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Hesperornithiformes
Hesperornithes is an extinct and highly specialized group of aquatic avialans closely related to the ancestors of modern birds. They inhabited both marine and freshwater habitats in the Northern Hemisphere, and include genera such as ''Hesperornis'', '' Parahesperornis'', '' Baptornis'', '' Enaliornis'', and '' Potamornis'', all strong-swimming, predatory divers. Many of the species most specialized for swimming were completely flightless. The largest known hesperornithean, '' Canadaga arctica'', may have reached a maximum adult length of . Hesperornitheans were the only Mesozoic avialans known to colonize the oceans. They were wiped out in the Cretaceous–Paleogene extinction event, along with enantiornitheans and all other non-avian dinosaurs. Anatomy and ecology Most of what is known about this group rests on analyses of single species, as few provide sufficiently complete fossils for analysis. Although some of the smaller and more basal species, like those belonging to th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hesperornis
''Hesperornis'' (meaning "western bird") is a genus of cormorant-like Ornithuran that spanned throughout the Campanian age, and possibly even up to the early Maastrichtian age, of the Late Cretaceous period. One of the lesser-known discoveries of the paleontologist O. C. Marsh in the late 19th century Bone Wars, it was an early find in the history of avian paleontology. Locations for ''Hesperornis'' fossils include the Late Cretaceous marine limestones from Kansas and the marine shales from Canada. Nine species are recognised, eight of which have been recovered from rocks in North America and one from Russia. Description ''Hesperornis'' was a large bird, measuring about long and weighing around . It had virtually no wings, and swam with its powerful hind legs. Studies on the feet initially indicated that ''Hesperornis'' and kin had lobed toes similar to modern-day grebes, as opposed to webbed toes as seen in most aquatic birds such as loons. More recent work looking at the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hesperornis Regalis
''Hesperornis'' (meaning "western bird") is a genus of cormorant-like Ornithuran that spanned throughout the Campanian age, and possibly even up to the early Maastrichtian age, of the Late Cretaceous period. One of the lesser-known discoveries of the paleontologist O. C. Marsh in the late 19th century Bone Wars, it was an early find in the history of avian paleontology. Locations for ''Hesperornis'' fossils include the Late Cretaceous marine limestones from Kansas and the marine shales from Canada. Nine species are recognised, eight of which have been recovered from rocks in North America and one from Russia. Description ''Hesperornis'' was a large bird, measuring about long and weighing around . It had virtually no wings, and swam with its powerful hind legs. Studies on the feet initially indicated that ''Hesperornis'' and kin had lobed toes similar to modern-day grebes, as opposed to webbed toes as seen in most aquatic birds such as loons. More recent work looking at the m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parahesperornis
''Parahesperornis'' is a genus of prehistoric flightless birds from the Late Cretaceous. Its range in space and time may have been extensive, but its remains are rather few and far between, at least compared with its contemporary relatives in ''Hesperornis''. Remains are known from central North America, namely the former shallows of the Western Interior Seaway in Kansas. Found only in the upper Niobrara Chalk, these are from around the Coniacian-Santonian boundary, 85–82 million years ago (mya). ''Parahesperornis alexi'' (Martin, 1984) was long lumped with specimen YPM 1478, described initially as ''Hesperornis gracilis'' and later moved to the monotypic genus ''Hargeria'' (Lucas, 1903). It then turned out that this genus' description actually referred to specimen KUVP 2287, which eventually became the holotype of ''P. alexi''. Nonetheless, the taxon description of ''Hargeria'' was about ''"Hesperornis" gracilis'' exclusively, and thus despite the misidentification it appli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brodavidae
''Brodavis'' is a genus of freshwater hesperornithiform birds known from the Late Cretaceous (possibly Campanian and Maastrichtian stage) of North America and Asia. It was first described and named by Larry D. Martin, Evgeny N. Kurochkin and Tim T. Tokaryk in 2012 and assigned to a new monogeneric family, Brodavidae. Four species were described and assigned to ''Brodavis''. The type species, ''B. americanus'', is known from the holotype left metatarsal, RSM P 2315.1 which was collected in the Maastrichtian-age Frenchman Formation of Canada. ''B. baileyi'' is known from the holotype left metatarsal, UNSM 50665, which was collected in the Maastrichtian-age Hell Creek Formation of South Dakota, United States (dated to between 66.8 and 66 Ma agoLongrich, N.R., Tokaryk, T. and Field, D.J. (2011). "Mass extinction of birds at the Cretaceous–Paleogene (K–Pg) boundary." ''Proceedings of the National Academy of Sciences'', 108(37): 15253-15257. ) ''B. mongoliensis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brodavis
