Archaeopteryx

Taxobox
name = "Archaeopteryx"
fossil_range = fossil range|155.0|150.0Late Jurassic

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image_width = 300px
image_caption = A model of "Archaeopteryx lithographica" on display at the Oxford University Museum.
regnum = Animalia
phylum = Chordata
classis = Aves
ordo = Archaeopterygiformes
familia = Archaeopterygidae
genus = "Archaeopteryx"
genus_authority = Meyer, 1861
subdivision_ranks = Species
subdivision ="A. lithographica" Meyer, 1861 (type)
synonyms = See below

"Archaeopteryx", sometimes referred to by its German name "Urvogel" ("original bird" or "first bird"), is the earliest and most primitive bird known. The name is from the Ancient Greek Polytonic| "archaios" meaning 'ancient' and Polytonic| "pteryx" meaning 'feather' or 'wing'; pronEng|ˌɑrkiːˈɒptərɨks respell|AR|kee|OP|ter-iks.

"Archaeopteryx" lived in the late Jurassic Period around 155–150 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 and shape to a European Magpie, "Archaeopteryx" could grow to about 0.5 metres (1.6 ft) in length. Despite its small size, broad wings, and ability to fly, "Archaeopteryx" has more in common with small theropod dinosaurs than it does with modern birds. In particular, it shares the following features with the deinonychosaurs (dromaeosaurs and troodontids): jaws with sharp teeth, three fingers with claws, a long bony tail, hyperextensible second toes ("killing claw"), feathers (which also suggest homeothermy), and various skeletal features.

The features above make "Archaeopteryx" the first clear candidate for a transitional fossil between dinosaurs and birds. [ [http://www.ucmp.berkeley.edu/diapsids/birds/archaeopteryx.html "Archaeopteryx": An Early Bird] - University of California, Berkeley Museum of Paleontology. Retrieved 2006-OCT-18] [ [http://www.ucalgary.ca/~longrich/archaeopteryx.html "Archaeopteryx lithographica"] - Nick Longrich, University of Calgary. Discusses how many wings an "Archaeopteryx" had and other questions.] Thus, "Archaeopteryx" plays an important role not only in the study of the origin of birds but in the study of dinosaurs.

The first complete specimen of "Archaeopteryx" was announced in 1861, only two years after Charles Darwin published "On the Origin of Species", and it became a key piece of evidence in the debate over evolution. Over the years, nine more fossils of "Archaeopteryx" have surfaced. Despite variation among these fossils, most experts regard all the remains that have been discovered as belonging to a single species, though this is still debated.

Many of these eleven fossils include impressions of feathers—among the oldest (if not the oldest) direct evidence of feathers. Moreover, because these feathers are an advanced form (flight feathers), these fossils are evidence that feathers had been evolving for quite some time.cite book|title=Feathered Dragons|year=2004|chapter=The Plumage of "Archaeopteryx"|editor=Currie PJ, Koppelhus EB, Shugar MA, Wright JL|author=Wellnhofer P|pages=282–300|publisher=Indiana University Press|id=ISBN 0-253-34373-9]

Description

"Archaeopteryx" was a primitive bird that lived during the Tithonian stage of the Jurassic Period, around 155–150 million years ago.cite book| last = Lambert| first = David| authorlink =| coauthors =| title = The Ultimate Dinosaur Book| publisher = Dorling Kindersley| date = 1993| location = New York| pages = 38–81| url =| doi =| isbn = 1-56458-304-X ] The only specimens of "Archaeopteryx" that have been discovered come from Bavaria in southern Germany.

"Archaeopteryx" was roughly the size of a medium-sized modern-day bird, with broad wings that were rounded at the ends and a long tail compared to its body length. In all, "Archaeopteryx" could reach up to 500 millimeters (1.6 ft) in body length. "Archaeopteryx" feathers, although less documented than its other features, were very similar in structure and design to modern-day bird feathers. However, despite the presence of numerous avian features,cite web| last = Holtz| first = Thomas, Jr.| authorlink =| coauthors =| title = "Archaeopteryx"s Relationship With Modern Birds| work =| publisher = Journal of Dinosaur Paleontology| date = 1995| url = http://www.dinosauria.com/jdp/archie/archie.htm| format =| doi =| accessdate = 2007-03-01 ] "Archaeopteryx" had many theropod dinosaur characteristics. Unlike modern birds, "Archaeopteryx" had small teeth as well as a long bony tail, features which "Archaeopteryx" shared with other dinosaurs of the time. [Palaeogeography, Palaeoclimatology, Palaeoecology 130 (1997) 275-292 ]

