48-485: Angelinornis Kashin 1972 Colonosaurus Marsh, 1872c Plegadornis Wetmore 1962 ( preoccupied ) Ichthyornis (meaning "fish bird", after its fish-like vertebrae) is an extinct genus of toothy seabird -like ornithuran from the late Cretaceous period of North America . Its fossil remains are known from the chalks of Alberta , Alabama , Kansas ( Greenhorn Limestone ), New Mexico , Saskatchewan , and Texas , in strata that were laid down in
96-663: A Corresponding Member of the Royal Australasian Ornithologists Union He wrote A Systematic Classification for the Birds of the World (1930, revised in 1951 and 1960). This Wetmore Order received widespread acceptance, remaining popular until the end of the twentieth century. From 1944 to 1946, Wetmore served as the 15th president of The Explorers Club . Between 1946 and 1966, Wetmore made annual trips to Panama to study and collect specimens of
144-855: A better sense of smell. The following cladogram is based on the analysis by Hartman et al . (2019), which found flight likely evolved five separate times among paravian dinosaurs, two of those among Avialae (in Scansoriopterygids and other avialans). Archaeopteryx and "anchiornithids" were placed in Deinonychosauria, Avialae's sister group. † Archaeopterygidae † Unenlagiidae † Dromaeosauridae † Troodontidae † Scansoriopterygidae † Yandangornis † Bauxitornis † Balaur † Shenzhouraptor † Jixiangornis † Zhongornis † Sapeornis † Confuciusornithidae † Changchengornis † Chongmingia † Jinguofortis † Zhongjianornis Ornithothoraces In
192-426: A definition similar to "all theropods closer to birds than to Deinonychus ." A nearly identical definition, "the theropod group that includes all taxa closer to Passer than to Dromaeosaurus ", was used by Agnolín and Novas (2013) for their clade Averaptora , operating under the assumption that troodontids and birds were more closely related to each other than to dromaeosaurs. They also redefine Avialae as
240-481: A friend of Mudge when they were younger, so when Mudge learned of Marsh's request, he changed the address on the shipping crate containing the Ichthyornis specimen (which had already been addressed to Cope and was ready to be sent), and shipped it to Marsh instead. Marsh had narrowly won the prestige of studying and naming the important fossil at the expense of his rival. However, Marsh did not initially recognize
288-421: A humerus about 58 millimetres (2.3 in) long. In many geologically younger specimens like YPM 1742, the same wing bone was 71.5 millimetres (2.81 in) long. Both the older, smaller specimens, and the more recent, larger specimens show signs that they had reached skeletal maturity and were adults, and came from the same geographic area. It is likely that Ichthyornis dispar as a species increased in size over
336-421: A new species of marine reptile, named Colonosaurus mudgei after their discoverer. The similarity of the lower jaw and teeth to those of mosasaurs is so great that as late as 1952, J.T. Gregory argued that it really belonged to a diminutive species or young individual related to the genus Clidastes . By early in 1873, Marsh had recognized his error. Through further preparation and exposure of skull bones from
384-512: A skeletal wingspan (not taking feathers into account) of around 43 centimetres (17 in), though there is considerable size variation among known specimens, with some smaller and some much larger than the type specimen of I. dispar . Ichthyornis is notable primarily for its combination of vertebrae which are concave both in front and back (similar to some fish, which is where it gets its name) and several more subtle features of its skeleton which set it apart from its close relatives. Ichthyornis
432-482: A specimen now attributed to I. dispar as Graculavus anceps . Clarke argued that because the rules for naming animals laid out by the ICZN state that a type species for a genus must have originally been included in that genus, Ichthyornis anceps is ineligible to replace I. dispar as the type species and so must be considered a junior synonym even though it was named first. However, Michael Mortimer pointed out that this
480-514: A variety of different specimens to make the piece appear more complete (it did not, however, contain any part of the actual " I. victor " holotype specimen). At some point before 1937, the catalogue number of the actual " I. victor " type specimen was mistakenly reassigned to the panel mount. Later reports of the specimen, even by the Peabody Museum's staff, therefore mistakenly stated that the original " I. victor " specimen comprised most of
528-410: Is also occasionally defined as an apomorphy-based clade (that is, one based on derived characteristics that were not present among lineage predecessors). Jacques Gauthier , who named Avialae in 1986, re-defined it in 2001 as all dinosaurs that possessed feathered wings used in flapping flight , and the birds that descended from them. The clade Avialae was given a formal phylogenetic definition in
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#1732790166329576-492: Is incorrect; while I. anceps cannot become the type species of Ichthyornis , the ICZN does not preclude it from becoming the senior synonym of the type species I. dispar . Therefore, I. anceps should have been considered the correct name for the only recognized Ichthyornis species. All other supposed species of Ichthyornis have not been supported as valid. The presumed "Ichthyornis" lentos , for example, actually belongs into
