A new scientific study has been published into the sound resonating capabilities of ornate head crests of four genera of Lambeosaurine Hadrosaurs, (duck-billed dinosaurs), building on earlier American studies from the 1980s and 1990s.
Why the Bizarre Crests on Hadrosaurs?
For many years scientists have puzzled over the exact function of the duck-billed dinosaur crests. Hadrosaurs are split into two main groups, the Hadrosaurines (example being Edmontosaurus) animals with small or no head crests and the Lambeosaurines (Corythosaurus, Charonosaurus etc.) with flamboyant crests.
From the extensive Hadrosaur fossil remains now known, it can be seen that the size and shape of the crest changed as animals grew and reached maturity. Also, some Lambeosaurine species seem to show differences in crest shape and size between species. A number of fossil skulls of the species Parasaurolophus walkeri have different sized crests and this may indicate that the males had larger more prominent crests than females. There are a number of studies and reviews being conducted at the moment to try to identify medullary bone in the Hadrosaur fossil record. Finding evidence of this particular type of bone tissue in duck-billed dinosaurs with their skulls and crests preserved would help scientists to identify females amongst the fossil record.
Medullary Bone Helping to Separate the Girls from the Boys
Medullary bone is a thin layer of very vascular bone that is formed in modern birds during ovulation. The formation of this bone type is linked to high levels of the female hormone oestrogen. This type of bone is formed in the leg bones and exists until the last egg has been laid. It is then re-absorbed by the body. This tissue provides a source of calcium for the creation of eggshells. The presence of fossilised medullary bone structures may help scientists to pick out the girls from the boys. Using this data, a better understanding of head crest shape and morphology could then be derived.
This new research carried out by a team of Canadian and American researchers, and published in the scientific journal "The Anatomical Record", concludes that duck-billed dinosaurs were capable of producing a variety of sounds, and the size and shape of the crest influenced the sound produced. The researchers go on to theorise that as these dinosaurs grew and reached sexual maturity their voices altered. The larger crests of mature animals would help make different sounds compared to the voices of juveniles.
In a way, this is similar to our own species in which the male voice "breaks" prior to the onset of adulthood.
Building on Earlier Studies
Building on earlier research into Hadrosaur vocalisation, the team were able to study crests and nasal passages in great detail using CAT scans to determine the internal structure of these ornate items of dinosaur headgear. In addition, studies of casts from Hadrosaur brain cases were included in the work to help clarify the relationship between these crests and the olfactory part of the brain (sense of smell). The team's results seems to confirm one of the earlier theories, that the head crests were used for vocal communication - not to enhance the sense of smell.
And if the research is validated, it would indicate that when a Lambeosaurine made calls, air would travel through the nasal passages enclosed by the head crest. Since the sizes and shapes of head crests (and nasal passages) differed among Lambeosaurine genera and amongst individuals of a species, this would be evidence that each dinosaur had its own distinct voice.
Girl make different animals voices very funny by KhanTune.com
Article Source: http://EzineArticles.com/7302177
Why the Bizarre Crests on Hadrosaurs?
For many years scientists have puzzled over the exact function of the duck-billed dinosaur crests. Hadrosaurs are split into two main groups, the Hadrosaurines (example being Edmontosaurus) animals with small or no head crests and the Lambeosaurines (Corythosaurus, Charonosaurus etc.) with flamboyant crests.
From the extensive Hadrosaur fossil remains now known, it can be seen that the size and shape of the crest changed as animals grew and reached maturity. Also, some Lambeosaurine species seem to show differences in crest shape and size between species. A number of fossil skulls of the species Parasaurolophus walkeri have different sized crests and this may indicate that the males had larger more prominent crests than females. There are a number of studies and reviews being conducted at the moment to try to identify medullary bone in the Hadrosaur fossil record. Finding evidence of this particular type of bone tissue in duck-billed dinosaurs with their skulls and crests preserved would help scientists to identify females amongst the fossil record.
Medullary Bone Helping to Separate the Girls from the Boys
Medullary bone is a thin layer of very vascular bone that is formed in modern birds during ovulation. The formation of this bone type is linked to high levels of the female hormone oestrogen. This type of bone is formed in the leg bones and exists until the last egg has been laid. It is then re-absorbed by the body. This tissue provides a source of calcium for the creation of eggshells. The presence of fossilised medullary bone structures may help scientists to pick out the girls from the boys. Using this data, a better understanding of head crest shape and morphology could then be derived.
This new research carried out by a team of Canadian and American researchers, and published in the scientific journal "The Anatomical Record", concludes that duck-billed dinosaurs were capable of producing a variety of sounds, and the size and shape of the crest influenced the sound produced. The researchers go on to theorise that as these dinosaurs grew and reached sexual maturity their voices altered. The larger crests of mature animals would help make different sounds compared to the voices of juveniles.
In a way, this is similar to our own species in which the male voice "breaks" prior to the onset of adulthood.
Building on Earlier Studies
Building on earlier research into Hadrosaur vocalisation, the team were able to study crests and nasal passages in great detail using CAT scans to determine the internal structure of these ornate items of dinosaur headgear. In addition, studies of casts from Hadrosaur brain cases were included in the work to help clarify the relationship between these crests and the olfactory part of the brain (sense of smell). The team's results seems to confirm one of the earlier theories, that the head crests were used for vocal communication - not to enhance the sense of smell.
And if the research is validated, it would indicate that when a Lambeosaurine made calls, air would travel through the nasal passages enclosed by the head crest. Since the sizes and shapes of head crests (and nasal passages) differed among Lambeosaurine genera and amongst individuals of a species, this would be evidence that each dinosaur had its own distinct voice.
Girl make different animals voices very funny by KhanTune.com
Article Source: http://EzineArticles.com/7302177