Because it displays a number of features common to both birds and dinosaurs, "Archaeopteryx" has often been considered a link between them—possibly the first bird in its change from a land dweller to a bird. In the 1970s, John Ostrom, following T. H. Huxley's lead in 1868, argued that birds evolved from theropod dinosaurs and "Archaeopteryx" was a critical piece of evidence for this argument; it preserves a number of avian features, such as a wishbone, flight feathers, wings and a partially reversed first toe, and a number of dinosaur and theropod features. For instance, it has a long ascending process of the ankle bone, interdental plates, an obturator process of the ischium, and long chevrons in the tail. In particular, Ostrom found that "Archaeopteryx" was remarkably similar to the theropod family Dromaeosauridae. [Bühler, P. & Bock, W.J. (2002). "Zur Archaeopteryx-Nomenklatur: Missverständnisse und Lösung". Journal of Ornithology. 143(3): 269–286. [Article in German, English abstract] DOI|10.1046/j.1439-0361.2002.02006.x (HTML abstract)] [Feduccia, A. (1993). "Evidence from claw geometry indicating arboreal habits of Archaeopteryx". Science. 259(5096): 790–793.] [Feduccia, A. & Tordoff, H.B. (1979). "Feathers of Archaeopteryx: Asymmetric vanes indicate aerodynamic function". Science. 203(4384): 1021–1022.] [Huxley T.H. (1868). "On the animals which are most nearly intermediate between birds and reptiles". Geol. Mag. 5, 357–65; Annals & Magazine of Nat Hist 2, 66–75; Scientific Memoirs 3, 3–13.] [Huxley T.H. (1868) "Remarks upon Archaeopteryx lithographica". Proc Roy Soc 16, 243–48; Sci Memoirs 3, 340-45.] [Huxley T.H. (1870) "Further evidence of the affinity between the dinosaurian reptiles and birds". Quart J Geol Soc 26, 32–50; Sci Mem 3, 487–509.] [Kennedy, Elaine (2000). " [http://www.grisda.org/georpts/3001.htm Solnhofen Limestone: Home of Archaeopteryx] ". Geoscience Reports. 30: 1–4. Retrieved 2006-10-18.] [Nedin, C. (1999). " [http://www.talkorigins.org/faqs/archaeopteryx/info.html All About Archaeopteryx] . talk.origins archive. Version of June 10, 2002; retrieved 2006-10-18.] [Olson, S.L. & Feduccia, A. (1979). "Flight capability and the pectoral girdle of Archaeopteryx". Nature. 278(5701). 247–248. doi|10.1038/278247a0 (HTML abstract)] [Ostrom, J.H. (1976). "Archaeopteryx and the origin of birds". Biol. J. Linn. Soc.. 8: 91–182.] [Ostrom, J.H. (1985). "Introduction to Archaeopteryx". In: Hecht, M.K.O.; Ostrom, J.H.; Viohl, G. & Wellnhofer, P. (eds.) The Beginnings of Birds: Proceedings of the International Archaeopteryx Conference: 9–20. Eichstätt, Freunde des Jura-Museums Eichstätt.] [Owen, R. (1863). "On the Archaeopteryx of Von Meyer, with a description of the fossil remains of a long-tailed species from the lithographic stone of Solnhofen". Phil. Trans. Roy. Soc. London. 153: 33–47.]

The first remains of "Archaeopteryx" were discovered in 1861; just two years after Charles Darwin published "On the Origin of Species". "Archaeopteryx" seemed to confirm Darwin's theories and has since become a key piece of evidence in the origin of birds, transitional fossils debate and the confirmation of evolution. Indeed, further research on dinosaurs from the Gobi Desert and China has since provided more evidence of a link between "Archaeopteryx" and the dinosaurs, such as the Chinese feathered dinosaurs. "Archaeopteryx" is close to the ancestry of modern birds, and it shows most of the features one would expect in an ancestral bird. However, it may not be the direct ancestor of living birds, and it is uncertain how much evolutionary divergence was already present among other birds at the time.

Paleobiology

=Plu

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. The tail feathers were less asymmetrical, again in line with the situation in modern birds and also had firm vanes. The thumb, however, did not yet bear a separately movable tuft of stiff feathers.

The body plumage of "Archaeopteryx" is less well documented and has only been properly researched in the well-preserved Berlin specimen. Thus, as more than one species seems to be involved, the research into the Berlin specimen's feathers does not necessarily hold true for the rest of the species of "Archaeopteryx". In the Berlin specimen, there are "trousers" of well-developed feathers on the legs; some of these feathers seem to have a basic contour feather structure but are somewhat decomposed (they lack barbicels as in ratites),Christensen P, Bonde N. (2004). "Body plumage in Archaeopteryx: a review, and new evidence from the Berlin specimen". Comptes Rendus Palevol. 3: 99–118. [http://dinonews.net/rubriq/biblio.php#plumes_archaeopteryx_christiansen PDF fulltext] ] but in part they are firm and thus capable of supporting flight.Longrich N. (2006): "Structure and function of hindlimb feathers in Archaeopteryx lithographica". Paleobiology. 32(3): 417–431. DOI|10.1666/04014.1 (HTML abstract)]

There was a patch of pennaceous feathers running along the back which was quite similar to the contour feathers of the body plumage of modern birds in being symmetrical and firm, though not as stiff as the flight-related feathers. Apart from that, the feather traces in the Berlin specimen are limited to a sort of "proto-down" not dissimilar to that found in the dinosaur "Sinosauropteryx", being decomposed and fluffy, and possibly even appeared more like fur than like feathers in life (though not in their microscopic structure). These occur on the remainder of the body, as far as such structures are both preserved and not obliterated by preparation, and the lower neck.

However, there is no indication of feathering on the upper neck and head. While these may conceivably have been nude as in many closely related feathered dinosaurs for which good specimens are available, this may still be an artifact of preservation. It appears that most "Archaeopteryx" specimens became embedded in anoxic sediment after drifting some time on their back in the sea — the head and neck and the tail are generally bent downwards, which suggests that the specimens had just started to rot when they were embedded, with tendons and muscle relaxing so that the characteristic shape of the fossil specimens was achieved. This would mean that the skin was already 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.Elżanowski A. (2002): Archaeopterygidae (Upper Jurassic of Germany). "In:" Chiappe, L. M. & Witmer, L. M (eds.), "Mesozoic Birds: Above the Heads of Dinosaurs": 129–159. University of California Press, Berkeley.]

