USA 1997 "The World of Dinosaurs"

Issue Date	01.05.1997
ID	Michel: 2814-2828 Scott: 3136a-3136o Stanley Gibbons: 3825-3299 Yvert: 2590-2604 UPU: N/A Category: pR
Design	Original artwork by James Gurney
Stamps in set	15
Value	32c x15 "A scene in Colorado, 150 million years ago" Ceratosaurus, Camptosaurus, Camarasaurus, Brachiosaurus, Stegosaurus, Allosaurus, Goniopholis, Opisthias. In the margin: a bird (Archaeopteryx), flying reptiles Comodactylus ostromi, Mesadactylus ornithosphyos on tree trunk. "A scene in Montana, 75 million years ago" Edmontonia, Einiosaurus, Daspletosaurus, Corythosaurus, Ornithomimus, Parasaurolophus, Palaeosaniwa. In the margin: a turtle, frogs, a heron-like bird, Alphadon, Stegoceras head, Lambeosaurus head and nest with young, Quetzalcoatlus.
Size (width x height)	199mm x 260mm
Layout	15 stamps per sheet, divided for two parts
Products	FDC x 15
Paper
Perforation	11x11
Print Technique	Lithography, Multicolor
Printed by	Sterling Sommers for Ashton-Potter (USA) Ltd
Quantity	219,000,000
Issuing Authority	U.S. Postal Service

On May 1^st, 1997, the U.S. Postal Service issued the stamp set “The World of Dinosaurs”. The set consists of 15 stamps presented in a large mini-sheet. Eight of the stamps depict prehistoric animals that roamed the area of present-day Colorado around 150 million years ago, while the remaining seven feature species that lived in what is now Montana approximately 75 million years ago.
These stamps were designed by famous American paleoartist James Gurney.
The United States Postal Service has a rule: A person must be dead for at least ten years before they can appear on a stamp, says artist James Gurney. Dinosaurs have been dead for 65 million years, so they definitely qualify!" At the time this issue was released, dinosaurs had appeared only twice in the 150-year history of U.S. postage stamps.
It is easy to imagine how excited James Gurney was to be selected by the U.S. Postal Service to create the artwork for these dinosaur stamps.
Gurney was chosen by a special U.S. Postal Service committee responsible for the project. Initially, the committee asked him to design a scene featuring four dinosaur stamps. He selected four species that would have lived together in North America during the same period.
In September 1995, he quickly produced an initial sketch, featuring the head of a Tyrannosaurus rex alongside the bodies of three other dinosaurs.
The committee was impressed with his concept and requested an expanded design that would include additional stamps. In January 1996, Gurney presented a revised composition consisting of two scenes, each depicting five dinosaurs. One scene represented North American dinosaurs of the Cretaceous Period, while the other illustrated those of the Jurassic Period.

At this stage, Gurney’s stamp project was still top secret, and he was not allowed to discuss it with anyone. However, he wanted to ensure that his artwork was scientifically accurate. To achieve this, he requested permission to consult a small number of dinosaur experts. The U.S. Postal Service agreed — on the condition that he speak only with them.
One of the scientific advisers he consulted was the renowned American paleontologist Jack Horner, whose discoveries have greatly advanced our understanding of dinosaurs. Horner also served as a consultant on "Jurassic Park" and "The Lost World: Jurassic Park", directed by Steven Spielberg.
With expert input in hand, Gurney moved on to his final sketch. His goal was to depict a rich and diverse ecosystem, illustrating not only dinosaurs but also the broader environment in which they lived.

