News for Schools from the Smithsonian Institution. Office of Elementary and Secondary Education. Washington, D.C. 20560

April 1992

Continued on page 2

This huge

red mudstone about sixfeet wide and three feetdeep. They theorized thatthe red mudstone bowlcould have been a nest forthe babies. It looked as if ithad been made by thebabies' mother who hadmounded up the earth andscooped out the middle.They believed the greenmudstone had filled thenest during the manymillions of years since thebabies had died.When Horner finisheddigging through the smallmound, he had found theremains of 15 three-foot­long baby dinosaurs.(Adult hadrosaurs of thetype found in this nestgrow to be 25-30 feetlong.) These were not 15complete skeletons. Theywere disconnected bonesbelonging to 15 babieswho had died in the nestand whose skeletons hadbeen subjected to time andweather until they fellapart; then they werefossilized.

John Horner had manyquestions about these babydinosaurs. Reading thesequestions and learningabout how he answeredthem will help you

understand how a paleontologist thinks. If you hadmade this discovery, what would your questions havebeen?

First, Horner wondered if these were babies'remains or the remains of another kind of very smalldinosaur such as Microvenator, who was 3-5 feet longwhen full grown and weighed a mere 12-15 pounds. Inorder to answer his questions, he had to "read" theevidence found at the site: the number, condition, andplacement of the bones, and the soil type. The firstthing he did was to look at the development of thebones. His close examination told him that these wereindeed the bones of baby dinosaurs. The signs that heread were found in the vertebrae (bones of the spine)near the base of the spine. These vertebrae were notyet fused together as they are in mature dinosaurs.When he saw that the ends of the limb bones were notfUlly formed either, Horner knew these were theremains of very young dinosaurs.

But these were not merely newborn babies who hadmet sudden death right after their birth. Homer

. found a sign of their age from a sourcethat yields a great deal ofinformation; he looked at thebabies' jaws and teeth. Hefound that their teeth wereworn down from chewing.In order to show wear ontheir teeth, these babies musthave been chewing for sometime. Their worn teethThis drawing of the dinosaur nest shows the red

mudstone "bowl" that held the mixed-up remainsof 15 baby dinosaurs. Braginetz and Ellingsen, Digging Dinosaurs

Medicine Formation. Choosing a place to look forbones is often the first important choice apaleontologist makes, and John Homer had chosen hissite. Baby dinosaurs had been of special interest to himsince he had found the Western Hemisphere's firstintact dinosaur egg while out prospecting in 1977. Hehad more than a hunch that looking for baby dinosaurfossils in the Two Medicine Formation would payoff.

Though his scientific plans had been carefullymade, John Horner's first discovery of a babyhadrosaur's jawbone occurred while he wasrummaging through a coffee can full of dinosaurbones in a rock shop in Bynum, Montana. The shopowner had discovered the bones and saved them. Shewas glad to show them to Homer, and he identifiedthem for her. He believed the tiny bones belonged to ababy duckbilled dinosaur, or hadrosaur, a commontype of dinosaur during the Late Cretaceous Period, 84to 72 million years ago. She took him to the placewhere she found the fossils, and John Homer'ssearch for the babies began.

John and his partner Bob Makela foundfossils (which looked like grayish­black bits of stone) sitting right ontop of the small mound they hadbeen shown. When they dug intothe mound to see what the groundheld, they discovered many babydinosaur bones mixedhaphazardly into green mudstone.Digging deeper, however, theysaw that the green mudstone satwithin a large, shallow bowl of

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How many paleontologists does it take to mount a Diplodocus leg?sauropod dinosaur demanded the talents ofseven men.

Each year, thousands of visitors stroll throughdinosaur exhibits in museums across the country. Theycrane their necks to see the top of Brachiosaurus'sskeleton and marvel at the ferocious look ofTyrannosaurus rex. Adult visitors try to comprehendthe passage of time when it's counted in hundreds ofmillions of years instead of hours. Dinosaurs makeadults think about evolutionary change and abruptextinction; they wonder what the dinosaurs'experience on earth can teach us.

Rather than being merely curious, children arepassionate about dinosaurs. They gaze at the hugeskeletons, imagining a landscape that could hold suchcreatures. They read and mouth the difficult-to­pronounce dinosaur names. Children possessencyclopedic knowledge about dinosaurs. Any teacherwho has studied dinosaurs with a class has beencorrected by a ten-year-old expert. "Actually, Ms.Miller, since the 1970s, Iguanodon has been depictedwith the tall aloft." Children are fascinated by theunique place dinosaurs occupy in the panoply ofmonsters. Dinosaurs were huge, ferocious,preposterous-looking and, best of all, real. Theyrequire none of the suspended disbelief that RedRiding Hood's wolf calls upon. Their gigantic formsstrike awe without causing fear since they are notmerely dead, they are extinct.

However, few people understand paleontology, thescience that brought dinosaur remains to humanunderstanding. The purpose of this issue of Art to Zoois to introduce you and your students to this uniquelyspeculative science. First you will be introduced to apracticing paleontologist, John Horner, and hisremarkable discoveries about how dinosaurs nurturedtheir young. The next sections tell how fossils formand how paleontologists find, stabilize, and transportfossils from the field to the laboratory. In thePracticing Paleontology section, students participate inactivities designed to help them think about the fossilrecord the way paleontologists do. The Pull-Out Pageinvites students to collaborate in science teams and tocreate miniature model fossil finds. In addition to thefun they will have with boxes of sand, chicken bones,and plaster of Paris plant fossils, students will learnabout geology, paleontology, anatomy, and scientificmethod.

BackgroundDiscovering the "Good Mother lizard"John R. Homer is a famous paleontologist (a personwho studies ancient life) whose analysis of thedinosaur remains he found in Montana have led manypeople to believe that at least some dinosaurs took careof their babies after they were hatched. Before Homermade his discoveries, most paleontologists believedthat dinosaurs, like most reptiles, merely depositedtheir eggs and left the infant dinosaurs to fend forthemselves. Learning about John Homer's discoverieswill teach you a lot about dinosaurs, but it will alsoteach you how paleontologists think and how theypose the questions that shape what they look for, andthus, what they find.

