Lambeosaurus is one of the hadrosaurs that is frequently depicted in dinosaur books and toys, and study of this genus is required learning for anyone who wishes to know more about the hadrosaurs in general.
Lambeosaurus is best known from Canada and upper Montana USA, although other attributed fossils in the past have suggested that Lambeosaurus had a significantly broader range. The most distinctive feature of Lambeosaurus is the crest which is often described as being either hatchet or axe shaped, the broader forward portion being the blade while the thin rearward projection is the handle. This rear projection is solid; however the forward portion is hollow with a network of passages inside (a signature feature of the lambeosaurine hadrosaurids).
The function of the crest is one of the most often talked about areas of the body. One explanation is that the crest was used as either a snorkel or an air chamber for trapping a supply of breathable air so that Lambeosaurus could hold their heads underwater for extended periods. This however would require Lambeosaurus to regularly be active within bodies of water, and it does not explain the variance in form of head crests between Lambeosaurus and other lambeosaurine genera.
One exciting theory is that the crests allowed for the storage of salt glands, special organs that allow excess salt from the environments to be excreted. However the presence of salt glands is usually associated with animals that live in marine (saltwater) ecosystems which have higher levels of salts, thus necessitating the presence of salt glands. This is not actually that much of a stretch to believe however since during the late Cretaceous most of central North America was submerged by a shallow sea called the Western Interior Seaway that ran North to South from what is now Upper Canada into the Gulf of Mexico. The areas that Lambeosaurus remains are known from have been interpreted as being marshes and swamps that were in close proximity to the coastline of the Western Interior Sea. Additionally a 1979 paper by palaeontologist Jack R. Horner described what appeared to be Lambeosaurus jaws (L. magnicristatus) from marine sediment. The problems with this theory however is that it is that with this evidence it is only relevant to Lambeosaurus, with many other hadrosaurs being known from different ecosystems. Additionally this does not explain the difference in crest form between not only hadrosaur genera, but the two main Lambeosaurus species.
The only theory that explains the different crest forms is that of display. Firstly different species of Lambeosaurus would be able to tell each other apart by the different form of head crest, as well as any hadrosaurid other genera that were active in the same locations as they were. Additionally the crests of adult Lambeosaurus were more developed than juveniles which indicates that they were also a sign of maturity. Specimens thought to be females also have more rounded crests than the males.
Another factor concerning display is that of sound. The forward portion of the crest is hollow with a network of tubes, and assuming this is not just a weight saving feature to reduce stress on the head and neck, this may have formed a resonating chamber for amplifying the calls. Not only have studies continually revisited this area, but different crest variations between species should allow for different sounding calls. Study in one specimen of the related Corythosaurus also suggests that lambeosaurine hadrosaurids in particular had very good hearing, further supporting the auditory hypothesis for the crest.
Size estimates for Lambeosaurus can vary greatly depending upon source because of the large amounts of fossil remains that have been attributed to the genus. The confirmed Lambeosaurus remains that are known from Alberta Canada and Montana, USA point to individuals around the nine to nine and a half meter mark for total length. Upper estimates of fifteen meters long still exist in some sources however, though this estimate is based upon material that is no longer attributed to the Lambeosaurus genus. This stems back to the description of a dubious species of Lambeosaurus in 1981 called L. laticaudus from fossils found in Baja California. The Lambeosaurus connection however could never be confirmed since the crest is missing. In 2012 these remains were re-established as a new genus called Magnapaulia.
As with all hadrosaurids, Lambeosaurus seems to have been primarily quadrupedal with the ability to balance and possibly walk on just the rear legs when it had to. Out of the original five digits of the fore-arm hand, the first digit is missing, lost through selective evolutionary factors. Digits two, three and four are developed into weight bearing hooves, and when combined with footprints of other hadrosaurids, confirms the idea that Lambeosaurus, and other hadrosaurids, were mostly bipedal. The fifth digit is free from the others and may have been to help grip and/or balance when the body weight was shifted forward.
By being both quadrupedal and occasionally bipedal, Lambeosaurus could browse upon anything from low to moderately high growing vegetation. The anterior portion of the mouth however is narrower than in many other hadrosaurids, something that suggests that Lambeosaurus were more selective in their browsing habits. Once food was removed from the main plant, it was then processed by the grinding teeth that were arranged in batteries at the back of the mouth.
Lambeosaurus possibly shared its habitat with other genera of hadrosaur such as Corythosaurus, though this genus is currently known from slightly older Campanian deposits, which indicates that Lambeosaurus may have actually replaced Corythosaurus. Other dinosaurs roughly active around that time and locale include the ceratopsians Chasmosaurus and Centrosaurus, the nodosaur Edmontonia as well as the ankylosaur Euoplocephalus. However the exact relationships between these different dinosaurs is still being established since some such as ankylosaurs seem to have been better adapted to dryer more arid environments due to the arrangements of their nasal passages. Predators of Lambeosaurus may have included Campanian era tyrannosaurs such as Albertosaurus and Daspletosaurus.
