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Joanusaurus: Difference between revisions
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==Paleobiology== | ==Paleobiology== | ||
[[File:Allosaurus_attacks_Stegosaurus.jpg|thumb|''Joanusaurus'' and ''Stegosaurus'', [[Gabion Natural History Museum]]]] | [[File:Allosaurus_attacks_Stegosaurus.jpg|thumb|''Joanusaurus'' and ''Stegosaurus'', [[Gabion Natural History Museum]]]] | ||
The wealth of ''Joanusaurus'' fossils, from nearly all ages of individuals, allows scientists to study how the animal grew and how long its lifespan may have been. Remains may reach as far back in the lifespan as eggs—crushed eggs from Vollardie have been suggested as those of ''Joanusaurus''. Based on histological analysis of limb bones, bone deposition appears to stop at around 22 to 28 years, which is comparable to that of other large theropods like ''Caphirosaurus''. From the same analysis, its maximum growth appears to have been at age 15, with an estimated growth rate of about 150 kilograms (330 lb) per year. | The wealth of ''Joanusaurus'' fossils, from nearly all ages of individuals, allows scientists to study how the animal grew and how long its lifespan may have been. Remains may reach as far back in the lifespan as eggs—crushed eggs from Vollardie have been suggested as those of ''Joanusaurus''. Based on histological analysis of limb bones, bone deposition appears to stop at around 22 to 28 years, which is comparable to that of other large theropods like ''[[Caphirosaurus]]''. From the same analysis, its maximum growth appears to have been at age 15, with an estimated growth rate of about 150 kilograms (330 lb) per year. | ||
Paleontologists accept ''Joanusaurus'' as an active predator of large animals. There is dramatic evidence for ''Joanusaur'' attacks on ''Stegosaurus'', including a ''Joanusaurus'' tail vertebra with a partially healed puncture wound that fits a ''Stegosaurus'' tail spike, and a ''Stegosaurus'' neck plate with a U-shaped wound that correlates well with a ''Joanusaurus'' snout. Sauropods seem to be likely candidates as both live prey and as objects of scavenging, based on the presence of scrapings on sauropod bones fitting ''Joanusaurus'' teeth well and the presence of shed ''Joanusaurus'' teeth with sauropod bones. However, as Cadeaux noted in 1981, ''Joanusaurus'' was probably not a predator of fully grown sauropods, unless it hunted in packs, as it had a modestly sized skull and relatively small teeth, and was greatly outweighed by contemporaneous sauropods. | Paleontologists accept ''Joanusaurus'' as an active predator of large animals. There is dramatic evidence for ''Joanusaur'' attacks on ''Stegosaurus'', including a ''Joanusaurus'' tail vertebra with a partially healed puncture wound that fits a ''Stegosaurus'' tail spike, and a ''Stegosaurus'' neck plate with a U-shaped wound that correlates well with a ''Joanusaurus'' snout. Sauropods seem to be likely candidates as both live prey and as objects of scavenging, based on the presence of scrapings on sauropod bones fitting ''Joanusaurus'' teeth well and the presence of shed ''Joanusaurus'' teeth with sauropod bones. However, as Cadeaux noted in 1981, ''Joanusaurus'' was probably not a predator of fully grown sauropods, unless it hunted in packs, as it had a modestly sized skull and relatively small teeth, and was greatly outweighed by contemporaneous sauropods. | ||