"Long before it's in the papers"
January 27, 2015


Scientists report first “semiaquatic” dino, larger than T. rex

Sept. 11, 2014
Courtesy of the National Geographic Society
and World Science staff

A di­no­saur dis­cov­ered over a cen­tu­ry ago turns out to have probably been “semi­aquat­ic”—the only known di­no­saur adapted for liv­ing and hunt­ing in a wa­ter en­vi­ron­ment, sci­en­tists say.

Ac­cord­ing to the re­port, new fos­sils of the huge pred­a­tor re­veal it adapted to life in the wa­ter some 95 mil­lion years ago, pro­vid­ing the strongest ev­i­dence to da­te of a di­no­saur able to live and hunt in an aquat­ic en­vi­ron­ment.

A dig­it­al skele­tal re­con­struc­tion of Sp­ino­sau­rus. The light gray out­line in­di­cates where the flesh would have been. The re­con­struc­tion is a com­pos­ite of bones from dif­fer­ent fos­sils. The bones col­ored blue are mis­sing bones that are in­ferred. (Mod­el by T. Keil­lor, L. Con­roy, & E. Fitz­ger­ald; cour­te­sy Ibra­him et al., Sci­ence)

“Work­ing on this an­i­mal was like stu­dy­ing an al­ien from out­er space; it’s un­like any oth­er di­no­saur I have ev­er seen,” said lead au­thor Ni­zar Ibra­him, of the Uni­vers­ity of Chica­go. 

The di­no­saur, Spi­no­sau­rus ae­gyp­ti­a­cus, lived to­ward the end of the age of the di­no­saurs in what is to­day North Af­ri­ca. The beast is es­ti­mat­ed to have been more than nine feet long­er than the larg­est known Ty­ran­no­saur­us rex spec­i­men.

“In the last two dec­ades, sev­eral finds dem­on­strat­ed that cer­tain di­no­saurs gave ori­gins to birds. Spi­no­sau­rus rep­re­sents an equally bi­zarre ev­o­lu­tion­ary pro­cess, re­vealing that pred­a­tory di­no­saurs adapted to a semia­quat­ic life and in­vad­ed riv­er sys­tems,” added Cris­tiano Dal Sasso of the Nat­u­ral His­to­ry Mu­se­um in Mi­lan, It­a­ly, a mem­ber of the re­search team.

The find­ings are pub­lished Sept. 11 in the re­search jour­nal Sci­ence and fea­tured in the Oc­to­ber Na­t­ional Ge­o­graph­ic mag­a­zine co­ver sto­ry. The an­i­mal is al­so the sub­ject of a new ex­hi­bi­tion at the Na­t­ional Ge­o­graph­ic Mu­se­um, open­ing Sept. 12, as well as a Na­t­ional Ge­o­graph­ic/NOVA spe­cial air­ing on PBS Nov. 5 at 9 p.m.

The re­search­ers con­clud­ed that Spi­no­sau­rus de­vel­oped ma­ny pre­vi­ously un­known adapta­t­ions to live in the wa­ter. They an­a­lyzed new fos­sils un­co­vered in the Mo­roc­can Sa­hara, a par­tial skull and oth­er re­mains housed in mu­se­ums around the world as well as his­tor­i­cal records and im­ages from the first re­ported Spi­no­sau­rus  disco­very in Egypt. 

Spi­no­sau­rus had ear­li­er rel­a­tives that ate fish but that lived on land, sci­en­tists said. Spi­no­sau­rus’ aquat­ic adapta­t­ions are said to go a good deal fur­ther. 

Artist's re­con­struc­tion of Spi­no­saur­us. (Cour­te­sy of NGS)

These in­clud­ed: small nos­trils at mid-skull, so it could breath with its head part­ly sub­merged; small open­ings at the end of the snout, like in crocodiles, that may have ena­bled it to sense wa­ter move­ment; gi­ant, slanted teeth well-suit­ed for catch­ing fish; a long neck and trunk that made walk­ing on land nearly im­pos­si­ble but facilita­ted move­ment in wa­ter; short hind legs with mus­cu­lar thighs, good for pad­dling; long, flat claws si­m­i­lar to those of shore birds, pos­sibly sup­port­ing webbed feet; loosely con­nect­ed tail bones so its tail could bend in a wave-like ma­n­ner; and im­mense, skin-co­vered spines that crea­ted a gi­gantic “sail” on the back. That was likely meant for dis­play and would have been vis­i­ble even when the an­i­mal en­tered the wa­ter, ac­cord­ing to the re­search­ers.

More than a cen­tu­ry ago, Ger­man pa­le­on­tol­ogist Ernst Frei­herr Stromer von Rei­chen­bach first dis­cov­ered ev­i­dence of Spi­no­sau­rus in the Egyptian Sa­hara. Sad­ly, all of Stromer’s fos­sils were de­stroyed dur­ing the April 1944 Al­lied bomb­ing of Mu­nich, Ger­ma­ny. Ibra­him, howev­er, tracked down Stromer’s sur­viv­ing notes, sketches and pho­tos in ar­chives and at the Stromer family cas­tle in Ba­var­ia to sup­ple­ment Stromer’s sur­viv­ing pub­lica­t­ions.

