Editing Archaeopteryx (section)

== Description ==
[[File:Archiesizeall1.svg|thumb|400px|alt=Archaeopteryx sizes ranging between about 25 and 50&nbsp;cm long and between 25 and 60&nbsp;cm in wingspan|Specimens compared to a [[human]] in scale]]
Most of the specimens of ''Archaeopteryx'' that have been discovered come from the Solnhofen limestone in Bavaria, southern Germany, which is a {{lang|de|italics=unset|[[Lagerstätte]]}}, a rare and remarkable geological formation known for its superbly detailed fossils laid down during the early Tithonian stage of the Jurassic period,<ref name=Lambert/> approximately 150.8–148.5{{nbsp}}million years ago.<ref>{{Cite journal |last=Schweigert |first=G. |year=2007 |title=Ammonite biostratigraphy as a tool for dating Upper Jurassic lithographic limestones from South Germany – first results and open questions |journal=Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen |volume=245 |issue=1 |pages=117–125 |doi=10.1127/0077-7749/2007/0245-0117|s2cid=140597349 |url=http://doc.rero.ch/record/13825/files/PAL_E722.pdf }}</ref>

''Archaeopteryx'' was roughly the size of a [[raven]],<ref name=Erickson_etal_2009/> with broad wings that were rounded at the ends and a long tail compared to its body length. It could reach up to {{convert|0.5|m|ftin}} in body length and {{convert|0.7|m|ftin}} in [[wingspan]], with an estimated mass of {{convert|0.5|to|1|kg}}.<ref name=Erickson_etal_2009/><ref>{{Cite book |last=Paul |first=Gregory S. |url=http://worldcat.org/oclc/985402380 |title=The Princeton Field Guide to Dinosaurs |publisher=Princeton University Press |year=2016 |isbn=978-1-78684-190-2 |pages=144 |oclc=985402380}}</ref> ''Archaeopteryx'' feathers, although less documented than its other features, were very similar in structure to modern-day bird feathers.<ref name=Lambert/> Despite the presence of numerous avian features,<ref name=Holtz/> ''Archaeopteryx'' had many non-avian [[Theropoda|theropod dinosaur]] characteristics. Unlike modern birds, ''Archaeopteryx'' had small teeth,<ref name=Lambert/> as well as a long bony tail, features which ''Archaeopteryx'' shared with other dinosaurs of the time.<ref name=Paleogeo/>

Because it displays features common to both birds and non-avian dinosaurs, ''Archaeopteryx'' has often been considered a link between them.<ref name=Lambert/> In the 1970s, [[John Ostrom]], following [[Thomas Henry Huxley]]'s lead in 1868, argued that birds evolved within theropod dinosaurs and ''Archaeopteryx'' was a critical piece of evidence for this argument; it had several avian features, such as a wishbone, flight feathers, wings, and a partially reversed first toe along with dinosaur and theropod features. For instance, it has a long ascending process of the [[ankle bone]], [[interdental plate]]s, an [[obturator foramen|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]].<ref name=Buhler/><ref name=Olson_1/><ref name=Ostrom_1/><ref name=Ostrom_2/>

Archaeopteryx had three separate digits on each fore-leg each ending with a "claw". Few birds have such features. Some birds, such as [[duck]]s, [[swan]]s, [[Jacana (genus)|Jacanas]] (''Jacana'' sp.), and the [[hoatzin]] (''Opisthocomus hoazin''), have them concealed beneath their leg-feathers.<ref>{{cite book |last=Attenborough |first=David |title=The Life of Birds |publisher=BBC Books |year=1998 |isbn=0563387920 |author-link=David Attenborough}}</ref>

=== Plumage ===
[[File:Archaeopteryx-modern bird tails.png|thumb|left|Anatomical illustration comparing the "frond-tail" of ''Archaeopteryx'' with the "fan-tail" of a modern bird]]
Specimens of ''Archaeopteryx'' were most notable for their well-developed [[flight feather]]s. They were markedly asymmetrical and showed the structure of flight feathers in modern birds, with vanes given stability by a [[barb (feather)|barb]]-[[barbule]]-[[barbicel]] arrangement.<ref name="Feduc 2"/> The tail feathers were less asymmetrical, again in line with the situation in modern birds and also had firm vanes. The [[thumb]] did not yet bear a separately movable tuft of [[alula|stiff feathers]].

