Pleuroloma flavipes Rafinesque 1820

Pleuroloma flavipes Rafinesque, 1820 Pleuroloma flavipes Rafinesque, 1820: 8. Fontaria luminosa Kenyon, 1893: 16. New synonymy. Detailed taxonomic history in Appendix 1. Remarks. The status of Fontaria luminosa Kenyon, 1893 has been uncertain for some time. See the following articles for a discussion of the matter: Hoffman (1999), Shelley & Whitehead (1986), Shelley & McAllister (2007), and Marek et al. (2014). It was described as a luminous or phosphorescent member of the genus Fontaria from Omaha, Nebraska (Bruner 1891, Kenyon 1893). There are other bioluminescent family members: the 11 species of the genus Motyxia in California (Marek & Moore 2015). However, Kenyon’s and Bruner’s description of the shape of its photic organs as round and dorsally situated do not correspond with Motyxia nor any bioluminescent millipede known. The entire exoskeleton is bioluminescent in these millipedes. The type specimens of Kenyon’s are lost, but Shelley did find material in the USNM that is labeled “ Fontaria luminosa (Type?)”. Although this material is labeled from Omaha, which is the type locality mentioned by Kenyon, the single male specimen’s gonopods were missing (Shelley & Whitehead 1986). Despite searching the Omaha area, Shelley and Hoffman were unable to find any millipedes of the genus Apheloria. Pleuroloma flavipes is known to occur in the Omaha area and is commonly encountered in eastern Nebraska (Shelley 1980). For more than 130 years since its discovery, the only material of the family found in the area was that of P. flavipes. Based on this information, and to bring order to the classification, we here synonymize F. luminosa with P. flavipes. In the unlikely event there is a bioluminescent Apheloria from the region, then F. luminosa can be revived, but for the present time and based on much collections of P. flavipes in the area, the synonymy seems justifiable. The description of the bioluminescence (Bruner 1891) matches that of the glowworm beetle genus Phengodes (Phengodidae), whose adult females are larviform and predaceous on millipedes, and are sometimes themselves confused for millipedes (Ferreira et al. 2024). It may be that Bruner observed Phengodes females glowing and collected their millipede prey, thereby convincing himself that the millipedes were producing the bioluminescence.