[1] T. lineatus was first formally described in 1935 by the Canadian-American botanist and marine biologist William Harding Longley with its type locality given as Tortugas in Florida.

[2] In 1968 the American ichthyologist James C. Tyler classified this genus, alongside Hollardia in a new subfamily of the family Triacanthodidae, the Hollardiinae.

[3] The 5th edition of Fishes of the World classifies the family Triacanthodidae in the suborder Triacanthoidei in the order Tetraodontiformes.

[9] Parahollardia spikefishes are found in the Western Atlantic Ocean off the southeatern United States, in the Gulf of Mexico and the Caribbean Sea.

P. lineata is found at depths between 119 and 396 m (390 and 1,299 ft) over soft substrates close to the edge of the continetal shelf and along the continental slope.