| Name | Saurolophus | Diet | Herbivorous |
| Name Meaning | Lizard crest | Height | 2.5-4 meters (8.2-13.1 feet) |
| Pronunciation | Sore-oh-loaf-us | Length | 8.2-13 meters (27-42.7 feet) |
| Era | Mesozoic – Late Cretaceous | Weight | 3-11 metric tons (3.3-12.1 short tons) |
| Classification | Dinosauria, Ornithischia, & Ornithopoda | Location | Alberta, Canada, Mongolia, China |
Saurolophus Pictures
The Saurolophus
The discovery of Saurolophus, an ornithopod hadrosaurid, marked a turning point in paleontology.
The genus served as a reference point for describing other hadrosaurs like Parasaurolophus.
Otherwise known as the lizard crest, Saurolophus walked on our planet approximately 70-66 million years ago during the Late Cretaceous.
It was an inhabitant of today’s Asia and North America, probably more common on the Asian continent.
Saurolophus was a herbivorous dinosaur with a distinctive spike-like crest.
Although it was primarily quadrupedal, it could move bipedally as well, most likely while foraging or escaping predators.
Having been discovered in fossil-crowded formations, we assume that Saurolophus shared its habitat with many other prehistoric creatures, including herbivorous and carnivorous dinosaurs.
Naturally, there may have been some competition for food with plant eaters, and they may have fallen prey to predators.
Don’t hesitate to keep reading if you want to learn what else we’ve discovered about the Saurolophus!
Physical Characteristics
The Saurolophus is most renowned thanks to its long, spike-like cranial crest.
It rises from over the eyes and projects upward and backward, forming a 45-degree angle with the skull.
The crest in juveniles is slightly smaller than in adults. Additionally, scientists argue that the crest is likely longer in Saurolophus angustirostris than in Saurolophus osborni.
The size differs between the species.
The type species, S. osborni, measured approximately 8.2-8.5 meters (27-28 feet) long and weighed roughly three metric tons (3.3 short tons).
Its skull was only 1 meter (3.3 feet) long.
The second species in the genus, S. angustirostris, had a larger skull that reached 1.22 meters (4 feet) long.
Based on these estimations and other postcranial remains, scientists estimate a maximum length for S. angustirostris of 13 meters (42.7 feet) and a weight of 11 metric tons (12.1 short tons) – almost three times the weight of the type species.
Apart from size, the two species were likely similar.
They had bulky bodies, short U-shaped necks, sturdy legs, and long tails.
The forelimbs were probably shorter than the hind limbs, which ensured a slightly bent, downward quadrupedal posture.
Some S. angustirostris specimens showed evidence of rectangular scales arranged in a row along the back and the tail.
Although these weren’t preserved in the type species, we cannot rule out the possibility that they were present.
Soft tissue reconstructions point to another possible difference between the two – S. angustirostris may have had a striped coloration, while S. osborni was probably mottled or spotted.
Habitat and Distribution
Saurolophus fossils were unearthed from the following locations:
- Horseshoe Canyon Formation, near Tolman Ferry on the Red Deer River, Alberta
- Heilongjiang, China
- Nemegt Formation, Mongolia
Fossils were more abundant on the Asian continent; the Saurolophus may have had quite a wide distribution there.
However, few fossils were recovered on the North American continent, but scientists aren’t yet fully sure precisely how rare Saurolophus was in North America.
The Canadian Horseshoe Canyon Formation probably featured floodplains, coal swamps, and estuarine channels.
From the late Campanian until the early Maastrichtian, this territory underwent paleoenvironmental and paleoclimatic changes linked to soil drainage conditions.
The climate was still relatively warm and humid, although it registered a slight drop in temperature and precipitation.
The mentioned soil drainage conditions may have also ensured an unstable landscape and migratory barriers.
The Nemegt Formation is located in the Gobi Desert in Mongolia.
This territory was likely a wet ecosystem covered in forests filled with streams, floodplains, and shallow lakes.
It supported the growth of coniferous trees, flowering aquatic plants, and freshwater plants.
The habitat was diverse enough to sustain the thriving of numerous prehistoric animals, including various dinosaurs.
Behavior and Diet
Saurolophus is often portrayed as a quadrupedal herbivore.
