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Big Gulp?Neck ribs may havegiven aquatic beastunique feeding style

The fossilized neck bones of a 230-million-year-old sea creature have features sug-gesting that the animal’s snakelike throatcould flare open and create suction thatwould pull in prey. Such a feeding strategyhas never before been proposed for anancient aquatic reptile.

Paleontologists working in southernChina recently unearthed the partialremains of Dinocephalosaurus orientalis,which translates as “terrible-headed lizardfrom the Orient.” The trunk of the creature’sbody was less than 1 meter long, but its neckhad 25 vertebrae and measured 1.7 m, saysOlivier Rieppel, a paleontologist at the FieldMuseum in Chicago. Like other membersof the reptile group called protorosaurs,Dinocephalosaurus had thin bones, or cer-vical ribs, attached to and extending along-side its neck vertebrae.

“At first glance, those ribs would seem tomake the neck stiff and inflexible,” saysMichael C. LaBarbera of the University ofChicago. The presence of certain protrusionson the cervical ribs, however, suggest toLaBarbera and his coworkers that the bonesserved in hunting. When Dinocephalosaurusthrust forward its head to capture prey, mus-cles that connected the cervical ribs to theneck vertebrae contracted, splaying the ribsand increasing the internal diameter of theanimal’s esophagus, says Rieppel. That cre-ated suction that pulled water and prey intoDinocephalosaurus’ maw.

Rieppel, LaBarbera, and Chun Li of theInstitute of Vertebrate Paleontology andPaleoanthropology in Beijing describe theiranalysis of the fossil in the Sept. 24 Science.

Most modern fish and some aquatic rep-tiles, such as snapping turtles, take their preyvia mouth suction. The suction results whenmuscles in the animals’ mouths rapidly pulldown the tongue and floor of the oral cavity.

Expansion of the entire throat, as pro-posed for Dinocephalosaurus, could havecreated a much stronger suction, accord-

ing to P. Martin Sander, a paleontologist atthe University of Bonn in Germany. In otherprotorosaurs, cervical ribs spanned severalvertebrae and probably weren’t as mobileas they were in Dinocephalosaurus.

“This is an intriguing fossil,” says NicholasC. Fraser, a paleontologist at the VirginiaMuseum of Natural History in Mar-tinsville. The feeding style proposed forDinocephalosaurus is a “plausible solutionfor why this animal had such a strangeneck,” Fraser says. He adds that the pro-posal remains speculative because the fos-sils don’t indicate where muscles attachedto the neck vertebrae or the cervical ribs.

The bones in the fossil’s skull and spinewere fully ossified, but the bones in thecreature’s feet were only partially ossified,says Rieppel. Moreover, the protrusionswhere foot muscles would have attachedwere relatively small.

The fossil’s bone-ossification pattern andunusually small foot-muscle attachment sitesmatch those characteristics in modernaquatic reptiles, such as sea turtles, and there-fore suggest that the Dinocephalosaurus leda fully aquatic lifestyle.

The newly described specimen ofDinocephalosaurus was found in limestonelaid down as sediments in an ancient sub-tropical ocean. Although the predator prob-ably inhabited shallow waters near theshoreline, the researchers conclude that itsremains came to rest at an offshore site atleast 200 m deep. Waters of that depth wouldhave protected the carcass from wave actionthat might otherwise have torn it apart.

Long-necked aquatic creatures such asDinocephalosaurus presumably were wellcamouflaged because, in dim or murkywaters, the true bulk of an approachingpredator could be hidden from the view ofprey. Several independent lineages of seabeasts evolved long necks, either by attain-

ing additional vertebrae in the neck, asDinocephalosaurus did, or by growinglonger neck bones. —S. PERKINS

Sleep on ItFitful slumber tied to diabetes risk

Many people have brief bouts of inter-rupted breathing during the night thatcause fluctuations in blood pressure andheart rate, decreased concentrations of oxy-gen in the blood, and other effects. Smallstudies have implicated this disturbed slum-ber, known as sleep apnea, in the develop-ment of diabetes and other chronic diseases(SN: 7/14/01, p. 31).

Now, the results of a large study led byNaresh M. Punjabi of the Johns HopkinsMedical Institutions link apnea with twoconditions—glucose intolerance andimpaired insulin function—that are asso-ciated with the onset of type 2 diabetes. “Wethink the sleep problems are more likelycontributing to glucose intolerance and dia-betes instead of those conditions explain-ing the apnea,” says coauthor Rachel Givel-ber of the University of Pittsburgh.

The findings, which appear in the Sept. 15American Journal of Epidemiology, couldhave important implications for identify-ing and managing diabetes, says Givelber.“Based on this study,” she says, “if you haveglucose intolerance or diabetes, it might bewise to treat the sleep [apnea] because thatmay be contributing to the condition.”

Sleep apnea, often accompanied by loudsnoring (SN: 3/11/00, p. 172), occursbecause the airways narrow as the sur-rounding muscles relax during sleep.

In their investigation, the researchers ana-

THAT’S A STRETCH Features of the fossilized neck bones of Dinocephalosaurus suggest thatthe creature, at least 3 meters long, captured its prey by creating water suction as it struck.

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