The estuarine, air-breathing mudskipper Periophthalmodon
schlosseri has quite exceptional gill
lamellae because the basal layer is composed
almost exclusively of MRCs with a superficial
layer of very electron-dense pavement cells
(Wilson et al., ’99). The MRCs communicate to
the outside via very deep apical crypts. Very few
ACs could be found and MRC were isolated from
each other by intervening filament-rich cells. The
lamellae also fuse together at various points, and
the interlamellar space is reduced to a narrow
irregular channel that can no longer accommodate
a ventilatory flow of water.