Flight

—instead of the dorsally angled arrangement found in modern birds—suggests that "Archaeopteryx" was unable to lift its wings above its back, a requirement for the upstroke found in modern flapping flight. Thus, it seems likely that "Archaeopteryx" was indeed unable to use flapping flight as modern birds do, but it may well have utilized a downstroke-only flap-assisted gliding technique.Senter, P. (2006). "Scapular orientation in theropods and basal birds and the origin of flapping flight". Acta Palaeontologica Polonica. 51(2): 305–313. [http://www.app.pan.pl/acta51/app51-305.pdf PDF fulltext] ]

"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 could also have improved "Archaeopteryx ability to fly through cluttered environments such as trees and brush (similar wing shapes are seen in birds which 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", would also 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%.Longrich N. (2006). "Structure and function of hindlimb feathers in Archaeopteryx lithographica". Paleobiology. 32"'(3): 417–431. DOI|10.1666/04014.1 (HTML abstract)]

In 2004, scientists analyzing a detailed CT scan of "Archaeopteryx braincase 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.Witmer, L. M. (2004). "Palaeontology: Inside the oldest bird brain". Nature. 430(7000): 619–620. PMID 15295579 doi|10.1038/430619a ] The skull scan also revealed the structure of the inner ear. The structure more closely resembles that of modern birds than the inner ear of reptiles. These characteristics taken together suggest that "Archaeopteryx" had the keen sense of hearing, balance, spatial perception and coordination needed to fly.Alonso, P. D., Milner, A. C., Ketcham, R. A., Cookson, M. J. & Rowe, T. B. (2004). "The avian nature of the brain and inner ear of Archaeopteryx". Nature. 430"'(7000): 666–669. PMID 15295597. doi|10.1038/nature02706. [http://www.ucm.es/info/paleo/personal/patricio/DMKCR-2004.pdf PDF fulltext] [http://www.nature.com/nature/journal/v430/n7000/suppinfo/nature02706.html Supplementary info] ] "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 today 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. Considering the current knowledge of flight-related morphology, a scenario outlined by Elżanowski in 2002, namely 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 by (mainly) gliding down from cliffs or treetops, appears quite reasonable.

Paleoecology

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 lack of terrestrial sediments characteristic of rivers. Evidence of plants, though scarce, include cycads and conifers while animals found include a large number of insects, small lizards, pterosaurs and "Compsognathus".cite book| last = Chiappe| first = Luis M.| authorlink =| coauthors =| title = Glorified Dinosaurs | publisher = UNSW Press| date = 2007| location = Sydney| pages = 118–146| url =| doi =| isbn = 0-471-24723-5]

The excellent preservation of "Archaeopteryx" fossils and other terrestrial fossils found at Solnhofen indicates that they did not travel far before becoming preserved. [cite journal |last= Davis |first=P. |coauthors=and Briggs, D. |year=1998 |title=The impact of decay and disarticulation on the preservation of fossil birds |journal=Palaios |volume=13 |issue=1 |pages=3–13 |url=http://palaios.sepmonline.org/cgi/content/abstract/13/1/3 |accessdate=2007-03-25 |doi=10.2307/3515277 ] The "Archaeopteryx" specimens found are likely therefore to have lived on the low islands surrounding the Solnhofen lagoon rather than been corpses that drifted in from further away. "Archaeopteryx" skeletons are considerably less numerous in the deposits of Solnhofen than those of pterosaurs such as "Rhamphorhynchus", the group which dominated the niche currently occupied by seabirds, yet are common enough that it is unlikely that the specimens found are vagrants from the larger islands 50 km (31 miles) to the north.cite book |last=Paul |first=Gregory S. |authorlink=Gregory S. Paul |title=Dinosaurs of the Air: The Evolution and Loss of Flight in Dinosaurs and Birds |year=2002 |publisher=Johns Hopkins University Press |location=Baltimore |isbn=0-8018-6763-0 ]

The islands that surrounded the Solnhofen lagoon were low lying, semi-arid and sub-tropical with a long dry season and little rain. [cite book |last=Buisonje |first=P.H. de |editor=Hecht, M.K.; Ostrom, J.H.; Viohl, G.; and Wellnhofer, P. (eds.) |title=The beginnings of Birds: Proceedings of the International "Archaeopteryx" Conference, Eichstatt, 1984 |year=1985 |publisher=Freunde des Jura-Museums Eichstätt |location=Eichstätt |isbn=978-3980117807 |pages=45–65 |chapter=Climatological conditions during deposition of the Solnhofen limestones ] The flora of these islands was adapted to these dry conditions and consisted mostly of low (3 m [10 ft] ) shrubs. Contrary to reconstructions of "Archaeopteryx" climbing large trees, these seem to have been mostly absent from the islands; few trunks have been found in the sediments and fossilized tree pollen is also absent.

The lifestyle of "Archaeopteryx" is difficult to reconstruct and there are several theories regarding it. Some researchers suggest that it was primarily adapted to life on the ground, [cite journal |last=Ostrom |first=J.H. |authorlink=John Ostrom |year=1976 |title="Archaeopteryx" and the origin of birds |journal=Biological Journal of the Linnean Society |volume=8 |pages=91–182 |doi=10.1111/j.1095-8312.1976.tb00244.x] while other researchers suggest that it was principally arboreal. The absence of trees does not preclude "Archaeopteryx" from an arboreal lifestyle; several species of extant bird live exclusively in low shrubs. Various aspects of the morphology of "Archaeopteryx" point to either an arboreal or ground existence, the length of its legs, the elongation in its feet; and some authorities consider it likely to have been a generalist capable of feeding in both shrubs, open ground and even alongside the shores of the lagoon. It most likely hunted small prey, seizing it with its jaws if it was small enough or with its claws if it was larger.

