Featured Research

from universities, journals, and other organizations

Multiple species of seacows once coexisted

Date:
March 8, 2012
Source:
Smithsonian
Summary:
Sirenians, or seacows, are a group of marine mammals that include manatees and dugongs; Today, only one species of seacow is found in each world region. Scientists have discovered that this was not always the case. According to the fossil record of these marine mammals, which dates back 50 million years ago, it was more common to find three, or possibly more, different species of seacows living together at one time.

Sirenians, or seacows, are a group of marine mammals that include manatees and dugongs; today, only one species of seacow is found in each world region. Smithsonian scientists have discovered that this was not always the case.
Credit: Carl Buell

Sirenians, or seacows, are a group of marine mammals that include manatees and dugongs; today, only one species of seacow is found in each world region. Smithsonian scientists have discovered that this was not always the case. According to the fossil record of these marine mammals, which dates back 50 million years ago, it was more common to find three, or possibly more, different species of seacows living together at one time. This suggests that the environment and food sources for ancient seacows were also different than today.

Related Articles


The team's findings are published in the journal PLoS ONE.

Today there are only four species of seacows―three species of manatees, which are found in different coastal waters of the Atlantic Ocean, and one species of dugong, found along the coasts of the Indo-Pacific Ocean. All seacows are herbivores, and their diet is made up largely of seagrasses.

"The discovery that these multispecies seacow communities once existed revealed answers, but it also created new questions," said Nicholas Pyenson, curator of fossil marine mammals at the Smithsonian's National Museum of Natural History and co-author of the research. "Were these species competing against each other for seagrass resources, or were they avoiding competition by each species feeding in separate areas or on different grasses? Also, were seagrass beds structured differently in the past, or were they dominated by one seagrass species like we see today?"

To answer these questions, the team, lead by Smithsonian predoctoral fellow Jorge Velez-Juarbe, examined three localities from separate time periods, from the late Oligocene (about 23-28 million year ago) in Florida, the early Miocene (about 16-23 million years ago) in India and the early Pliocene (about 3-5 million years ago) in Mexico. All three areas showed conclusive fossil evidence that two or more species of seacow had once coexisted there.

By examining the size and dimensions of the skulls as well as estimating the body sizes, the team deduced that the different species of seacows had characteristics that allowed each to feed on different types of seagrass. Such separation among physical features, the team suggests, reduced any competition for food and allowed multiple species of seacows to coexist. This also suggests that, unlike today's seacow habitats that are dominated by one or two species of seagrass, many species of seagrass once coexisted.


Story Source:

The above story is based on materials provided by Smithsonian. Note: Materials may be edited for content and length.


Journal Reference:

  1. Jorge Velez-Juarbe, Daryl P. Domning, Nicholas D. Pyenson. Iterative Evolution of Sympatric Seacow (Dugongidae, Sirenia) Assemblages during the Past ∼26 Million Years. PLoS ONE, 2012; 7 (2): e31294 DOI: 10.1371/journal.pone.0031294

Cite This Page:

Smithsonian. "Multiple species of seacows once coexisted." ScienceDaily. ScienceDaily, 8 March 2012. <www.sciencedaily.com/releases/2012/03/120308143241.htm>.
Smithsonian. (2012, March 8). Multiple species of seacows once coexisted. ScienceDaily. Retrieved February 28, 2015 from www.sciencedaily.com/releases/2012/03/120308143241.htm
Smithsonian. "Multiple species of seacows once coexisted." ScienceDaily. www.sciencedaily.com/releases/2012/03/120308143241.htm (accessed February 28, 2015).

Share This


More From ScienceDaily



More Plants & Animals News

Saturday, February 28, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Whale-Watching Scientists Spot Baby Orca

Whale-Watching Scientists Spot Baby Orca

AP (Feb. 28, 2015) Researchers following endangered killer whales spotted a baby orca off the coast of Washington state, the third birth documented this winter but still leaving the population dangerously low. (Feb. 28) Video provided by AP
Powered by NewsLook.com
The Best Drinks for Your Health

The Best Drinks for Your Health

Buzz60 (Feb. 27, 2015) When it comes to health and fitness, there&apos;s lots of talk about what foods to eat, but there are a few liquids that can promote good nutrition. Krystin Goodwin (@krystingoodwin) has the healthiest drinks to boost your health! Video provided by Buzz60
Powered by NewsLook.com
Cherries, Snap Peas and More Tasty Spring Produce

Cherries, Snap Peas and More Tasty Spring Produce

Buzz60 (Feb. 27, 2015) From sweet cherries to sugar snap peas, spring is the peak season for some of the tastiest and healthiest produce. Krystin Goodwin (@Krystingoodwin) has the best seasonal fruits and veggies to spring in to good health! Video provided by Buzz60
Powered by NewsLook.com
The Best Foods to Battle Stress

The Best Foods to Battle Stress

Buzz60 (Feb. 26, 2015) If you&apos;re dealing with anxiety, there are a few foods that can help. Krystin Goodwin (@krystingoodwin) has the best foods to tame stress. Video provided by Buzz60
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins