Neolithodes flindersi

Neolithodes flindersi is deep-red in colour – slightly more vivid dorsally than ventrally.^[5][4] The dorsal surface of its pyriform carapace is armed with scattered major spines and a dense, uniform cover of small, secondary spinules.^[6] The carapace is longer than it is wide by 1.01–1.15 times, with the largest specimen – the male holotype – reaching 126.1 mm (4.96 in) in postorbital length^[a] and 115.8 mm (4.56 in) in width.^[7]

Its walking legs are long and slender, and like in all Neolithodes, its third pair are the longest.^[8][9] Like the dorsal surface, the walking legs are densely covered with small spines inbetween the major ones.^[8] The coxae of the walking legs in males and juvenile females are covered in short, conical spines. The meral extensor spines of the walking legs are notably uniform in size rather than markedly uneven, distinguishing this species from its congeners. The secondary spines covering the surfaces of the walking legs are distinctly shorter compared to related species, with the spinulation extending in longitudinal rows along the ischium, merus, carpus, and propodus.^[10]

Neolithodes flindersi have been found to be parasitised by the snailfish genus Careproctus, who deposit eggs in the crabs' gill chambers.^[11] They have been found in Octocorallia corals such as Chrysogorgia orientalis.^[11]