James Gurney in Studio

The scientists provided me with extensive information about the other creatures and plants that shared the dinosaurs’ world. These included frogs, turtles, insects, crocodiles, mammals, and birds, as well as a wide variety of plant life. There were many plants and animals that looked very similar to those found in modern-day Florida.
I wanted the scene to tell multiple stories—not just predators hunting prey, but also hatchlings emerging from eggs and small mammals hiding in the trees. To suggest a fossil in the making, I placed the skull of a dinosaur in the mud at the edge of a pond.
One committee member suggested that some of the creatures in the margins of the scene could also be turned into stamps. He was right—it was a great idea, and there were at least five additional stamp designs hidden within the artwork.
At one point, we even considered adding another stamp featuring a nest full of hatchlings. If you look closely, you can see that a white egg was positioned to leave space for the “USA 32” inscription.
It was important that the sheet could be easily separated into individual stamps without confusion between stamps and leftover paper, although those scraps might still be fun to use as decorative stickers. Naturally, the Postal Service hoped that people would purchase multiple sheets—one to use and another to keep intact in a collection.
As for me, I would have liked to stick the entire sheet onto my T-shirt and mail myself back to the Mesozoic Era via Priority Mail.
The stamp committee approved Gurney’s final design, and he proceeded to complete the painting. "The World of Dinosaurs" stamps were issued on May 1, timed to coincide with the release of "The Lost World: Jurassic Park", the sequel to "Jurassic Park". The film captivated audiences with its lifelike portrayal of dinosaurs.
First Day of Issue ceremonies took place at the Dinosaur Valley Museum, located in the heart of the famous Dinosaur Triangle — a region stretching from western Colorado to north-eastern Utah, known for its rich concentration of significant dinosaur fossil sites.

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A scene in Colorado, 150 million years ago

Ceratosaurus

Ceratosaurus on stamp of USA 1997

This medium-sized carnivorous dinosaur measured approximately 6 metres in length and weighed up to 540 kilograms. Although its exact range is uncertain, fossil evidence suggests it lived in what is now Colorado, Wyoming, and Utah during the Jurassic Period, around 150 million years ago.
What makes Ceratosaurus particularly distinctive is the prominent horn on its snout and the pair of bony ridges above its eyes, which gave it a striking and formidable appearance. Its name literally means “horned reptile”. The precise function of these features is unknown, but they were likely used for display — perhaps to attract mates or to establish dominance, similar to how modern elk use their antlers.
In another unusual trait, Ceratosaurus is one of the few theropods known to have had a form of body armour. The small bony plates embedded in their skin may have served a protective function, though they could also have played a role in visual display, possibly favoured through sexual selection.
Unlike Tyrannosaurus rex, which had two fingers, or Allosaurus, which had three, Ceratosaurus possessed four fingers on each hand. These digits were likely not strong enough for grasping or tearing prey and may have had a reduced or specialized function.
Its teeth were sharp and blade-like, and the structure of its jaws suggests that Ceratosaurus may have attacked by slicing large chunks from its prey, possibly allowing victims to weaken or bleed out before feeding.

Camptosaurus

Camptosaurus on stamp of USA 1997

This early member of the iguanodontids is represented in North America by a single recognized species, Camptosaurus dispar. It reached lengths of over 6 metres and is estimated to have weighed up to around 1.1 tonnes. Later relatives included Iguanodon and the hadrosaurs.
It is highly likely that this Late Jurassic herbivore was a common prey animal for large predators such as Allosaurus. Its name means “bent lizard,” referring to the curved femur, which positioned the legs farther apart to accommodate its broad ribcage.
Based on its anatomy and lifestyle, Camptosaurus probably spent much of its time moving on two legs. Although its body was somewhat bottom-heavy, this build may have made it relatively agile and manoeuvrable.
Its teeth were adapted for grinding and were well suited for processing leafy vegetation. Food was likely stored in cheek pouches and thoroughly chewed before swallowing. Fossils of Camptosaurus are often found alongside those of Stegosaurus and Camarasaurus. This suggests that it occupied a slightly different ecological niche, feeding on vegetation that was less accessible or less preferred by the much larger sauropods, thereby reducing direct competition.

Camarasaurus

Camarasaurus on stamp of USA 1997

A close relative of the brachiosaurs and titanosaurs, Camarasaurus was a common sauropod during the Late Jurassic in North America, and it is also known from parts of Europe and Africa. Although smaller than some of its giant relatives, it still reached lengths of about 15 to 18 metres and weighed roughly 27 to 36 tonnes. Its name, meaning “chambered lizard,” refers to the hollow cavities within its vertebrae, which likely helped reduce body weight.
This heavily built dinosaur had a distinctive head shape, somewhat reminiscent of a combination of a bulldog and a horse. Its teeth were unusual, broad and spoon-shaped, similar to ivory spoons, well suited for processing tough, fibrous plant material. Camarasaurus likely fed by biting off large portions of vegetation, such as branches and shrubs, and swallowing them whole.
Its digestive system was adapted to handle this coarse diet, probably using gastroliths (swallowed stones) to help grind plant matter in the stomach. One prominent paleontologist once compared Camarasaurus to an elephant, though with its head at the end of its neck and its “teeth” effectively located in its gizzard.

