The cuticle (or external layer)
All Apteryx species presented thin cuticles with a wax-like
appearance, which in contrast to the smooth sponge like texture of the
crystalline layer made it easy to identify (Figure 2A). Seen from
outside the cuticle was smooth and unpigmented, pores seemed to radiate
from underneath the cuticle (Figure 2B).
The cuticle thickness decreased significantly with latitude, being
thicker in Brown Kiwi and thinnest in Rowi and Tokoeka; the significance
was due to differences between Brown Kiwi and Rowi (Table 3). Under the
micro CT scan, the crystalline structure of the cuticle became apparent,
and it was possible to discern the individual crystals that formed it
(Figure 4).