Құрғакөлдік динозаврлардың жоғалып кеткен туысы

Extinct genus of bird like dinosaurs
the ancient animal

Archaeopteryx (,/ɑːr//k//iː/'/ɒ//p//t//ər//ᵻ//k//s/; ), sometimes referred to by its German name, "Urvogel" ( Primeval Bird) is a genus of bird like dinosaurs. The name derives from the ancient Greek (archaīos), meaning "ancient", and (ptéryx), meaning "feather" or "wing". Between the late 19th century and the early 21st century, Archaeopteryx was generally accepted by palaeontologists and popular reference books as the oldest known bird (member of the group Avialae). Older potential avialans have since been identified, including Anchiornis, Xiaotingia, and Aurornis. Archaeopteryx lived in the Late Jurassic around 150 million years ago, in what is now southern Germany, during a time when Europe was an archipelago of islands in a shallow warm tropical sea, much closer to the equator than it is now. Similar in size to a Eurasian magpie, with the largest individuals possibly attaining the size of a raven, Most of these twelve fossils include impressions of feathers. Because these feathers are of an advanced form (flight feathers), these fossils are evidence that the evolution of feathers began before the Late Jurassic. It is currently located at the Natural History Museum of Berlin. Though it was the initial holotype, there were indications that it might not have been from the same animal as the body fossils. This conclusion was challenged in 2020 as being unlikely; the feather was identified on the basis of morphology as most likely having been an upper major primary covert feather.) to the Natural History Museum in London, where it remains. The Haarlem Specimen (TM 6428/29, also known as the Teylers Specimen) was discovered in 1855 near italics=unset, Germany, and described as a Pterodactylus crassipes in 1857 by Meyer. It was reclassified in 1970 by John Ostrom and is currently located at the Teylers Museum in Haarlem, the Netherlands. It was the very first specimen found, but was incorrectly classified at the time. It is also one of the least complete specimens, consisting mostly of limb bones, isolated cervical vertebrae, and ribs. In 2017 it was named as a separate genus Ostromia, considered more closely related to Anchiornis from China. The Eichstätt Specimen (JM 2257) was discovered in 1951 near Workerszell, Germany, and described by Peter Wellnhofer in 1974. Currently located at the Jura Museum in Eichstätt, Germany, it is the smallest known specimen and has the second best head. It is possibly a separate genus (Jurapteryx recurva) or species (A. recurva). The Solnhofen Specimen (unnumbered specimen) was discovered in the 1970s near Eichstätt, Germany, and described in 1988 by Wellnhofer. Currently located at the Bürgermeister Müller Museum in Solnhofen, it originally was classified as Compsognathus by an amateur collector, the same mayor Friedrich Müller after which the museum is named. It is the largest specimen known and may belong to a separate genus and species, Wellnhoferia grandis. It is missing only portions of the neck, tail, backbone, and head. The Munich Specimen (BSP 1999 I 50, formerly known as the Solenhofer Aktien Verein Specimen) was discovered on 3 August 1992 near Langenaltheim and described in 1993 by Wellnhofer. It is currently located at the Paläontologisches Museum München in Munich, to which it was sold in 1999 for 1.9 million Deutschmark. What was initially believed to be a bony sternum turned out to be part of the coracoid, but more recent studies suggest it belongs to A. siemensii. After a lengthy period in a closed private collection, it was moved to the Museum of Evolution at Knuthenborg Safaripark (Denmark) in 2022, where it has since been on display and also been made available for researchers. Another fragmentary fossil was found in 2000. It is in private possession and, since 2004, on loan to the Bürgermeister Müller Museum in Solnhofen, so it is called the Bürgermeister Müller Specimen; the institute itself officially refers to it as the "Exemplar of the families Ottman & Steil, Solnhofen". As the fragment represents the remains of a single wing of Archaeopteryx, it is colloquially known as "chicken wing". Long in a private collection in Switzerland, the Thermopolis Specimen (WDC CSG 100) was discovered in Bavaria and described in 2005 by Mayr, Pohl, and Peters. Donated to the Wyoming Dinosaur Center in Thermopolis, Wyoming, it has the best preserved head and feet; most of the neck and the lower jaw have not been preserved. The "Thermopolis" specimen was described on 2 December 2005 Science journal article as "A well preserved Archaeopteryx specimen with theropod features"; it shows that Archaeopteryx lacked a reversed toe—a universal feature of birds—limiting its ability to perch on branches and implying a terrestrial or trunk climbing lifestyle. Palaeontologists of the Ludwig Maximilian University of Munich studied the specimen, which revealed previously unknown features of the plumage, such as feathers on both the upper and lower legs and metatarsus, and the only preserved tail tip. A twelfth specimen had been discovered by an amateur collector in 2010 at the Schamhaupten quarry, but the finding was only announced in February 2014. It was scientifically described in 2018. It represents a complete and mostly articulated skeleton with skull. It is the only specimen lacking preserved feathers. It is from the Painten Formation and somewhat older than the other specimens. The existence of a thirteenth specimen (the Chicago specimen) was announced in 2024 by the Field Museum in Chicago, US. One of two specimens in an institution outside Europe, the specimen was originally identified in a private collection in Switzerland, and had been acquired by these collectors in 1990, prior to Germany's 2015 ban on exporting Archaeopteryx specimens. The specimen was acquired by the Field Museum in 2022, and went on public display in 2024 following two years of preparation. The specimen is to be studied by famed paleornithologist Jingmai O'Connor.