However, like other herbivores, it could also walk on two legs.
Scientists suggest the Saurolophus specialized in eating a wide variety of plants thanks to its grinding motion, similar to chewing, and its teeth that were replaced continuously.
Like other herbivores, the Saurolophus had a broad beak used for cropping plants, further widening its dietary adaptations.
It has been suggested that the preferred plants were at most 4 meters (13 feet) tall.
Studies on the Saurolophus scleral rings show it was likely a cathemeral creature.
This means it went out to feed during the day and the night, but only at short, irregular intervals.
When active, it may have exhibited a certain degree of gregariousness, which is quite common in hadrosaurines.
However, scientists haven’t been able to confirm this fully yet.
One essential thing to mention when discussing Saurolophus behavior is the function of its crest.
Some scientists argued that the crest helped with thermoregulation, which is supported by the fact that the main purpose of this structure was likely to extend the respiratory surface of the nasal passage.
Additionally, the crest may have helped acclimatize the inhaled air.
Other scholars suggested it functioned as a visual signal structure. It may have even functioned as a chameleon-like crest.
Life Cycle
It has been suggested that the distinctive crest described in Saurolophus may have served as sexual identification or for sexual display.
However, how it was used and to what extent it marked the sexual display remain unknown.
All dinosaurs reproduced by laying eggs, and Saurolophus was no exception.
Since fossilized dinosaur eggs and nests are quite rare, very little is known about the other reproductive behaviors of many of the dinosaurs known today.
That’s why presuming something about their nesting or incubating behavior would be speculation.
However, luckily for us, paleontologists discovered a partial nest with fragmentary eggshells and 3-4 juveniles associated with Saurolophus angustirostris.
Guiding themselves by the size of the skulls, scientists confirmed that the juveniles were in the earliest developmental stage when they died.
They also confirmed that the juveniles lacked the distinctive crest observed in adults or, at least, poorly developed.
It has been suggested that hadrosaurs didn’t always rely primarily on quadrupedal movement.
As juveniles, they likely walked mostly on their hind legs, switching to a preponderantly quadrupedal lifestyle once they matured.
This occurred once the front limbs became more robust and could bear more weight.
Evolution and History
Saurolophus is a hadrosaurid.
The Hadrosauridae family dates back to 86 million years ago and is now one of the most well-studied families of dinosaurs in terms of phylogenetics, morphology, and paleoecology.
Some studies argue that hadrosaurids originated in Asia and subsequently migrated to North America and Europe, while others state otherwise – that hadrosaurids originated in North America and dispersed into Asia.
It hasn’t been concluded yet which is the most primitive hadrosaurid.
Some sources list the Telmatosaurus, others the Protohadros, but both are outside the Hadrosauridae family, although all three are hadrosauromorphs.
Another study points to Eotrachodon as one of the oldest and most basal hadrosaurids.
The Saurolophus is part of the Hadrosauridae family and is classified in the Saurolophini tribe, which consists of saurolophins that lived in the United States, Canada, and Asia.
Remains belonging to this hadrosaurid were first discovered in 1911 and included a nearly complete skeleton, which you can now see displayed in the American Museum of Natural History.
Barnum Brown classified this creature in a subfamily of its own, the Saurolophinae, now known to include the traditional hadrosaurines.
Since its discovery, the Saurolophus has represented an early reference for describing other hadrosaurs.
Over the years, paleontologists recovered new fossils, which led to the description of several species, of which only two are recognized today, S. osborni and S. angustirostris.
Another species, S. kryschtofovici, is now considered invalid or at least dubious.
Scientists named one more species in 2013 – S. morrisi.
It was named based on two partial skeletons discovered in California.
However, these two individuals were later associated with Augustynolophus.
Interactions with Other Species
Since Saurolophus fossils were more abundant in Asia than North America, it is widely believed that this dinosaur filled an important ecological niche in Asia.
At the same time, North American individuals probably faced more competition from other herbivores, as they were much rarer on the continent.
However, as happens with many statements about our world’s prehistory, these assumptions remain only assumptions until further findings are made.
Before providing you with a list of creatures the Saurolophus may have crossed paths with, we’d like to mention that it includes the inhabitants of both the Horseshoe Canyon Formation and the Nemegt Formation.