History of discovery

Over the years, ten body fossil specimens of "Archaeopteryx" and a feather that may belong to it have been found. All of the fossils come from the limestone deposits, quarried for centuries, near Solnhofen, Germany. [http://news.nationalgeographic.com/news/2005/12/1201_051201_archaeopteryx.html National Geographic News- "Earliest Bird Had Feet Like Dinosaur, Fossil Shows"] - Nicholas Bakalar, December 1, 2005, Page 1. Retrieved 2006-10-18.] The initial discovery, a single feather, was unearthed in 1860 and described a year later by Christian Erich Hermann von Meyer. It is currently located at the Humboldt Museum für Naturkunde in Berlin. This is generally assigned to "Archaeopteryx" and was the initial holotype, but whether it actually is a feather of this species or another, as yet undiscovered, proto-bird is unknown. There are some indications it is indeed not from the same animal as most of the skeletons (the "typical" "A. lithographica").Griffiths, P. J. (1996). "The Isolated Archaeopteryx Feather". Archaeopteryx 14: 1–26.]

Soon after, the first skeleton, known as the London Specimen (BMNH 37001 ) was unearthed in 1861 near Langenaltheim, Germany and given to a local physician Karl Häberlein in return for medical services. He then sold it to the Natural History Museum in London, where it remains. Missing most of its head and neck, it was described in 1863 by Richard Owen as "Archaeopteryx macrura", who assumed it did not belong to the same species as the feather. In the subsequent 4th edition of his "On the Origin of Species" (chap. 9 [http://darwin-online.org.uk/content/frameset?viewtype=text&itemID=F385&pageseq=399 p. 367] ), Charles Darwin described how some authors had maintained "that the whole class of birds came suddenly into existence during the eocene period; but now we know, on the authority of Professor Owen, that a bird certainly lived during the deposition of the upper greensand; and still more recently, that strange bird, the Archeopteryx, with a long lizard-like tail, bearing a pair of feathers on each joint, and with its wings furnished with two free claws, has been discovered in the oolitic slates of Solenhofen. Hardly any recent discovery shows more forcibly than this how little we as yet know of the former inhabitants of the world."cite book| last = Darwin| first = Charles| authorlink = Charles Darwin | title = On the Origin of Species| publisher = John Murray| date = 1859| location = | pages = | url = http://www.readprint.com/chapter-2217/Charles-Darwin| doi = | id = | isbn = ]

The Greek term "pteryx" (πτερυξ) primarily means "wing", but can also designate merely "feather". Von Meyer suggested this in his description. At first he referred to a single feather which appeared like a modern bird's remex (wing feather), but he had heard of and been shown a rough sketch of the London specimen, to which he referred as a "Skelet eines mit Federn bedeckten _de. Thiers" ("skeleton of an animal covered in feathers"). In German, this ambiguity is resolved by the term "Schwinge" which does not necessarily mean a wing used for flying. "Urschwinge" was the favored translation of "Archaeopteryx" among German scholars in the late 19th century. In English, "ancient pinion" offers a rough approximation.

Since then nine specimens have been recovered:The Berlin Specimen (HMN 1880) was discovered in 1876 or 1877 on the Blumenberg near Eichstätt, Germany, by Jakob Niemeyer. He exchanged this precious fossil for a cow, with Johann Dörr. Placed on sale in 1881, with potential buyers including O.C. Marsh of Yale University's Peabody Museum, it was bought by the Humboldt Museum für Naturkunde, where it is now displayed. The transaction was financed by Ernst Werner von Siemens, founder of the famous company that bears his name. Described in 1884 by Wilhelm Dames, it is the most complete specimen, and the first with a complete head. Once classified as a new species, "A. siemensii", a recent evaluation supports the "A. siemensii" species definition.

Composed of a torso, the Maxberg Specimen (S5) was discovered in 1956 or 1958 near Langenaltheim and described in 1959 by Heller. It is currently missing, though it was once exhibited at the Maxberg Museum in Solnhofen. It belonged to Eduard Opitsch, who loaned it to the museum. After his death in 1991, the specimen was discovered to be missing and may have been stolen or sold. The specimen is missing its head and tail, although the rest of the skeleton is mostly intact.

The Haarlem Specimen (TM 6428, also known as the "Teyler Specimen") was discovered in 1855 near Riedenburg, Germany and described as a "Pterodactylus crassipes" in 1875 by von 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, despite the classification error. It is also one of the least complete specimens, consisting mostly of limb bones and isolated cervical vertebrae and ribs. The Eichstätt Specimen (JM 2257) was discovered in 1951 or 1955 near Workerszell, Germany and described by Peter Wellnhofer in 1974. Currently located at the Jura Museum in Eichstätt, Germany, it is the smallest specimen and has the second best head. It is possibly a separate genus ("Jurapteryx recurva") or species ("A. recurva").

The Solnhofen Specimen (BSP 1999) was discovered in the 1960s near Eichstätt, Germany and described in 1988 by Wellnhofer. Currently located at the Bürgermeister-Müller-Museum in Solnhofen, it was originally classified as "Compsognathus" by an amateur collector. 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 (S6, formerly known as the "Solnhofen-Aktien-Verein Specimen") was discovered in 1991 near Langenaltheim and described in 1993 by Wellnhofer. It is currently located at the Paläontologisches Museum München in Munich. What was initially believed to be a bony sternum turned out to be part of the coracoid,Wellnhofer, P. & Tischlinger, H. (2004). "Das "Brustbein" von Archaeopteryx bavarica Wellnhofer 1993 - eine Revision". Archaeopteryx. 22: 3–15. [Article in German] ] but a cartilaginous sternum may have been present. Only the front of its face is missing. It may be a new species, "A. bavarica".

