Inviato 11 febbraio 2006 - 01:51
Inviato 11 febbraio 2006 - 06:56
Basta che per spinosauridi non intendi anche lo spino-godzilla di Jurassic Park3[;)]
Inviato 12 febbraio 2006 - 02:54
Inviato 13 febbraio 2006 - 06:16
THE biggest, and possibly the baddest predatory dinosaur of them all was not the fabled Tyrannosaurus rex, or even its slightly larger rival Gigantosaurus, but a long-jawed, sail-backed creature called Spinosaurus.
An examination of some newly obtained fossils shows that Spinosaurus stretched an impressive 17 metres from nose to tail, dwarfing its meat-eating relatives. As well as being longer than its rivals, Spinosaurus also had stronger arms with which to catch its prey, unlike the puny-armed T. rex and its ilk.
Until 10 years ago, T. rex held the mantle of the biggest predatory dinosaur. Of the 30 specimens collected so far, the largest and most complete is a fossil called Sue, kept at the Field Museum of Natural History in Chicago. She measures 12.8 metres long and is thought to have weighed 6.4 tonnes when alive 67 million years ago.
Enter Gigantosaurus, a meat-eating dinosaur that lived in what is now Argentina. Reconstruction of a partial skeleton indicated that it stretched 13.7 metres. It lived about 100 million years ago at around the same time as two other huge predatory dinosaurs were stalking other continents. The slightly smaller Carcharodontosaurus lived in Africa while Acanthosaurus lived in North America, the only one of the three dinosaurs for which we have more than a handful of fragmentary fossils. All three predators were closely related to Allosaurus, a 9 to 12-metre-long predator of a lighter build than T. rex which was common in North America 150 million years ago.
However, Spinosaurus has been casting its fearsome shadow over all these beasts for some time. German palaeontologist Ernst Stromer discovered the first and best specimen in 1912 in Egypt. He identified it as a long-snouted giant predator which he believed was bigger than T. rex, and published a detailed study of the bones, including a partial backbone with long spines on the vertebrae, which may have supported a sail. Stromer's fossils were obliterated when allied bombers hit a Munich museum in 1944. Since then, all that has been discovered are some specimens of related smaller spinosaurs, as well as some isolated bones of Spinosaurus itself.
But a new examination of two skull fragments of Spinosaurus has confirmed its early reputation. Cristiano Dal Sasso of the Civic Natural History Museum in Milan, Italy, and his colleagues analysed a snout the museum acquired from an Italian collector, and previously unidentified bones from the upper rear of the skull collected by the University of Chicago, both of which were originally unearthed in Morocco.
After measuring their sizes, he estimates that the 99-centimetre-long snout came from a skull 1.75 metres long. From what we know of the body shapes of other spinosaurs, Dal Sasso calculates that the new Spinosaurus was 17 metres long and weighed 7 to 9 tonnes (Journal of Vertebrate Paleontology, vol 14, p 888).
Spinosaurus lived alongside Carcharodontosaurus in Africa 100 million years ago, and like T. rex and Giganotosaurus was a theropod, the group of dinosaurs that gave rise to birds. But Dal Sasso says spinosaurs, with their very long and slender snouts are more like "theropods with crocodile mouths". Their long teeth interlocked to catch prey, and a sawfish vertebra stuck between a tooth socket and an emerging tooth in one fossil specimen supports the idea that Spinosaurus preyed largely on fish. Other specimens also suggest that spinosaurs had arms "strong enough to be used in catching prey", says Eric Buffetaut of France's National Centre for Scientific Research in Paris, who collaborated with Dal Sasso.
T. rex and Gigantosaurus "were doing very different things", says palaeontologist Larry Witmer of Ohio University in Athens. T. rex had puny arms, but its stout skull had massive banana-shaped teeth that could crunch through bone, where Giganotosaurus had a much more slender skull, with blade-like teeth to slice through flesh.
Inviato 13 febbraio 2006 - 09:08
Inviato 14 febbraio 2006 - 03:06
Inviato 14 febbraio 2006 - 06:52
Sono confuso... troppo gentili...
Grazie a tutti
Inviato 14 febbraio 2006 - 08:39
Inviato 15 febbraio 2006 - 12:39
Inviato 15 febbraio 2006 - 07:44
Messaggio inserito da SAMURAI
ops quella ? una ricostruzione,eccoti il vero cranio :
Come fanno ad essere stupendi gli spinosauri...[^][^][^][^][^][^][^][^][^]
Inviato 15 febbraio 2006 - 08:24
Messaggio inserito da tribolit
Non vorreste scrivere un articolo sullo Spinosaurus?
non so se ne sarei all'altezza...ma mi farebbe davvero piacere.Aspetto di ascoltare Spino88 perch? adesso causa scuola ho poco tempo,in 2 ci sarebbero migliori probabilit? di ruscire a fare qualcosa [:D]
Inviato 16 febbraio 2006 - 03:09
Inviato 16 febbraio 2006 - 05:07
Messaggio inserito da Spino88
Ma,scusate,quest'articolo sar? pubblicato su fossili e minerali?
Sarebbe interessante anche solo una ricostruzione del scheletro - dato che esistono ancora dubbi, ed poi come ? imparentato coi altri carnivori, dove e quando viveva, a cosa serviva il "velo", cosa mangiava, perch? si incc...... se odorava la pi.. di un t-rex?[:o)] domande, domande, domande....
P.S: c?e anche la teoria che il Baryonix fosse un giovane Spinosaurus...
Inviato 16 febbraio 2006 - 06:03
Ps:anche il Suchomimus si pensa sia un sdulto di Baryonyx[^][^]
Ps2:scusa l'ignoranza ma ho solo una teoria del perch? si incz s sentiva la pip? del t-rex e poi e spuntato in un film...n ? scientificamente provato,no?[B)][B)]