New Spi­no­sau­rus fos­sils were dis­cov­ered in the Mo­roc­can Sa­hara along des­ert cliffs known as the Kem Kem beds. This ar­ea was once a large riv­er sys­tem, stretch­ing from pre­s­ent-day Mo­roc­co to Egypt. At the time, a va­ri­e­ty of aquat­ic life popula­ted the sys­tem, in­clud­ing large sharks, coela­canths, lung­fish and crocodile-like crea­tures, along with gi­ant fly­ing rep­tiles and pred­a­tory di­no­saurs.

The most im­por­tant of the new fos­sils, a par­tial ske­l­e­ton found by a lo­cal fos­sil hunt­er, was spir­it­ed out of the coun­try, the sci­en­tists said. As a re­sult, crit­i­cal in­forma­t­ion about the con­text of the find was seem­ingly lost, and lo­cat­ing the lo­cal fos­sil hunt­er in Mo­roc­co was nearly im­pos­si­ble. “It was like search­ing for a nee­dle in a des­ert,” said Ibra­him, but af­ter a long search he fi­nally found the man and con­firmed the site of the find.

* * *

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A dinosaur discovered over a century ago turns out to have probably been “semiaquatic”—the only known dinosaur adapted for living and hunting in a water environment, scientists say. According to the report, new fossils of the huge predator reveal it adapted to life in the water some 95 million years ago, providing the strongest evidence to date of a dinosaur able to live and hunt in an aquatic environment. “Working on this animal was like studying an alien from outer space; it’s unlike any other dinosaur I have ever seen,” said lead author Nizar Ibrahim, of the University of Chicago. The dinosaur, Spinosaurus aegyptiacus, lived toward the end of the age of the dinosaurs in what is today North Africa. The beast is estimated to have been more than nine feet longer than the largest known Tyrannosaurus rex specimen. “In the last two decades, several finds demonstrated that certain dinosaurs gave origins to birds. Spinosaurus represents an equally bizarre evolutionary process, revealing that predatory dinosaurs adapted to a semiaquatic life and invaded river systems,” added Cristiano Dal Sasso of the Natural History Museum in Milan, Italy, a member of the research team. The findings are published Sept. 11 in the research journal Science and featured in the October National Geographic magazine cover story. The animal is also the subject of a new exhibition at the National Geographic Museum, opening Sept. 12, as well as a National Geographic/NOVA special airing on PBS Nov. 5 at 9 p.m. The researchers concluded that Spinosaurus developed many previously unknown adaptations to live in the water. They analyzed new fossils uncovered in the Moroccan Sahara, a partial skull and other remains housed in museums around the world as well as historical records and images from the first reported Spinosaurus discovery in Egypt. Spinosaurus had earlier relatives that lived on land but ate fish, scientists said, but Spinosaurus’ aquatic adaptations went further. These included: small nostrils at mid-skull, so it could breath with its head partway underwater; small openings at the end of the snout, like in crocodiles, that may have enabled it to sense water movement; giant, slanted teeth well-suited for catching fish; a long neck and trunk that made walking on land nearly impossible but facilitated movement in water; short hind legs with muscular thighs, good for paddling; long, flat claws similar to those of shore birds, possibly supporting webbed feet; loosely connected tail bones so its tail could bend in a wave-like manner; and immense, skin-covered spines that created a gigantic “sail” on the back. That was likely meant for display and would have been visible even when the animal entered the water, according to the researchers. More than a century ago, German paleontologist Ernst Freiherr Stromer von Reichenbach first discovered evidence of Spinosaurus in the Egyptian Sahara. Sadly, all of Stromer’s fossils were destroyed during the April 1944 Allied bombing of Munich, Germany. Ibrahim, however, was able to track down Stromer’s surviving notes, sketches and photos in archives and at the Stromer family castle in Bavaria to supplement Stromer’s surviving publications. New Spinosaurus fossils were discovered in the Moroccan Sahara along desert cliffs known as the Kem Kem beds. This area was once a large river system, stretching from present-day Morocco to Egypt. At the time, a variety of aquatic life populated the system, including large sharks, coelacanths, lungfish and crocodile-like creatures, along with giant flying reptiles and predatory dinosaurs. The most important of the new fossils, a partial skeleton uncovered by a local fossil hunter, was spirited out of the country, the scientists said. As a result, critical information about the context of the find was seemingly lost, and locating the local fossil hunter in Morocco was nearly impossible. Remarked Ibrahim, “It was like searching for a needle in a desert.” After a long search, Ibrahim said he finally found the man and confirmed the site of his original discovery.