February 4, 2009

Chemical Ecology

Reptile Bouquet

A bounty of greasy molecules make up the personal cologne of the ancient tuatara

Michael Jacob Photography EAU DE TUATARA A cornucopia of more than 150 molecules, including the newly identified tuataric acid, are produced in the skin glands of the ancient tuatara.

Researchers peeking into the skin glands of the tuatara, a reptile with an ancient lineage, are reporting that it contains an unexpectedly diverse cocktail of chemicals that may help the beast communicate and fight skin fungi. The work could also provide new clues to reptilian evolution.

More than 150 different greasy glyceride-based molecules are produced by the tuatara, the only existing member of a reptile order called the Rynchocephalia, which thrived some 200 million years ago. The tuatara now mostly burrows in the wilds of New Zealand (Chem. Biodiversity 2009, 6, 1).

Stefan Schulz, a chemist at the University of Braunschweig, in Germany, and collaborator Paul J. Weldon at the Smithsonian Institution, in Washington, D.C., say they identified an unexpectedly diverse assortment of chemical combinations made from glycerol and short-chain fatty acids, including a never-before-seen molecule that they dubbed tuataric acid. "No other vertebrate skin gland produces such a structurally diverse array of glycerides," Schulz says.

Because every tuatara produces the skin glycerides in unique relative concentrations, the molecules may play a role in identifying individual tuataras or in territorial marking. Schulz also proposes that free acids released during the degradation of the glycerides could have antifungal activity. But these conclusions remain provisional pending behavioral studies on the tuatara, Schulz adds.

"This is a fine first step, but it is only half the story, since what we really need to know is the biological roles of these lipids," chemical ecologist Jerrold Meinwald of Cornell University comments. "So the chemistry is ahead of the biology, but it is still a good start."