Ornithodoros madagascariensis is a "soft tick" (family Argasidae) that parasitizes cave-inhabiting fruit bats in the genus Megachiroptera.

[1] When engorged with the blood of their host, the larvae of O. madagascariensis measure slightly over 1.0 mm from the apex of the anterior hypostome to the posterior body margin.

[1] In the larval stage, O. madagascariensis and other members of the subgenus Reticulinasus are characterized by a reticulated Haller's organ, and in the adult stage by small size; piriform shape; absence of eyes, cheeks, a distinct hood and dorsal tarsal humps; and mammillated integument.

[1] O. madagascariensis larvae have a heartshaped squamous area on the medial dorsal surface.

Other members of the subgenus have been collected in Malaya, Mindanao, Borneo, the Solomon Islands, Timor, India, Egypt, Lebanon, Palestine, and the Congo River region of Africa.