Brachiosaurus

Brachiosaurus on stamp of USA 1997

One of the largest of all sauropods was Brachiosaurus. Many will recall the iconic scene in the film "Jurassic Park", where these magnificent animals emerge from the water and rise to browse from the tops of tall trees. The name means “arm lizard,” referring to its forelimbs, which were longer than its hind legs.
In terms of size, Brachiosaurus was a true giant, reaching lengths of up to about 25 metres and weighing as much as 70 to 80 tonnes, with its head towering up to around 15 metres above the ground.
Like many large sauropods, weight reduction was essential. The skull of Brachiosaurus was relatively small and lightweight, containing numerous air-filled cavities. As a fully grown adult, it likely had no natural predators, as even large carnivores, or groups of them, would have struggled to attack such an enormous herbivore.
This species was probably restricted to regions with abundant tall vegetation, particularly forests rich in high-growing trees. Fossil evidence from North America is relatively scarce, and no completely intact skeleton has been discovered. Its range may have been limited to riverine environments in areas such as present-day Utah and Colorado. A somewhat more slender relative, often referred to as Giraffatitan, has been found in greater numbers in Africa.

Stegosaurus

Stegosaurus on stamp of USA 1997

A well-known dinosaur from the Middle Jurassic to Late Jurassic is Stegosaurus, whose name means “roof lizard,” referring to the large plates that ran along its back and grew directly from the skin. It reached lengths of about 6 to 9 metres, with a body size comparable to that of a modern rhinoceros.
Many will recall the dramatic depiction in Walt Disney’s Fantasia, in which a Stegosaurus is portrayed being killed to intense music by a Tyrannosaurus rex. Like its relatives the ankylosaurs, Stegosaurus was a heavily armoured dinosaur, well adapted for defence.
Its back plates likely served multiple functions, including thermoregulation—helping with both heat absorption and dissipation, as well as display and protection. These plates were not covered in thick horn as once thought, but were instead embedded in skin and richly supplied with blood vessels. Around the neck, a series of bony structures provided additional protection. The tail bore long spikes, some exceeding 1 metre in length, which served as a powerful deterrent against predators and may also have been used in dominance displays or courtship behaviour.
As an ornithischian, Stegosaurus likely fed on low-growing vegetation, though it may have occasionally reared up to reach higher foliage. Its feeding behaviour has been compared to that of a “living lawn mower”, consuming large amounts of vegetation within reach before moving on. Its digestive system has been described as a large fermentation chamber, producing significant body heat during the breakdown of plant material, which may also explain a thermoregulatory role for its plates.
In North America, two species of Stegosaurus are known. The smaller is Stegosaurus stenops, while the larger is Stegosaurus ungulatus, which was about 50% bigger. Other species have been found in different parts of the world and time periods. Over time, stegosaurs were eventually replaced ecologically by their more derived relatives, the ankylosaurs.

Stegosaurus

Allosaurus on stamp of USA 1997

Allosaurus was a highly successful and abundant theropod dinosaur found across much of the world from the Middle Jurassic to the Late Jurassic. Some of the largest known carnivorous dinosaurs belong to this genus. In North America, this formidable predator, whose name means “different lizard”, reached lengths of approximately 9 to 12 metres and weighed between 2 and 5 tonnes.
Fossil remains have been discovered at numerous sites across the western United States, including South Dakota, Wyoming, Utah, Montana, New Mexico, and Oklahoma. One remarkable site, the Dinosaur Quarry in Utah, has yielded the remains of at least 44 individuals, ranging from juveniles to adults. This concentration of fossils suggests that Allosaurus may have been a social animal and possibly hunted in groups.
It has been proposed that the habitats occupied by North American Allosaurus were similar to modern savanna environments such as the Amboseli region of Africa. These areas experience hot, seasonally variable climates with alternating wet monsoon periods and dry seasons. Such conditions would have supported abundant herbivorous prey, which likely moved in herds in search of food and water, in turn attracting large predators like Allosaurus.
This ecological setting may have supported semi-territorial behaviour, with family groups or individuals occupying seasonal ranges while following prey migrations when necessary.