Beginning in 1985, an amateur group including astronomer Fred Hoyle and physicist Lee Spetner, published a series of papers claiming that the feathers on the Berlin and London specimens of Archaeopteryx were forged. Archaeopteryx was roughly the size of a raven, Archaeopteryx feathers, although less documented than its other features, were very similar in structure to modern day bird feathers.

Specimens of Archaeopteryx were most notable for their well developed flight feathers. They were markedly asymmetrical and showed the structure of flight feathers in modern birds, with vanes given stability by a barb barbule barbicel arrangement. This would mean that the skin already was softened and loose, which is bolstered by the fact that in some specimens the flight feathers were starting to detach at the point of embedding in the sediment. So it is hypothesized that the pertinent specimens moved along the sea bed in shallow water for some time before burial, the head and upper neck feathers sloughing off, while the more firmly attached tail feathers remained.]] In 2011, graduate student Ryan Carney and colleagues performed the first colour study on an Archaeopteryx specimen. In a 2013 study published in the Journal of Analytical Atomic Spectrometry, new analyses of Archaeopteryxs feathers revealed that the animal may have had complex light and dark coloured plumage, with heavier pigmentation in the distal tips and outer vanes. This analysis of colour distribution was based primarily on the distribution of sulphate within the fossil. An author on the previous Archaeopteryx colour study argued against the interpretation of such biomarkers as an indicator of eumelanin in the full Archaeopteryx specimen. Carney and other colleagues also argued against the 2013 study's interpretation of the sulphate and trace metals, and in a 2020 study published in Scientific Reports demonstrated that the isolated covert feather was entirely matte black (as opposed to black and white, or iridescent) and that the remaining "plumage patterns of Archaeopteryx remain unknown". This suggestion was upheld by the ICZN after four years of debate, and the London specimen was designated the neotype on 3 October 2011. Below is a cladogram published in 2013 by Godefroit et al. Phylogenetic studies conducted by Senter, et al. (2012) and Turner, Makovicky, and Norell (2012) also found Archaeopteryx to be more closely related to living birds than to dromaeosaurids and troodontids. On the other hand, Godefroit et al. (2013) recovered Archaeopteryx as more closely related to dromaeosaurids and troodontids in the analysis included in their description of Eosinopteryx brevipenna. The authors used a modified version of the matrix from the study describing Xiaotingia, adding Jinfengopteryx elegans and Eosinopteryx brevipenna to it, as well as adding four additional characters related to the development of the plumage. Unlike the analysis from the description of Xiaotingia, the analysis conducted by Godefroit, et al. did not find Archaeopteryx to be related particularly closely to Anchiornis and Xiaotingia, which were recovered as basal troodontids instead. Agnolín and Novas (2013) found Archaeopteryx and (possibly synonymous) Wellnhoferia to be form a clade sister to the lineage including Jeholornis and Pygostylia, with Microraptoria, Unenlagiinae, and the clade containing Anchiornis and Xiaotingia being successively closer outgroups to the Avialae (defined by the authors as the clade stemming from the last common ancestor of Archaeopteryx and Aves). Another phylogenetic study by Godefroit, et al., using a more inclusive matrix than the one from the analysis in the description of Eosinopteryx brevipenna, also found Archaeopteryx to be a member of Avialae (defined by the authors as the most inclusive clade containing Passer domesticus, but not Dromaeosaurus albertensis or Troodon formosus). Archaeopteryx was found to form a grade at the base of Avialae with Xiaotingia, Anchiornis, and Aurornis. Compared to Archaeopteryx, Xiaotingia was found to be more closely related to extant birds, while both Anchiornis and Aurornis were found to be more distantly so. Wang et al. (2018) and Hartman et al. (2019) found Archaeopteryx to have been a deinonychosaur instead of an avialan. More specifically, it and closely related taxa were considered basal deinonychosaurs, with dromaeosaurids and troodontids forming together a parallel lineage within the group. Because Hartman et al. found Archaeopteryx isolated in a group of flightless deinonychosaurs (otherwise considered "anchiornithids"), they considered it highly probable that this animal evolved flight independently from bird ancestors (and from Microraptor and Yi). The following cladogram illustrates their hypothesis regarding the position of Archaeopteryx:

