Bopyrus squillarum Latreille, 1804 Nomenclatural and taxonomic changes in parasitic isopods (Isopoda: Epicaridea) including two new families and note on the questionable association between monogeneans and bopyrids Boyko, Christopher B. Williams, Jason D. Zootaxa 2023 2023-03-29 5258 3 251 269 e1e90989-081d-4e86-84bd-def96092e69f (Fabricius, 1798) Fabricius 1798 [151,614,289,316] Malacostraca Bopyridae Bopyrus Animalia Isopoda 3 254 Arthropoda species crangorum  ( Fig 2)  =  Bopyrus squillarum Latreille, 1804  n. syn.   Material examined: Ovigerous female neotype, 9.5 mm( RMNH. CRUS.  I.1667) and mature male ( 2.15 mm) from non-ovigerous female  Palaemon adspersus( 22.1 mmCL, including rostrum) collected by P. Buitendijkfrom Genoa, Italy,  July 1927.   Distribution:Eastern part of the temperate Northern Atlantic, western part of the temperate Northern Pacific ( Bourdon 1968).   Hosts:Temperate Northern Atlantic:  Palaemon adspersusRathke, 1836(=  P. squilla( Linnaeus, 1758); typehost),  P. elegansRathke, 1836,  P. serratus(Pennant, 1777),  P. xiphiasRisso, 1816,  Processa edulis(Risso, 1816); temperate Northern Pacific:  P. pacificus(Stimpson, 1860),  P. serrifer(Stimpson, 1860) ( Bourdon 1968).   Remarks:The typespecies of the genus  Bopyrushas almost universally been cited as  Bopyrus squillarumLatreille, usually with a publication date of 1802; however, the author and date of the genus name, the correct name for the typespecies, and the date of the species name are all incorrect. The genus name  Bopyrusfirst appeared on page 83 of Bosc (1801a)(“An X” of the French Republican calendar; published before 22 October 1801 fide Low 2012) with a description of the characters of the genus and a reference to the paper of Fougeroux de Bondaroy (1772)that described, but did not name, a bopyrid found on a shrimp. As no mention of any included species was given, this is not an available name according to the ICZN. The genus name Bopryusnext appeared on page 213 of Bosc (1801b)(“An X”; published before 26 December 1801 fide Low 2012) with another description, attribution of the name to Latreille, another reference to the paper of Fougeroux de Bondaroy (1772)and inclusion of  Monoculus crangorum Fabricius, 1798as the sole species in the genus as  Bopyrus crangorum(i.e., the typespecies by monotypy). Note that the genus  Monoculus Linnaeus, 1758was suppressed by the International Commission of Zoological Nomenclature (1954; Opinion 288) but this Opinion did not mention  Monoculus crangorum; ostensibly because it is not one of the names originally included in the genus. The genus and species are therefore correctly cited as  BopyrusBosc, 1801and  Bopyrus crangorum( Fabricius, 1798), however, the use of this name for the typespecies was questioned by subsequent authors. The genus name  Bopyrusnext appeared on page 43 of Latreille (1802)(“An X”; published 6 Nov 1802 fide Dupuis 1986) but with no mention of  Bopyrus squillarum. The only species included in  Bopyrusby Latreille (1802)was  Monoculus crangorum Fabricius, 1798as was also true for Bosc (1801b). Latreille (1804)(“An XII”; published Feb–Mar 1804 fide Dupuis, 1986) more fully diagnosed  Bopyrusand introduced the name  Bopyrus squillarum(as “  bopyrus squillarum”) as a replacement name for  Bopyrus crangorum. Latreille’s (1804: 55)rationale as to the need for a replacement name was faulty in that he stated “This species of bopyre will be for me the prawn bopyre, bopyrus ( sic) squillarum. As it is not found on the crustaceans that make up the crangon( sic) genus of Fabricius, I do not think I should retain the specific name given to it by this author, monoculus ( sic) crangorum” (translated from the French). Latreille (1804), therefore, replaced the name of the typespecies for a reason that is not permissible under the ICZN, i.e., simply because he believed that the parasite did not occur on a species of  Crangon Fabricius, 1798. The parasite does not, in fact, occur on crangonids but this is irrelevant as to the correct name of the species.  Giard & Bonnier (1890)recognized the priority of  Monoculus crangorumas the typespecies of  Bopyrusbut further confused matters by abandoning both Fabricius’ and Latreille’s species names and replacing them with their own set of names, each linked to a single species of host (reflecting Giard’s belief that each parasite species had only a single host; see Kuris 1974). They wrote: “The name  B. squillarumgiven by Latreille in 1804 does not have priority: Fabricius had previously (1798) called the same crustacean  Monoculus crangorum. As this designation may have suggested that it was a  Crangonparasite, it was rejected by all subsequent zoologists, with the exception of Bosc, which was renamed  Bopyrus crangorum. But the name  Bopyrus squillarumis subject to similar criticism. It may be assumed that the epicarid in question is only a parasite of  Palaemon squillaLinné. Evenby restricting the use of this appellation and applying it only to the  P. squillaparasite, the inextricable complication of synonymy would not be avoided. Therefore, we believe it is better to completely abandon the name given by Latreille, as Latreille abandoned the name given by Fabricius, and we will designate the various species of European bopyrids as follows...” (translated from the French). Giard & Bonnier (1890)provided five new names for what they considered distinct species of  Bopyrus, one for each host, and all of which were synonymized with  B. squillarumby Sars (1898). However, while Sars (1898)likewise recognized  M. crangorumas the senior synonym