[2] Found in the Southern Hemisphere, it has been recorded from mainland Australia, New Zealand, the Pacific region, the Caribbean, and India.

[4] The thallus of Fissurina insidiosa is characterised by its dull grey to dingy olive-grey colour and glossy appearance.

They range in shape from simple to occasionally forked and can be straight, curved, or sinuous, extending up to 2.5 mm in length.

Over time, these develop into a pair of swollen, pale beige-brown lips, which are often cracked and rough, measuring 0.3 to 0.9 mm in width.

[6] This species has a broad distribution in the Southern Hemisphere, with recorded presences in mainland Australia, New Zealand, the Pacific region, the Caribbean, and India.