Archaeopteryx fossil is "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 in 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
Specimens of Archaeopteryx Tischlinger & Unwin (2004), who reclassified it as part of the sternum, albeit minimally ossified (mostly cartilagenous). This supports the idea that the Berlin "Archaeopteryx" was not a full-grown individual at the time of its death, and instead represents an immature animal. The pelvis of the Berlin specimen was considered by Dames to be markedly different from that of the London specimen, which was a major point in favor of his assigning a new species to the Berlin "Archaeopteryx", "siemensii", after its generous donor. Other researchers, however, disputed this difference, claiming it could be entirely accounted for by deformation of