Pennaceous feather

The rectrix and remex seen above are two examples of pennaceous feathers.

An ostrich down feather is an example of a plumulaceous feather. Its rudimentary rhachis with long flexible barbs and elongate barbules cannot form vanes.

The pennaceous feather is a type of feather present in most modern birds and in some other species of maniraptoriform dinosaurs.^[1]

^ "GEOL 204 The Fossil Record: Feathered Dragons: The Origins of Birds and of Avian Flight". www.geol.umd.edu. Archived from the original on 2017-03-17. Retrieved 2015-06-01.

[1] "GEOL 204 The Fossil Record: Feathered Dragons: The Origins of Birds and of Avian Flight". www.geol.umd.edu. Archived from the original on 2017-03-17. Retrieved 2015-06-01.

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