Goniopholis

Goniopholis on stamp of USA 1997

A Late Jurassic reptile closely related to dinosaurs—but with descendants still living today — is Goniopholis, whose name means “angled scutes”. This ancient crocodilian resembled many modern crocodiles in both form and lifestyle.
It is a common misconception that the Mesozoic world was dominated solely by dinosaurs. In reality, this view is highly misleading. In terms of both abundance and diversity, the ancient ecosystems were likely much more similar to those of today, populated by turtles, tortoises, frogs, lizards, crocodilians, and a wide variety of smaller animals, including insects, salamanders, and even small dinosaurs.
While the large dinosaurs were undoubtedly impressive and often fearsome, they represented only a small part of the overall ecosystem. The majority of life consisted of these smaller, less conspicuous creatures that formed the foundation of the food web.
Crocodilian ancestors have existed since the Late Triassic, around 235 million years ago. Early forms were long-legged, fast-moving archosaurs, and over time they evolved into a wide range of body types and ecological roles. Goniopholis represents one branch of this long evolutionary history, closely resembling the semi-aquatic predators we are familiar with today.

Opisthias

Opisthias on stamp of USA 1997

One of the most unusual reptiles still living today is the tuatara of New Zealand. Opisthias is considered an ancestral form of this true “living fossil” and likely resembled it closely in appearance and lifestyle. Although the Sphenodontians are now represented by only a single surviving species, the tuatara (Sphenodon punctatus), this was not always the case.
These “lizard-like” reptiles are not true lizards but instead represent a distinct evolutionary lineage that diverged in the Middle Triassic Period and persisted through time to the present day. Some members of this group adapted to aquatic environments and became known as pleurosaurs, while others retained a body plan very similar to the modern tuatara. In fact, this basic morphology and ecological role has remained remarkably stable for nearly 200 million years.
Opisthias lived during the Late Jurassic and likely fed on small prey such as insects, worms, and small lizards, occupying a niche similar to that of the modern tuatara, the last surviving member of this ancient lineage.

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A scene in Montana, 75 million years ago

Edmontonia

Edmontonia on stamp of USA 1997

A member of the nodosaurids (a group of ankylosaurian dinosaurs lacking tail clubs), Edmontonia was a heavily armoured dinosaur weighing around 4 tonnes and reaching lengths of over 6 metres. Its name means “near Edmonton,” referring to the region where its fossils were first discovered. It was among the most well-protected herbivores in the Late Cretaceous ecosystems of what is now the Pacific Northwest.
With its flexible body armour, long sharp shoulder spines, and a two-layered bony skull shield, Edmontonia would have been extremely difficult for predators to attack. Despite this, members of this nodosaur group were still occasionally preyed upon by large carnivorous dinosaurs.
During this period, approximately 75 million years ago, the climate and environment of the region favoured a diverse range of dinosaur species. Temperatures and humidity levels were high, supporting extensive peat bogs and bald cypress swamps. Inland areas consisted of broad floodplains shaped by river systems flowing toward the sea, with numerous tributaries and channels crossing the landscape and influencing local ecosystems.
Nearly half of the plant species in this region were flowering plants. The flora included cycads, ferns, fern trees, conifers, and other vegetation typical of Late Cretaceous ecosystems. Edmontonia likely fed on the lower, tougher vegetation and may have preferred more open scrubland closer to coastal areas.