The body plumage of ''Archaeopteryx'' is less well-documented and has only been properly researched in the well-preserved [[The Berlin specimen|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 [[ratite]]s).<ref name=Christ_Bond_04/> In part they are firm and thus capable of supporting flight.<ref name=Longrich_1/>

A patch of [[pennaceous feather]]s is found running along its back, which was quite similar to the contour feathers of the body plumage of modern birds in being symmetrical and firm, although 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 feather|down]]" not dissimilar to that found in the dinosaur ''[[Sinosauropteryx]]'': decomposed and fluffy, and possibly even appearing more like fur than feathers in life (although not in their microscopic structure). These occur on the remainder of the body—although some feathers did not fossilize and others were obliterated during preparation, leaving bare patches on specimens—and the lower neck.<ref name=Christ_Bond_04/>

There is no indication of feathering on the upper neck and head. While these conceivably may have been nude, this may still be an artefact of preservation. It appears that most ''Archaeopteryx'' specimens became embedded in [[Oxygen saturation|anoxic]] sediment after drifting some time on their backs in the sea—the head, neck and the tail are generally bent downward, which suggests that the specimens had just started to rot when they were embedded, with tendons and muscle relaxing so that the characteristic shape ([[death pose]]) of the fossil specimens was achieved.<ref name="reisdorf2012">{{Cite journal |last1=Reisdorf |first1=A. G. |last2=Wuttke |first2=M. |year=2012 |title=Re-evaluating Moodie's Opisthotonic-Posture Hypothesis in fossil vertebrates. Part I: Reptiles – The taphonomy of the bipedal dinosaurs ''Compsognathus longipes'' and ''Juravenator starki'' from the Solnhofen Archipelago (Jurassic, Germany) |journal=Palaeobiodiversity and Palaeoenvironments |volume=92 |issue=1 |pages=119–168 |doi=10.1007/s12549-011-0068-y |bibcode=2012PdPe...92..119R |s2cid=129785393}}</ref> 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.<ref name=Elzanowski2002/>

==== Colouration ====
[[File:Archaeopteryx NT.jpg|thumb|right|Artist's restoration illustrating one interpretation of Carney's study<ref name="NatureComm">{{Cite journal |last1=Carney |first1=R. |last2=Vinther |first2=Jakob |last3=Shawkey |first3=Matthew D. |last4=d'Alba |first4=Liliana |last5=Ackermann |first5=Jörg |year=2012 |title=New evidence on the colour and nature of the isolated Archaeopteryx feather |journal=Nature Communications |volume=3 |page=637 |bibcode=2012NatCo...3..637C |doi=10.1038/ncomms1642 |pmid=22273675 |doi-access=free}}</ref>]]