An eighth, fragmentary specimen, the Bürgermeister-Müller Specimen was discovered in 1997 and it is currently kept at the Bürgermeister-Müller Museum. Other than the above remains discovered, a further fragmentary fossil was found in 2004.

Long in a private collection, the Thermopolis Specimen (WDC CSG 100) was discovered in Germany 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 in the December 2, 2005 "Science" journal article as "A well-preserved "Archaeopteryx" specimen with theropod features"; it shows that the "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. [Mayr G, Pohl B & Peters DS. (2005). "A well-preserved Archaeopteryx specimen with theropod features". Science. 310(5753): 1483–1486. doi|10.1126/science.1120331 [http://www.sciencemag.org/cgi/content/full/sci;310/5753/1483/DC1 See commentary on article] ] This has been interpreted as evidence of theropod ancestry. The specimen also has a hyperextendible second toe. "Until now, the feature was thought to belong only to the species' close relatives, the deinonychosaurs." [http://news.nationalgeographic.com/news/2005/12/1201_051201_archaeopteryx_2.html National Geographic News- "Earliest Bird Had Feet Like Dinosaur, Fossil Shows"] - Nicholas Bakalar, December 1, 2005, Page 2. Retrieved 2006-10-18.] This tenth and latest specimen was assigned to "Archaeopteryx siemensii" in 2007.Mayr, G., Phol, B., Hartman, S. & Peters, D.S. (2007). "The tenth skeletal specimen of Archaeopteryx". Zoological Journal of the Linnean Society, 149, 97–116.] The specimen itself, currently on loan to the Forschungsinstitut Senckenberg in Frankfurt, is considered the most complete and well preserved "Archaeopteryx" remains yet.Mayr, G., Phol, B., Hartman, S. & Peters, D.S. (2007). "The tenth skeletal specimen of Archaeopteryx". Zoological Journal of the Linnean Society, 149, 97–116.]

Some reports claim that they provide evidence to prove that "Archaeopteryx" is a fake.cite journal |last=Trop |first=M. |year=1983 |title=Is Archaeopteryx a fake? |journal=Creation Res. Soc. Quart. |month=September |pages=121–122] However, such reports are not confirmed.cite web |url=http://wiki.cotch.net/index.php/Archaeopteryx_is_a_fake |title=Archaeopteryx is a fake |accessdate=2007-07-05 ] The issue is further discussed below.

Taxonomy

Today, the fossils are usually assigned to a single species "A. lithographica", but the taxonomic history is complicated. Dozens of names have been published for the handful of specimens, most of which are simply spelling errors ("lapsus"). Originally, the name "A. lithographica" only referred to the single feather described by von Meyer. In 1960, Swinton proposed that the name "Archaeopteryx lithographica" be officially transferred from the feather to the London specimen.Swinton, W. E. (1960). Opinion 1084, Proposed addition of the generic name "Archaeopteryx" VON MEYER, 1861 and the specific name "Lithographica", VON MEYER, 1861, as published in the binomen "Archaeopteryx Lithographica" to the official lists (Class Aves). "Bulletin of Zoological Nomenclature" 17(6–8): 224–226.] The ICZN did suppress the plethora of alternative names initially proposed for the first skeleton specimens,ICZN. (1961). Opinion 607, "Archaeopteryx" VON MEYER, 1861 (Aves); Addition to the Official list. "Bulletin of Zoological Nomenclature" 18(4): 260–261.] which mainly resulted from the acrimonious dispute between von Meyer and his opponent Johann Andreas Wagner (whose "Griphosaurus problematicus"—"problematic riddle-lizard"—was a vitriolic sneer at von Meyer's "Archaeopteryx"). [Wagner A (1861) Über ein neues, angeblich mit Vogelfedern versehenes Reptil aus dem Solnhofener lithographischen Schiefer. "Sitzungberichte der Bayerischen Akademie der Wissenschaften, mathematisch-physikalisch Classe" 146–154] In addition, descriptions of "Archaeopteryx" fossils as pterosaurs before their true nature was realized were also suppressed.ICZN. (1977). Opinion 1070. Conservation of "Archaeopteryx lithographica" VON MEYER 1861 (Aves). "Bulletin of Zoological Nomenclature" 33: 165–166.]

The relationships of the specimens are problematic. Most subsequent specimens have been given their own species at one point or another. The Berlin specimen has been designated as "Archaeornis siemensii", the Eichstätt specimen as "Jurapteryx recurva", the Munich specimen as "Archaeopteryx bavarica" and the Solnhofen specimen was designated as "Wellnhoferia grandis".

Recently, it has been argued that all the specimens belong to the same species."Archaeopteryx" turns out to be singular bird of a feather. "New Scientist" 2443:17. 17 April 2004. [http://www.newscientist.com/article/mg18224432.300-archaeopteryx-turns-out-to-be-singular-bird-of-a-feather.html See commentary on article] .] However, significant differences exist among the specimens. In particular, the Munich, Eichstätt, Solnhofen and Thermopolis specimens differ from the London, Berlin, and Haarlem specimens in being smaller or much larger, having different finger proportions, having more slender snouts, lined with forward-pointing teeth and possible presence of a sternum. These differences are as large as or larger than the differences seen today between adults of different bird species. However, it is also possible that these differences could be explained by different ages of the living birds.

