Archaeopteryx

***Archaeopteryx*** (Greek for ancient wing, old wing, or ancient feather) was the first bird to evolve and unlike most birds today, still had teeth. It lived in the late Jurassic period in Germany, about 150-148 million years ago.

The first *Archaeopteryx* was found in 1861 near Solnhofen in Bavaria, Germany. *Archaeopteryx* looks like a reptile with wings and feathers. It had a mouth with teeth, claws at the hands and a long tail like dinosaurs or reptiles. Today, it is known that some dinosaurs looked like birds and that some had feathers. When they are born, today's South American hoatzin have claws on their wings when they are young, just like *Archaeopteryx*.

## Description

*Archaeopteryx* is a theropod that lived in the early Jurassic Period, 150.8–148.5 million years ago.[1] Most of the specimens of *Archaeopteryx* that have been found come from the Solnhofen limestone in Bavaria, Germany, which is a *lagerstätte*, a rare and stunning geological formation known for its superbly full fossils.

*Archaeopteryx* was close to the size of a raven, with broad wings that were rounded at the ends and a long tail. It could reach up to 20 inches in length, with a weight of 1.8 to 2.2 pounds.[4] *Archaeopteryx* feathers, though less documented than its other traits, looked a lot like bird feathers in structure and design. But,*Archaeopteryx* had a lot of theropod dinosaur traits too. Unlike modern birds, *Archaeopteryx* had small teeth [5] as well as a long bony tail, traits which *Archaeopteryx* shared with other dinosaurs of the time.[6]

As it shows quite a few traits of both birds and dinosaurs, *Archaeopteryx* has often been deemed a link between them.[7] In the 1970s, John Ostrom, following T. H. 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 a number of bird traits, 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 plate, 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.[8] [9] [10] [11] [12] [13] [14] [15] [16]

The first bones of *Archaeopteryx* were found in 1861; just two years after Charles Darwin wrote *On the Origin of Species*. *Archaeopteryx* seemed to prove Darwin's theories and has since been a key piece of proof for the origin of birds, the transitional fossil debate, and proof of evolution. Indeed, more research on dinosaurs from the Gobi Desert and China has since given more proof 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. But, it may not be the direct ancestor of living birds, and it is not clear how much evolutionary divergence was already found in other birds at the time.

## Classification

To this day, most of the fossils are classed in a single species *A. lithographica*, but the taxonomic history is complex. A lot of names have been put out for the specimens, most of which are just spelling errors. As interpreted today, the name *A. lithographica* just referred to the single feather described by Christian Erich Hermann von Meyer. But in 1954, Gavin de Beer said that the London specimen was the holotype. So in 1960, Swinton proposed that the name *Archaeopteryx lithographica* be placed on the official genera list making the alternative names *Griphosaurus* and *Griphornis* invalid. [17] The ICZN, fully accepting de Beer's view, did indeed hold back the alternative names at first proposed for the first skeleton specimens, [18] [19] In 1977 the first specific name of the Haarlem specimen, *crassipes*, described by von Meyer as a pterosaur before its true nature was known, was also held back. [20] [21]

The relationships of the specimens are hard. Most later specimens now have their own species. The Berlin specimen has been classed as *Archaeornis siemensii*, the Eichstätt specimen as *Jurapteryx recurva*, the Munich specimen as *Archaeopteryx bavarica* and the Solnhofen specimen was classed as *Wellnhoferia grandis*.

Recently, it has been claimed that all the specimens are from the same species.[22] But, there are big differences in 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 likely presence of a sternum. These differences are as large as or larger than the differences seen today between adults of different bird species. But, it could be that these differences could be explained by different ages of the living birds.

Last, some note that the feather, the first specimen of *Archaeopteryx* described, does not agree well with the flight-related feathers of *Archaeopteryx*. It's clearly a flight feather of a species of the time, but its size is a sign that it may be from to another, smaller species of feathered theropod, of which just this feather is so far known. [23] As the feather was in the early 21st century seen as the type specimen, this would have made significant nomenclatorial confusion because the name *Archaeopteryx* should then no longer be applied to the skeletons. In 2007, two sets of scientists thus petitioned the ICZN asking that the London specimen be clearly made the type by classing it as the new holotype specimen.[24] This was upheld by the ICZN after four years of debate, and the London specimen was classed on October 3, 2011.[25]

### SynonymsEdit

If two names are given, the first means 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 means that the taxon was first 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, 1862 [*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[26]
* *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 four taxa may be valid genera and species.

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