Einiosaurus

Einiosaurus on stamp of USA 1997

Among the more unusual-looking ceratopsian dinosaurs was Einiosaurus, whose name means “buffalo lizard”. This Late Cretaceous horned dinosaur has so far been found only in northern Montana, suggesting that it may have been relatively rare and part of an isolated population, separated from more widespread contemporaries such as Triceratops and Styracosaurus.
It lived approximately 74–76 million years ago during the Late Cretaceous in what is now the Two Medicine Formation. In overall body plan, Einiosaurus resembled other ceratopsians: a large, quadrupedal herbivore with a parrot-like beak, powerful jaw muscles, and a body adapted for cropping tough vegetation such as ferns, cycads, and early flowering plants.
One of its most distinctive features is the strongly forward-curving nasal horn, which gives the animal a striking, almost bison-like appearance. Unlike the upright horns of Triceratops, this horn curved forward in a hooked shape, making Einiosaurus immediately recognizable among horned dinosaurs. Its frill was relatively short and solid compared to more elaborately ornamented relatives such as Styracosaurus, suggesting a different balance between display and defence structures.
Although not much is known in detail due to limited fossil material, Einiosaurus likely behaved like other ceratopsians. It was almost certainly a herd animal, relying on group living for protection against predators such as Daspletosaurus, a large tyrannosaurid that shared its environment.
Some paleontologists also suggest that Einiosaurus may represent an evolutionary transition within centrosaurine ceratopsians, illustrating how horn shapes and skull ornamentation could evolve rapidly over relatively short geological timescales in response to environmental pressures and social behaviour.

Daspletosaurus

Daspletosaurus on stamp of USA 1997

This large tyrannosaurid theropod, a close relative and likely evolutionary precursor to Tyrannosaurus rex, was truly a “frightful lizard”, Daspletosaurus reached lengths of over 9 metres and weighed around 2.5 to 3 tonnes, making it one of the dominant predators of its Late Cretaceous ecosystem. With its powerful build and highly developed sensory system, it was well adapted for pursuing and subduing large prey.
Although it lived slightly earlier than Tyrannosaurus rex, Daspletosaurus likely hunted many of the same herbivorous dinosaurs in a similar manner. It shared its environment with another major predator, the more lightly built tyrannosaurid Albertosaurus. These two species probably occupied slightly different ecological niches, reducing direct competition—much like lions and leopards coexisting on the African savanna.
Like all tyrannosaurids, Daspletosaurus had a reduced forelimb structure with only two functional fingers, but compensated with massive skull musculature, a powerful bite, and thick, serrated teeth designed for delivering devastating strikes. Rather than relying solely on blood loss, its bite may have caused severe internal trauma and shock, which could have rapidly incapacitated prey even if the initial wounds were not immediately fatal.
Fossil evidence suggests that Daspletosaurus was an apex predator in its environment, occupying a top position in the food chain and playing a crucial role in regulating herbivore populations within Late Cretaceous ecosystems.

Corythosaurus

Corythosaurus on stamp of USA 1997

This hadrosaur from the Late Cretaceous is known for its distinctive cranial crest, which resembles the helmets worn by ancient Greek warriors. Its name means “Corinthian helmet lizard”. Corythosaurus is closely related to Iguanodon and belongs to the group commonly known as duck-billed dinosaurs (hadrosaurs). These dinosaurs are characterized by a toothless, keratin-covered beak at the front of the mouth, giving them a duck-like appearance, while the chewing teeth were located far back in the jaw.
This dental arrangement is unusual compared to many other herbivorous dinosaurs, which often swallowed vegetation with minimal processing. In contrast, hadrosaurs possessed highly specialized dental batteries consisting of tightly packed teeth that were continuously replaced and self-sharpening, allowing them to efficiently grind tough plant material.
There has long been debate about the degree to which hadrosaurs were bipedal versus quadrupedal. While their hind limbs suggest strong bipedal capability, the structure of the forelimbs indicates they were also well adapted for walking on all fours, likely allowing flexible movement depending on behaviour such as feeding or migration.
The function of the large hollow crest on the head has been widely studied. Modern imaging techniques, including CT scans, suggest that these structures likely played a role in sound production, functioning as resonating chambers for vocal communication. These sounds may have been used for mate attraction, herd coordination, or species recognition.
One can imagine large herds of hadrosaurs producing a complex range of calls, perhaps resembling a chaotic orchestra of overlapping sounds. Such vocalizations may have served both to communicate within the herd and to deter predators, depending on whether the listener was a hungry theropod or, humorously, a “music critic”.