Finally, it is worth noting that the feather, the first specimen of "Archaeopteryx" described, does not agree well with the flight-related feathers of "Archaeopteryx". It certainly is a flight feather of a contemporary species, but its size and proportions indicate that it may belong to another, smaller species of feathered theropod, of which only this feather is so far known. As the feather was the original type specimen, this has created significant nomenclatorial confusion.

Synonyms

If two names are given, the first denotes the original describer of the "species", the second the author on whom the given name combination is based. As always in zoological nomenclature, putting an author's name in parentheses denotes that the taxon was originally described in a different genus.
* "Pterodactylus crassipes" Meyer, 1857 [suppressed in favor of "A. lithographica" 1977 per ICZN Opinion 1070]
* "Rhamphorhynchus crassipes" (Meyer, 1857) (as "Pterodactylus (Rhamphorhynchus) crassipes") [suppressed in favor of "A. lithographica" 1977 per ICZN Opinion 1070]
* "Archaeopteryx lithographica" Meyer, 1861 [nomen conservandum]
* "Scaphognathus crassipes" (Meyer, 1857) Wagner, 1861 [suppressed in favor of "A. lithographica" 1977 per ICZN Opinion 1070]
* "Archaeopterix lithographica" Anon., 1861 ["lapsus"]
* "Griphosaurus problematicus" Wagner, 1861 ["nomen oblitum" 1961 per ICZN Opinion 607]
* "Griphornis longicaudatus" Woodward, 1862 ["nomen oblitum" 1961 per ICZN Opinion 607]
* "Griphosaurus longicaudatum" (Woodward, 1862) ["lapsus"]
* "Griphosaurus longicaudatus" (Owen, 1862) ["nomen oblitum" 1961 per ICZN Opinion 607]
* "Archaeopteryx macrura" Owen, 1862 ["nomen oblitum" 1961 per ICZN Opinion 607]
* "Archaeopterix macrura" Owen, 1862 ["lapsus"]
* "Archaeopterix macrurus" Egerton, 1862 ["lapsus"]
* "Archeopteryx macrurus" Owen, 1863 [unjustified emendation]
* "Archaeopteryx macroura" Vogt, 1879 ["lapsus"]
* "Archaeopteryx siemensii" Dames, 1897
* "Archaeopteryx siemensi" Dames, 1897 ["lapsus"]
* "Archaeornis siemensii" (Dames, 1897) Petronievics, 1917
* "Archaeopteryx oweni" Petronievics, 1917 ["nomen oblitum" 1961 per ICZN Opinion 607]
* "Gryphornis longicaudatus" Lambrecht, 1933 ["lapsus"]
* "Gryphosaurus problematicus" Lambrecht, 1933 ["lapsus"]
* "Archaeopteryx macrourus" Owen, 1862 "fide" Lambrecht, 1933 ["lapsus"]
* "Archaeornis siemensi" (Dames, 1897) "fide" Lambrecht, 1933? ["lapsus"]
* "Archeopteryx macrura" Ostrom, 1970 ["lapsus"]
* "Archaeopteryx crassipes" (Meyer, 1857) Ostrom, 1972 [suppressed in favor of "A. lithographica" 1977 per ICZN Opinion 1070]
* "Archaeopterix lithographica" di Gregorio, 1984 ["lapsus"]
* "Archaeopteryx recurva" Howgate, 1984
* "Jurapteryx recurva" (Howgate, 1984) Howgate, 1985
* "Archaeopteryx bavarica" Wellnhofer, 1993
* "Wellnhoferia grandis" Elżanowski, 2001

The last 4 taxa may be valid genera and species.

"Archaeopteryx" vicensensis" (Anon. "fide" Lambrecht, 1933) is a "nomen nudum" for what appears to be an undescribed pterosaur.

Controversies

Authenticity

Beginning in 1985, a 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.cite journal |last=Hoyle |first=F. |authorlink=Fred Hoyle |coauthors=Wickramasinghe, N.C.; and Watkins, R.S. |year=1985 |title="Archaeopteryx" |journal=British Journal of Photography |volume=132 |pages=693–694 ] cite journal |last=Watkins |first=R.S. |coauthors=Hoyle, F.; Wickrmasinghe, N.C.; Watkins, J.; Rabilizirov, R.; and Spetner, L.M. |year=1985 |title="Archaeopteryx" - a photographic study |journal=British Journal of Photography |volume=132 |pages=264–266 ] cite journal |last=Watkins |first=R.S. |coauthors=Hoyle, F.; Wickrmasinghe, N.C.; Watkins, J.; Rabilizirov, R.; and Spetner, L.M. |year=1985 |title="Archaeopteryx" - a further comment |journal=British Journal of Photography |volume=132 |pages=358–359, 367 ] cite journal |last=Watkins |first=R.S. |coauthors=Hoyle, F.; Wickrmasinghe, N.C.; Watkins, J.; Rabilizirov, R.; and Spetner, L.M. |year=1985 |title="Archaeopteryx" - more evidence |journal=British Journal of Photography |volume=132 |pages=468–470 ] Their claims were repudiated by Alan J. Charig and others at the British Museum (Natural History).cite journal |last=Charig |first=A.J. |authorlink=Alan J. Charig |coauthors=Greenaway, F.; Milner, A.N.; Walker, C.A.; and Whybrow, P.J. |year=1986 |title="Archaeopteryx" is not a forgery |journal=Science |volume=232 |issue=4750 |pages=622–626 |doi=10.1126/science.232.4750.622 |pmid=17781413 ] Most of their evidence for a forgery was based on unfamiliarity with the processes of lithification; for example, they proposed that based on the difference in texture associated with the feathers, feather impressions were applied to a thin layer of cement, without realizing that feathers themselves would have caused a textural difference. They also expressed disbelief that slabs would split so smoothly, or that one half of a slab containing fossils would have good preservation, but not the counterslab. These, though, are common properties of Solnhofen fossils because the dead animals would fall onto hardened surfaces which would form a natural plane for the future slabs to split along, leaving the bulk of the fossil on one side and little on the other. They also misinterpreted the fossils, claiming that the tail was forged as one large feather, when this is visibly not the case. In addition, they claimed that the other specimens of "Archaeopteryx" known at the time did not have feathers, which is untrue; the Maxberg and Eichstätt specimens have obvious feathers. Finally, the motives they suggested for a forgery are not strong, and contradictory; one is that Richard Owen wanted to forge evidence in support of Charles Darwin's theory of evolution, which is unlikely given Owen's views toward Darwin and his theory. The other is that Owen wanted to set a trap for Darwin, hoping the latter would support the fossils so Owen could discredit him with the forgery; this is unlikely because Owen himself wrote a detailed paper on the London specimen, so such an action would certainly backfire.cite web |url=http://www.talkorigins.org/faqs/archaeopteryx/forgery.html |title=On "Archaeopteryx", Astronomers, and Forgery |accessdate=2007-03-17 |last=Nedin |first=Chris |date=2007-12-15 ]

