Description and habitat

These large millipedes are typically 17 centimeters in length with a girth of 1.4 centimeters. The ground color is ochre yellow, with the anterior margins of the plates being dark or olive gray, thus presenting a banded appearance. Appearancewise, these are similar to the Chinese Spirobolus walkeri and S. bungii, though in very mature specimens, the amount of yellow coloring decreases and the darker shade predominates; under bright lighting, the dark bands can appear slate blue. The legs and antennae are jet black. Prior to molting, the coloration wanes into a dingy shade.

Whereas many millipede species curl up when disturbed, the Mindoro Giant will bow their heads downwards and expel a noxious chemical to deter perceived threats. These foul-smelling ejecta should be especially effective against potential predators that try to grab a mouthful of millipede prey. Most millipedes possess hydrogen cyanide -- infamously used by the Nazis for their Zyklon-b gas chambers -- but other chemicals are also known to be produced. Due to the scarcity of studies done on millipede chemical defenses and the uncertain identity of the species at hand, I would not pretend to know exactly the type of secretion that this millipede uses.

In common with many other large species, the Mindoro Giant calls the limestone forests its home. Limestone is rich in calcium carbonate, which plays an important role in the maintenance of millipede armor. These animals are crepuscular and nocturnal, foraging out in the open in search of food or potential mates. Perhaps due to their defensive nature, these millipedes are more apt to wander off into the open and even on road cuts, even when the sun still has not set. In comparison, other species from other genera will usually stay on rock walls and debris, and will often venture out in the open only when it is dark.

I have only observed this species in Oriental Mindoro at an altitude of about 370 meters in limestone forests. They prefer a very narrow altitudinal band, only within the vicinity of limestone rocks. Cool breezes constantly flow in their preferred habitat and it quickly dissipates whatever heat is generated through open gaps in the forest.