taxonID	type	description	language	source
03F54574FF85FF9D4DCEFF0CFD419922.taxon	description	“ bopyrid isopod parasites ” Poore, 2000: 151 (Japan, infesting Grynaminna tamakii Poore, 2000). “ another species of bopyrid isopod ” Anonymous, 2003: 4, 3.? “ parasit bopyrid ” Wardiatno, 2004: 81 – 84 (Japan, infesting N. japonica; see Remarks).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF85FF9D4DCEFF0CFD419922.taxon	materials_examined	Material examined. Mexico: Mature female (7.2 mm), mature male (3.3 mm), ex left branchial chamber of female Neotrypaea gigas (5.7 mm CL), ovigerous female (11.0 mm), mature male (6.0 mm), ex right branchial chamber of intersex N. gigas (8.0 mm CL), ovigerous female (9.0 mm), mature male (4.0 mm), ex left branchial chamber of female N. gigas (9.2 mm CL), ovigerous female (8.0 mm), mature male (4.5 mm), ex left branchial chamber of female N. gigas (6.0 mm CL), Bahia de Los Angeles, Baja California Norte, coll. F. Mantelatto, J. Cuesta & R. Robles, 6 Dec 2001 (ULLZ 10196 [3 [pairs]; USNM 1437637 ex ULLZ 10196 [1 pair; female incomplete, tissue removed for molecular analysis]). Japan: Ovigerous female (10.2 mm), mature male (5.2 mm), ex left branchial chamber of female Grynaminna tamakii (12.0 mm CL), Minami-Arima-cho sandflat, near south end of Shimabara Peninsula, Nagasaki Prefecture, Kyushu (32 ° 37 ' N, 130 ° 13 ' E), coll. A. Tamaki, 8 Jul 1998 (NSMT-Cr 12529).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF85FF9D4DCEFF0CFD419922.taxon	distribution	Distribution. Japan, South Korea, China; British Columbia, Canada to California, U. S. A., and Gulf of California, Baja California Norte, Mexico.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF85FF9D4DCEFF0CFD419922.taxon	biology_ecology	Hosts. Grynaminna tamakii Poore, 2000, Nihonotrypaea harmondi (Bovier, 1901), N. japonica (Ortmann, 1891), N. petalura (Stimpson, 1860), Neotrypaea californiensis (Dana, 1854), N. gigas (Dana, 1852) (type host), Upogebia major (De Haan, 1841).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF85FF9D4DCEFF0CFD419922.taxon	discussion	Remarks. The records of this species from an upogebiid host (An et al. 2009) may seem questionable as I. cornuta is otherwise only known from callianassid hosts but the congener I. thoracica (Montagu, 1808) has been reported to infest both callianassid and upogebiid hosts in the Mediterranean (Markham 2001). However, there are no records of I. cornuta from the west coast of the United States on any upogebiid host. Many early records had the host cited as Callianassa longimana, a synonym of N. gigas. Although Campos et al. (2009) listed I. cornuta as a parasite of N. gigas (based on data from Richardson 1905) and “ Ione sp. ” as a parasite of N. californiensis (based on data from Haig & Abbott 1980), they did not find infested hosts of either species from the Gulf of California. The Mexican specimens reported here therefore represent the first record of I. cornuta from the Gulf of California. The specimens from Grynaminna tamakii are the first bopyrids recorded from this host species. The inclusion of “ Nobuhiro & Kyoko 2004 ” in the synonymy list for this species by An et al. (2009) is an error as these are the first names of the authors Saito and Kinoshita (2004). The specimens studied by Wardiatno (2004) were never named or figured; they are likely either this species or Pseudione longicauda Shiino, 1937, as these are the only species known from Nihonotrypaea japonica.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF82FF9C4DCEFC4FFEC798F5.taxon	materials_examined	Material examined. United States: Mature female (17.9 mm), mature male (5.3 mm) (YPM IZ 089393), ex left branchial chamber of female Gilvossius setimanus (15.6 mm CL) (YPM IZ 005658. CR), Long Island Sound, outer island, Thimble Islands, Branford, New Haven County, Connecticut, 4 – 6 ft (1.2 – 1.8 m), coll. A. E. Verrill, 17 May 1910.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF82FF9C4DCEFC4FFEC798F5.taxon	distribution	Distribution. North Falmouth, Massachusetts to Long Island Sound; and possibly to St. Augustine, Florida.