Charig "et al". pointed to the presence of hairline cracks in the slabs running through both rock and fossil impressions, and mineral growth over the slabs that had occurred before discovery and preparation, as evidence that the feathers were original. Spetner "et al". then attempted to show that the cracks would have naturally propagated through their postulated cement layer,cite journal |last=Spetner |first=L.M. |authorlink=Lee Spetner |coauthors=Hoyle, F.; Wickramasinghe, N.C.; and Magaritz, M. |year=1988 |title="Archaeopteryx" - more evidence for a forgery |journal=The British Journal of Photography |volume=135 |pages=14–17 ] but neglected to account for the fact that the cracks were old and had been filled with calcite, and thus were not able to propagate. They also attempted to show the presence of cement on the London specimen through X-ray spectroscopy, and did find something that was not rock. However, it was not cement, either, and is most probably from a fragment of silicone rubber left behind when molds were made of the specimen. Their suggestions have not been taken seriously by paleontologists, as their evidence was largely based on misunderstandings of geology, and they never discussed the other feather-bearing specimens, which have increased in number since then.

"Archaeopteryx" and "Protoavis"

In 1984, Sankar Chatterjee discovered fossils which he claimed in 1991 belonged to a fossil bird far older than "Archaeopteryx". These fossils, believed to be around 210 to 225 million years old, have been assigned the name "Protoavis". cite journal | last = Chatterjee | first = Sankar | authorlink = | coauthors = | year = 1991 | month = | title = Cranial anatomy and relationships of a new Triassic bird from Texas | journal = | volume = 332 | issue = 1265 | pages = 277–342 | doi = | url = | accessdate = | quote = ] The fossils are too badly preserved to allow an estimate of flying ability; although Chatterjee's reconstructions usually show feathers, many paleontologists, including Paul (2002) and Witmer (2002) have rejected the claims that "Protoavis" was an earlier bird (or, alternately, that it existed at all).cite book |title=Dinosaurs of the Air: The Evolution and Loss of Flight in Dinosaurs and Birds |last=Paul |first=Gregory S. |authorlink= |coauthors= |year=2002 |publisher=Johns Hopkins University Press |location=Baltimore |isbn=0801867630 |pages= ] cite book |title=Mesozoic Birds: Above the Heads of Dinosaurs |chapter=The debate on avian ancestry |last=Witmer |first=Lawrence M. |authorlink= |coauthors= |editor=Witmer, L.; Chiappe, L. |year=2002 |publisher=University of California Press |location=Berkeley |isbn=0520200942 |pages=3–30 ] The fossils were found disarticulated, and were collected from different locations. Because the fossils are in poor condition, "Archaeopteryx" remains the earliest universally recognized bird. cite journal | last = Ostrom | first = J. H. | authorlink = | coauthors = | year = 1996 | month = | title = The questionable validity of "Protoavis" | journal = Archaeopteryx | volume = 14 | issue = | pages = 39–42 | id = | url = | accessdate = | quote = ]

Phylogenetic position

Modern paleontology has consistently placed "Archaeopteryx" as the most primitive bird. It is not thought to be a true ancestor of modern birds but, rather, a close relative of that ancestor (see Avialae and Aves). cite journal | last = Clarke | first = Julia. A. | authorlink = | coauthors = Norell, Mark. A. | year = 2002 | month = | title = The Morphology and Phylogenetic Position of Apsaravis ukhaana from the Late Cretaceous of Mongolia | journal = American Museum Novitates | volume = 3387 | issue = 1 | pages = 1&ndash;46 | doi = 10.1206/0003-0082(2002)387<0001:TMAPPO>2.0.CO;2 | url = | accessdate = | quote = ]

