Xylotoles costatus was first described and named by Francis Polkinghorne Pascoe in 1875, based on male and female specimens collected by Henry H. Travers on Pitt Island.

However, if a longhorn beetle specimen is found in the Chatham Islands that is greater than 16 mm in length it is likely to be X.

[5] As X. costatus is flightless and will spend time moving on the ground between trees, it is vulnerable to rodent predation.

Knowing its exact habitat requirements as an adult and at the larval stage is thought to be a conservation priority.

This species is the only longhorn beetle that is legally protected under schedule 7 of the 1953 Wildlife Act, making it an offense to kill, possess, buy or sell a specimen.