In 2011, graduate student Ryan Carney and colleagues performed the first colour study on an ''Archaeopteryx'' specimen.<ref name="NatureComm"/> Using [[Scanning electron microscope|scanning electron microscopy]] technology and [[Energy-dispersive X-ray spectroscopy|energy-dispersive X-ray]] analysis, the team was able to detect the structure of [[melanosome]]s in the isolated feather specimen described in 1861. The resultant measurements were then compared to those of 87{{nbsp}}modern bird species, and the original colour was calculated with a 95% likelihood to be black. The feather was determined to be black throughout, with heavier pigmentation in the distal tip. The feather studied was most probably a dorsal [[Covert (feather)|covert]], which would have partly covered the primary feathers on the wings. The study does not mean that ''Archaeopteryx'' was entirely black, but suggests that it had some black colouration which included the coverts. Carney pointed out that this is consistent with what is known of modern flight characteristics, in that black melanosomes have structural properties that strengthen feathers for flight.<ref>{{Cite news |last=Switek |first=Brian |date=9 November 2011 |title=Archaeopteryx was robed in black |work=New Scientist |location=Las Vegas |url=https://www.newscientist.com/article/dn21146-archaeopteryx-was-robed-in-black.html |archive-date=26 April 2015 |access-date=24 August 2017 |archive-url=https://web.archive.org/web/20150426132408/http://www.newscientist.com/article/dn21146-archaeopteryx-was-robed-in-black.html |url-status=live }}</ref> In a 2013 study published in the ''Journal of Analytical Atomic Spectrometry'', new analyses of ''Archaeopteryx''{{'}}s feathers revealed that the animal may have had complex light- and dark-coloured plumage, with heavier pigmentation in the distal tips and outer vanes.<ref>{{Cite journal |last1=Manning, Phillip. L. |last2=Edwards |first2=Nicholas P. |last3=Wogelius |first3=Roy A. |last4=Bergmann |first4=Uwe |last5=Barden |first5=Holly E. |last6=Larson |first6=Peter L. |last7=Schwarz-Wings |first7=Daniela |last8=Egerton |first8=Victoria M. |last9=Sokaras |first9=Dimosthenis |display-authors=etal |year=2013 |title=Synchrotron-based chemical imaging reveals plumage patterns in a 150 million year old early bird |journal=Journal of Analytical Atomic Spectrometry |volume=28 |issue=7 |page=1024 |doi=10.1039/c3ja50077b |doi-access=free}}</ref> 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.<ref name="Vinther2015">{{Cite journal |last=Vinther |first=J |year=2015 |title=A guide to the field of palaeo colour: melanin and other pigments can fossilise: reconstructing colour patterns from ancient organisms can give new insights to ecology and behaviour |journal=BioEssays |volume=6 |issue=37 |pages=643–656 |doi=10.1002/bies.201500018 |pmid=25854512 |s2cid=24966334}}</ref> Carney and other colleagues also argued against the 2013 study's interpretation of the sulphate and trace metals,<ref>{{Cite journal |last1=Carney |first1=Ryan |last2=Molnar |first2=Julia |last3=Updike |first3=Earl |last4=Brown |first4=William |last5=Jackson |first5=Jessie |last6=Shawkey |first6=Matthew |last7=Lindgren |first7=Johan |last8=Sjövall |first8=Peter |last9=Falkingham |first9=Peter |last10=Gauthier |first10=Jacques |date=2014 |title=Archaeopteryx in 4D |url=http://vertpaleo.org/GlobalPDFS/SVP-2014-Program-and-Abstract-Book-9-18-2014.aspx |journal=Journal of Vertebrate Paleontology |language=en |volume=103 |access-date=15 January 2018 |archive-date=25 April 2018 |archive-url=https://web.archive.org/web/20180425135859/http://vertpaleo.org/GlobalPDFS/SVP-2014-Program-and-Abstract-Book-9-18-2014.aspx |url-status=dead }}</ref><ref name=":0">{{Cite web |title=SVP – Press Release – Taking a Deeper Look at "Ancient Wing" |url=http://vertpaleo.org/Society-News/SVP-Paleo-News/Society-News,-Press-Releases/Press-Release-Taking-a-Deeper-Look-at-Ancient-Wing.aspx |access-date=3 April 2016 |website=vertpaleo.org |archive-date=19 April 2016 |archive-url=https://web.archive.org/web/20160419054434/http://vertpaleo.org/Society-News/SVP-Paleo-News/Society-News,-Press-Releases/Press-Release-Taking-a-Deeper-Look-at-Ancient-Wing.aspx |url-status=dead }}</ref> 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".<ref name=Carney2020/>