"Invertebrates are animals that neither possess nor develop a vertebral column, derived from the notochord. This includes all animals apart from the subphylum Vertebrata." - Wikipedia
Put simply, invertebrates have no spine.
If you also checked Wikipedia in the past few days for additional hot invertebrate facts, you might have stumbled upon the page's latest edition.
Paul Ryan, the 54th and current speaker of the House of Representatives joined the ranks of the spineless.
First spotted by Buzzfeed's Alp Ozcelik the page has now been edited but you can check it out here.
He might have been added for stripping funding from Planned Parenthood, or possibly for his efforts to axe the Affordable Care Act before finding a suitable replacement for the many people who need it.
We may never know.
We're just going to be waiting patiently to see whether any other prominent politicians pop up on any other animal pages.