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Joanusaurus: Difference between revisions
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==Description== | ==Description== | ||
[[File:Allosaurus_jimmadseni_skeletal.png|thumb|''J. iscastae'' skeletal reconstruction]] | [[File:Allosaurus_jimmadseni_skeletal.png|thumb|''J. iscastae'' skeletal reconstruction]] | ||
''Joanusaurus'' was a typical large bipedal theropod, having a massive skull on a short neck, a long, slightly sloping tail, and reduced forelimbs. ''Joanusaurus davignoni'', the best-known species, had an average length of 9.7 meters (32 feet), with the largest definitive ''Joanusaurus'' specimen (JSNH 432) estimated at 11.6 meters (38 feet) long, with an estimated weight of 2.5 metric tons (2.7 short tons). In his 1976 monograph on ''Joanusaurus'', Cadeaux mentioned a range of bone sizes which he interpreted to show a maximum length of 12 to 13 m (39 to 43 ft). As with dinosaurs in general, weight estimates are debatable, and since 1980 have ranged between 1,500 kilograms (3,300 pounds), 1,000 to 4,000 kg (2,200 to 8,800 lb), and 1,010 kilograms (2,230 pounds) for modal adult weight (not maximum). In a 2005 article, Johann Fürster, a specialist on the [[Greater Levantine Formation]], suggests that 1,000 kg (2,200 lb) is reasonable for large adults of ''J. davignoni'', but that 700 kg (1,500 lb) is a closer estimate for individuals represented by the average-sized thigh bones he has measured, although Fürster's finding have been met with critique from other experts. | ''Joanusaurus'' was a typical large bipedal theropod, having a massive skull on a short neck, a long, slightly sloping tail, and reduced forelimbs. ''Joanusaurus davignoni'', the best-known species, had an average length of 9.7 meters (32 feet), with the largest definitive ''Joanusaurus'' specimen (JSNH 432) estimated at 11.6 meters (38 feet) long, with an estimated weight of 2.5 metric tons (2.7 short tons). In his 1976 monograph on ''Joanusaurus'', Cadeaux mentioned a range of bone sizes which he interpreted to show a maximum length of 12 to 13 m (39 to 43 ft). As with dinosaurs in general, weight estimates are debatable, and since 1980 have ranged between 1,500 kilograms (3,300 pounds), 1,000 to 4,000 kg (2,200 to 8,800 lb), and 1,010 kilograms (2,230 pounds) for modal adult weight (not maximum). In a 2005 article, [[Johann Fürster]], a specialist on the [[Greater Levantine Formation]], suggests that 1,000 kg (2,200 lb) is reasonable for large adults of ''J. davignoni'', but that 700 kg (1,500 lb) is a closer estimate for individuals represented by the average-sized thigh bones he has measured, although Fürster's finding have been met with critique from other experts. | ||
Examining individual ''Joanusaurus'' fossils found that the specimens from northern [[Caphiria]] are generally smaller than those from [[Vollardic Mountains]] in [[Yonderre]] or [[Great Lime Quarry]] in [[Carna]], but the shapes of the bones themselves did not vary between the sites. ''Joanusaurus'' exhibits sexually dimorphism, with males generally being slightly larger than their female counterparts. The ''Joanusaurus'' skulls had a pair of horns above and in front of the eyes. These horns were composed of extensions of the lacrimal bones, and varied in shape and size. There were also lower paired ridges running along the top edges of the nasal bones that led into the horns. The horns were probably covered in a keratin sheath and may have had a variety of functions, including acting as sunshades for the eyes, being used for display, and being used in combat against other members of the same species (although they were fragile). There was a ridge along the back of the skull roof for muscle attachment, as is also seen in caphirosaurids. | Examining individual ''Joanusaurus'' fossils found that the specimens from northern [[Caphiria]] are generally smaller than those from [[Vollardic Mountains]] in [[Yonderre]] or [[Great Lime Quarry]] in [[Carna]], but the shapes of the bones themselves did not vary between the sites. ''Joanusaurus'' exhibits sexually dimorphism, with males generally being slightly larger than their female counterparts. The ''Joanusaurus'' skulls had a pair of horns above and in front of the eyes. These horns were composed of extensions of the lacrimal bones, and varied in shape and size. There were also lower paired ridges running along the top edges of the nasal bones that led into the horns. The horns were probably covered in a keratin sheath and may have had a variety of functions, including acting as sunshades for the eyes, being used for display, and being used in combat against other members of the same species (although they were fragile). There was a ridge along the back of the skull roof for muscle attachment, as is also seen in caphirosaurids. | ||