Identification of a unique barb from the dorsal body contour feathers of the Indian Pitta Pitta brachyura (Aves: Passeriformes: Pittidae)

Abstract

Earlier research on feather morphology emphasized comprehensively on the body contour feather than various other types of feathers. Therefore, we conducted a systematic study on all feather types of the Indian Pitta Pitta brachyura, a passerine bird native to the Indian subcontinent. Feather barbs from wing contour, tail contour, body contour, semiplume, down, powder down, and bristle feathers were retrieved from the bird and observed under a light microscope. Primary flight feathers from the right and left wing were longest (85.17 mm and 87.32 mm, respectively), whereas bristle feathers were the shortest (5.31 mm). The mean barb length was observed to be the highest (11.37±0.47 mm) in the wing feather followed by body contour (8.31±0.39 mm), semiplume (8.27±0.22 mm), tail feather (7.85±0.50 mm), down (6.45±0.21 mm), powder down (6.04±0.23 mm), and bristle (2.70±0.07 mm).  Pearson correlation was found positive for barb length and feather length of down feathers (r= 0.996, p ≤0.05). We observed a novel type of barb the first time from dorsal body contour feather having plumulaceous barbules at the base followed by pennaceous barbules. This unique barbule arrangement is termed ‘sub-plumulaceous’ as it is distinct and analogous to known ‘sub-pennaceous’ type arrangement found absent in passerines.