Ornithomimus

Ornithomimus on stamp of USA 1997

Meaning “bird mimic,” Ornithomimus was a remarkably fast “ostrich dinosaur” that closely resembled modern flightless ratites in overall body plan. It reached lengths of around 4 to 4.5 metres and weighed approximately 130 to 150 kilograms, making it lightly built and highly adapted for speed.
These Late Cretaceous omnivores are often considered among the fastest dinosaurs known, with long, powerful hind limbs suggesting running speeds comparable to modern large ground birds such as ostriches. Closely related forms include Struthiomimus, another well-known member of the ornithomimid group.
A famous popular depiction of their vulnerability comes from Jurassic Park, where a Tyrannosaurus rex ambushes a fleeing Gallimimus. While dramatic, this scene reflects a plausible ecological reality: despite their speed, ornithomimids could still fall prey to large, ambush-hunting theropods.
Ornithomimus had a toothless beak resembling that of modern birds, suggesting a diet that likely included a mix of plants, insects, and small animals. Its relatively large eyes and enlarged braincase (compared to many other dinosaurs) have led some researchers to propose that ornithomimids were among the more behaviourally complex dinosaur groups, with keen vision and advanced sensory abilities suited for fast, alert movement in open environments.

Parasaurolophus

Parasaurolophus on stamp of USA 1997

Truly one of the most unusual-looking of all dinosaurs, this duck-billed dinosaur, Parasaurolophus, gets its name meaning “like or beside Saurolophus”, reflecting its close relationship within the hadrosaur group. It belonged to the lambeosaurine hadrosaurs, a subfamily known for their elaborate hollow cranial crests.
Although relatively few complete skeletons of this Late Cretaceous species have been discovered, it is known from parts of western North America, including regions of modern-day Canada, Utah, and New Mexico. This suggests it may have been less common than some of its hadrosaur relatives, but still widely distributed across varied habitats.
A large ornithopod, Parasaurolophus could reach lengths of around 10 metres. It was primarily bipedal but likely capable of moving on all fours while feeding. Its most striking feature was its long cranial crest, which in some individuals could extend over 1.5 metres, potentially connecting with soft tissues or skin structures along the head or neck.
It is widely believed that the elaborate crests of lambeosaurine hadrosaurs served multiple functions, particularly in sound production. These structures likely acted as resonating chambers, enabling individuals to produce distinctive calls for communication, alarm signals, and possibly mating displays. This supports the idea that hadrosaurs were highly social animals, living in herds and potentially undertaking seasonal migrations for protection and resource access.
Such herd behaviour would have provided important defence against large predators, which likely targeted isolated individuals whenever the opportunity arose.

Palaeosaniwa

Palaeosaniwa on stamp of USA 1997

A close relative of modern monitor lizards, Palaeosaniwa (“before Saniwa”) was a large varanoid lizard that lived during the Late Cretaceous, roughly comparable in size to the modern Komodo dragon. It likely reached lengths of about 3–3.5 metres and weighed up to approximately 150–160 kilograms. This places it among the largest terrestrial lizards of its time.
Varanoid lizards of the broader past included a wide range of forms, from giant marine reptiles such as Mosasaurus, which could exceed 15 metres in length, to smaller terrestrial and semi-arboreal species like Estesia, which has been suggested by some studies to have had venomous capabilities and may be related to modern-day Gila monsters.
Some researchers have proposed that snakes may have evolved from early varanoid lizards such as Palaeosaniwa, although this hypothesis remains debated and is not universally accepted within the scientific community.
Like modern monitor lizards, Palaeosaniwa was likely an opportunistic predator. Today’s monitors are highly adaptable feeders, consuming a wide range of food including insects, worms, fish, small mammals, birds, carrion, and eggs. Larger species such as the Komodo dragon rely on ambush hunting but will also scavenge when the opportunity arises. It is therefore likely that Palaeosaniwa occupied a similar ecological role, behaving as a versatile predator and scavenger within its Late Cretaceous environment, with little fundamental difference in lifestyle compared to its modern relatives.

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Other prehistoric animals on the sheet margin

