The Franconiasaurus fossil material was discovered in sediments of the Mistelgau fossil pit of the lower Jurensismergel Formation (Grammoceras thouarsense Zone) in Bayreuth District, Bavaria, Germany. The holotype specimen, BT 011224.00, was discovered between 2014 and 2018 and consists of a nearly complete, partially articulated skeleton. BT 011241.00, an incomplete disarticulated specimen discovered in 2005, was also referred to Franconiasaurus.[1]
In 2024, Sachs, Eggmaier & Madzia describedFranconiasaurus brevispinus as a new genus and species of plesiosauroid based on these fossil remains. The generic name, "'Franconiasaurus", combines Franconia, after the Bavarian region of the type locality, with the Greek "σαῦρος" ("sauros"), meaning "reptile". The specific name, "brevispinus", references the short neural spines of some of the cervical and dorsal vertebrae.[1]