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF82FF9C4DCEFC4FFEC798F5.taxon	biology_ecology	Host. Gilvossius setimanus (DeKay, 1844) (type host).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF82FF9C4DCEFC4FFEC798F5.taxon	discussion	Remarks. The specimens from Long Island Sound match the original description of Ione thompsoni, with females possessing highly digitate lateral plates, five pairs of biramous pleopods, and large, slightly curled, uniramous uropods (Fig. 1 A, B); the oostegites are covered in short, thin cuticular extensions (Fig. 1 B). Males are found attached between the pleopods (Fig. 1 B) and have long, lanceolate lateral plates (Fig. 1 C). Ione thompsoni is a rare bopyrid, with the pair of specimens reported herein first being mentioned without description or illustration in a footnote in Kunkel (1918) and only now having their identity verified, nearly 100 years later. This rarity is surprising considering the relatively large size of the host, Gilvossius setimanus, and its distribution in the wellstudied fauna of the shallow water, northeastern American coastal region. The range of the host is from Nova Scotia to southern Georgia (Heard et al. 2007), whereas that of I. thompsoni is apparently from Cape Cod, Massachusetts to northern Florida. However, the only records of I. thompsoni from outside Massachusetts (type locality) and Long Island Sound (present specimens) are from Georgia and Florida but with both as “ pers. observ. ” cited in Heard et al. (2007); these specimens are not known to have been deposited in any museum collection and are not described or illustrated. Although Heard et al. (2007) stated that the southern end of the range of the host was Georgia, they also mentioned a parasitized host from St. Augustine, Florida, without comment that such a record would extend the known host range somewhat farther south. Williams (1984) gave the host range as extending to Franklin County, Florida, but this locality is in the Florida panhandle; Manning and Felder (1991) suggested that specimens from the northeastern Gulf of Mexico might belong to an undescribed species of Gilvossius. No bopyrids have been reported from specimens of Gilvossius from the Gulf of Mexico. Richardson (1904) described the species based on “ two specimens … collected by Mr. G. M. Gray at North Falmouth, Massacusetts ” and listed the “ type ” as USNM 29091. However, it is clear that Richardson (1904) had at least three specimens on hand because she described both the male and female of the species, but also mentioned a “ young female ” and an “ adult female ” (p. 75, footnote). USNM 29091 is the female holotype, whereas USNM 29230, also labeled as being collected from the type locality by Gray, contains one female and one male, both of which are paratypes.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF83FF904DCEF954FC249A89.taxon	description	“ a parasite … makes its home within the thoracic plate of the burrowing crab (Callianassa subterranea) ” Wood & Holder, 1885: 478 (mention).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF83FF904DCEF954FC249A89.taxon	description	Ione — Reveberi, 1947 b: figs. 2 – 7, 9 (Naples, infesting C. laticauda = P. tyrrhena and U. littoralis = U. pusilla [experimental infestation]). Ione Thoracica — Brezeanu & Elian, 1958: 1181 (mention). Jone [sic] vicina — Restivo, 1968: 505 (none found at Naples on C. truncata). Jone [sic] gebiae — Restivo, 1968: 506, table 3 (none found at Naples on Upogebia littoralis = U. pusilla). “ a bopyrid parasite ” Hughes, 1998: 60 – 61 (summary of data from Rowden & Jones, 1994). not Ione thoracica — Olaosebikan, 1986: iv, vi, vii, viii, 9, 27 – 32, 39, 40, fig. 13 (Nigeria, infesting Callianassa balssi Monod, 1933 = Callichirus balssi (Monod, 1933 )) (= Ione undescribed sp.).