Triceratops and Torosaurus dinosaurs 'two species, not one'
by Admin
Posted on 18-07-2023 09:48 AM
More than 120 years ago, the yale paleontologist othniel charles marsh described two of the most spectacular horned dinosaurs of all
time
. The first, named triceratops in 1889 , had three impressive horns jutting out of its face and a solid, curved frill. Two years later, marsh named torosaurus, another great, three-horned dinosaur, but with a longer frill perforated by two round holes. Although the two overlapped in space and time, they seemed distinct enough that paleontologists considered them to be separate dinosaur genera.
That is, until museum of the rockies paleontologists john scannella and jack horner suggested that these two dinosaurs were really one in the same.
(phys. Org) —a study of triceratops fossils at hell creek formation in montana has provided insight into the evolution of these dinosaurs. John scannella of montana state university and his team examined more than 50 skulls of the two known triceratops species and, based on morphological differences and placement in the strata, determined that one species transformed into the other. The research appears in the proceedings of the national academy of sciences. Paleontologists have identified two triceratops species, triceratops horridus and triceratops prorsus, based on the length and shape of the horns and the size and structure of the skull.
Nicholas longrich and daniel field, of yale university, looked at 35 specimens ascribed to both species and concluded they represented two distinct creatures. "we looked at a bunch of changes in the skulls as the animals age and used a programme to arrange the skulls from youngest to oldest," explained dr longrich to bbc news. "what we found is there are youngtorosaurusindividuals and very oldtriceratopsindividuals and that's inconsistent withtorosaurusbeing an adulttriceratops. "skulls attributed to thetorosaurusboast a longer frill with large holes whiletriceratopshas a smaller solid frill. Dr longrich argues that if these were the same animal, they would also expect to find transitional specimens in which the skull is morphing between the two skull types.
Specimens of triceratops and centrosaurus were examined for evidence of bony abnormalities. In order to increase sample size, it was assumed that isolated chasmosaurine ceratopsid elements from the hell creek and lance formations were referable to triceratops. This is appropriate because triceratops is overwhelmingly the most common ceratopsid taxon in these formations, and because the cranial morphology (particularly the horns) is quite similar to other chasmosaurine from these formations (torosaurus and diceratus). No distinction was made between triceratops species, triceratops horridus and triceratops prorsus, because of general similarity in horn morphology as well as the difficulty in assessing species for incomplete skulls.
W tym filmie profesor dr rodolfo coria opowiada o swoich odkryciach w auca mahuevo. Niezliczone kości i jaja dinozaurów pozwoliły mu zdobyć szczegółową wiedzę na temat prehistorycznych olbrzymów, ich gatunków i rozmiarów, a także uświadomić sobie, że gigantyczne zwierzęta roślinożerne, grupa zauropodów, wyrosły kiedyś z maleńkiego jaja.
Obejrzyj to.
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