624-421: Is perhaps most well known for its teeth. The teeth were present only in the middle portion of the upper and lower jaws. The jaw tips had no teeth and were covered in a beak. The beak of Ichthyornis , like the hesperornithids , was compound and made up of several distinct plates, similar to the beak of an albatross , rather than a single sheet of keratin as in most modern birds. The teeth were more flattened than
672-464: The PhyloCode by Juan Benito and colleagues in 2022 as "the largest clade containing Vultur gryphus , but not Dromaeosaurus albertensis and Saurornithoides mongoliensis ". This definition ensures that both dromaeosaurids and troodontids are excluded from Avialae . Gauthier and de Queiroz (page 34) identified four conflicting ways of defining the term "Aves", which is a problem since
720-592: The Academy of Natural Sciences in Philadelphia . However, as described by S.W. Williston in 1898, Mudge was soon contacted by Othniel Charles Marsh , Cope's rival in the so-called Bone Wars , a rush to collect and identify fossils in the American West. Marsh wrote to Mudge in 1872 and offered to identify any important fossils free of charge, and to give Mudge sole credit for their discovery. Marsh had been
768-840: The Northwestern Hawaiian Islands , Johnston Atoll and Wake Island . In 1924, Wetmore joined the Smithsonian Institution as the superintendent of the National Zoo in Washington, D.C. In 1925, Wetmore was appointed assistant secretary of the Smithsonian Institution , becoming secretary between 1945 and 1952. In 1929, he participated in the Pinchot South Sea Expedition . In 1939, he was elected
816-726: The Tiaojishan Formation of China , which has been dated to the late Jurassic period ( Oxfordian stage), about 160 million years ago. The avialan species from this time period include Anchiornis huxleyi and Aurornis xui . Xiaotingia zhengi used to be considered a member, but was later classified within the clade Dromaeosauridae . The well-known Archaeopteryx dates from slightly later Jurassic rocks (about 155 million years old) from Germany . Many of these early avialans shared unusual anatomical features that may be ancestral to modern birds, but were later lost during bird evolution. These features include enlarged claws on
864-630: The Western Interior Seaway during the Turonian through Campanian ages, about 95–83.5 million years ago . Ichthyornis is a common component of the Niobrara Formation fauna, and numerous specimens have been found. Ichthyornis has been historically important in shedding light on bird evolution . It was the first known prehistoric bird relative preserved with teeth, and Charles Darwin noted its significance during
912-665: The Wetmore Glacier in the Antarctic , have also been named after him. Wetmore is commemorated in the scientific names of one species and two subspecies of reptiles: Pholidoscelis wetmorei , Uromacer frenatus wetmorei , and Anolis brevirostris wetmorei . In 1953, he married Annie Beatrice van der Biest Thielan , who became guarantor of the American Ornithologists' Union after his death in 1978. His papers and an oral history interview are held at
960-436: The enantiornithines , the species appears to have matured to adulthood in a rather short, continuous process. A study on an Ichthyornis endocast reveals that it had a relatively basal brain compared to modern birds, similar to that of Archaeopteryx and other non-avian theropods. Conversely, it had a palate remarkably convergent with that of modern neognaths . Ichthyornis fossils have been found in almost all levels of
1008-627: The Biological Survey of the Department of Agriculture . In 1915, he researched the use of lead shot in causing death in waterfowl. His paleontological research led to his work on the fossil birds Palaeochenoides mioceanus and Nesotrochis debooyi . From April 1923 to July 1924, Wetmore was the lead scientist of the Tanager Expedition , a series of five biological surveys to study the flora , fauna and geology of
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#17327901663291056-578: The Committee for Research and Exploration, from 1933 until his death, in his final years as a trustee emeritus. Several taxa of birds have been named in his honor, including the Cretaceous genus Alexornis and the tanagers Wetmorethraupis sterrhopteron and Buthraupis wetmorei . Insects, mammals, amphibians, mollusks, and one plant (an Argentinian cactus), as well as a bridge in Panama and
1104-657: The Niobrara Chalk, from beds dating to the late Coniacian age (about 89 million years ago) to the Campanian age (about 83.5 million years ago). Even earlier remains attributed to Ichthyornis have been found in the Greenhorn Formation of Kansas, dating to the early Turonian age (about 93 million years ago). Specimens of Ichthyornis from earlier eras were, on average, smaller than later ones. The holotype specimen of Ichthyornis dispar , YPM 1450, had
1152-423: The Smithsonian Institution. # denotes an acting secretary Avialans Avialae ("bird wings") is a clade containing the only living dinosaurs , the birds , and their closest relatives. It is usually defined as all theropod dinosaurs more closely related to birds (Aves) than to deinonychosaurs , though alternative definitions are occasionally used (see below). Archaeopteryx lithographica , from
