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- Hesperornis was a toothed bird found in the late Cretaceous, 80-65 million years ago. It was 2 metres long and could not fly and could not walk properly. It spent most of its time eating (and being eaten) at sea, where it preyed on fish, ammonites and belemnites. It was popular food with most predators in the Cretaceous seas. Its brain was tiny even by bird standards. they would usualy spend most of the day on the beach, playing with each other . [1] <--- a hesperonis skeleton.
- Hesperornis were flightless aquatic birds from the Late Cretaceous which hunted in the waters of the North American Inland Sea.
- Hesperornis was a flightless bird from the Cretaceous. Due to its design, it was cumbersome on land but was a fabulous swimmer.
- Hesperornis were very large birds, reaching up to 2 meters (6.5 feet) in length. They had virtually no wings, swimming with powerful hind legs. Their toes were probably lobed rather than being webbed, as in today's grebes; like in these, the toes could rotate well, which is necessary to decrease drag in lobed feet but not in webbed ones such as in loons, where the toes are simply folded together.
- Hesperornis was a large bird, reaching up to 1.8 metres (5.9 ft) in length.[2] It had virtually no wings, and swam with its powerful hind legs. Fossil evidence shows that the toes were probably lobed, as in today's grebes, rather than webbed as in those of loons.
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| abstract
| - Escribe la primera sección de tu artículo aquí.
- Hesperornis was a toothed bird found in the late Cretaceous, 80-65 million years ago. It was 2 metres long and could not fly and could not walk properly. It spent most of its time eating (and being eaten) at sea, where it preyed on fish, ammonites and belemnites. It was popular food with most predators in the Cretaceous seas. Its brain was tiny even by bird standards. they would usualy spend most of the day on the beach, playing with each other . [1] <--- a hesperonis skeleton.
- Hesperornis was a large bird, reaching up to 1.8 metres (5.9 ft) in length.[2] It had virtually no wings, and swam with its powerful hind legs. Fossil evidence shows that the toes were probably lobed, as in today's grebes, rather than webbed as in those of loons. Like many other Mesozoic birds such as Ichthyornis, Hesperornis had teeth as well as a beak, which were used to hold prey. In the hesperornithiform lineage they were of a different arrangement than in any other known bird (or in non-avian theropod dinosaurs), with the teeth sitting in a longitudinal groove rather than in individual sockets, in a notable case of convergent evolution with mosasaurs.[3][4] The teeth of Hesperornis were present along nearly the entire lower jaw (dentary) and the back of the upper jaw (maxilla). The front portion of the upper jaw (premaxilla) and tip of the lower jaw (predentary) lacked teeth and were probably covered in a beak. Studies of the bone surface show that at least the tips of the jaws supported a hard, keratinous beak similar to that found in modern birds.[5] The palate (mouth roof) contained small pits that allowed the lower teeth to lock into place when the jaws were closed.[6] They also retained a dinosaur-like joint between the lower jaw bones. It is believed that this allowed them to rotate the back portion of the mandible independently of the front, thus allowing the lower teeth to disengage.
- Hesperornis were flightless aquatic birds from the Late Cretaceous which hunted in the waters of the North American Inland Sea.
- Hesperornis was a flightless bird from the Cretaceous. Due to its design, it was cumbersome on land but was a fabulous swimmer.
- Hesperornis were very large birds, reaching up to 2 meters (6.5 feet) in length. They had virtually no wings, swimming with powerful hind legs. Their toes were probably lobed rather than being webbed, as in today's grebes; like in these, the toes could rotate well, which is necessary to decrease drag in lobed feet but not in webbed ones such as in loons, where the toes are simply folded together. Like many other Mesozoic birds such as Ichthyornis, Hesperornis had teeth in its beak which were used to hold prey (most likely fish). In the hesperornithiform lineage they were of a different arrangement than in any other known bird (or in non-avian theropod dinosaurs), with the teeth sitting in a longitudinal groove rather than in individual sockets, in a notable case of convergent evolution with mosasaurs. Of the many species described in this genus - such as the famous H. regalis or the huge H. rossicus -, not all may be valid. Some, such as H. macdonaldi, are known from very few or even a single bone and cannot be properly compared against the more plentiful (but also incomplete) remains of other similar-sized and contemporary taxa. Coniornis altus (which includes H. montana) may also belong into this genus. In addition, there are some unassigned remains, such as SGU 3442 Ve02 and LO 9067t and bones of an undetermined species from Tzimlyanskoe Reservoir near Rostov. The small form, initially called H. gracilis, was later moved into a monotypic genus Hargeria, and ultimately placed in Parahesperornis.
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