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF83FF904DCEF954FC249A89.taxon	materials_examined	Material examined. Croatia: Mature female (11.8 mm), mature male (4.5 mm) (NHMW 25382), ex branchial chamber of Pestarella tyrrhena (sex and size unknown), Volosko, coll. D. Abed-Navandi, 18 May 2000; mature female (5.5 mm), mature male (2.2 mm) (NHMW 25807), ex branchial chamber of female Callianassa truncata (4.9 mm CL) (NHMW 14779 / K 6), Kvarner, Volosko, coll. D. Abed-Navandi, 15 Jul 1996; mature female (9.4 mm), mature male (3.3 mm) (NHMW 25810), ex left branchial chamber of male N. truncata (9.0 mm CL) (NHMW 25014, Fig. 1 D), Volosko, Croatia, coll. D. Abed-Navandi, Apr 2003. Italy: Mature female (12.0 mm), mature male (5.7 mm) (NHMW 25231), ex branchial chamber of female P. tyrrhena (13.2 mm CL) (NHMW 25853), Lido di Staranzano, coll. P. Dworschak, 11 May 1988; 4 ovigerous females (8.7 – 11 mm), 2 mature males (5.1 – 5.3 mm), 1 partial mature male (posterior end only), ex unknown host, Naples Aquarium, coll. unknown, 17 Nov 1890 (NMV J 62892). Tunisia: Mature female (4.8 mm), mature male (2.5 mm) (NHMW 25809), ex branchial chamber of male C. truncata (6.4 mm CL) (NHMW 18819 / 7), Hammamet, ca. 2 m, coll. P. Dworschak 15 Jan 2000.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF83FF904DCEF954FC249A89.taxon	distribution	Distribution. Northwestern Atlantic (Netherlands, Belgium, United Kingdom, France); Mediterranean (Spain, Tunisia, Italy); Adriatic Sea (Croatia); and Black Sea.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF83FF904DCEF954FC249A89.taxon	biology_ecology	Hosts. Callianassa subterranea (Montagu, 1808) (type host), C. truncata Giard & Bonnier, 1890, and Pestarella tyrrhena (Petagna, 1792).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF83FF904DCEF954FC249A89.taxon	discussion	Remarks. Bourdon (1968) compared Ione thoracia with I. vicina based on Bonnier’s (1900) data as he did not have any bopyrids from Callinassa truncata available to examine. Bourdon (1968) concluded that the only apparent differences between the two species were in the shapes of the endopods and lateral plates of the first pleopods (Fig. 2). We examined five pairs of Ione from C. truncata and Pestarella tyrrhena, including: three from Croatia (Figs 1 D, 2 C, E), one from Italy (Fig. 2 D), and one from Tunisia (Fig. 2 F). Whereas the Croatian females show near identical morphology to the Italian specimen illustrated by Bonnier (1900; repeated by Bourdon 1968: fig. 9 A; Fig. 2 A herein) in the morphology of the first pleopod endopods, lateral plates, and appearance of short endopods (Fig. 2 C, E), the Tunisian (Fig. 2 F) and newly examined Italian females (Fig. 2 D) have first pleopods that are identical to that of the “ typical ” I. thoracica (Bourdon 1968: fig. 9 B; Fig. 2 B herein) in possessing long endopods. The specimen Bonnier (1900) identified as I. thoracica came from an unspecified locality that was most likely Wimereux, France. In other respects the females are essentially identical, as are the males. This leads us to conclude that there is no good reason to maintain I. vicina as distinct from I. thoracica; therefore, we herein synonymize the two species. Interestingly, specimens occurring on Pestarella tyrrhena from Italy and Croatia both show “ typical ” I. thoracica morphology for the first pleopod, suggesting there may be a population on C. truncata around Italy and Croatia that show the “ vicina ” morphology of the first pleopod, perhaps due to isolation from other populations on these hosts in the Mediterranean. Note that several spellings of Ione thoracica / thoracicus were incorrectly given by Bourdon (1968) in his synonymy list and are corrected herein. Boyko et al. (2013) erred when they stated that Ione spp. were unlikely to occur on gebiid hosts and also in their agreement with Bourdon (1968) in discounting the earlier report by Fraisse (1877; 1878 a) of I. thoracica from Upogebia pusilla (Petanga, 1792) (not U. stellata (Montagu, 1808 )). In addition, data from An et al. (2009) strongly support the rare occurrence of Ione spp. on gebiid hosts. We consider the material from Nigeria reported by Olaosebikan (1986) to be distinct from Ione thoracica. The form of the females’ uropods is very different from that seen in any specimens of I. thoracica (based on material examined in this study, as well as illustrations from other papers, e. g., Reverberi & Pitotti 1943; Bourdon 1968) and the coxal plates of the first two pereomeres are not elongated as in true I. thoracica. Additionally, the host, Callichirus balssi (Monod, 1933), and locality occur well outside of the range of I. thoracica. Callianassa balssi Monod, 1933 is the type species of Balsscallichirus Sakai, 2011, but is better left in Callichirus Stimpson, 1866, pending revision of these and related genera (Poore, pers. commun.).