of  B. squillarum(or, as spelled by Sars, “ sqvillarum”), he nevertheless attempted to justify the continued use of the junior name for the species: “This form was first recorded by O. Fabricius as  Monoculus crangorum; but as the specific name proposed by that author involves a confusion of shrimps with prawns, it is impossible to retain it and therefore, though the older one, it ought to give place to that proposed by Latreille.” We are unclear as to what Sars’ precise issue with shrimps versus prawns was, as these are common names and have been subject to different interpretations over time. Currently, “shrimps” are generally considered to be carideans while “prawns” are dendrobranchiates but also  Palaemonspp.and  Macrobrachiumspp.; however, it may have been different in 1898 (both  Crangonand  Palaemonare caridean genera). It should also be pointed out that the author of  M. crangorumwas J. C. Fabricius, not O. Fabricius. The reasons given for replacing the name  Monoculus crangorumby Latreille (1804)and Giard & Bonnier (1890)are not allowed under ICZN Article 18 (“The availability of a name is not affected by inappropriateness…”). If these names were competing names independently given to the same taxon by different authors (i.e., synonyms), then the argument could be made to have the senior synonym suppressed in favor of the commonly used  B. squillarumbut these are not competing names sensuICZN Article 23 as  B. squillarumis an invalid replacement name for  M. crangorumand reversal of precedence is therefore not possible. The valid name for the typespecies of  BopyrusBosc, 1801(not Latreille 1802) is  Monoculus crangorum Fabricius, 1798in the combination  Bopyrus crangorum( Fabricius, 1798). The type host of  B. crangorumis  Palaemon squilla( Linnaeus, 1758) fide Fabricius (1798); the current name for this species is  Palaemon adspersusRathke, 1836(see De Grave & Fransen 2011). It is not clear how many female specimens Fabricius examined and he did not describe the male of the species. In any case, the type specimen(s) of  Monoculus crangorumis/are not extant ( Zimsen 1964). Given the multiple names used by Giard & Bonnier (1890)for specimens occurring on different hosts and the possibility of cryptic species, especially given the geographic and host range of this species, we, in the interest of fixing the name of the type species, hereby select a dextral ovigerous female, 9.5 mm(RMNH.CRUS. I.1667) as the neotypeof  Monoculus crangorum Fabricius, 1798( Fig. 2C, D); the neotypeis accompanied by a mature male ( 2.2 mm) ( Fig. 2E, F) and parasitized a non-ovigerous female  Palaemon adspersus( Fig. 2A, B; 22.1 mmCL including rostrum; originally identified as  P. squillaby A.M. Buitendijk; ID verified by C.H.J.M. Fransen, Aug 2022), collected by Buitendijk from Genoa, Italyin July 1927. The species was redescribed in detail by Bourdon (1968)based on a female and male pair obtained from a specimen of  P. serratus( 18.9 mmCL excluding the rostrum); he examined numerous specimens obtained from four different species of  Palaemonfrom Franceand Italy, including the specimen selected here as the neotype. Note that records of  B. squillarum(e.g., Chopra 1923; Savant & Kewalramani 1964; Deshmukh 1987) from the Western Indo-Pacific on  Palaemon styliferus(H. Milne Edwards, 1840)and  Nematopalaemon tenuipes(Henderson, 1893)should all probably be referred to  Bopyrus bimaculatus Chopra, 1923.  Note on monogenean flatworms putatively associated with bopyrid isopods:The monogenean  Allodiclidophora squillarum( Parona & Perugia, 1889) Yamaguti, 1963was originally reported from  Bopyrus squillarumcollected in the Adriatic Sea. Although there are verified reports of monogeneans attached to cymothoid isopods that feed on primary fish hosts (see Bouguerche et al.2022), Parona & Perugia (1889)is the only report of a monogenean/bopyrid association. Parona & Perugia (1889)did not mention the identity of the host of  B. squillarumand many authors have repeated this record without comments ( Price 1943; Dawes 1956; Bychowsky 1961). At least some authors erroneously assumed that the host of  B. squillarumwas a fish ( Bychowsky 1961; Radujković & Šundić 2014). In fact, Yamaguti (1963)erected  Allodiclidophorawith  Mesocotyle squillarumas the typespecies and indicated as part of the generic diagnosis that species in this genus were “parasitic on Cymothoba(sic) in mouth cavity of Maenidae.” This is clearly in error and other authors may have similarly assumed that  B. squillarumis a cymothoid. As indicated by Overstreet (1983)and Bouguerche et al.(2021), the host of  B. squillarumis a shrimp. Considering that subsequent to the report of Parona & Perugia (1889)no monogeneans have been recorded from any bopyrid, it is possible that the report is a case of a sampling error (i.e., the monogenean fell off a fish host and was incidentally collected with  B. squillarum). A study of the morphology of  A. squillarumand the fact that other monogeneans associated with parasitic crustaceans (cymothoids and caligid copepods) are epibionts of the crustaceans that feed on the fish hosts ( Ohtsuka et al.2018; Bouguerche et al.2022), we feel it is highly unlikely that  A. squillarumfeeds on a bopyrid or shrimp host. Bouguerche et al.(2021)listed  B. squillarumas a host of the monogenean  Cyclocotyla bellonesOtto, 1823but presumably this is an error due to others (e.g., Radujković & Šundić 2014) who previously considered  A. squillaruma synonym of  C. bellones. 4067138301 1667-01 1927-07 1667-01 RMNH, CRUS P. Buitendijk Italy Italy 3 254 1 neotype