''Brodavis'' is a genus of freshwater hesperornithiform birds known from the Late Cretaceous (possibly Campanian and Maastrichtian stage) of North America and Asia. It was first described and named by Larry D. Martin, Evgeny N. Kurochkin and Tim T. Tokaryk in 2012 and assigned to a new monogeneric family, Brodavidae. Four species were described and assigned to ''Brodavis''. The type species, ''B. americanus'', is known from the holotype left metatarsal, RSM P 2315.1 which was collected in the Maastrichtian-age Frenchman Formation of Canada. ''B. baileyi'' is known from the holotype left metatarsal, UNSM 50665, which was collected in the Maastrichtian-age Hell Creek Formation of South Dakota, United States (dated to between 66.8 and 66 Ma agoLongrich, N.R., Tokaryk, T. and Field, D.J. (2011). "Mass extinction of birds at the Cretaceous–Paleogene (K–Pg) boundary." ''Proceedings of the National Academy of Sciences'', 108(37): 15253-15257. ) ''B. mongoliensis'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enaliornis
''Enaliornis'' is a genus of hesperornithine which lived during the late Albian to the early Cenomanian, making them the oldest known hesperornithines. Fossils have been found near Cambridge, England. Due to its lack of certain hesperornithid apomorphies, they were much more "conventional" birds and were initially held to be Gaviiformes (loons/divers). Description Based on the remnants that have been studied, it has not been determined if these birds had teeth like the others from this order. However, they were believed to not have well-developed wings. Like other hesperornithines, they probably had lobed feet for swimming, rather than webbed feet.Lim, J. D., Zhou, Z., Martin, L. D., Baek, K. S., & Yang, S. Y. (2000). The oldest known tracks of web-footed birds from the Lower Cretaceous of South Korea. ''Naturwissenschaften'', 87(6), 256-259. Classification ''Enaliornis'' was originally named '' Pelagornis'' ("sea bird") by Seeley in 1866, but that name was preoccupied by a Mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fumicollis
''Fumicollis'' is a genus of prehistoric flightless birds from the Late Cretaceous (Coniacian-Santonian) Niobrara Chalk of Kansas. Description Diagnostic traits of ''Fumicollis'' include presacral vertebrae with expanded ventral processes, an elongate pelvis with reduced acetabulum (acetabulum width: pelvis length is approximately 0.096 meters), a femur with expanded lateral condyle (transverse extent of condyle over 75% of midshaft width) and moderately expanded trochanter. The genus name refers to the Smoky Hill Chalk Member of the Niobrara Chalk in which it was found.Bell A, Chiappe LM (2015) Identification of a New Hesperornithiform from the Cretaceous Niobrara Chalk and Implications for Ecologic Diversity among Early Diving Birds. PLoS ONE 10(11): e0141690. https://doi.org/10.1371/journal.pone.0141690 Discovery The holotype of ''Fumicollis'', USNM 20030, was found by Harold Shepherd and George Sternberg in 1937 in the Smoky Hill Member of the Niobrara Chalk of Logan County, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bird
Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a four-chambered heart, and a strong yet lightweight Bird skeleton, skeleton. Birds live worldwide and range in size from the bee hummingbird to the common ostrich. There are over 11,000 living species and they are split into 44 Order (biology), orders. More than half are passerine or "perching" birds. Birds have Bird wing, wings whose development varies according to species; the only known groups without wings are the extinct moa and elephant birds. Wings, which are modified forelimbs, gave birds the ability to fly, although further evolution has led to the Flightless bird, loss of flight in some birds, including ratites, penguins, and diverse endemism, endemic island species. The digestive and respiratory systems of birds are also uniquely a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baptornis
''Baptornis'' ("diving bird") is a genus of flightless, aquatic birds from the Late Cretaceous, some 87-80 million years ago (roughly mid-Coniacian to mid-Campanian faunal stages). The fossils of ''Baptornis advenus'', the type species, were discovered in Kansas, which at its time was mostly covered by the Western Interior Seaway, a shallow shelf sea. It is now known to have also occurred in today's Sweden, where the Turgai Strait joined the ancient North Sea; possibly, it occurred in the entire Holarctic. Othniel Charles Marsh discovered the first fossils of this bird in the 1870s. This was, alongside the ''Archaeopteryx'', one of the first Mesozoic birds to become known to science. Ecology More material evidence exists for the ecology of ''B. advenus'' than for any other member of the Hesperornithes, with the possible exception of ''Hesperornis regalis'', but still much is left to conjecture. The loon-sized bird was of middle size among its relatives and had a markedly elonga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