Nonetheless, "Archaeopteryx" is so often used as a model of the true ancestral bird that it has seemed almost heretical to suggest otherwise. Several authors have done so. Lowe (1935) cite journal | last = Lowe | first = P. R. | authorlink = | coauthors = | year = 1935 | month = | title = On the relationship of the Struthiones to the dinosaurs and to the rest of the avian class, with special reference to the position of "Archaeopteryx" | journal = Ibis | volume = 5 | issue = 2 | pages = 398&ndash;432 | issn = 0019-1019 | url = | accessdate = | quote =| doi = 10.1111/j.1474-919X.1935.tb02979.x ] and Thulborn (1984) cite journal | last = Thulborn | first = R. A. | authorlink = | coauthors = | year = 1984 | month = | title = The avian relationships of "Archaeopteryx", and the origin of birds | journal = Zoological Journal of the Linnean Society | volume = 82 | issue = 1-2 | pages = 119&ndash;158 | doi = 10.1111/j.1096-3642.1984.tb00539.x | url = | accessdate = | quote = ] questioned whether "Archaeopteryx" truly was the first bird. They suggested that "Archaeopteryx" was a dinosaur that was no more closely related to birds than were other dinosaur groups. Kurzanov (1987) suggested that "Avimimus" was more likely to be the ancestor of all birds than "Archaeopteryx". cite journal | last = Kurzanov | first = S. M. | authorlink = | coauthors = | year = 1987 | month = | title = Avimimidae and the problem of the origin of birds | journal = Transactions of the joint Soviet-Mongolian Paleontological Expedition | volume = 31 | issue = | pages = 31&ndash;94 | issn = 0320-2305 | url = | accessdate = | quote = ] Barsbold (1983) cite journal | last = Barsbold | first = Rhinchen | authorlink = | coauthors = | year = 1983 | month = | title = Carnivorous dinosaurs from the Cretaceous of Mongolia | journal = Transactions of the joint Soviet-Mongolian Paleontological Expedition | volume = 19 | issue = | pages = 5&ndash;119 | issn = 0320-2305 | url = | accessdate = | quote = ] and Zweers and Van den Berge (1997) cite journal | last = Zweers | first = G. A. | authorlink = | coauthors = Van den Berge, J.C. | year = 1997 | month = | title = Evolutionary patterns of avian trophic diversification | journal = Zoology: Analysis of Complex Systems | volume = 100 | issue = | pages = 25&ndash;57 | issn = 0944-2006 | url = | accessdate = | quote = ] noted that many maniraptoran lineages are extremely birdlike, and suggested that different groups of birds may have descended from different dinosaur ancestors.

In popular culture

"Archaeopteryx" is the best known early bird and has thus received widespread attention. Its easily recognizable appearance and the intense public interest in dinosaurs have caused "Archaeopteryx" to become a feature of worldwide popular culture. For example, the second book in the "Time Machine" series, "Search for Dinosaurs", takes the reader on a journey to the Mesozoic to find and photograph an "Archaeopteryx". [Bischoff, David; "Search for Dinosaurs" ("Time Machine", No. 2); published 1984 by Bantam Books; introduction] In one of the "strangest" appearances of "Archaeopteryx" in popular culture, Alfred Jarry's play _fr. "Ubu cocu, ou l'Archéopteryx" ('Ubu cuckolded, or the Archaeopteryx') includes an "Archaeopteryx" as an important character.Buffetaut, E. (1985). "The strangest interpretation of "Archaeopteryx" " In: Hecht, M.K.O.; Ostrom, J.H.; Viohl, G. & Wellnhofer, P. (eds.) The Beginnings of Birds: Proceedings of the International Archaeopteryx Conference: 369-370. Eichstätt, Freunde des Jura-Museums Eichstätt.] The iconic appearance of the Berlin Specimen has been adapted into the logo of Arc'teryx Equipment Inc. The company's name is a contraction of "Archaeopteryx". A main belt asteroid discovered in 1991, 9860 Archaeopteryx , was named in honour of the genus. [cite web | title = JPL Small-Body Database Browser: 9860 Archaeopteryx (1991 PW9) | publisher = NASA | url= http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=9860 | accessdate = 2007-03-01] cite web | author = Williams, Gareth | title = Minor Planet Names: Alphabetical List |publisher = Smithsonian Astrophysical Observatory | url= http://www.cfa.harvard.edu/iau/lists/MPNames.html | accessdate = 2007-03-01] The name is mentioned regularly in the children's novel, "Skellig". In Neil Cicierega's Dinosaurchestra album, there is a song named after and written about "Archaeopteryx".

See also

* Dinosaur
* Origin of birds
* Feathered dinosaurs

Footnotes

Further reading

* de Beer, G.R. (1954). "Archaeopteryx lithographica: a study based upon the British Museum specimen". Trustees of the British Museum, London.
* Chambers, P. (2002). "Bones of Contention: The Fossil that Shook Science." John Murray, London. ISBN 0-7195-6059-4.
* Feduccia, A. (1996). "The Origin and Evolution of Birds". Yale University Press, New Haven. ISBN 0-300-06460-8.
* Heilmann, G. (1926). "The Origin of Birds". Witherby, London.
* Huxley T.H. (1871). "Manual of the anatomy of vertebrate animals". London.
* von Meyer, H. (1861). "Archaeopteryx litographica (Vogel-Feder) und Pterodactylus von Solenhofen". Neues Jahrbuch für Mineralogie, Geognosie, Geologie und Petrefakten-Kunde. "1861": 678–679, plate V [Article in German] [http://books.google.com/books?id=6RAFAAAAQAAJ&pg=PR1 Fulltext at Google Books] .
* Wellnhofer, P. (2008). "Archaeopteryx. Der Urvogel von Solnhofen" (in German). Verlag Friedrich Pfeil, Munich. ISBN 978-389937076-8

External links

* [http://www.dinosauria.com/jdp/jdp.htm Journal of Dinosaur Paleontology] - With many articles on dinosaur-bird links.
* [http://www.talkorigins.org/faqs/archaeopteryx/info.html All About "Archaeopteryx"] from Talk.Origins