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF8FFF924DCEFE67FBA499B1.taxon	materials_examined	Material examined. Singapore: Mature non-ovigerous holotype female (7.5 mm), ex right branchial chamber of female Austinogebia spinfrons (8.6 mm CL), Sta. 6, Pulau Tekong (type locality) (ZRC 1990.4330).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF8FFF924DCEFE67FBA499B1.taxon	etymology	Etymology. This species is named for the tapered and marginally constricted lateral plates and pleopods that are reminiscent of the “ segmented ” appearance of species in the algal genus Halimeda J. V. Lamoroux, 1812 (e. g., H. cylindracea Descaisne, 1842) with subquadrate or cylindrical plates. In Greek mythology, Halimeda was a Nereid, the daughter of Nereus and Doris.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF8FFF924DCEFE67FBA499B1.taxon	distribution	Distribution. Singapore.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF8FFF924DCEFE67FBA499B1.taxon	biology_ecology	Host. Austinogebia spinfrons (Haswell, 1881) (type host).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF8FFF924DCEFE67FBA499B1.taxon	description	Description. Female (Fig. 3 A, B), body length 8.0 mm, maximal width 6.4 mm, head length 1.5 mm, head width 1.9 mm. No body pigmentation. Pereon weakly sinistral (15 °) with coxal plates and pereomeres of right side slightly larger on segments 1 – 4 (Fig. 3 A). Head slightly wider than long, with thin frontal lamina (Fig. 3 A), deeply embedded medially in first pereomere; eyes lacking. Antennules of three articles each, antennae of four articles each (Fig. 3 C). Maxilliped with rounded distal end and subacute recurved spur; palp present as setose, non-articulated lobe (Fig. 3 E). Barbula with 2 pairs of irregular lateral projections with numerous short, finger-like marginal lobes; medial margin with few finger-like, short fleshy projections (Fig. 3 D). First oostegite anterior lobe rounded, external posterior face with patch of irregular low, fleshy lobes, inner ridge with numerous small rounded projections along ¾ of length; distal lobe subtriangular, slightly recurved (Fig. 3 F, G). Fourth and fifth oostegites with fringe of setae on posterior margin (Fig. 3 B). Pereon composed of 7 pereomeres (Fig. 3 A), first 2 markedly curved and rounded at lateral margins, third and fourth nearly laterally straight, rounded at lateral margins except for one side of pereomere 7 which has a posterolateral point (Fig. 3 J), last 3 slightly curved posteriorly at truncate lateral margins; broadest across pereomere 4, gradually tapering anteriorly and posteriorly; Pereomere 1 with convex posterior margin; posterior margins of pereomeres 2 and 3 nearly straight; posterior margins of pereomeres 4 – 7 convex (Fig. 3 A). Pereomeres 1 – 4 with rounded coxal plates, no dorsolateral bosses. Pereomere 4 bilobed laterally, remainder undivided with rounded coxal plates. First pair of pereopods near anterolateral margin of head; pereopods evenly spaced. Pereopods subequal in size (Fig. 3 H, I), carpi and meri fused, small tubercles present on lateral faces of some ischia; basis with ridge of larger tubercles (Fig. 3 H, I). Pleon with 5 distinct pleomeres plus small pleotelson (Fig. 3 A), pleomeres resembling posterior three pereomeres, but with tapered lateral plates. Lateral plates present distally on pleomeres as elongate, tapered lobes with numerous constrictions along length (Fig. 3 A, J, K); lateral region of pleomeres with few, low warty lobes on margins and surface (Fig. 3 A, K). First five pleomeres with pair of tapered, elongate, biramous pleopods with lateral constrictions as seen in lateral plates (Fig. 3 L); pleopods extending beyond lateral plates and visible in dorsal view, mostly on left side of body (Fig. 3 A), all endopods and exopods subequal in size and shape (Fig. 3 B). Pleotelson not easily seen in dorsal view (Fig. 3 A), bearing pair of uniramous uropods with endopod and exopod subequal in size, both resembling lateral plates and pleopods in having numerous marginal constrictions (Fig. 3 A, L). Male unknown.