The bignose galaxias is yet another non-diadromous galaxiid from the South Island that has only recently been described. It was distinguished as a new species based on DNA sequencing and its morphology. The bignose galaxias is closely related to what are referred to as the “pencil galaxias”, small, slender (pencil-shaped), non-diadromous, mainly sub-alpine galaxiids with small fins and long, slender caudal peduncles (G. divergens, G. paucispondylus, G. prognathus and G. cobitinis). It can be distinguished from these species because it has only 4–6 pelvic fin rays (usually only 5) and only 11–14 caudal rays. It also has a distinctly rounded lateral head profile with the upper margins of the eyes being well below the dorsal profile.
Bignose galaxias are found in several locations in the Mackenzie Basin in the upper Waitaki River catchment. Generally it is found in small spring or wetland-fed tributaries. Little is know about its life history, although this is probably similar to the other pencil galaxiids. Sexually mature fish were found in June and July, suggesting spawning takes place in winter.