The species was identified by John Charles Watt in 1988, based on a specimen collected from Manawatāwhi / Great Island by Evan Graham Turbott in 1946.

[5] Watt's original text (the type description) reads as follows: MALE: Broader and less convex than M. elongatus.

Labrum slightly emarginate anteriorly, punctures larger and deeper than in M. elongatus, yellow setae stout.

Dorsal surface of head as in M. elongatus but punctures deeper and microsculpture of interstices very strong, clearly visible at 25x magnification.

Pronotal punctures larger, deeper, and more steep-sided than in M. elongatus, those of disc sparse, separated by more than twice their own diameter.

Prosternal intercoxal process broader posteriorly than in M. elongatus, prosternum bearing a few small granules.

[3] Watt noted that the species was closest morphologically to M. elongatus, and could be distinguished by differing aedeagus structures and M. turbotti being larger and broader in size.