[2][3] This centipede is one of only a few species in the genus Mecistocephalus or in the family Mecistocephalidae with more than 55 leg pairs.

[2] This species was first described under the name Lamnonyx diversisternus in 1919 by the Italian zoologist Filippo Silvestri based on a male holotype with 57 pairs of legs, which he collected on the island of Honshu in Japan.

[8][9] The type material is deposited in the Museo Civico di Storia Naturale Giacomo Doria in Genoa, Italy.

[9] In 1920, the American biologist Ralph V. Chamberlain placed this species in the genus Mecistocephalus.

[11] In 1934, the German zoologist Karl W. Verhoeff described Mecistocephalus takakuwai as a new species with 59 pairs of legs.

[12] He based the original description of this centipede on ten specimens including both sexes.

Specimens with 57 leg pairs have been recorded from Honshu, the Ryukyu Islands, and Taiwan.

[17] The species M. japonicus features 63 or 65 pairs of legs and is also found from Honshu to Taiwan, including Shikoku, Kyushu, and the Ryukyu Islands.

The species M. smithii is found in mainland China and features 59 pairs of legs.

For example, like other centipedes in the same genus, this species features an elongated head with spicula and second maxillae ending in claws.

Moreover, the clypeus in M. japonicus is wider relative to its length, with a width/length ratio that ranges from 1.9 to 2.2, greater than that observed in M.