seal,” Helgen explains.

The genetic work was conducted in collaboration with scientists at the Leibniz Institute of Zoo and Wildlife Research in Germany and Fordham University in New York. Major genetic distinctions, along with the morphological differences Slater found between the Mediterranean species and the two New World species (Caribbean and Hawaiian), led the team to classify the Caribbean and Hawaiian monk seals in the a newly named genus, Neomonachus.

Diorama with a Mediterranean Monk seal at the The Natural history museum in Milan, Italy. (Photo: Giovanni Dall'Orto)

Diorama with a Mediterranean monk seal at the The Natural History Museum in Milan, Italy. (Photo: Giovanni Dall’Orto)

“We occasionally identify new species of larger mammals, like the olinguito we announced last year,” Slater says. “But to be able to name a new genus, and a seal genus at that, is incredibly rare and a great honor.”

Beyond the reclassification, the study has also shed light on how the evolution of the Caribbean and Hawaiian monk seals directly relates to a major geological event.

“The Caribbean and Hawaiian monk seals split into distinct species around 3 to 4 million years ago,” Slater explains. “This is about the same time the Panamanian Isthmus, the bridge between North and South America, closed off the connection between the Atlantic and Pacific Oceans, which would have naturally separated the two.”

With both species being listed as “critically endangered” by the International Union for Conservation of Nature, this discovery has real implications for the conservation of both species.

“This work has really upped the stakes in terms of trying to conserve these species,” says Charles Littnan, lead scientist for the NOAA Fisheries Hawaiian Monk Seal Research Program. “There are multiple groups working across the planet trying to save the Mediterranean and Hawaiian monk seals. We were hoping to save both species, or at least one of them, to maintain some legacy of the Monachus genus on the planet. But now, as a result of this paper, we now know they are different lineages, and are both too valuable to lose.”

Paper link: “Biogeography and taxonomy of extinct and endangered monk seals illuminated by ancient DNA and skull morphology,” ZooKeys 409 (2014): 1-33, by Dirk-Martin Scheel, Graham Slater, Sergios-Orestis Kolokotronis, Charles Potter, David Rotstein, Kyriakos Tsangaras, Alex Greenwood and Kristofer M. Helgen.



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  • Ralph Huggler

    I am familiar with Harbor seals having seen them in early spring while digging clams in the great South Bay of Long Island, NY. I now reside in Florida.
    The encounter I had with what I believe to be a Caribbean Monk Seal was not a Harbor seal and does not resemble any seal searched for in all archives available on the net. It did resemble a Harbor Seal in size and shape with mottled skin coloring though a little darker. The difference between this seal and all others was that it had very large bulbous eyes about the size of a large mans closed fist. They are round, deep black and protrude from the face about 2″ to 2 1/2″.
    My encounter happened 2013 while body surfing near shore about 16 miles south of Cape Canaveral and lasted about 15 seconds. The creature must have been curious as to what I was and perhaps I could be a mate as seals are known to frolic in surf. It surfaced about 8 feet away from me and we stared at each other for what seemed like half a minute but was probably 15 seconds or so. I did not have another close encounter but did spy it the next 2 days.
    The other thing that stood out to me was the speed at which it moved. Following the day of the encounter I watched it move along parallel to the beach popping up from time to time. I estimate the speed at nearly 45 MPH.
    Haven’t seen it since and it was alone for the 3 days observed.

  • Bernard McKenna

    Back in July of 2000, I watched two seals swimming near the dock adjacent to a friend’s apartment in Miami, north shore of the Bay, near the Venetian Causeway. There were clearly seals. I had seen seals in the West of Ireland when I lived in Galway. These were different.They were bigger. I have also seen manatees and the creatures I saw were not manatees.

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