In 1978, John Homer, a paleontology technicianworking at Princeton University, was interested infinding the remains of baby dinosaurs. He had readabout the few places such remains had been found inthe past, such as Mongolia, Canada, Montana, andNew Mexico. His research had given him the idea thathe might find more juvenile dinosaur remains in afossil-rich rock formation in Montana, called the Two

Digging Up DirtHow Paleontologists Bring DinosaursBack to Life

Paleontologists use fossils to decipher the history of life on earth. The fossil record shows that different plants andanimals lived at different times. Paleontologists invented a special "calendar' called a Geologic Time Scale to showwho and what lived when. The three eras of ancient life are the Paleozoic, Mesozoic, and Cenozoic. Paleo means"ancient, JJ Meso means "middle," and Ceno means "recent."

Dinosaurs lived during the Mesozoic Era. They were reptiles who so dominated the land that the Mesozoic Era isknown as the "Age of Reptiles. JJ The Mesozoic began about 240 million years ago and dinosaurs appeared about210 million years ago. Dinosaurs' extinction marks the end of the Mesozoic Era, about 65 million years ago.Dinosaurs were the largest land animals of all time - they never flew and did not habitually swim. Flying reptiles,known as pterosaurs, and many marine reptiles lived at the same time as dinosaurs did, but these flying andswimming reptiles were NOT dinosaurs.

Era Period Epoch Beginning of Interval Important Eventsmimon.~ of year:> ugc

Recent .01 Modern man spreads worldwideQuaternary

Pleistocene 1.5-2 Many mammals vanish

li Pliocene 5 Oldest known hominids (human creatures)t!.

"" Miocene 22-23 Mammals reach their maximum diversity'0~:=

Oligocene 37-38'" TertiaryU

Eocene 55 Modem types of flowering plants appear

Paleocene 65 Spread and diversification of mammals

,-., Dinosaurs and many other organisms become extinctl!< Cretaceous 138::!- Peak of dinosaur diversity; flowering plants appear

"" Jurassic 205'0 First birds~~ Triassic 240 First dinosaurs, first mammals~

Permian 290 Extinction of many animals

. . Pennsylvanian*360

First reptiles"'" Carbomferous Mississippian* Great coal forests (first conifers, first cycads)l!<;,

Devonian First amphibians; first insects; fishes abundante 410""'0

Silurian First land life (plants and invertebrates)"" 435Q

~i=l.. Ordovician 500

Cambrian 570 First abundant record of marine life: first vertebrates

Precambrian (approximately 84% of the history of life) First living things-perhaps 3.5 billion years ago

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bury its body. The carcass can be buried deeper anddeeper on the riverbank as the sediments gather over itor it is covered by the soft sand of the river bottom.The soft parts of the animal's body the organs,muscles, and skin - decay rapidly, but the animal'sbones may remain intact under the protectingsediments.

Over many millions of years, water passing throughthe accumulating sediments affects the dinosaur bones.The water dissolves some of the chemicals in the boneand replac~s these chemicals with others. The newchemicals in the bone preserve the bone's shape andsize but give it a different chemical make-up.Sometimes the chemicals petrify the bone, turning it tostone and making the bone much heavier and denserthan it was when the animal lived. The "new" petrifiedbone usually has the same shape as the original, evendown to the tiny spaces for blood vessels within thebone.

Over time, water may add minerals to the sedimentsin which the bone is buried; minerals act as a glue tobind the sediments together. These sediments aroundthe bone harden and become rock, rock that nowencases the animal's fossilized bones.

Another turn in the process of fossilization canoccur, leaving the print of the dinosaur's remains butdestroying the bones themselves. Imagine that the softsediments have buried the bones. The sediments beginto harden and, like clay or mud, they take theimpression of the animal's remains. During themillions of years that the remains are entombed inthese sediments they can be dissolved, but theirimpression in the sediments-turned-to-rocksurrounding them lasts. The impression or the stampof the remains is also a fossil, and it can offer thepaleontologist a wealth of information, too. You couldsay that this kind of fossil teaches us about the foot byshowing us the footprint.

A Variety of FossilsBecause dinosaur skeletons are rarely found fullyarticulated (connected or joined together)paleontologists rely on all the "fossilized information"they find at a site to understand the dinosaur. Fossilscome in many forms and instruct eager learners aboutdinosaurs' physiques and behavior.Trackways. Dinosaur footprints reveal whetherdinosaurs traveled singly, in pairs, or even in herds.Tracks help us understand how rapidly a dinosaurwalked, and thus how much food he had to eat tosustain that level of activity. Tracks can show the storyof an encounter between dinosaurs.Plants. Preserved plants offer evidence of thedinosaur's feeding habits. Paleontologists occasionallyhave found remains of the dinosaur's stomachcontents, even such foods as pine needles, and in thecase of the recently discovered theropod, Baryonyx,fish. Some sites have yielded dinosaur coprolites (fecaldroppings) that give specific information about theanimal's diet, containing flesh and ground bones if thedinosaur were a flesh-eater, or leaves and seeds forherbivorous dinosaurs.

How Dinosaur RemainsBecome FossilsWhen a vertebrate animal dies on land, scavengersusually tear apart its carcass while feeding. However,if the carcass becomes buried quickly in mud or sand ithas a chance of being fossilized because it is notexposed to quick destruction. If a dinosaur dies on ariverbank, or if a flood carries a dinosaur carcass to abody of water, mud and silt from the river may slowly

Talk about walking in your parents' footsteps! On theleft, above the four-inch ruler, is the hind foot of a babyduckbill dinosaur. On the right, you are looking at onetoe bone of an adult duckbill!

Geologic Time Scale

How the Earth Makes FossilsThe process of fossilization occurs during the cycle oferosion and deposition. This cycle is predictable andas old as running water and the earth's crust. Wind andwater erode rock, breaking it into tiny pieces that arecarried along as grit in the air and as sediment in thewater. These sediments .settle where the wind and thewater leave them, at the river's bottom and themountain's feet. Over millions of years, thetremendous pressure of accumulating sediments bindsthese sediments into rock. Shale, mudstone, sandstone,and limestone are types of sedimentary rock. Whensedimentary rocks are exposed to wind and water theybegin to erode, produce loose particles or grit, and thecycle continues. Fossilization of living things occursnaturally and randomly within this cycle of erosionand deposition.

A Quick Introduction toPaleontologyThe science of paleontology relies on severalprocesses. The flIst process, burial, occurs when bonesare buried by tiny particles of rock. The secondprocess, petrification, is the series of chemical changesthat cause buried bone to turn to stone. The thirdprocess is exposure. Over time, the rock wears awayor moves and reveals the bones millions of years afterthey were buried. Paleontology is itself a process ofanother kind: the meticulous and fascinating processof finding and studying fossils. Read about all theseprocesses in this section.

continued from page 1

These challenging questions are the type that facepaleontologists all the time. Match your wits withthe professionals' by suggesting answers to thefollowing Paleo-Puzzles. Find the solutions onpage 4.

Paleo-Puzzle I You are excavating a well­preserved dinosaur skeleton. You have beenworking back to front, from the tip of the tailtoward the head, when your digging reveals asharp change in the kind of rock you are digging inand, sadly, no more skeleton. Where is yourdinosaur's head? What force made the rock typechange so abruptly?

Paleo-Puzzle 11 Even an energetic paleontologistwould be exhausted by the thought of digging up asauropod. The tallest sauropod, Ultrasaurus, was55 feet high, and the longest sauropod,Supersaurus, stretched 125 feet from nose to tall.In addition to their great size, sauropods presentanother kind of challenge to paleontologists. Fewcomplete sauropod skeletons have ever beenfound; most are missing their extremities, such ashead, tail, and feet. Further, sauropod skulls arenearly impossible to find. Now, knowing what youdo about sauropods, can you tell why their remainsare so often incomplete? .

Paleo-Puzzle III Fossil remains of youngdinosaurs are extremely rare, while remains ofadult dinosaurs are much easier to find. Why doyou suppose this is true?

Paleo-Puzzle IV What unique characteristic ofreptiles makes it impossible for paleontologists tosay definitively, "This type of dinosaur grew to be30 feet long and none of them ever grew anylonger"?

Paleo-Puzzles

showed that they could not have died immediatelyafter birth.

Another aspect of this find was interesting andperplexing. The nests were mled with bits of crushedeggshell. How would you have explained the crushedeggshells? Homer believed that the babies had stayedin their nests for the early part of their life and thatthey trampled their own eggshells after they wereborn.

Now, here are the next thoughts that went throughHorner's mind. The babies' teeth were worn downfrom eating; fifteen of them had been fOl~nd in thesame nest, and all the eggshells in the nest werebroken up. It sure looked like the babies had stayed inthe nest for a long time. And if they actually did stayin the nest, someone had to bring them food for themto survive - someone, Horner believed, like theirmother. The idea that the parent dinosaur would carefor the baby dinosaur was unheard of until this time,and it caused a lot of controversy. Furthermore, thiswas a newly discovered species of dinosaur. Muchlater, after they'd found and studied a skull of an adultdinosaur of the same type, and compared it to allothers previously discovered, they confrrmed that thiswas a new species. They named it Maiasaurapeeblesorum, which means "Good Mother Lizard."

Homer and his colleagues went back to the samesite the next year to look for more nests. Instead ofblind luck, which had led them to their first babybones, this time they were relying on scrutiny. Theycrawled on their knees over sharp rocks keeping theireyes about a foot away from the ground, looking foreggshell fragments to indicate a nest. Their hard workpaid off, and after they had studied the same area fortwo more years, they discovered a total of eightmaiasaur nests.

The next two years brought even more excitingdiscoveries. Horner's measurements revealed that themaiasaur nests were spaced 23 feet apart. Can youexplain why they were always this far apart? Hebelieved that since 23 feet is the average length of anadult maiasaur, the mothers who made these nests keptthem one "body length" apart so they would be close,but not too close. Further digging revealed the kind ofremains Homer had been looking for. He found eggsthat had never hatched, 14-inch-long maiasaur babies,and finally, a site that gave a clear picture of the eggsand nests. The oval eggs were about 8 inches long andwere not smooth like chicken eggs but were ridged.They were arranged as two concentric circles, onelayer of eggs below the other layer.

John Horner went on to make many otherfascinating discoveries, including the eggs and nests ofanother brand-new species of dinosaur, which henamed Orodomus makelai, after his colleague BobMakela. He also found the remains of a herd of 10,000adult maiasaurs! His experience shows that no matterhow many millions of years old dinosaur remains maybe, a paleontologist's interpretation of the bones'message can add new, startling information to ourunderstanding of the past.

2

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EXPLANATION

Severn and Mt. Laurel formations

• Magothy and Matawanformations (and equivalents)

Arundel clay

Potomac group undifferentiated

• Gettysburg shale

~ New Oxford formation

These two drawings were made during an excavationof an Iguanodon skeleton in Belgium in 1878. Theoutline sketch (top) shows how the skeleton wasdivided into 15 plastered blocks in the field. Thedrawing of the skeleton (bottom) shows the skeletonexactly as it was found. How do you think the paleon­tologist used these drawings as he studied theIguanodon in the laboratory?

Continued on page 4

Activity 1. Find a geologic map of your state. Wherewould you choose to hunt for remains of yourdinosaur? Why did you choose this region? If there isno area in your state that might yield fossils of the ageyou need, where is the closest place you could dig?

Activity 2. Draw a picture of one part of yourdinosaur's anatomy on a transparency. You mightchoose to draw only the skull, or perhaps even onlyone bone, like the femur, or thigh bone. In a darkenedroom, place the drawing on the overhead projector.Then pull the overhead projector back, away from the

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Cleaning FossilsOnce the fossil has been brought to the lab, thepainstaking and slow process of clearing all the rockmatrix away from the bone begins. Preparators(technicians who remove fossils from rocks) use allsorts of methods to clean away rock matrix whilepreserving dinosaur bone. If chisels and knives are notsuitable for the fossil remains, or if the risk of a humanhand slipping while using a chisel is too great, labworkers use tiny dental drills or picks to clear the boneaway. They drill lightly to remove the rock, and thenpaint newly exposed bone with glue to protect it. Ifdinosaur bones have been preserved in limestone,preparators may use acid baths to separate rock frombone.

Practicing Paleontology:ActivitiesThere are more than three hundred kinds of dinosaursto study, and you are not to be limited to the maiasaursyou read about in the beginning of this issue. Beforeyou do the following activities, visit your local naturalhistory museum or go to the library and look throughbooks about dinosaurs to find one that makes youcurious. You might be intrigued by the viciousDeinonychus, the four-ton Allosaurus, or the seven­homed Styracosaurus. For these activities, you shouldhave your "favorite" dinosaur in mind. You shouldalso know as many facts about your dinosaur aspossible. Use this questionnaire to help you get readyfor the activities.

~here to begin digging? This geologic map of the state of Maryland shows paleontologists where to finddmosaur-aged rock formations. Which counties promise the best fossil finds?

With the bone still safely embedded in the rock, or Dinosaur Background Informationmatrix, she paints the bone with quick-drying glue to Dinosaur's namekeep it from dissolving into powder as it is exposed to translation '-------------air. After it has been stabilized with glue, she covers When did this dinosaurthe bone with a layer of wet tissue paper. The most What did this dinosaur eat?protective step is the next one. A jacket is made for the Was this dinosaur ornith-is-c-h-ia-n-(b-l-'r-d-.h-i-p-p-ed-)-orbone so that it can be transported without damage. saurischian (lizard-hipped)?Using plaster bandages just like the ones doctors use to Find a picture of this dinosau-r-'s-s-k-e-le-to-n-.-W-he-r-e-h-a-veset broken human bones, or strips of burlap soaked in this dinosaur's remains been found?plaster, the paleontologist "jackets" the bone and the How big was this dinosaur? ------matrix. What are the dinosaur's unique features of

Because the fossil is fragile, the paleontologist appearance?cannot just dig a hole and pull it out. Instead, she chips Trace or pho-to-c-o-p-y-a-d-ra-w-i-n-g-o-f-th-e-d-i-no-s-a-u-r-to-u-seaway the rock all around the bone except directly for reference.underneath it so the specimen within the matrix sits ona pedestal of stone. At this point it looks like atoadstool. Finally, the paleontologist knocks theplaster-jacketed bone off its pedestal, then covers theunderside with more plaster bandages to seal it, thenclearly labels it "block A," for example, to indicatehow the plaster packages fit together for study in thelab.

Of course, dinosaur remains are so large that it isoften impossible for a person to carry the jacketedbones away from the site. The remains are sometimesput on a sled and dragged out of the excavation by abulldozer, then driven to the paleontology lab by truck.Some very large jacketed remains are lifted from thesite by helicopter. Even larger finds must be sliced inhalf just to become manageable for a helicopter!

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~I...- .-J::a:Reading the RocksPaleontologists believe that there is as muchinformation about a dinosaur locked up in the rocksaround the skeleton as in the skeleton itself. They readall aspects of the site closely to understand thefossilized remains. For example, even if apaleontologist fmds an intact skeleton, he must alsostudy the rock holding the skeleton. The structure ofsedimentary rocks gives important information aboutthe water that deposited the sediments. The speed ofthe water shows up in the grain size of the sediment.Finely grained sediment is deposited by slow-movingwater. Fast-moving water has more energy and carriessediment with larger particles in it. If the remains arefound in sedimentary rock with fine particles, the kinddeposited by very slow-moving water, you can assumethat the dinosaur died near a lake and that the waterdidn't carry it far. Because it has less energy, slow­moving water is more likely to leave a skeleton wellarticulated. Another benefit of reading the rock is togain more information about the climate of the placethe animal lived, especially if you study the plantremains too.

Gastroliths. Some paleontologists believe thatdinosaurs deliberately swallowed stones, for the samereasons that modern-day chickens peck up gravel.These stomach stones, or gastroliths, stayed in thedinosaur's gizzard and rolled around to morecompletely grind up the dinosaur's food.Nests. As we learned in our reading about Homer'sfinds, fossils may tell us if a dinosaur built a nest forits young. Close analysis of such remains might evenreveal how the parents treated their offspring.Skeletal Remains. These fossils show how the animalwas constructed. Teeth, scales, claws or talons, andbeaks can be fossils. Bones, the most common skeletalpart to be fossilized, may have valuable informationpreserved upon them, too. Paleontologists can examinebones and see how cartilage, tendon, and muscleattached to them and thus deduce an animal'smusculature and its appearaI).ce. Bones show traces ofdisease as well as evidence of combat or injury. Abroken bone creates a callus (a hard substance thatforms at the break in a fractured bone and reunites theparts) as it heals and shows clearly where the bonereunited. Sometimes paleontologists will findpreserved impressions of dinosaur skin; hadrosaur skinwas nubby, textured like a football.

Complete skeletons are extremely rare; usually asite contains individual bones or teeth. These bonesand teeth are often in poor condition. During theirtravels in ancient waters and before their burial, thebones are scraped and the joint ends are broken off.Often bones are fractured by the pressure of thesediments piling up above them. A fossil so manymillions of years old as a dinosaur bone may be a veryplain thing to look at: small, broken, dull-colored anddifficult to understand.

Choosing Where to DigA dinosaur fossil hunter sometimes is lucky enough tosee dinosaur remains on the surface of the earth ratherthan having to dig for them. Such forces as wind andwater erosion and volcanic activity can expose rockthat is millions of years old. Erosion wears away at therock covering the fossils. Sometimes, powerfulmovements under the earth's surface, such as theformation of mountains or the activity of volcanoes,will push very old rock to the surface. Such rock maycontain dinosaur remains. Ancient fossil debris may beexposed in the rock and found right on the ground wewalk upon.

Paleontologists use special maps, known asgeologic maps, to suggest which regions might havedinosaur fossils buried within them. Whiletopographic maps offer information about a region'spresent-day surface features, such as rivers, roads, andmountains, geological maps tell a paleontologist whichplaces are promising for digging for fossils.Geological maps help identify the name, location, andage of rock formations.

Thus, if a paleontologist knows what he is lookingfor, he may try to simply go after it. He might sit downwith a geological map of his state and look for an areacontaining rock formations of a certain period. Apaleontologist might say, ''I'm looking for dinosaursof the Lower Cretaceous period (144 97.5 millionyears ago) and I'm going to see if I can find any ofthem in Maryland." The geologic map of Marylandabove reveals that the Arundel Clay, cutting a diagonalpath along the eastern side of the state, is a rock unit ofEarly Cretaceous age. As this map shows, apaleontologist would have several options about whereto dig to find remains of such Early Cretaceousdinosaurs as the giant flesh-eater Dryptosaurus. Afossil hunter would choose where to dig, then go to thesite and prospect the area.

Preserving and Transporting BonesIf a paleontologist is lucky enough to find bone shemust watch that she does not harm it while trying toget it out of the ground. First, she gently chips away atthe rock around the bone using small picks and chisels.

Solution I The skeleton was deposited on a fault line,or a fracture in the rock holding the dinosaur. A faultline is found where changes in the earth's surface havecaused huge segments of rock beneath the surface todrop, lift, or slide away from each other. The rocksthat were next to each other when the dinosaurremains were buried have moved. You will have to gohiking to find the dinosaur's head; the fault may havedragged it miles away.

Solution II These animals were so large that theextremities rotted away before the whole carcasscould be buried by sediments. Complete burial of asauropod could take several years!

Solution III There are several solutions to this puzzle.Large, adult bones fossilize more readily than small,delicate, juvenile bones. Quite simply, the remains ofjuvenile dinosaurs may not have a chance to fossilize.Another reason for the scarcity of young dinosaurs'remains is that young dinosaurs may have liveddifferently and in different places than their parents.For example, they may have lived in environmentsthat did not lead to preservation.

Solution IV Mammals and birds stop growing at acertain point in their lives, well before they die.Reptiles do not stop growing; they become bigger andbigger until they die, though they grow very slowly atthe end of their lives. Therefore, paleontologistscannot say that the remains they have found, even ifthey are the largest remains found to date, representthe limits of the dinosaur's full growth. Anotherdinosaur, whose remains have yet to be dug up, mayhave lived an easier, longer life, found more to eat,and may have grown even larger.

ART TO ZOO l>rings IltlWS fro.m theSmithsollian Illstitutioll toteachers of grades three tl~rough eight. The, purpOSt~ is to helpyou usemuset~ms, parks, libraries, zoos, and many otherresources within YOUI' community to open up learningopportunities for your students.

Our reason for producing a publicatioll dedicated topromoting the use of community resources amongstudents and teachers nationally stems from a fUlldamentalbelief, shared by all of us here at the Smithsonian, in thepower Cif objects. Working as we do with a vast collection ofnatiollal treasures that literally contain the spectrum from"art" to "zoo," we believe that objects (be they works (,f alt,natural history specimens, histo!'icalilltifacts, or live animals)have a tremendous power to educate. We maintain that it isequally important for students to learn to use objects asresearch tools as it is for thccm to )eal'l1 to use words andnumbers--and you can find obJects close at lland, bydrawing on the resources of yoqr own COn\munity.

Our idea, then,' in producing ART TO ZOO is to share withyou-·and you with uS~methods of working with stud~rlts

and ob.iec.ts th.al Smithsonian staf~' members have fOllndsuccessful.

National Museum of American History: Lynn Dierking

And thanks to Wendy Binder, National Science ResourcesCentcr, and Pat: Collett, Marshall High School, FallsChurch, Virginia.

Books for ChildrenAIiki. Digging Up Dinosaurs. New York: Y. T.

Crowell, 1988.Copeland, Peter F. Dinosaurs and Other Strange

Creatures: A Smithsonian Coloring Book.Washington, D.C.: SmithsonianInstitution Press, 1983.

Gaffney, Eugene S. Dinosaurs: A Golden Guide.New York: Western Publishing Co., 1990.

Homer, John R., and James Gorman. Maia: ADinosaur Grows Up. Philadelphia: RunningPress, 1989.

National Wildlife Federation. Ranger Rick'sDinosaur Book. Washington, D.C., 1984.

Paleo-Puzzle Solutions

BibliographyBooks for TeachersBenton, Michael. On the Trail of the Dinosaurs.

New York: Crown, 1989.Colbert, Edwin. The Great Dinosaur Hunters

and Their Discoveries. New York: Dover, 1984.Czerkas, Sylvia, and Everett Olson. Dinosaurs

Past and Present, Volumes 1 and 2.University of Washington Press, 1987.

Homer, John R., and James Gorman. DiggingDinosaurs. New York: Workman,.l988.

Kranz, Peter. Dinosaurs in Maryland. Baltimore:Maryland Geological Survey, 1989.

Lambert, David, and The Diagram Group. TheDinosaur Databook. New York: Avon, 1990.

Norman, David. The Illustrated Encyclopedia ofDinosaurs. New York: Crescent Books, 1985.

Many thanks to the following people at the Smithsonian fortheir help in preparing this issue of ART TO Zoo:

National Museum of Natural History: Laura McKie,Rebecca Mead, Raymond Ryc and Hans-Dieter Sues

NATIONAL PORTRAIT GALLFJ~Y

NATIONAL ZOOLOGICAL PARK

SMITHSONIAN ENVIRONMENTAI, RESEARCH CENTER

SMITHSONIAN TROPICAL RESEARCH INSTITUTE

ART "l'o Zoo

is a publication of theOffice of Elementary and Secondary .EducationSmithsonian Institution, Washington, D.C. 20560.Write to this address if you want your school to be placed,free of charge, on the ART TO ZOO mailing list.

Director of Publications: Michelle SmithWriter: Leslie O'F'lahavanTranslator: Maria del Rosario BasterraIllustrator: Ryan Clennan, senior at Marshall HighSchool, Falls Church, VirginiaDesigner: The Watermark Design Office

Reg~tlar Contributors:ANA-COSTIA NEIGHBORHOOD MUSEUM

ARTHUR M, SACKLER GALLERY

journal when they return to the lab, especially if morethan one skeleton was found at the site.

Above are two entries from the field book offamous paleontologist Walter Granger. These noteswere made in 1923, while Granger was collectingfossils in Mongolia. This expedition was to yieldremarkable results: the skeletons, nest, and eggs ofProtoceratops. This find, at the Flaming Cliffs, in BainDzak, Mongolia, offered the first proof that dinosaurslaid eggs.

Try to read the field journal entry (some words areillegible) and look at the map. What can you learnabout the practice of paleontology from thesedocuments?

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Walter Granger's field journal contains severaldifferent kinds of valuable information: a map of thesite, finds, and camp, description of the rock holdingthe Protoceratops fossils, and a drawing of theskeleton found near the nest.

This drawing shows how faults disturb rock layers. Thesedimentary rock layers drop, move upwards; or movesideways when the Earth's crust breaks and a faultoccurs. A fault can destroy a dinosaur fossil embeddedwithin sedimentary rock.

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screen or wall, until the image you have drawn is aslarge on the screen as it was in real life. Tell yourclassmates about your dinosaur and about thedimensions of the body part on the transparen9Y, aswell as the rest of its "vital statistics." (Of course,you will have to measure out your dimensions beforeyou begin. For example, if your dinosaur's femur wasseven feet long, measure out seven feet of string andstretch it out as you enlarge the transparency to knowwhen the image is big enough.)

Activity 3. Paleontologists rarely find a completeskeleton. If they want to mount a skeleton for displayin a museum, they will probably have to use someoriginal bones and many fabricated bones. These man­made bones may be casts of originals from othersimilar skeletons, or replicas of drawings of bones.Using modeling clay, recreate one of your dinosaur'sbones or teeth. Making this model will be easier if youcan find a drawing of one of your dinosaur's bonesfrom different angles so you can see it from all"sides.If it is too hard to model a dinosaur bone from apicture, try modeling a real bone, such as a chickenleg. Remember, modem birds are dinosaurs' remotecousins!

Activity 4. Dinosaur footprints can be fossilized whena special set ofWE-.: circumstances occurs.

~.. u ~ If a dinosaur made........~ .. footprints in stiff mud~ ~ ~~~ and the indentationsit...... ,~~~ 4 hardened, and if the~..~ ~., ~.k. if tracks were then

ltit¥ ...» /. ij.- covered with anotherf ~~ ~ layer of dirt, which~ )!'u"....~ would protect the1/('" <l> trackway, the prints

lL ' .~ might be saved for us• .P ~ to study today.if ~ Trackways are a~ ~ valuable source of

"information for~ paleontologistsa:l because they reveal

Every picture tells a story. details about the type,What story can you invent toexplain this drawing of dinosaur gait, size, and speedtrackways? How many of the animal thatdinosaurs appear in this tale? made them. "Read"are they the same kind of these tracks anddinosaur? How did this story answer the questionsend? in the caption.

Activity 5. When a paleontologist discovers dinosaurtracks in the field, the tracks are usually hollowimpressions, the kind your foot makes as you walk inwet sand. Because it is more difficult to study theimpression a foot makes, a footprint, than a model ofthe foot sole itself, paleontologists sometimes use thefootprint as a mold, and fIll it to make a replica of thedinosaur's sole.

Try this experiment with your own footprint. Fill ashoebox with two inches of wet plaster of Paris mixedto the consistency of heavy paste. Firmly press yourbare foot into the plaster of Paris, creating an exactimpression. This is a mold of your foot. Let the plasterdry, then coat the whole surface (even the plaster thatdid not receive your footprint) with a thin layer ofpetroleum jelly. Pour another two inches of thickplaster of Paris into the mold of your foot. Let it dry.Tear away the shoebox, then pull the two layers ofplaster apart.

You now have a positive version of your footprint,the cast, and a negative version, the mold. Whatinformation can you learn about your foot's sole, skin,and bone structure from the cast that was difficult todetect in the mold?

Activity 6. To record their experiences and to helpstudy their finds in the laboratory, paleontologists keepjournals about their discoveries while in the field.These journals contain day-by-day records of theprogress of the excavation. The paleontologist drawsthe location of all the specimens he finds and maymake hypotheses about what the finds might be. Thepaleontologist and field wbrkers will rely on the

ART TO ZOO April 1992News for Schools from the Smithsonian Institution

Fossil Finds ... In the Classroom?

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Now that you havelearned about JohnHorner's maiasaurdiscovery and howpaleontologistssearch for andinterpret fossils, it isyour turn to try thescience. This Pull­Out Page invitesyou and yourclassmates to builda model of a fossilfind.

Science is a col­laborative activity. Scientists practice ingroups as they collect, record, and interpretdata. It is easy to understand whypaleontologists work in groups. They benefitfrom each other's understanding, certainly.Also, it is nice to have fellow paleontologistsnearby when you unearth a six-foot-long limbbone!

Form YourPaleontologyTeamJoin the classmateswho will bemembers of yourscience team andtell them about the"favorite" dinosauryou studied in thePracticing Paleon­tology activities.Encourage yourteam to ask you

questions about your dinosaur. When yourgroup has heard about all the teams'dinosaurs, choose one that interests the groupmost. This dinosaur will be the one your teamdisplays in the fossil find.

Give your team a name, to represent itspersonality, interests, and focus dinosaur.

Now your science team should learn asmuch about the dinosaur as it possibly can.Find out when and how long the dinosaurlived and where its remains have beendiscovered. What did the dinosaur look like?

Crested or frilled? Homed or armor-plated?What shape print did its feet leave? If it wasan herbivore, which plants did it eat? If itwas a flesh-eater, which animals became itsprey? Become hunters yourselves, huntersof materials to inform you about yourdinosaur, beginning with library books.

Record the knowledge you gain aboutyour team's dinosaur in your field journal,the written account of the progress of your"expedition." The background informationwill be the first entry in your field journal.As you construct your site, you will noteyour findings, draw maps of the site, andmake hypotheses about the fossils in thefield. Read more about the field journalahead.

Gather Your MaterialsYour science team is going to build a miniaturelandscape that holds fossilized "dinosaurremains"... right in your own classroom. Thisproject will take some imagination. Your wholeclass will have to imagine that modernmaterials are really Mesozoic remains, thatchicken bones are dinosaur bones, that sandscooped from the backyard sandbox was oncethe bank of a Late Triassic river. Imagination isa natural part of science; paleontologists rely onit to conceive of the world dinosaurs occupiedso long ago. In addition to imagination, youwill need:• a large, strong cardboard box• plastic for lining the box• spray adhesive or spray acrylic glaze to keep

the top layer of sand or soil in place• soil of different colors and textures: sand, clay,

topsoil or potting soil, and gravel• plant leaves, seeds, stalks, or needles. Make

plant fossils by pressing any part of a plantinto plaster of Paris to make an impression.Then peel the plant matter away and let theimpression dry. Or simply use the plant in

your model to represent a plant fossil.Learn whieh plant grew at the time and in the

region your dinosaur lived. During dinosaurs'millions of years on earth, climate and plantsehanged greatly. The hot, dry Triassie Periodsupported evergreens and ferns. During themilder, wetter Jurassie Period, forests grew andbecame denser. The cooler, drier Cretaceousbrought a range of new, flowering plants suchas oaks and daffodils.• Bones. No one in your science team has a

pile of dinosaur bones in his or herbasement. Because birds are the dinosaurs'dosest living relatives, chicken bones aregood substitutes Ask your parents toprepare a whole chicken for dinner, insteadof cut pieces. Carefully clean the meat fromthe bones and learn about how the parts ofthe skeleton fit together Then use thisskeleton for imitation dinosaur bones. Or

make bones from modeling day.• Tracks. Make dinosaur footprints by pressing

heavy cardboard footprint cutouts into wetsoil to create a trackway. Build a Maiasaur,Protoceratops, or hypsilophodont nest usingchicken eggshells or plastic eggs.

A final option: reconstruct an authentic site.If you learn about a site while doing research,try to duplicate that site, or part of it, in yourbox.

Build Your Fossil FindBefore your group decides how you will displayyour fossils, create a story to explain how thefossils arrived at the site. Write the story in yourfield journal. A sample background story: "Webelieve this Edmontosaurus died trying todefend itself from Tyrannosaurus rex.Edmontosaurus had been eating leaves from amagnolia tree that grew by the side of a fast­moving river. (We can tell this ancient river wasfast-moving because the grain size of the matrixholding the remains is so tiny and fine.) AfterEdmontosaurus died, the fast waters picked up

its body, rolling it over and over beforedepositing it in its burial place. We found footbones, some plant remains, and a brokenEdmontosaurus forearm bone (radius)." Yourstory will help you decide what to put in yourfossil find.

Write in Your Field Journal

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As professionals, do, your team will keep afield journal as a record of your excavation'sprogress. The journal should include hand­drawn maps of your site. If your site is basedupon a real place, in your state or otherwise,copy or trace an authentic map of that place. Ifyour team invents a site, draw in and name allthe important topographic (surface) features ofyour site as they appear before you breakground, then as you dig. As your workproceeds, draw a picture of each fossil yourteam finds, and its position at the site.

Dse your field journal as a science diary.Write a daily account of what your science teamfinds, describing what you find first, second,etc., the kind of rock your fossils are embeddedin, the condition of the fossils. Mention anyfossils you see. Write about how well or poorlythe work is going. To make your field journal asauthentic as possible, use scientific words asoften as you can. For example, a realpaleontologist calls a thigh bones the "femur."A list of useful words appears in the

Paleontology Lexicon (dictionary) on this page.In many ways, this imaginary fossil find

happens backwards. Real paleontologists freefossils from rock; your science team is covering"fossils" with dirt! Real paleontologistscompose stories about what happened at theirsite after they dig up the bones; your scienceteam created the story before assembling thesite model. Real paleontologists jacket bonescarefully and carry them away; you will leavebones exposed for your classmates to examine.But your purpose is the same as a realpaleontologist's: to learn about prehistoric lifeby studying fossils.

Present Your Fossil Find toYour ClassmatesWhen you have completed your model and theaccompanying field journal, present your findto your class. If your team wants to offer theclass a chance to discover still-hidden remains,invite another science team to expose andanalyze the fossils in your box. Or, your teamcould show the class fully exposed remains andask for interpretations.

Paleontology LexiconUse these scientific words to discuss and writeabout your fossil find.

Articulated: joined or connected,pertaining to skeletons

Carnivore: a flesh-eatinganimal

~ Clutch: a nest of eggs",d>

~ Coprolite: fossilizediZ dung

Cranium: the part of the skull that coversthe brain

Enamel: the hard outer covering of a tooth

Femur: thigh bone

Fenestra: opening in a skull or otherbone

Fibula: the narrower shin bone

Fossil: any evidence of life from thegeologic past

Gastrolith: stomach stone or pebble

• -,","",q Herbivore: a plant-" $ ~'\j~ eating animalf/' I

--/-:'~ Humerus: the upper arm/ bone

"~ Keratin: a protein that~ makes feathers, claws,iZ beaks, horns, hooves, and

scales, as well as human hair and fIngernails

Matrix: the rock surrounding a fossil

Nestling: a young dinosaur not yet readyto leave the nest

Preparator: a technician who removesfossils from rock matrix

Radius: a forearm bone

Sedimentary rock: rock formed bydeposited partIcles; shale, sandstone, andlimestone

Scapula: shoulder blade

Tendon: the tissue that attaches muscle tobone

Tibia: the larger shin bone

Ulna: a forearm bone

Vertebra: a bone of the backbone

Del Arte al Zool6gico Abril 1992Noticias para las escuelas del Smithsonian InstitutionTraducido por Maria del Rosario Basterra

l.Descubrimiento deen la Clase?Ahora que has lefdo lahistoria del descubrimientodel maiasaurio de JohnHorner y aprendido acercade como los paleontologosinvestigan e interpretanfosiles, es tu turno de tratarde hacer 10 mismo. Estapagina de sacar, les invitaa ti y a tus compafieros declase a construir unmodelo para la busqueda de fosiles.

Ciencia es una actividad que se hace encolaboracion. Los cientfficos trabajan enequipos cuando recolectan, codifican einterpretan informacion. Es facil entenderporque los paleontologos trabajan en grupos.Ciertamente, se benefician del conocimientode cada uno de sus compafieros. A su vez, esagradable tener a un compafiero paleontologocerca cuando desentierras un hueso de unaextremidad que mide seis pies de largo.

osiles.. 11

GTenia cresta 0 un cuello adornado? GTeniacuemos 0 tenia la pie1 como un acorazado?GQue tipo de huellas imprimian sus patas?Si era herbiboro Gque tipo de plantas cornia?Si cornia carne, Gque animales eran suspresas? Conviertanse en cazadores,cazadores de informaci6n acerca deldinosaurio que han escogido, empezandopor los libros de la biblioteca.

Anoten 10 que van aprendiendo acerca desu dinosauno en un diario, diano en dondeiran anotando el progreso de su"expedici6n". La primera entrada queincluiran en su diario sera la informaci6nbasica sobre el dinosaurio. En la medida enque vayan construyendo su area deinvestigaci6n, iran anotando susdescubrimientos, dibujaran mapas del area,y haran hip6tesis sobre los f6siles queencuentren aUi. Encontraras masinformaci6n sobre tu diano mas adelante.

Reline Tus MaterialesTu equipo va a construir un paisaje de miniaturaque contiene "restos de dinosauriofosilizados" ...alli mismo en tu propia clase. Esteproyecto requiere algo de imaginacion. Tu clasetendra que imaginar que los materiales deconstruccion modernos son realmente restosMesozoicos, que huesos de polIo son huesos dedinosaurio, que la arena recogida de la caja dearena del patio fue alguna vez parte de la orillade un ulterior rio Triasico. La imaginacion esparte natural de la ciencia; los paleontologos seapoyan en ella para concebir el mundo que losdinosaurios habitaron hace mucho tiempo.Ademas de imaginacion, necesitanin• una caja de carton grande y resistente• plastico para fonar la caja• roceador adhesivo 0 barniz acrilico para

mantener la capa superior de arena 0 tienafirme

• tiena de diferentes colores y texturas: arena,arcilla, tiena natural 0 comercial, y cascajo 0

arena gruesa• piedras de varios tamafios• hojas, semillas, tallos, u hojas aciculadas.

Hagan fosiles de plantas imprimiendocualquier parte de una planta en un molde deyeso para lograr una impresion. Luego saquenlos restos de la planta y dejen que laimpresion se seque. 0 simplemente usen las

plantas que tienen en su modelo de tal formaque representen f6siles. Averiguen que tipo deplantas existian en la epoca y regi6n en la quevivi6 tu dinosaurio. Durante los millones dealios en que los dinosaurios existieron, el climay las plantas cambiaron significativamente. Elcaluroso y seco Periodo Triasico permiti6 elcrecimiento de siempre verdes y helechos.Durante el templado y humedo PeriodoJurasico, bosques crecieron y la vegetaci6n sehizo mas densa. El frio y seco Cretaceo trajo unnuevo tipo de plantas tales como los robles ylos narcisos.

• huesos. Nadie en tu equipo cientifico tiene unapila dc huesos de dinosaurio en su zotano. Dadoque los pajaros son los seres vivientes masproximos a los dinasaurios, los huesos de polloson buenos substitutos. Pidele a tus padres quepreparen un polIo entero para cenar en vcz departes de polIo. Separa cuidadosamente la carnede los huesos y observa como las diferentespartes del esqueleto se juntan. Luego utilizaesc esqueleto como una imitaci6n de loshuesos de dinosaurio. 0 utilizen huesoshechos de arcilla tal y como hicimos en laPractica de Paleontologia Actividad 3.

• rastros. Fabriquen huellas de dinosaurioapretando recortes de huellas hechas concartulina gruesa en tierra humeda. Construyanel nido de un Maiasaurio, Protoceratopo, 0

hypsilophodonto utilizando cascaras de huevos• huevos de plastico.

Una ultima opci6n: reconstruyan una areaautentica. Si descubren algun area mientras hacensu investigaci6n, traten de reproducirla en sutotalidad, 0 parte de ella en su caja.

Construyan un Modelo delArea del Hallazgo de F6silesAntes que el grupo decida como van a exhibir susfosHes, inventen una historia que explique comolos fosiles llegaron al lugar. Escriban la historiaen su diario de investigaci6n. Ejemplo de unahistoria: "Pensamos que este Edmontosaurius

muri6 tratando de defenderse del reyTyrannosaurius.

Los Edmontosaurius habian estadoalimentandose de hojas de un arbol de magnoliasque creci6 a la orilla de un rio con un flujo deagua muy rapida. (Podemos decir que este rioancestral tenia un flujo rapido porque el tamafiodel grano de la matriz que sujeta los restos sonpequefios y finos.) Despues que elEdmontosaurus mud6, las rapidas aguasarrastraron su cuerpo, haciendolo rodar una y otravez antes de depositarlo en el lugar donde qued6enterrado. Encontramos huesos de pie, restos dealgunas plantas, y un hueso roto de un radio(radius) del Edmontosaurius." Tu historia teayudara a decidir que poneI' en su modelo.

Escriban en Su Diario deInvestigaci6n

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Tal y como hacen los profesionales, tu equipomantendra un diario de investigaci6n como unrecord del progreso de sus excavaciones. Eldiario debera incluir mapas hechos a mana delarea del hallazgo. Si su area esta basada en algunlugar real, en el estado en donde vives 0 en otrositio, copia 0 calca un mapa auntentico del lugar.Si tu equipo se ha inventado el area, dibujen eindiquen la topografia (supericie) mas importantetal y como aparecia antes que iniciasen laexcavaci6n, luego como se veia cuandoexcabavan. En la medida en que progrese sutrabajo hagan dibujos de cada f6sil que el equipoencuentre, y su posici6n en el area.

Usen su diario de investigacion como un diariocientifico. Escriban los descubrimientos de suequipo diariamente, describiendo que encontraronprimero, segundo, etc., e1 tipo de roca que cubrfalos fosiles, la condicion de los fosHes. Mencionencualquier fosil que vean. Describan 10 bien 0 10mal que esta yendo el trabajo. Para hacer su diariode investigacion tan autentico como sea posible,usen palabras cientificas cada vez que puedan. Porejemplo, un paleonto10go de verdad Ie llama"femur" al hueso de la pantorrilla. Una lista depa1abras utiles aparece en e1 Lexico dePa1eontologia (diccionario) al final de la pagina desacar.

De muchas maneras, esta busqueda imaginariade fosiles sucede a 1a inversa. Los verdaderospa1eontologos remueven a los fosiles de las rocas;tu equipo cientifico iesta cubriendo a los "fosi1es"con tierra! Los verdaderos pa1eontologos escribenhistoria acerca de 10 que paso en e1 area despuesque ellos desenterraron los huesos; tu equipocientifico creo 1a historia antes de construir elmode10. Los verdaderos pa1eonto10gos cubren loshuesos cuidadosamente y se los llevan; ustedesdejaran los huesos expuestos para que tu c1ase lospueda examinm;. Pero su proposito es e1 mismoque el de los verdaderos paleontologos: aprendersobre la vida prehistorica estudiando fosiles.

Presenta Ius F6siles a IusCompaneros de ClaseCuando hayan acabado su modelo y el diariocientifico, hagan una presentacion de sus fosHes ala clase. Si tu equipo quiere ofrecerle a la clase laoportunidad de descubrir algunos restosadicionales, inviten a otro equipo .cientifico apresentar y analizar los fosiles de la caja. 0, tuequipo podria mostrarle a 1a clase todos loshallazgos y pedir interpretaciones a loscompafieros de clase.

Lexico Paleontol6gicoUsen estos terminos cientffico para discutir yescribir acerca de los fosiles descubiertos.

Articulados: unidos 0 conectados,perteneciente a esqueletos

Carnivoro: un animal queCorne carne

c~

~ Nidada: un nido con huevos

~ Coprolito: excremento fosH

Craneo: la parte osea que cubre el cerebro

Enamel: la parte dura que cubre los dientes

Femur: hueso de la pantorrilla

Fenestra: orificio en el cnineo u otro hueso

Perone: hueso angosto de la espinilla

Fosil: cualquier evidencia de vida del periodogeologico

Gastrolito: piedra del estomago

Herbivoro: un animal quecorne plantas

Humero: el hueso de la~ parte superior del brazog

~ Queratina: protefna que se~ encarga de producir plumas,

harras, picos, cuemos, cascos y escamas, ytambien pelo humano y ufias

Matriz: la roca que rodea un fosH

Polluelo: un joven dinosaurio que todavfa noesta listo para abandonar el nido

Preparador: tecnico que remueve fosiles dela roca matriz

Radio: hueso del antebrazo

Roca sedimentaria: roca formada porparticulas depositadas; esquisto, piedraarenisca y piedra caliza

Escapula: omoplato

Tendon: el tejido que adhiere el musculo alhueso

Tibia: hueso alargado de la espinilla

Cubito: hueso del antebrazo

Vertebra: hueso del espinazo