Lambeosaurus is best known from Canada and upper Montana USA, although other attributed fossils in the past have suggested that Lambeosaurus had a significantly broader range. The most distinctive feature of Lambeosaurus is the crest which is often described as being either hatchet or axe shaped, the broader forward portion being the blade while the thin rearward projection is the handle. This rear projection is solid; however the forward portion is hollow with a network of passages inside (a signature feature of the lambeosaurine hadrosaurids).
The function of the crest is one of the most often talked about areas of the body. One explanation is that the crest was used as either a snorkel or an air chamber for trapping a supply of breathable air so that Lambeosaurus could hold their heads underwater for extended periods. This however would require Lambeosaurus to regularly be active within bodies of water, and it does not explain the variance in form of head crests between Lambeosaurus and other lambeosaurine genera.
One exciting theory is that the crests allowed for the storage of salt glands, special organs that allow excess salt from the environments to be excreted. However the presence of salt glands is usually associated with animals that live in marine (saltwater) ecosystems which have higher levels of salts, thus necessitating the presence of salt glands. This is not actually that much of a stretch to believe however since during the late Cretaceous most of central North America was submerged by a shallow sea called the Western Interior Seaway that ran North to South from what is now Upper Canada into the Gulf of Mexico. The areas that Lambeosaurus remains are known from have been interpreted as being marshes and swamps that were in close proximity to the coastline of the Western Interior Sea. Additionally a 1979 paper by palaeontologist Jack R. Horner described what appeared to be Lambeosaurus jaws (L. magnicristatus) from marine sediment. The problems with this theory however is that it is that with this evidence it is only relevant to Lambeosaurus, with many other hadrosaurs being known from different ecosystems. Additionally this does not explain the difference in crest form between not only hadrosaur genera, but the two main Lambeosaurus species.
The only theory that explains the different crest forms is that of display. Firstly different species of Lambeosaurus would be able to tell each other apart by the different form of head crest, as well as any hadrosaurid other genera that were active in the same locations as they were. Additionally the crests of adult Lambeosaurus were more developed than juveniles which indicates that they were also a sign of maturity. Specimens thought to be females also have more rounded crests than the males.
Another factor concerning display is that of sound. The forward portion of the crest is hollow with a network of tubes, and assuming this is not just a weight saving feature to reduce stress on the head and neck, this may have formed a resonating chamber for amplifying the calls. Not only have studies continually revisited this area, but different crest variations between species should allow for different sounding calls. Study in one specimen of the related Corythosaurus also suggests that lambeosaurine hadrosaurids in particular had very good hearing, further supporting the auditory hypothesis for the crest.
Size estimates for Lambeosaurus can vary greatly depending upon source because of the large amounts of fossil remains that have been attributed to the genus. The confirmed Lambeosaurus remains that are known from Alberta Canada and Montana, USA point to individuals around the nine to nine and a half meter mark for total length. Upper estimates of fifteen meters long still exist in some sources however, though this estimate is based upon material that is no longer attributed to the Lambeosaurus genus. This stems back to the description of a dubious species of Lambeosaurus in 1981 called L. laticaudus from fossils found in Baja California. The Lambeosaurus connection however could never be confirmed since the crest is missing. In 2012 these remains were re-established as a new genus called Magnapaulia.
As with all hadrosaurids, Lambeosaurus seems to have been primarily quadrupedal with the ability to balance and possibly walk on just the rear legs when it had to. Out of the original five digits of the fore-arm hand, the first digit is missing, lost through selective evolutionary factors. Digits two, three and four are developed into weight bearing hooves, and when combined with footprints of other hadrosaurids, confirms the idea that Lambeosaurus, and other hadrosaurids, were mostly bipedal. The fifth digit is free from the others and may have been to help grip and/or balance when the body weight was shifted forward.
By being both quadrupedal and occasionally bipedal, Lambeosaurus could browse upon anything from low to moderately high growing vegetation. The anterior portion of the mouth however is narrower than in many other hadrosaurids, something that suggests that Lambeosaurus were more selective in their browsing habits. Once food was removed from the main plant, it was then processed by the grinding teeth that were arranged in batteries at the back of the mouth.
Lambeosaurus possibly shared its habitat with other genera of hadrosaur such as Corythosaurus, though this genus is currently known from slightly older Campanian deposits, which indicates that Lambeosaurus may have actually replaced Corythosaurus. Other dinosaurs roughly active around that time and locale include the ceratopsians Chasmosaurus and Centrosaurus, the nodosaur Edmontonia as well as the ankylosaur Euoplocephalus. However the exact relationships between these different dinosaurs is still being established since some such as ankylosaurs seem to have been better adapted to dryer more arid environments due to the arrangements of their nasal passages. Predators of Lambeosaurus may have included Campanian era tyrannosaurs such as Albertosaurus and Daspletosaurus.
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