Wellnhoferia

Wellnhoferia grandis, also known as the Solnhofen Archaeopteryx specimen.

• Germany, Region Eichstätt ( Solnhofen limestone )

• Wellnhoferia grandis

Wellnhoferia was a genus original birds and a close relative of Archaeopteryx. Until now, a single skeleton is known, which is traditionally attributed to Archaeopteryx and is also known as the Solnhofen Archaeopteryx specimen. Whether it is a stand-alone class or to another Archaeopteryx specimen with Wellnhoferia, is still controversial. The skeleton was recovered in the region Eichstätt from the Solnhofen limestones, one of the most important fossil deposits in the world, and is dated to the Upper Jurassic (lower Tithonian ). It is slightly larger than any Archaeopteryx specimens, reaching the size of a domestic chicken.

The skeleton was located initially in the private collection of fossils by Friedrich Müller, the former mayor of Solnhofen. Müller prepared the fossil and sold it in 1987 to the municipality of Solnhofen, where it is now displayed in the mayor -Müller Museum. The Fund year and the exact location is not known. Peter Wellhofer published in 1988, first description of this fossil.

Discovery

The skeleton was found within the Upper Solnhofen layers, which are dated to the lower Untertithonium. It is located on a 39 × 52 cm large rock plate, which was assembled from several fragments. Since the fossil was covered by a clayey layer, there is no counter-plate, as found in Archaeopteryx specimens. The skeleton is not fully obtained, lacks, inter alia, the large part of the skull, the rear tail end part of the back and the cervical spine. From the skull, only the front tip of the snout is obtained, while only 15 caudal vertebrae are preserved. Müller has the missing tail end adds artificial. Evidence of feathers are preserved only dimly - shallow ripples emanating from the left ulna ( ulna ), but are interpreted as Federschäfte the long arm springs. However, evidence of tail feathers and feathers of the right wing are entirely absent.

The rock record shows the right side of the fossil. The tail is steeply upward, while the neck is very strongly curved over the back; then the skull found in the vertebrae. The rust-brown coloration of the bone is due to the diagenetic Überkrustung by iron-containing minerals, such as limonite ago.

Demarcation to Archaeopteryx

The genus was described in 2001 by Andrzej Wellnhoferia Elzanowski first time scientifically, with the only kind Wellnhoferia grandis. From Archaeopteryx, it differs mainly by the construction of the foot skeleton: So the fourth toe has only four phalanges ( phalanges ) - not five, as in Archaeopteryx. In addition, the fourth toe is shorter overall. Elzanowski argued that the number of phalanges today's birds is very variable, so the distinction is given to Archaeopteryx. Ostrom (1992 ) noticed that sometimes reduce in today's amphibians by mistakes during the embryonic phalanges, which is why this feature might actually have been only a peculiarity of this individual.

While some researchers the argument of Elzanowski follow and recognize Wellnhoferia as a separate genus, write other researchers continue the fossil of the genus Archaeopteryx to. Peter Wellhofer which the fossil was first described in 1988, it ranks as before Archaeopteryx to, however, writes that the assignment to a separate genus "can not be unequivocally ruled out ."