1200-745: The age of eight. By 1900, Wetmore published his first paper "My Experience with a Red-headed Woodpecker," in the magazine Bird-Lore. To further his education Wetmore enrolled at the University of Kansas in 1905. During his studies there he did a stint as an assistant in the University Museum, under the direction of Charles D. Bunker. Alexander Wetmore later received his BA from the University of Kansas in 1912; finally receiving his MS in 1916 and his PhD in 1920 from George Washington University . Wetmore began federal service in 1910, working for
1248-752: The birds of the Isthmus. His 4-volume magnum opus, Birds of the Republic of Panama , was published by the Smithsonian between 1965 and 1984, the last volume appearing posthumously. He also served on the boards of trustees of Science Service, now known as Society for Science & the Public , from 1946 to 1953, and of the National Geographic Society , where he served successively as vice chairman, acting chairman, and chairman emeritus of
1296-750: The early galliform genus Austinornis . "Ichthyornis" minusculus from the Bissekty Formation (Late Cretaceous) of Kyzyl Kum , Uzbekistan , is probably an enantiornithine. All other Ichthyornis species are synonymous with I. dispar . The cladogram below is the result of a 2014 analysis by Michael Lee and colleagues that expanded on data from an earlier study by O’Connor & Zhou in 2012. The clade names are positioned based on their definitions. † Ichthyornis † Hesperornithes † Limenavis Aves (modern birds) [REDACTED] [REDACTED] Alexander Wetmore Frank Alexander Wetmore (June 18, 1886 – December 7, 1978)
1344-462: The early years of the theory of evolution . Ichthyornis remains important today as it is one of the few Mesozoic era ornithurans known from more than a few specimens. It is thought that Ichthyornis was the Cretaceous ecological equivalent of modern seabirds such as gulls , petrels , and skimmers . An average specimen was the size of a pigeon , 24 centimetres (9.4 in) long, with
1392-534: The field of paleontology and bird evolution, though the exact definitions applied have been inconsistent. Avialae, initially proposed to replace the traditional fossil content of Aves, is sometimes used synonymously with the vernacular term "bird" by these researchers. † Anchiornis † Archaeopteryx † Rahonavis † Jixiangornis † Jeholornis [REDACTED] † Sapeornis † Confuciusornis [REDACTED] † Chongmingia Ornithothoraces [REDACTED] The earliest known avialans come from
1440-459: The former order Ichthyornithiformes and the family Ichthyornithidae are now superseded by the clade Ichthyornithes , which in the paper was also defined according to phylogenetic taxonomy as all descendants of the most recent common ancestor of Ichthyornis dispar and modern birds. Of the several described species, only one, Ichthyornis dispar , is currently recognized, following the seminal review by Julia Clarke. Marsh had previously named
1488-613: The fossils or intentionally created a hoax by associating reptilian jaws with the body of a bird, accusations that continued to surface even as late as 1967. However, an overwhelming majority of researchers have demonstrated that Marsh's interpretation of the fossils was correct, and he was fully vindicated by later finds. At the turn of the 20th century, the Peabody Museum of Natural History at Yale University , where most Ichthyornis specimens were housed, began placing many of its most interesting or important specimens on display in
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1536-526: The late Jurassic Period Solnhofen Formation of Germany , is usually considered the earliest known avialan which may have had the capability of powered flight; a minority of studies have suggested that it might have been a deinonychosaur instead. Several older (but non flight-capable) possible avialans are known from the late Jurassic Tiaojishan Formation of China , dated to about 160 million years ago. Most researchers define Avialae as branch-based clade, though definitions vary. Many authors have used
1584-437: The latter were lost independently in a number of avialan groups, including modern birds (Aves). While the earliest forms, such as Archaeopteryx and Shenzhouraptor , retained the long bony tails of their ancestors, the tails of more advanced avialans were shortened with the advent of the pygostyle bone in the group Pygostylia . In the late Cretaceous, around 95 million years ago, the ancestor of all modern birds also evolved
1632-411: The museum's Great Hall. Two panel mounts (that is, pieces where the skeleton is arranged and set into a plaster slab) were created for Ichthyornis ; one for I. dispar , and one for " I. victor ". Both were created by Hugh Gibb, who prepared many of Marsh's fossils for study and display. The I. dispar mount contained only the holotype fossils, while the " I. victor " mount was a composite incorporating
1680-500: The rock, he found that the toothed jaws must have come from the bird itself and not a marine reptile. Due to the previously unknown features of Ichthyornis (vertebrae concave on either side and teeth), Marsh chose to classify it in an entirely new sub-class of birds he called the Odontornithes (or "toothed birds"), and in the new order Ichthyornithes (later Ichthyornithiformes). The only other bird Marsh included in these groups
1728-432: The rounded teeth found in crocodilians , though they became wider towards the base of the crown. The tips of the teeth were curved backward and lacked any serrations. They were arranged in a groove , much like those of marine reptiles. The wings and breastbone were very modern in appearance, suggesting strong flight ability and placing it with modern birds in the advanced group Carinatae . Unlike earlier avialans such as
