YOU'VE HEARD OF BATMAN... BUT HOW ABOUT BAT TICK?.
What is THAT?
It may not look like any tick you've ever seen, but this is a bat tick (Carios kelleyi) . Quite a bit different than the more recognized hard ticks in the family Ixodidae (which includes blacklegged ticks, American dog ticks, Lone Star ticks, and others), bat ticks and other soft ticks are in the family Argasidae. This widely distributed group of ticks mostly stays hidden, dwelling in their preferred hosts' roost or nesting habitat. And that's where this one likely strayed from, too...rarely seen, bat ticks are most frequently encountered loose and wandering in buildings frequented by bats, including houses, barns, and churches.
While the mouthparts of hard ticks extend anteriorly from the tick body, the mouthparts of soft ticks are hidden from above under a hood, and so appear to be underneath the tick, only visible if you turn the tick over. There are other notable differences between hard ticks and soft ticks. Hard ticks feed only once in each life stage--larva, nymph and adult. In soft ticks, there can be two or more nymphal stages, and adult female soft ticks take repeated small blood meals, and then lay a small batch of eggs after each feeding. Soft ticks are long-lived and can withstand starvation for years—GREAT, right?
The good news, if there ever really is any good news attributable to ticks, is that bat ticks feed almost exclusively on bats. It's true that experimental evidence1 exists that every once in a while, these ticks might take a "nip" from a human host, probably by accident. And in another study2, nymphal and adult bat ticks collected from residential and community buildings in Jackson County, Iowa and tested by PCR for various tickborne pathogens, demonstrated that 28 of 31 live-collected ticks tested positive for a novel spotted fever group (SFG) rickettsia, but only 1 of 31 tested positive for a relapsing fever group Borrelia. Perhaps more importantly, none were positive for the Lyme disease germ or Anaplasma phagocytophilum. It's still unknown whether either of the bat tick germs have ever or would actually be able to cause human disease, but the chance of any disease would be rare anyway since bat ticks so rarely bite humans.
If you do happen to find bat ticks in your home, contact a pest control expert who can guide you on how best to seal crevices and prevent future bat entry, and they can treat areas where the ticks may be hiding, too. Given their longevity even without a blood meal source, the chance for encountering bat ticks can persist even long after bats have left a roost site.
1 Gill JS, et al. 2004. Journal of Medical Entomology 41:1179-81
2 Loftis AD, et al. 2005. Journal of Medical Entomology 42:473-480