[5] In his 1928 book The Moths and Butterflies of New Zealand, Hudson discussed and illustrated this species and noted catching the holotype in 1882 in Nelson.

[7] The epithet is derived from sisyrota, meaning wearing a hairy garment, and refers to the hairs on the inner margin of the hindwings.

Anterior legs dark fuscous, apex of joints obscurely whitish (middle and posterior pair broken).

It has been hypothesised that the whitish border of the wings assists the moth's camouflage against mottled bark, indicating a possible preference for forest habitat.

[7][8][11] The most recent collection of this species occurred at Waipapa Dam in the Waikato in 1959, where it was attracted to the floodlights; Charles Hudson Guard sent the specimen to John Dugdale at the Forest Research Institute, temporarily stored in a tobacco tin which was subsequently mislaid, so the most recent specimen in any collection – Te Papa in this case – is from 1921.

[11] On 2 March 2024, a Swedish birdwatching group led by biologist and school teacher Pav Johnsson visited Stewart Island / Rakiura.

On returning to Sweden, he uploaded a photo to iNaturalist, where it was identified by Robert Hoare as Titanomis sisyrota, making Johnsson the only living person to have observed the species and the first one to photograph it.

[7][8] The host niche is unknown, but based on the morphology of the species, it has been hypothesised to be woody branches or stems of living plants, rotten wood, or even bracket fungi, into which females likely insert their eggs.

[10] The larvae of this species may be associated with rotten podocarp wood, as all the collection localities are close to valley floor kahikatea and mataī forest.

[10] This lack of observations likely reflected the small number of entomologists searching for this species, although notable lepidopterists such as John Dugdale, Neville Hudson, and Brian Patrick had looked for it for many years without success.