Figure 2: DIP-V-15100 photomicrographs.

(a) Overview of dorsal wing surface, with claws (red arrows), dorsal details in a–h. (b) Primary feathers and barbs truncated by amber surface. (c) Primaries (white arrows), secondaries (yellow arrows) and indeterminate feather (orange arrow), in basal zone of overlap (slightly oblique view). (d) Detail of primary rachis, with weak ventral ridge (inclined arrow) and barb ramus attachment somewhat low on side of rachis (horizontal arrow). (e) Primary feather microstructure and pigment distribution (t.l.), with hooklets on distal barbules (arrow). (f) Alula barbs with blunted apices and blade-like barbules with banded pigmentation. (g) Anterodorsal view highlighting alula separation from wing surface (arrows), as well as overall colour patterning (light hitting bubbles in amber creates a bright band paralleling edge of wing). (h) Bone and integument breaching amber surface, with well-preserved osteon complexes (circle of mottled bone at arrow), while most voids in bone and tissue have been permeated by milky amber, and skin is reduced to a translucent film not visible at this scale. (i) Extent of gas vacuoles and milky amber emanating from dorsal and ventral surfaces of wing, in anterior view. (j) Contrast between coverts and ventral coat of down and contours, with ventral details in j–l. (k) Current position of claw (red arrow) and claw marks within flow lines (yellow arrows). (l) Bases of down feathers attached to apterium with preserved skin texture and signs of saponification. Scale bars, 2.5 mm (a,c); 1 mm (b,h–l); 0.5 mm (d); 0.25 mm (e,f); 1.5 mm (g); t.l., transmitted light.