Tuesday, November 2, 2010

Protofeathers on the wing membrane

Here is a reference to the "pycnofibres"  - even as early as the Rhamphorhynchus.
If they are  related to feathers they correspond to downy feathers and not pennaceous (contour) feathers. 

"The wings were long, and the wing membranes appear to have lacked the furry covering of pycnofibres present in some other pterosaurs (such as Pterorhynchus and Jeholopterus)."

"This type specimen consists of an articulated, nearly-complete skeleton with remains of the integument. These included the wing membrane, hair-like structures, a long version of the vane found at the end of "rhamphorhynchoid" tails, and a head crest with both a low bony base and a large keratin extension"

"The specimen is crushed into a slab and counterslab pair, so that parts of the specimen are preserved on one side of a split stone and some on the other. This includes exquisite preservation of carbonized skin fibers and, arguably, "hair" or "protofeathers." The fibers are preserved around the body of the specimen in a "halo." Wing tissue is preserved, though its extent is debatable, including the exact points of attachment to the legs (or if it attached to the legs at all). In 2009 Alexander Kellner published a study reporting the presence of three layers of fibres [actinofibrils] in the wing, allowing the animal to precisely adapt the wing profile.[3]"

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