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF8FFF924DCEFE67FBA499B1.taxon	discussion	Remarks. All species of Acrobelione have females with the barbula possessing lateral projections with numerous short, finger-like lobes on the margins, and lateral plates and pleopods with numerous constrictions along their lengths, as well as pereopods with scattered tubercles on the ischia and a ridge of pronounced tubercles on the bases. This new species is most similar to A. langi (Van Name, 1920) (see also Bourdon 1981 b) but differs from it in the shape of the female’s head (flat frontal margin in A. halimedae n. sp. vs. distinctly medially produced in A. langi) and the overall body shape (nearly circular in A. halimedae n. sp. vs. ovate in A. langi). The material (2 females and 2 males) of A. langi examined by Bourdon (1981 b) came from hosts collected at the same time and from the same locality as the unique holotype but were not seen by Van Name (1920) and are not type specimens. Acrobelione anisopoda Bourdon, 1981 b was described from an immature female and mature male (type host and locality: Gebiacantha talismani (Bouvier, 1915) from off Príncipe, Gulf of Guinea); both show characters of species in Acrobelione, but the female does not have well developed tubercles on the pereopods nor laterally constricted lateral plates or pleopods. However, these differences may be due to the specimen’s immaturity. A key to species in the genus based on mature females is given below, including type host and type locality data. Although not common, Acrobelione has species known from both gebiidean and axiidean hosts (An et al. 2009). However, Bourdon (1981 b) erred when he listed Acrobelione reverberii (Restivo, 1970) as occurring on U. pusilla because the 66 individuals said by Bourdon (1981 b: 120, footnote) to be from this upogebiid host are clearly stated by Restivo (1968) to be from C. truncata. Likewise, the listing by Markham (2001) of A. reverberii occurring on U. pusilla is erroneous; his supposed source for that data (Restivo, 1970) does not list any host other than Callianassa truncata. Restivo (1968), although listing a “ nuova specie ” from U. pusilla, also lists one from C. truncata, and this is the correct data that should be associated with A. reverberii.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF8DFF944DCEF99DFEF098F0.taxon	description	Not Gyge branchialis — Pandey, 1990: 494 – 494, figs. 1, 2 (India, infesting Macrobrachium birmanicum choprai (Tiwari, 1949) = M. gangeticum Bate, 1868) (almost certainly a species of Probopyrus Giard & Bonnier, 1888).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF8DFF944DCEF99DFEF098F0.taxon	materials_examined	Material examined. Italy: 2 ovigerous females (9.7 – 10.1 mm) not affiliated with any host, 1 ovigerous female (9.3 mm), 1 mature male (3.3 mm), ex right branchial chamber of female Upogebia stellata (14.3 mm CL), Naples Aquarium, coll. unknown, 17 Nov 1890 (NMV J 71549).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF8DFF944DCEF99DFEF098F0.taxon	distribution	Distribution. Denmark, United Kingdom, France, Spain, Portugal, Italy, Algeria, Croatia, Romania, and Russia.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF8DFF944DCEF99DFEF098F0.taxon	biology_ecology	Hosts. Upogebia deltaura (Leach, 1816), U. pusilla (Petagna, 1792) (type host), U. stellata (Montagu, 1808), and U. tipica (Nardo, 1869).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF8DFF944DCEF99DFEF098F0.taxon	discussion	Remarks. Although old, these specimens are exceptionally well-preserved and match prior descriptions (e. g., Bourdon 1968).