Isosoma Billberg, 1820a : 56

Bezděk, Jan & Biondi, Maurizio, 2018, On the generic names proposed in Chrysomelidae (Coleoptera) by Gustaf Johan Billberg, Zootaxa 4422 (2), pp. 184-190 : 185-186

Isosoma Billberg, 1820a: 56

Names originally included:

1. 14punctatus available name for Chrysomela quatuordecimpunctata Linnaeus, 1767 ; now Podontia quatuordecimpunctata (Linnaeus, 1767) ; genus Podontia Dalman, 1824 ( Galerucinae ,

Alticini)

2. affinis available name for Galleruca affinis Gröndal, 1808 ; now Podontia affinis (Gröndal, 1808) ; genus Podontia Dalman, 1824 ( Galerucinae , Alticini)

3. grandis available name for Galleruca grandis Gröndal, 1808 ; synonym of Podontia lutea Olivier, 1790 ; genus Podontia Dalman, 1824 ( Galerucinae , Alticini)

4. concolor available name for Chrysomela concolor Fabricius, 1781 ; now Phygasia concolor (Fabricius, 1781) ; genus Phygasia Dejean, 1836 ( Galerucinae , Alticini)

5. lusitanica nomen nudum

6. mutabilis var. c unavailable name

7. bivittata available name for Crioceris bivittata Fabricius, 1801 ; now Acalymma bivittatum (Fabricius, 1801) ; genus Acalymma Barber, 1947 ( Galerucinae , Luperini )

8. innuba available name for Cistela innuba Fabricius, 1775 ; now Acalymma innubum (Fabricius, 1775) ; genus Acalymma Barber, 1947 ( Galerucinae , Luperini )

Type species. Chrysomela concolor Fabricius, 1781 , designated by Barber (1947).

Current status. Phygasia Chevrolat, 1836 (nomen protectum) = Isosoma Billberg, 1820 (nomen oblitum).

Comments. Billberg (1820a) listed under the genus Isosoma eight names. Two of these names are not available (lusitanica because nomen nudum, mutabilis var. c because unavailable one-letter name of variety). Additional six names are instead available names (see above).

Barber (1947) designated Chrysomela concolor Fabricius, 1781 as type species of the genus Isosoma . Fabricius (1781) described Chrysomela concolor from „Africa aequinoctialis“ from Banks collection. Later, Fabricius (1792) himself transferred this species to the genus Galleruca and finally (Fabricius 1801) to the genus Adorium Fabricius, 1801 . Because Adorium is a synonym of Oides Weber, 1801 , subsequent authors (Gemminger & Harold 1876, Weise 1924, Barber 1947) attributed Chrysomela concolor to this latter genus. Barber (1947) did not examined the types but simply chose Chrysomela concolor as type species for synonymizing Isosoma with Oides . Subsequent Galerucinae catalogues ( Wilcox 1971, Beenen 2010, Nie et al. 2017) followed Barber´s act and listed Isosoma as synonym of Oides .

Vachon (1980) examined the types of Chrysomela concolor Fabricius, 1781 deposited in Banks collection in BMNH and found it is not a representative of Oides , but of the flea beetle genus Phygasia Dejean, 1836 ( Galerucinae , Alticini). Vachon probably did not know Barber´s publication with the designation of the type species of Isosoma , because this topic is not commented on.

In 2017, one of us (JB) re-examined the Fabrician type specimens in Banks collection and confirmed the generic assesment of Chrysomela concolor in Phygasia Chevrolat, 1836 (for the photo of the type specimen see Figs 1-3 ). The acceptance of the above mentioned acts would led to restoration of Isosoma as valid genus with the species-rich Phygasia as its synonym. In order to preserve the stability, we proposed to activate the Art. 23.9 of ICZN (1999), considering Isosoma as nomen oblitum and Phygasia as nomen protectum. To our knowledge, Isosoma was not treated as a valid generic name after 1900 and, thus, the conditions in Article 23.9.1.1 are complied. In addition, also Barber (1947) explicitely mentioned Isosoma as synonym of Oides . To meet the conditions of Art. 23.9.1.2, we supply the references of 25 papers below, published by at least 10 authors in the immediately preceeding 50 years, and encompassing a span of not less than 10 years, where Phygasia Chevrolat is used as valid genus name: Biondi & D’Alessandro (2010, 2012, 2013, 2016), Chen & Wang (1980), Ge et al. (2008, 2010), Hua et al. (2014), Jolivet (1991), Kimoto (1971, 2000a, 2000b), Lee (2012), Medvedev (1995, 1996, 2001, 2004, 2007, 2009), Scherer (1969a, 1969b, 1972), Tiberghien (1976), Wagner (1999), Wang & Yu (1992).

Figures

FIGURES 1–5. Type specimens and their labels. 1–3: Chrysomela concolor Fabricius, 1781 (holotype, female); 4–5: Galleruca lausoniae Fabricius, 1798 (lectotype, male).