Luciola Laporte, 1833

Ballantyne, Lesley, Kawashima, Itsuro, Jusoh, Wan F. A. & Suzuki, Hirobumi, 2022, A new genus for two species of Japanese fireflies having aquatic larvae (Coleoptera, Lampyridae) and a definition of Luciola s. str., European Journal of Taxonomy 855, pp. 1-54 : 42-44

Systematics of Luciola Laporte, 1833 – quo vadis?

Luciola s. str.

Ballantyne and colleagues identified very early on that the grouping of 276 species under Luciola in McDermott (1966) was at best arbitrary, and morphological phylogenetic analyses (see Ballantyne et al. 2019 for a review) identified within McDermott’s Luciola many new genera, many including species which were transferred from what McDermott had placed under Luciola . It became clear that ‘ Luciola ’ was a heterogeneous assemblage of species and that it was necessary to be able to define what constituted Luciola s. str.

This was achieved by comparison of morphological features of the type species Luciola italica with the other species. Fu et al. (2010) first identified two species, Luciola italica and the Japanese species Luciola parvula Kiesenwetter, 1874 as Luciola s. str., and Fu et al. (2012a) an additional species but without further definition. Ballantyne et al. (2013) first formally addressed and redescribed Luciola s. str. Subsequently Ballantyne et al. (2015: fig. 1; 2016: figs 1–2; 2019: fig. s1), and Jusoh et al. (2021: 1) further refined the concept and composition of Luciola s. str.

Our exhaustive literature reviews and taxonomic revisions reveal two possible options to resolve Luciola taxonomy insofar as it relates to a definition of Luciola s. str. Such a definition is essential to our argument (and the status of Hotaria ) as well as the resolution of a position for Luciola cruciata and L. owadai . Here we follow Jusoh et al. (2021: 8, fig. 3).

The options are:

1. Subsume all three current members of Luciola subgenus Hotaria Yuasa, 1937 (unmunsana, papariensis and tsushimana) into one genus, i.e., Luciola s. str. ( Jusoh et al. 2021: fig. 3 Clade G), and retain the remaining five species in Luciola s. str. Luciola s. str. thus comprises the 7 species from Jusoh et al. (2021: fig. 3) including the type species L. italica , and is clearly distinct from the clade E which includes L. cruciata / owadai and species of Aquatica .

2. Subsume all current members of Luciola subgenus Hotaria into one genus, i.e., Luciola s. str. ( Jusoh et al. 2021: Clade G) which subsequently restricts Luciola s. str. to four species within the same clade as Luciola italica (Clade G Part II), and erect a new genus to accommodate Luciola pallidipes + niah Jusoh, 2019 (Clade G Part I)

Option 2 while extreme, may indicate a future path, but is untenable at present without evidence to support the split between niah/ pallidipes and Luciola s. str., the extensive and presently uninvestigated ‘ Luciola ’ of Africa (about 100 species are assigned to Luciola in McDermott 1966), and species of ‘ Luciola ’ in Europe such as L. lusitanica Charpentier, 1825 , L. italica , and L. mingrelica Motschulsky, 1854 . There is no present agreement on just which populations comprise the aforementioned three species.

Option 1 permits a wider definition of Luciola s. str., where all the species in Jusoh’s Clade G are assigned, and is supported by morphological considerations (including males females and larvae). This definition of Luciola s. str. will accommodate possible future directions as well as existing problems, while still defining a narrow group of species forming a clade with the type species.

Neither of these options address specifically what course of action should be taken with three of the four species of ‘ Hotaria ’ which the analysis indicates may well be the same species, distinct from L. parvula . However, as each option recommends that Hotaria be subsumed under Luciola s. str. (as already undertaken by Kawashima et al. 2003) we advise this recommendation (Supp. file 1: 3).

All comments above relating to suggested placements of species still listed as Luciola sp. relate specifically to the wide, and defined study area of Ballantyne et al. (2019: 5) in SE Asia and the Australopacific area.

The remaining Luciola

The situation with regard to the remaining species still standing under Luciola by McDermott (1966) can also be addressed. Ballantyne et al. (2019) addressed Luciola s. str. from 17 species, including the type species L. italica . However, they did not regard their treatment of all the species listed by McDermott (1966) under Luciola as finished. Clearly they did not attempt to address the Luciola of Africa (ca 100 species), nor the Luciola of Europe. Their specified area of coverage extended from India in the west through Asia (excluding Russia), the Philippines to the Australopacific region (see listing in Ballantyne et al. 2019: 5), where in the Australopacific region the firefly fauna is exclusively Luciolinae .

In attempting to address the range of species, Ballantyne et al. (2019) were confronted with many of the problems we have outlined here. Two solutions were proposed specifically for the remaining species still standing under Luciola , occurring in the study area as defined above:

1. Species incertae sedis. Thirty-five species of ‘ Luciola ’ were assigned to species incertae sedis ( Ballantyne et al. 2019: 151, table 28). While each species was individually addressed, each had certain attributes which the authors felt would preclude any further attempt to conclusively identify them. These included absence of types, poor condition of types (if represented at all what body parts that remained were not useful in diagnosis), and types that were females. This sex is presently of little use in what is still a male based Luciolinae taxonomy.

2. Luciola s. lat. The second solution addressed the remaining species from the defined study area still assigned to Luciola in McDermott (1966). Although a ‘heterogeneous assemblage of species’ ( Ballantyne et al. 2019: 102), they were considered sufficiently distinctive (usually in colour, and in many cases because of the existence of a type specimen in some sort of condition that might permit re-examination), that the very real possibility existed for future assignment of males and elucidation of generic affinities. All are in MNHN. Of the thirty-three species listed in Ballantyne et al. (2019: 103–104, table 18) seven have female types but distinctive colouration, 18 have male types in various condition, and types were not found for 11.

It was anticipated that a visit to the MNHN in Paris and work on the collection would eventuate, as this museum will no longer loan types. However Covid intruded, as did the very real financial situation the retired senior author finds herself in, that further precludes any possibilities of additional investigation in the immediate future.