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF8BFF974DCEFD64FEFB9A88.taxon	materials_examined	Material examined. Taiwan: Immature female (3.8 mm), mature male (2.1 mm), ex right branchial chamber of female Austinogebia edulis (8.0 mm CL), Yilan County, port at Tai-Chi, shallow water, coll. inland trawlers (ZRC 2016.0440)	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF8BFF974DCEFD64FEFB9A88.taxon	distribution	Distribution. Japan, South Korea, Taiwan, and China.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF8BFF974DCEFD64FEFB9A88.taxon	biology_ecology	Hosts. Austinogebia edulis (Ngoc-Ho & Chan, 1992), A. narutensis (Sakai, 1986), A. wuhsienweni (Yu, 1931), Upogebia carinicauda (Stimpson, 1860), U. issaeffi (Balss, 1913) (possible type host), U. major (De Haan, 1841) (probable type host), and U. yokoyai Makarov, 1938.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF8BFF974DCEFD64FEFB9A88.taxon	discussion	Remarks. The host of the types was originally reported as Upogebia major (De Haan, 1841) in Shiino (1939 b) but was changed to U. issaeffi (Balss, 1913) in Shiino (1958) and back again to U. major in Shiino (1972). This species has been reported several times from U. major, including in a large-scale study of the host / parasite relationship by Ubaldo et al. (2014), but only once subsequently from U. issaeffi (Itani 2004 b). The identity of the type host is therefore most likely U. major, but only examination of the type host can solve this question. Markham (2004) included Codreanu (1941: 140) in his synonymy list under Metabopyrus ovalis, but nowhere in that paper is the species mentioned and there is no p. 140 in that article; the page was probably from Codreanu (1961) where the species is mentioned and the “ 1941 ” citation is therefore a lapsus for 1961. Chapman et al. (2012) incorrectly stated that the record of Gyge ovalis from Itani (2004 b) was a misidentification of Orthione griffenis Markham, 2004. Itani’s (2004 b) identification was correct, albeit under the original combination of Metabopyrus ovalis. The record in Itani’s (2004 b) Table 3 that is referrable to O. griffenis is actually “ Pseudioninae sp. 1 ” (Williams & An 2009; Itani et al. 2014). The present record (Fig. 4) is only the second from Taiwan and A. edulis is the only known host in Taiwan.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF88FF964DCEFA65FD37989F.taxon	materials_examined	Material examined. Panama: Ovigerous female (6 mm; incomplete, tissue sampled for molecular analysis) (USNM 14376368 ex ULLZ 10202), ex right branchial chamber of Neotrypaea uncinata (6.5 mm CL, lacking gonopores) (ULLZ 10202), beach across road from NOAA / STRI lab, Panama, coll. D. L. Felder, 10 Sept 1995.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF88FF964DCEFA65FD37989F.taxon	distribution	Distribution. Pacific Panama, and coast of Chile.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF88FF964DCEFA65FD37989F.taxon	biology_ecology	Hosts. Neotrypaea uncinata (H. Milne Edwards, 1837) (type host).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF88FF964DCEFA65FD37989F.taxon	discussion	Remarks. This specimen is more similar to the female illustrated by Shiino (1964 a) than that illustrated by Bonnier (1900), in that the lateral plates of the pleomeres are strongly asymmetrical, though not as strongly so as in Shiino’s (1964 a) specimen. This Panamanian record is a significant range extension for Ionella agassizi, which was previously known only from localities in Chile. However, the host, Neotrypaea uncinata, is known to have the broadest longitudinal range of any thalassinidean: from 34 ° N to 47 ° S (i. e., southern California to southern Chile) (Dworschak 2005). Despite the numerous records of this host from localities in Chile, Sakai (2011) inexplicably stated it was known only from the type locality. The host has been previously recorded from Panama (Ayón- Parente et al. 2014) but without this parasite.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF89FF964DCEFC8EFBC39F11.taxon	materials_examined	Material examined. None.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF89FF964DCEFC8EFBC39F11.taxon	distribution	Distribution. Japan.