As such, here are some prehistoric animals that Saurolophus likely shared its habitat with:
- Ankylosaurs like Anodontosaurus, Edmontonia, and Euoplocephalus
- Theropods like Atrociraptor, Ornithomimus, Albertosaurus, Mononykus, Nemegtonykus, Gobiraptor, Deinocheirus, Therizinosaurus, Adasaurus, Tarbosaurus
- Ceratopsians like Eotriceratops, Montanoceratops, Pachyrhinosaurus
- Other hadrosaurs like Edmontosaurus, Hypacrosaurus, Barsboldia
- Pachycephalosaurs like Homalocephale and Prenocephale
- Sauropods like Nemegtosaurus
- Mammals like Didelphodon
- Reptiles like Stangerochampsa (an alligatorid), Leurospondylus (a plesiosaur), Paralligator (a paralligatorid), and Basilemys (a turtle)
- Amphibians like Altanulia
- Various fish species (although Saurolophus likely never crossed paths with them!)
- Birds like Brodavis, Judinornis, and Subtiliolithus
As we’ve already mentioned, the Saurolophus shared its ecosystem with many other herbivores, and the extent to which they competed for food may have differed in Asia and North America.
Fossil evidence shows that North American Saurolophus dinosaurs may have fallen prey to predators like Albertosaurus and possibly other smaller theropods.
Asia was home to the almighty Tarbosaurus, known to have preyed on dinosaurs like Saurolophus, Nemegtosaurus, and Barsboldia.
Cultural Significance
Before naming the Parasaurolophus in 1922, the Saurolophus was among the most popular and widely known hadrosaurs.
It was a frequent character in illustrated books and television documentaries.
However, once the Parasaurolophus was discovered and described, the Saurolophus lost its popularity.
This is confirmed by the fact that Parasaurolophus is now much more popular in the media and has gained much more attention from dinosaur enthusiasts.
Despite this, the Saurolophus plays an important role in the evolution of hadrosaurs and dinosaurs, so discussing its traits and lifestyle is paramount.
After all, each dinosaur was unique and deserves a spot in our dinosaur textbooks!
Conclusion
The Saurolophus was undoubtedly one of nature’s most interesting creations, thanks to its distinctive spike-like crest projecting from the skull!
Although not as famous as other hadrosaurids, Saurolophus is still a significant family member.
It was a quadrupedal/bipedal herbivore that walked today’s North America and Asia roughly 70-66 million years ago.
Paleontological expeditions revealed two recognized species that likely differed in size, coloration, and crest form.
Thanks to its adaptation of walking both bipedally and quadrupedally, the Saurolophus had the advantage of choosing to feed on a wide range of plants.
As such, it is believed to have had a major ecological role in Asia, where it was more abundant.
FAQs
What is the difference between Saurlophus and Parasaurolophus?
The Parasaurolophus was likely larger than the Saurolophus, reaching approximately 11.45 meters (37.6 feet) long.
Additionally, while the Saurolophus crest was solid, the Parasaurolophus crest was hollow, so they’re now classified into different subfamilies.
Can Saurolophus swim?
No fossil evidence shows that Saurolophus could swim or was semi-aquatic.
Sources:
- https://en.wikipedia.org/wiki/Saurolophus
- https://www.cambridge.org/core/journals/paleobiology/article/abs/evolution-of-cranial-display-structures-in-hadrosaurian-dinosaurs/BA5F0809133845325E397883BD2CB17E
- https://en.wikipedia.org/wiki/Horseshoe_Canyon_Formation
- https://en.wikipedia.org/wiki/Nemegt_Formation
- http://www.palaeontologia.pan.pl/Archive/1981-42_5-24_1-2.pdf
- https://www.app.pan.pl/article/item/app20100061.html
- https://www.researchgate.net/figure/Soft-tissue-reconstructions-of-Saurolophus-based-on-preserved-skin-impressions_fig25_221818484
- https://www.tandfonline.com/doi/abs/10.1080/02724634.2015.1054495
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4605499/
- https://www.jstor.org/stable/4523950
- https://academic.oup.com/zoolinnean/article/159/2/435/2622978?login=false
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