com/articles/s41467-017-02088-w) open-access study , titled "Structural absorption by barbule
microstructures of super black bird of paradise feathers," was Teresa Feo of the National Museum of Natural History in Washington, D.
Variations in the microscopic characters such as node shape, length of downy barbule
, and pigmentation patterns may be used to assign an unknown feather sample to the taxonomic level of order or family if diagnostic characters are found in the sample.
Differently from barbule
and barb cortical cells that accumulate feather keratin, barb medullary cells undergo to lipid degeneration.
The jaw and lack of a chin barbule
reveal the difference when look alike coalfish, a fellow member of the cod family, hunt for food in the same area.
The scientists found that the outside layer of each barbule
consisted of a two-dimensional crystal structure composed of melanin rods.
feather shaft split in feather shaft barb barbule
View through a microscope
The overall feather quality was diminished with lack of barbule
integrity because the duck was unable to properly preen itself without falling.
Downy barbs that were initially sampled from the base of these feathers had microscopic characters that consisted of very long barbules
, many rounded nodes that were uniformly distributed along the barbule
, and pigment at the nodes.
Primary feathers were worn at the margins, with discontinuous barbules
between barbs, and the calamus was occasionally pinched.
Each day of oviposition, the barbules
with the eggs attached were removed with fine-tipped scissors and placed on sheets of blue paper to facilitate observation of the eggs.
For that, they examined the fossilized barbules
- tiny, rib-like appendages that overlap and interlock like zippers to give a feather rigidity and strength.
A separate, striking amber specimen shows a birdlike feather branching into secondary twigs, or barbules
, with hook-lets like those in modern bird feathers that zip together side-by-side barbules
to make a tight, interlocked surface.