It is only known from 17 specimens, caught at two sites – one at the entrance to Manila Bay in the Philippines, and one in the Timor Sea, north of Australia.

Due to the small number of specimens available, little is known about the species, but it appears to live up to five years, with a short larval phase.

Neoglyphea inopinata was named in 1975 by Jacques Forest and Michèle de Saint Laurent of the Muséum national d'histoire naturelle in Paris.

It was based on a single damaged specimen that had been caught by the USFC Albatross in the Philippines in 1908, and deposited in the United States National Museum.

[2][3] De Saint Laurent examined the unidentified specimen while working on Thalassinidea at the Smithsonian Institution.

Study of non-fossil specimens made it apparent that the similarities between the two groups resulted from analogy, rather than homology, and that Glypheoidea was closer to lobsters and crayfish.

[2] At the front, the carapace bears a fairly long rostrum, which is wide at the base, giving it a triangular outline when seen from above.

[2] The underside of the cephalothorax is dominated in the forward part by an unusually long epistome, which is a "most distinctive" feature of Neoglyphea.

The abdomen ends in a telson, which is about 1.5 times as long as the other abdominal segments, flanked by a pair of uropods.

[2] Neoglyphea inopinata shows a clear sexual dimorphism in the size and proportions of the first pereiopods and the shape of the abdominal pleurites.

In males, the first pereiopods are markedly longer than in females, with most of the additional length occurring in the merus and propodus (third and fourth segments).