The authors, however, found that the Archaeopteryx being an avialan was only slightly less likely than this hypothesis, and as likely as Archaeopterygidae and Troodontidae being sister clades. Archaeopteryx wings were relatively large, which would have resulted in a low stall speed and reduced turning radius. The short and rounded shape of the wings would have increased drag, but also could have improved its ability to fly through cluttered environments such as trees and brush (similar wing shapes are seen in birds that fly through trees and brush, such as crows and pheasants). The presence of "hind wings", asymmetrical flight feathers stemming from the legs similar to those seen in dromaeosaurids such as Microraptor, also would have added to the aerial mobility of Archaeopteryx. The first detailed study of the hind wings by Longrich in 2006, suggested that the structures formed up to 12% of the total airfoil. This would have reduced stall speed by up to 6% and turning radius by up to 12%. The degree of asymmetry seen in Archaeopteryx is more typical for slow flyers than for flightless birds. In 2010, Robert L. Nudds and Gareth J. Dyke in the journal Science published a paper in which they analysed the rachises of the primary feathers of Confuciusornis and Archaeopteryx. The analysis suggested that the rachises on these two genera were thinner and weaker than those of modern birds relative to body mass. The authors determined that Archaeopteryx and Confuciusornis, were unable to use flapping flight. This study was criticized by Philip J. Currie and Luis Chiappe. Chiappe suggested that it is difficult to measure the rachises of fossilized feathers, and Currie speculated that Archaeopteryx and Confuciusornis must have been able to fly to some degree, as their fossils are preserved in what is believed to have been marine or lake sediments, suggesting that they must have been able to fly over deep water. Gregory Paul also disagreed with the study, arguing in a 2010 response that Nudds and Dyke had overestimated the masses of these early birds, and that more accurate mass estimates allowed powered flight even with relatively narrow rachises. Nudds and Dyke had assumed a mass of for the Munich specimen Archaeopteryx, a young juvenile, based on published mass estimates of larger specimens. Paul argued that a more reasonable body mass estimate for the Munich specimen is about Paul also criticized the measurements of the rachises themselves, noting that the feathers in the Munich specimen are poorly preserved. Nudds and Dyke reported a diameter of for the longest primary feather, which Paul could not confirm using photographs. Paul measured some of the inner primary feathers, finding rachises across. Despite these criticisms, Nudds and Dyke stood by their original conclusions. They claimed that Paul's statement, that an adult Archaeopteryx would have been a better flyer than the juvenile Munich specimen, was dubious. This, they reasoned, would require an even thicker rachis, evidence for which has not yet been presented. Another possibility is that they had not achieved true flight, but instead used their wings as aids for extra lift while running over water after the fashion of the basilisk lizard, which could explain their presence in lake and marine deposits (see Origin of avian flight). In 2004, scientists analysing a detailed CT scan of the braincase of the London Archaeopteryx concluded that its brain was significantly larger than that of most dinosaurs, indicating that it possessed the brain size necessary for flying. The overall brain anatomy was reconstructed using the scan. The reconstruction showed that the regions associated with vision took up nearly one third