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF89FF964DCEFC8EFBC39F11.taxon	biology_ecology	Host. Neocallichirus jousseaumei (Nobili, 1904) (type host) and Paratrypaea bouvieri (Nobili, 1904).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF89FF964DCEFC8EFBC39F11.taxon	discussion	Remarks. The males and females of this species appear very similar to those of Ionella murchisoni Danforth, 1970 and Danforth (1970 a) actually compared and contrasted the two species although he did not transfer P. compressa to Ionella. Based on Shiino’s (1964 b) description and figures, we herein transfer P. compressa to Ionella. Examination of specimens, ideally from the vicinity of the type locality, is needed to confirm details of the morphology and to determine the relationship of I. compressa to other species of Ionella.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF89FF884DCEFA7DFDF79EB5.taxon	materials_examined	Material examined. United States: Ovigerous female (11.8 mm), ex branchial chamber of “ Panopeus herbstii ” H. Milne Edwards, 1834 [incorrect host identification; see below], Beaufort, North Carolina, coll. A. S. Pearse, 22 Aug 1946 (USNM 1424906 ex USNM 84049; also present in vial was a mature male (4.5 mm) and a single first oostegite of Progebiophilus upogebiae; both of the latter retain the USNM 84049 catalogue number); mature male (9.4 mm), ex branchial chamber of Upogebia affinis (size and sex unknown), Beaufort, North Carolina, coll. A. S. Pearse, 6 Aug 1946 (USNM 84052).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF89FF884DCEFA7DFDF79EB5.taxon	distribution	Distribution. Massachusetts to North Carolina, U. S. A.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF89FF884DCEFA7DFDF79EB5.taxon	biology_ecology	Hosts. Upogebia affinis (Say, 1818).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF89FF884DCEFA7DFDF79EB5.taxon	discussion	Remarks. This species was confounded with Progebiophilus upogebiae (Hay, 1917) by Pearse (1947) as evidenced by the female and male examined here that were included in separate USNM lots, each labeled as being Pseudione upogebiae. One of these lots (USNM 84049) contained a female Orthione furcata (Fig. 5 A), a male P. upogebiae, and the first oostegite of a P. upogebiae, whereas the other (USNM 84052) contained only a male O. furcata (Fig. 5 B). Markham (1988) also noted that four of the six specimens originally in USNM 84051, labeled as P. upogebiae, were likewise actually O. furcata. The male specimen (USNM 84052) was misidentified on the label as “ Pseudodione [sic] upogebia [sic] ”. The labeling and co-mingling of two species from different genera, both otherwise only known from upogebiid hosts, in a single lot supports our conclusion that Panopeus herbstii is an erroneous host identification for P. upogebiae (see additional Remarks under that species). Markham (1988) included Kaestner’s (1970) record of “ Pseudoione ” [sic] furcata from the Gulf of Mexico in his synonymy list for O. furcata, essentially without comment as to its validity, although he correctly noted that Kaestner (1970) gave no indication as to the source of his data. Markham (1988) logically interpreted Kaestner’s (1970) statement of the species’ occurrence on the “ Gulf coast ” to mean the Gulf of Mexico, but it is unusual that Kaestner, being a German researcher, would use a colloquial term such as “ Gulf coast. ” In fact, no mention of Pseudione furcata appears in the original edition of this book (Kaestner 1967). This information was added by one of the reviewers who provided “ numerous suggestions and changes ” when Kaestner (1967) was translated into English by H. W. and L. R. Levi (Kaestner 1970: vi – vii). Although three people (R. R. Hessler, R. J. Menzies, and S. M. Shiino) are thanked in Kaestner (1970) for contributing to the isopod section, none are identified as contributing text but the most likely source of this record of O. furcata is Menzies, then at Florida State University, which is in western Florida and very near to the “ Gulf coast. ” However, this record is almost certainly erroneous, as no other published records of O. furcata from south of North Carolina are known. The “ Gulf coast ” record is likely a misidentification of Progebiophilus upogebiae, a species known to occur in the northern Gulf of Mexico (see Material Examined under that species).