A scene in Colorado, 150 million years ago

Archaeopteryx

Archaeopteryx on stamp of USA 1997

Archaeopteryx (“original bird” or “first bird”) is a genus of small theropod dinosaur closely related to the origin of birds. Since its discovery in the late 19th century, it has traditionally been regarded by many palaeontologists, and widely presented in popular science literature, as the earliest known bird. However, more recent studies have questioned this classification, with some analyses interpreting it instead as a non-avialan dinosaur closely related to the lineage that gave rise to modern birds.
Archaeopteryx lived during the Late Jurassic approximately 150 million years ago, in what is now southern Germany. At that time, Europe consisted of a series of low-lying tropical islands situated in a warm, shallow sea, much closer to the equator than today.
In overall appearance, Archaeopteryx was similar in size and shape to a European magpie, with the largest individuals possibly approaching the size of a raven. It reached a body length of around 0.5 metres. Despite its small size, broad feathered wings, and inferred ability to glide or actively fly, Archaeopteryx retained many anatomical features typical of non-avian dinosaurs.
In fact, it shares several key characteristics with deinonychosaurs (including dromaeosaurids and troodontids), such as jaws lined with sharp teeth, three-fingered hands with claws, a long bony tail, and a hyperextensible second toe often referred to as a “killing claw”, In addition, its feathers suggest a degree of warm-blooded metabolism (homeothermy), and its overall skeletal structure reflects a clear transitional form between non-avian dinosaurs and modern birds.

Comodactylus ostromi

Comodactylus ostromi on stamp of USA 1997

Comodactylus is a genus of “rhamphorhynchoid” pterosaur from the Kimmeridgian–Tithonian stages of the Late Jurassic Morrison Formation of Wyoming, USA. It is known from a single fossil element—a wing metacarpal—which forms the basis of its scientific identification.

The history of its discovery dates back to 1879, when fossil collector William Harlow Reed sent material excavated from Como Bluff (Quarry N 9, also known as the “Mammal Quarry”) to his employer, palaeontologist Othniel Charles Marsh at Yale University. Among the specimens was a pterosaur bone that was subsequently catalogued and then largely forgotten for nearly a century.
In 1981, the material was formally described and named Comodactylus by Peter Galton. The type species is Comodactylus ostromi. The genus name derives from Como Bluff and the Greek daktylos (“finger”), referring to the elongated wing finger characteristic of pterosaurs. The species name honours the influential palaeontologist John Ostrom.
Based on the preserved material, the wingspan of Comodactylus has been estimated at approximately 2.5 metres, which is exceptionally large for a non-pterodactyloid pterosaur. It is also significant as one of the first pterosaurs outside the Pterodactyloidea to be identified from North America.

A scene in Montana, 75 million years ago

Stegoceras

Stegoceras on stamp of USA 1997

Stegoceras had an estimated length of up to 2 metres and weighed approximately 55–70 kilograms. It is best known for its relatively large braincase, which was enclosed within a dome of thick bone up to about 7.5 centimetres in thickness, internally divided into two regions. The dome’s outer surface appears relatively smooth but is irregularly pitted by numerous foramina, which likely served as openings for blood vessels and sensory structures within the bone.
Stegoceras validum can be distinguished by features such as a well-developed parietosquamosal shelf, open supratemporal fossae, early stages of frontal and parietal doming, and small clustered nodules on the postorbital and squamosal bones. Its rounded, forward-facing eye sockets suggest strong binocular vision and good depth perception.
The teeth of Stegoceras were small, curved, and finely serrated, indicating an herbivorous or omnivorous diet. The skull was supported by an S- or U-shaped neck, which helped balance its relatively heavy head. Early interpretations of its fossil remains suggested the presence of gastralia (belly ribs), but these structures were later correctly identified as ossified tendons, a feature more typical of ornithischian dinosaurs than true rib structures.
The hind limbs of Stegoceras were proportionally much longer than the forelimbs, with the legs exceeding the arm length by more than three times. This limb structure suggests a primarily bipedal stance and movement.
Stegoceras was first named in 1902 by Lawrence Lambe, and the type species is Stegoceras validum. All known specimens (approximately 40 individuals) have been recovered from the Belly River Group of Alberta, Canada. Most come from the Dinosaur Park Formation (Late Campanian, approximately 76.6 million years ago) within Dinosaur Provincial Park, while others have been found in the older Oldman Formation (middle Campanian, approximately 77.5–76.5 million years ago).

