NMS uncat. (paralectotypes), an isolated neural and an isolated costal V (Rütimeyer 1873a, pl. 7.3–4). Additional paralectotypes possibly exist but are impossible to identify with certainty based on the original publication. Rütimeyer (1873a) established Tropidemys langii based on a type series consisting of a large fragment of the pos- terior region of a carapace, several isolated neurals and costals, and several fragments of plastron from the Kimmeridgian of Solothurn, Switzerland. Since no specimen numbers are men- tioned in the original publication, it is difficult to be certain as to which specimens are part of the type series, notably, regard- ing the isolated neurals and costals. Bräm (1965) concluded that all but one of the plastron fragments should be referred to Tha- lassemys hugii, but the remaining specimen (NMS 8651, for- merly NMS 19) was subsequently also excluded from Tropidemys langii based on comparison with more complete material from the vicinity of Porrentruy (Püntener et al. 2014). Therefore, the large fragment of carapace (NMS 8554, formerly NMS 16) is the only unambiguous syntype. Bräm (1965) incorrectly referred to this specimen as the holotype, but, according to the ICZN rules, this should nevertheless be interpreted as a valid lectotype designation (ICZN 1999, art. 74.5). An isolated neural and costal V are the only known potential paralectotypes as they were illustrated by Rütimeyer (1873a), but no attempt has been made to find them in the NMS collections.

Tropidemys langii was named by Rütimeyer (1873). Its type specimen is NMS 8554 (lectotype; formerly NMS 16), a partial shell (posterior part of a carapace), and it is a 3D body fossil. Its type locality is Limestone quarry within or around Solothurn, which is in a Kimmeridgian shallow subtidal limestone in the Reuchenette Formation of Switzerland.

It was corrected as Tropidemys langi by Delair (1958), Bräm (1965) and Lapparent de Broin et al. (1996).