Homalosphodrus Stål, 1867 (Insecta: Heteroptera: Reduviidae): a junior objective synonym of Parsialus Stål, 1863 Author Swanson, Daniel R. Department of Entomology, University of Illinois at Urbana-Champaign drswanny@gmail.com text Zootaxa 2020 2020-02-20 4742 2 398 400 journal article 10.11646/zootaxa.4742.2.13 297922fc-8b25-4900-a34b-51cd286d810e 1175-5334 3754837 3AB8B5D6-4CE3-4B21-8A21-BDE223DA606E Homalosphodrus Stål, 1867 ( Insecta : Heteroptera : Reduviidae ): a junior objective synonym of Parsialus Stål, 1863 DANIEL R. SWANSON Department of Entomology, University of Illinois at Urbana-Champaign , 320 Morrill Hall, 505 South Goodwin Avenue, Urbana, IL 61801. Illinois Natural History Survey, Prairie Research Institute, University of Illinois at Urbana-Champaign, 1816 South Oak Street, Champaign, IL 61820-6960. E-mail: drswanny@gmail.com . urn:lsid:zoobank.org:author: 1F74F4E6-DA35-4A90-8572-EDC8F6660B43 The purpose of this note is to review the usage of the generic names Parsialus Stål, 1863 and Homalosphodrus Stål, 1867 ( type species: Parsialus depressus Stål, 1863 ) for a genus of harpactorine assassin bugs from the Oriental Region, the latter apparently being an unnecessary replacement name proposed for the former. Although Parsialus Stål, 1863 has been used rarely since its replacement and Homalosphodrus is undoubtedly in prevailing usage, it is demonstrated that neither name has been used extensively in the last century; thus, the case for suppression of Parsialus Stål, 1863 lacks strong support, similar to the case of Lanchnophorus Reuter, 1887 in Rhyparochromidae discussed by Kment et al. (2017) and nearly mirroring the case of Cutocoris Stål, 1859 and Cydnocoris Stål, 1867 in Reduviidae discussed by Swanson (2019) . As a consequence, Homalosphodrus Stål, 1867 is replaced by its senior objective synonym, Parsialus Stål, 1863 . 1. Stål (1863: 33) described a new genus, Parsialus Stål, 1863 , with two newly described species, Parsialus depressus Stål, 1863 from “ India orientalis” (= East Indies) and Parsialus brachialis Stål, 1863 from “Insulae Philippinenses” (= the Philippine Islands ). Stål (1863) did not designate a type species. 2. Stål (1867: 278) proposed the new genus Homalosphodrus Stål, 1867 as a replacement name for Parsialus Stål, 1863 and treated his two previously described species in combination with the new genus. No justification for replacing Parsialus was provided. In the case of Cutocoris - Cydnocoris , Swanson (2019) indicated that the senior synonym was likely replaced because it was a nomen hybridum . However, I have not been able to ascertain a derivation for Parsialus , including one comprising roots from different languages; thus, the reason for Stål’s replacement in the present case remains unclear. Nonetheless, this practice conflicts with current strictures of the International Code of Zoological Nomenclature ( ICZN 1999 ). Accordingly, Homalosphodrus must be considered an unnecessary replacement name, thus a junior objective synonym of Parsialus . Even so, to my knowledge, all subsequent authors, with one exception (see #3), have used Homalosphodrus as the valid name of this genus, i.e., Stål (1871: 683 ; 1874: 11 , 31); Lethierry & Severin (1896: 170) ; Distant (1903: 211 ; 1904: 348 ); Miller (1958: 83) ; Lim & Pan (1980: 1677) ; Putshkov & Putshkov (1985: 46 ; 1988: 95 ); Maldonado (1990: 218) ; Cai (1991: 284) ; Putshkov & Putshkov (1996: 241); Ambrose (2006: 2388 , 2398). The genus currently contains 7 species distributed throughout the Oriental Region ( Putshkov & Putshkov 1988 , Maldonado 1990 ). 3. Walker (1873: 83) treated Stål’s species as Sycanus ( Parsialus ) depressus ( Stål, 1863 ) . 4. Distant (1904: 348) treated Homalosphodrus Stål, 1867 as valid, listing Parsialus Stål, 1863 as its synonym, and selected Parsialus depressus Stål, 1863 as the type species of Homalosphodrus . This act also applies to the type species of Parsialus under Article 67.8 ( ICZN 1999 ). 5. Putshkov & Putshkov (1985: 46 , 1988: 95 ) asserted that Parsialus Stål, 1863 was preoccupied, although I have not been able to find any usage of this generic name other than Stål’s. 6. Although replacing Homalosphodrus with the lesser-used Parsialus is undesirable, a case arguing significant disruption to stability is weak at best. The case does not meet criteria for “automatic conservation” under Article 23.9.2 ( ICZN 1999 ): although the senior synonym, Parsialus , has not been used after 1899, thereby satisfying the first provision (i.e., Article 23.9.1.1), I could find neither twenty-five works, nor ten authors in a span of ten years from 1969 onward, that mention this genus, either as Homalosphodrus Stål, 1867 or as Parsialus Stål, 1863 . Therefore, the second provision, Article 23.9.1.2, cannot be satisfied. Further steps to conserve Homalosphodrus would require the Commission to use its plenary power ( ICZN 1999 , Article 23.9.3), and the taxa have only been referenced approximately 12–15 times in the last 150 years, mostly in faunal lists and taxonomic catalogs. 7. In conclusion, Homalosphodrus Stål, 1867 is replaced by Parsialus Stål, 1863 . This treatment results in five new combinations and two restored combinations. Throughout the period of etymological uncertainty, the gender of Parsialus is considered to be masculine, following Stål’s original treatment in combination ( ICZN 1999 , Article 30.2.3). The resulting nomenclatural changes are summarized below: Parsialus Stål, 1863 stat. restit. = Homalosphodrus Stål, 1867 syn. nov. Parsialus abdominalis ( Distant, 1903 ) comb. nov. Parsialus albogularis ( Miller, 1958 ) comb. nov. Parsialus brachialis Stål, 1863 comb. restit. Parsialus depressus Stål, 1863 comb. restit. Parsialus pendleburyi ( Miller, 1958 ) comb. nov. Parsialus philippinensis ( Miller, 1958 ) comb. nov. Parsialus sumatrensis ( Miller, 1958 ) comb. nov.