Quetzalcoatlus

Quetzalcoatlus on stamp of USA 1997

Quetzalcoatlus was a pterodactyloid pterosaur from the Late Cretaceous of North America (Maastrichtian stage, approximately 68–66 million years ago), and one of the largest flying animals ever known. It belonged to the Azhdarchidae, a group of advanced, toothless pterosaurs characterized by extremely long, stiffened necks and proportionally large heads. Its name is derived from the Mesoamerican feathered serpent deity Quetzalcoatl.
Fossil evidence indicates that Quetzalcoatlus possessed a long, sharply pointed beak, contrary to earlier reconstructions that depicted a blunter snout. Those earlier interpretations were based on the accidental inclusion of jaw material from other pterosaur groups, possibly tapejarids or forms related to Tupuxuara. A cranial crest may have been present, although its precise shape and size remain uncertain due to incomplete fossil material.
The first fossils of Quetzalcoatlus were discovered in 1971 in the Maastrichtian-aged Javelina Formation of Big Bend National Park, Texas, by geology graduate student Douglas A. Lawson of the University of Texas at Austin’s Jackson School of Geosciences. The original specimen consisted of a partial wing, including elements of the forelimb and the elongated fourth finger that supports the wing membrane in pterosaurs.
Subsequent estimates suggest that the largest individuals reached wingspans of over 10 metres, making Quetzalcoatlus one of the largest known flying vertebrates in Earth’s history. Its combination of size, skeletal structure, and likely flight capability makes it a key example of extreme adaptation in pterosaur evolution.

Alphadon

Alphadon on stamp of USA 1997

Alphadon (“first tooth”) was a genus of small, primitive mammal belonging to the metatherians, the broader group that includes modern marsupials. Its fossils were first described and named in 1929 by the American palaeontologist George Gaylord Simpson, who played a major role in the study of early mammalian evolution.
Because Alphadon is primarily known from isolated teeth and fragmentary remains, its full appearance is not well understood. However, based on comparative anatomy, it is estimated to have reached a body length of around 30 centimetres and may have resembled a modern opossum in general form and lifestyle.
The structure of its teeth suggests that Alphadon was likely an omnivore, feeding on a varied diet that included fruits, insects and other invertebrates, and possibly small vertebrates when available.
Alphadon lived during the Late Cretaceous, coexisting with iconic dinosaurs such as Tyrannosaurus rex and Triceratops. Its fossils have been discovered across a wide geographic range in North America, from Alberta in Canada to New Mexico in the southern United States, indicating it was a widespread and adaptable small mammal in Late Cretaceous ecosystems.

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Modern-like animals on the sheet margin

Turtle

Dragonfly

Frogs Heron-like bird

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Products and associated philatelic items

No official First Day Cover (FDC) was issued in connection with this stamp issue. The United States Postal Service did not produce an official FDC or a pictorial First-Day-of-Issue postmark. However, many pictorial postmarks were produced for special events related to the issue, most of them dated May 2^nd, 1997 (the second day of issue). Additional postmarks continued to be produced throughout the year.
All First Day Covers and maxi cards illustrated below are privately produced items.

FDC with entire sheet	Example of Circulated Cover	Example of a Maxi Card
Examples of personalized FDC

01.05.1997 "The World of Dinosaurs"	01.05.1997 "Dinosaur Valley Museum STA., Grand Junction, CO"	02.05.1997 "Dinosaur Station Bozeman, MT"
02.05.1997 "The real Dinosaurland Station, Vernal, Utah"	02.05.1997 "Dinosaur Station Agar, SD"	02.05.1997 "Denver Museum of Natural History, Dino Station, Denver, Colorado"
02.05.1997 "The world of Dinosaurs, Hinckley Library Station, Hinckley, Ohio"	02.05.1997 "Prehistory week in College of Eastern UT Sta., Price, UT"	03.05.1997 "New Mexico Museum of Natural History and Science"
15.05.1997 "Dinosaur station, Faith, SD"	15.05.1997 "Dinosaur station, Rolla, ND"	16.05.1997 "DINO Station Canton, OH"
17.05.1997 "Museum Day Station, Lubbock, TX"	19.05.1997 "Dinosaur station, Reva, SD"	24.05.1997 "Fossil Festival Station, Aurora, NO"

Other commemorative, pictorial postmarks, related to the dinosaur stamps can be seen in the USA page of the catalogue.

References

Education World, Everett Spruill, Biopark, Wikipedia, Stampedout, Mysticstamp, Wikipedia.

Acknowledgement

Many thanks to Dr. Peter Voice from Department of Geological and Environmental Sciences, Western Michigan University, for reviewing the draft page, his valuable comments and great help to find materials for this article.