of the brain. Other well developed areas involved hearing and muscle coordination. Newer research shows that while the Archaeopteryx brain was more complex than that of more primitive theropods, it had a more generalized brain volume among Maniraptora dinosaurs, even smaller than that of other non avian dinosaurs in several instances, which indicates the neurological development required for flight was already a common trait in the maniraptoran clade. Recent studies of flight feather barb geometry reveal that modern birds possess a larger barb angle in the trailing vane of the feather, whereas Archaeopteryx lacks this large barb angle, indicating potentially weak flight abilities. Archaeopteryx continues to play an important part in scientific debates about the origin and evolution of birds. Some scientists see it as a semi arboreal climbing animal, following the idea that birds evolved from tree dwelling gliders (the "trees down" hypothesis for the evolution of flight proposed by O. C. Marsh). Other scientists see Archaeopteryx as running quickly along the ground, supporting the idea that birds evolved flight by running (the "ground up" hypothesis proposed by Samuel Wendell Williston). Still others suggest that Archaeopteryx might have been at home both in the trees and on the ground, like modern crows, and this latter view is what currently is considered best supported by morphological characters. Altogether, it appears that the species was not particularly specialized for running on the ground or for perching. A scenario outlined by Elżanowski in 2002 suggested that Archaeopteryx used its wings mainly to escape predators by glides punctuated with shallow downstrokes to reach successively higher perches, and alternatively, to cover longer distances (mainly) by gliding down from cliffs or treetops. This study on Archaeopteryxs bone histology identified biomechanical and physiological adaptations exhibited by modern volant birds that perform intermittent flapping, such as pheasants and other burst flyers. Studies of Archaeopteryx's feather sheaths revealed that like modern birds, it had a center out, flight related molting strategy. As it was a weak flier, this was extremely advantageous in preserving its maximum flight performance.

An histological study by Erickson, Norell, Zhongue, and others in 2009 estimated that Archaeopteryx grew relatively slowly compared to modern birds, presumably because the outermost portions of Archaeopteryx bones appear poorly vascularized; One of the few modern birds that exhibit slow growth is the flightless kiwi, and the authors speculated that Archaeopteryx and the kiwi had similar basal metabolic rate.

The richness and diversity of the Solnhofen limestones in which all specimens of Archaeopteryx have been found have shed light on an ancient Jurassic Bavaria strikingly different from the present day. The latitude was similar to Florida, though the climate was likely to have been drier, as evidenced by fossils of plants with adaptations for arid conditions and a lack of terrestrial sediments characteristic of rivers. Evidence of plants, although scarce, include cycads and conifers while animals found include a large number of insects, small lizards, pterosaurs, and Compsognathus. The absence of trees does not preclude Archaeopteryx from an arboreal lifestyle, as several species of bird live exclusively in low shrubs. Various aspects of the morphology of Archaeopteryx point to either an arboreal or ground existence, including the length of its legs and the elongation in its feet; some authorities consider it likely to have been a generalist capable of feeding in both shrubs and open ground, as well as along the shores of the lagoon.