impennate

from The Century Dictionary.

• Featherless or wingless; specifically, characterized by short wings covered with feathers resembling scales, as the penguins.
• noun A bird, as the penguin, with short wings covered with scales.

from the GNU version of the Collaborative International Dictionary of English.

• adjective (Zoöl.) Characterized by short wings covered with feathers resembling scales, as the penguins.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective zoology Characterized by short wings covered with feathers resembling scales, as in the penguins.