Featured Research

from universities, journals, and other organizations

Warm-blooded marine reptiles at the time of the dinosaurs

Date:
June 15, 2010
Source:
CNRS (Délégation Paris Michel-Ange)
Summary:
Between 200 and 65 million years ago, fearsome marine reptiles reigned over the oceans. Were they warm-blooded like today's mammals and birds or cold-blooded like nowadays fish and reptiles? For the first time, a study has settled the debate: some large marine reptiles were warm-blooded (in other words, they were endothermic), giving them a considerable advantage to swim fast over long distances and to conquer cold regions.

Artist's impression (A. Bénéteau) of an ichthyosaur (Platypterygius). Ichthyosaurs had very obvious aquatic adaptations with an anatomy recalling that of a dolphin but with the caudal fin of a fish (oriented vertically or not horizontally as in Cetacea).
Credit: Copyright PEPS (CNRS/Université de Lyon 1)

Between 200 and 65 million years ago, fearsome marine reptiles reigned over the oceans. Were they warm-blooded like today's mammals and birds or cold-blooded like nowadays fish and reptiles? For the first time, a study has settled the debate: some large marine reptiles were warm-blooded (in other words, they were endothermic), giving them a considerable advantage to swim fast over long distances and to conquer cold regions.

Related Articles


This work, conducted by researchers from the Laboratoire PaléoEnvironnements et PaléobioSphère (PEPS, CNRS/Université de Lyon 1) in collaboration with scientists from the Muséum National d'Histoire Naturelle and the École Normale Supérieure, has been published in the journal Science on 11 June 2010.

During the Mesozoic era (between 200 and 65 million years ago), when dinosaurs roamed the continents, fearsome predatory reptiles such as ichthyosaurs, plesiosaurs and mosasaurs reigned over the oceans. How did these large marine reptiles regulate their temperature? This question, linked to body temperature and thermoregulation processes, is essential in deciphering the feeding, ecology and evolution strategies of these now disappeared vertebrates.

To determine the body temperature of certain marine reptiles, a French team of geochemists and paleontologists(1) used, for the first time, the compositions of stable oxygen isotopes (18O/16O) in the phosphate of their skeletons. The researchers analyzed the dental remains of three major groups of large marine reptiles: ichthyosaurs, plesiosaurs and mosasaurs. They compared the 18O/16O ratio present in the tooth enamel of these reptiles to that of fish remains from the same period, found at the same latitudes. Fish, which are cold-blooded animals (ectotherms), have an isotopic composition that reflects the temperature of the sea water in which they live. In fish, the 18O/16O ratio increases as the temperature of the ocean decreases. The differences in isotopic composition between marine reptiles and fish that lived in the same body of water reflect the differences in their body temperatures.

The researchers found that the body temperature of the studied reptiles was constant, whatever the water temperature. Thus, ichthyosaurs and plesiosaurs regulated their body temperature independently of sea water temperature within a temperature range from around 12 degrees (±2°C) to around 36 degrees (±2°C). In the case of the three large groups of reptiles studied, the body temperature estimations lie between 35 and 39°C (±2°C).

Some large marine reptiles, now extinct, were thus capable of maintaining a higher body temperature than that of their living environment, suggesting a high metabolism adapted to predation and fast swimming over long distances, even in cold water. These animals consequently had an "endothermic" metabolism (i.e. capable of producing heat), similar to that of present day Cetacea. How and from what point these warm-blooded animals produced such energy remains to be determined.

(1) Researchers from the Laboratoire PEPS (CNRS/Université de Lyon 1), the Centre de Recherche sur la Paléobiodiversité et les Paléoenvironnements (CNRS/MNHN/UPMC) and the Laboratoire de Géologie de l'École Normale Supérieure (CNRS/ENS)


Story Source:

The above story is based on materials provided by CNRS (Délégation Paris Michel-Ange). Note: Materials may be edited for content and length.


Journal Reference:

  1. A. Bernard, C. Lecuyer, P. Vincent, R. Amiot, N. Bardet, E. Buffetaut, G. Cuny, F. Fourel, F. Martineau, J.-M. Mazin, A. Prieur. Regulation of Body Temperature by Some Mesozoic Marine Reptiles. Science, 2010; 328 (5984): 1379 DOI: 10.1126/science.1187443

Cite This Page:

CNRS (Délégation Paris Michel-Ange). "Warm-blooded marine reptiles at the time of the dinosaurs." ScienceDaily. ScienceDaily, 15 June 2010. <www.sciencedaily.com/releases/2010/06/100614093341.htm>.
CNRS (Délégation Paris Michel-Ange). (2010, June 15). Warm-blooded marine reptiles at the time of the dinosaurs. ScienceDaily. Retrieved December 20, 2014 from www.sciencedaily.com/releases/2010/06/100614093341.htm
CNRS (Délégation Paris Michel-Ange). "Warm-blooded marine reptiles at the time of the dinosaurs." ScienceDaily. www.sciencedaily.com/releases/2010/06/100614093341.htm (accessed December 20, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Saturday, December 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Researchers Test Colombian Village With High Alzheimer's Rates

Researchers Test Colombian Village With High Alzheimer's Rates

AFP (Dec. 19, 2014) — In Yarumal, a village in N. Colombia, Alzheimer's has ravaged a disproportionately large number of families. A genetic "curse" that may pave the way for research on how to treat the disease that claims a new victim every four seconds. Duration: 02:42 Video provided by AFP
Powered by NewsLook.com
Monarch Butterflies Descend Upon Mexican Forest During Annual Migration

Monarch Butterflies Descend Upon Mexican Forest During Annual Migration

Reuters - Light News Video Online (Dec. 19, 2014) — Millions of monarch butterflies begin to descend onto Mexico as part of their annual migration south. Rough Cut (no reporter narration) Video provided by Reuters
Powered by NewsLook.com
Birds Might Be Better Meteorologists Than Us

Birds Might Be Better Meteorologists Than Us

Newsy (Dec. 19, 2014) — A new study suggests a certain type of bird was able to sense a tornado outbreak that moved through the U.S. a day before it hit. Video provided by Newsy
Powered by NewsLook.com
Navy Unveils Robot Fish

Navy Unveils Robot Fish

Reuters - Light News Video Online (Dec. 18, 2014) — The U.S. Navy unveils an underwater device that mimics the movement of a fish. Tara Cleary reports. Video provided by Reuters
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