1776-471: The same biological name is being used four different ways. They proposed a solution, number 4 below, which is to reserve the term Aves only for the crown group , the last common ancestor of all living birds and all of its descendants. Other definitions of Aves found in literature were reassigned to other clade names. Under the fourth definition Archaeopteryx is an avialan, and not a member of Aves. Gauthier's proposals have been adopted by many researchers in
1824-542: The second toe which may have been held clear of the ground in life, and long feathers or "hind wings" covering the hind limbs and feet, which may have been used in aerial maneuvering. It is also thought that early avialans were either cranially akinetic or had otherwise limited cranial kinesis . Avialans diversified into a wide variety of forms during the Cretaceous Period . Many groups retained primitive characteristics , such as clawed wings and teeth, though
1872-532: The several million years it inhabited the Western Interior Seaway ecosystem. Ichthyornis was one of the first Mesozoic avialans ever found and the first one known to have had teeth, making it an important discovery in the early history of paleontology. It remains important today, as it represents one of the closest non-avian relatives of modern birds, and one of a handful of Mesozoic bird relatives represented by numerous specimens. Ichthyornis
1920-439: The skeleton, when it was in fact only three bones. By 1997, the situation had become so confused that Jacques Gauthier , the current curator of the museum's vertebrate paleontology collection, authorized the dismantling of both panel mounts. This allowed the bones to be properly sorted out and studied in three dimensions, which had been impossible previously when they were embedded in plaster. A full re-description of these specimens
1968-552: The smallest clade containing Archaeopteryx and modern birds. Additionally, beginning in the late 2000s and early 2010s, several groups of researchers began adding the genus Troodon as an additional specifier in the definition of Avialae. Troodon had long been considered a close relative of the dromaeosaurids in the larger group Deinonychosauria, though some contemporary studies found it and other troodontids more closely related to modern birds, and so it has been specifically excluded from Avialae in more recent studies. Avialae
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2016-406: The true importance of the fossil. Soon after receiving it, he reported back to Mudge his opinion that the chalk slab contained the bones of two distinct animals: a small bird animal, and the toothed jaws of some unknown reptile. Marsh considered the unusual vertebrae of the bird to resemble those of a fish, so he named it Ichthyornis , or "fish bird." Later in 1872, Marsh described the toothed jaws as
2064-451: The world at that time. Soon after these discoveries, Ichthyornis was recognized for its significance to the theory of evolution recently published by Charles Darwin. Darwin himself told Marsh in an 1880 letter that Ichthyornis and Hesperornis offered "the best support for the theory of evolution" since he had first published On the Origin of Species in 1859. (While Archaeopteryx
2112-708: Was an American ornithologist and avian paleontologist . He was the sixth Secretary of the Smithsonian Institution . He was also an elected member of both the American Philosophical Society and the United States National Academy of Sciences . The son of a physician, Frank Alexander Wetmore was born in North Freedom, Wisconsin. Developing an interest in birds at an early age, he made his first field journal entry (a pelican seen while on vacation in 1894) at
2160-638: Was discovered in 1870 by Benjamin Franklin Mudge , a professor from Kansas State Agricultural College who recovered the initial fossils from the North Fork of the Solomon River in Kansas , United States. Mudge was a prolific fossil collector who shipped his discoveries to prominent scientists for study. Mudge had previously had a close partnership with paleontologist Edward Drinker Cope of
2208-511: Was published by paleontologist Julia Clarke in 2004. Ichthyornis is close to the ancestry of modern birds, the Aves , but represents an independent lineage. It was long believed that it was closely related to some other Cretaceous taxa known from very fragmentary remains – Ambiortus , Apatornis , Iaceornis and Guildavis – but these seem to be closer to the ancestors of modern birds than to Ichthyornis dispar . In Clarke's 2004 review,
2256-479: Was the first known Mesozoic avialan and is now known to have also had teeth, the first specimen with a skull was not described until 1884). Others at the time also recognized the implications of a nearly modern bird with reptilian teeth, and feared the controversy it caused. One Yale student described various men and women urging Marsh to conceal Ichthyornis from the public because it lent too much support to evolutionary theory. Many accused Marsh of having tampered with
2304-404: Was the newly named Apatornis , which he had previously named as a species of Ichthyornis , I. celer . Mudge later noted the rare and unique quality of these toothed birds (including Hesperornis , which was found to also have teeth by 1877), and the irony of their association with the remains of toothless pterosaurs , flying reptiles which were only known to have had teeth in other regions of
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