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF97FF8B4DCEFA19FECF9F6E.taxon	description	Pseudione — Campos & de Campos, 1989 a: 33 (Bahía Tortugas, Baja California Sur, Mexico, infesting U. macginitieorum Williams, 1986). — Campos & de Campos, 1989 b: 177 (Bahía Tortugas, Baja California Sur, Mexico, infesting U. macginitieorum).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF97FF8B4DCEFA19FECF9F6E.taxon	materials_examined	Material examined. Mexico: Ovigerous female (4.8 mm), mature male (1.5 mm), ex left branchial chamber of female Upogebia dawsoni (5.0 mm CL), ovigerous female (7.0 mm), mature male (2.0 mm), ex left branchial chamber of female U. dawsoni (7.0 mm CL), ovigerous female (7.0 mm), mature male (2.0 mm), ex left branchial chamber of female U. dawsoni (6.5 mm CL), immature female (2.0 mm), mature male (1.2 mm), ex right branchial chamber of juvenile U. dawsoni (3.5 mm CL), immature female (3.0 mm), mature male (1.5 mm), ex right branchial chamber of juvenile U. dawsoni (4.5 mm CL), immature female (2.3 mm), mature male (1.3 mm), ex right branchial chamber of juvenile U. dawsoni (4.0 mm CL), ovigerous female (8.0 mm, sacrificed for molecular work), mature male (2.5 mm), ex right branchial chamber of female U. dawsoni (7.0 mm CL), sandy beach, northwest, Puerto San Carlos, Baja California Sur, coll. R. Robles, J. Cuesta & F. Mantelatto, 4 Dec 2001 (ULLZ 10195); ovigerous female (4.8 mm), mature male (2.0 mm), ex left branchial chamber of immature U. dawsoni (5.0 mm CL), Bahia de Los Angeles, Baja California Norte, coll. F. Mantelatto, J. Cuesta & R. Robles, 6 Dec 2001 (ULLZ 10197). Nicaragua: mature female (6.0 mm; incomplete, sampled for molecular analysis), mature male (2.3 mm) (USNM 1437636 ex ULLZ 10194), ex right branchial chamber of male Upogebia spinigera (6.0 mm CL) (ULLZ 10194), Santa Julia, between Potosi and El Rosario, coll. J. A. Cuesta, R. Robles & J. T. Rodriguez, 19 Nov 2002.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF97FF8B4DCEFA19FECF9F6E.taxon	distribution	Distribution. Gulf of California from San Felipe, Baja California Norte to Laz Paz, Baja Californa Sur; Tortugas Bay, west coast of Baja California Sur and Todos Santos Bay, Ensenada, Baja California Sur, Mexico; Nicaragua (herein).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF97FF8B4DCEFA19FECF9F6E.taxon	biology_ecology	Hosts. Upogebia dawsoni Williams, 1986 (type host), U. spinigera (Smith, 1871), U. macginitieorum Williams, 1986, Pomatogebia rugosa (Lockington, 1878).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF97FF8B4DCEFA19FECF9F6E.taxon	discussion	Remarks. Although often cited as being published in 1989, the original description of this species was in an issue marked as “ dépot légal 1 er trimestre 1990. ” This species appears to be widely distributed throughout the Gulf of California, as well as on the west coast of Baja California. Its absence from the eastern coast of the Gulf of California may be an artifact of fewer hosts being collected in that region, either due to undersampling or less suitable habitats. The Nicaraguan specimen reported on here resembles P. bruscai in all details of the female except that none of the bases of the pereopods have swollen dorsal knobs (e. g., Salazar-Vallejo & Leija-Tristán 1990: fig 2 F; Campos & de Campos 1998: fig. 1 L – M). The male likewise shows all the characters of P. bruscai although the pleotelson has fused rather than articulated posterolateral lobes as described and illustrated by Salazar-Vallejo & Leija-Tristán (1990: fig. 3 A, C). However, the fusion of posterolateral lobes of the pleotelson in males is known to be variable in this species (see Campos & de Campos 1998). Identification of these specimens as P. bruscai greatly extends the known range of the species southward from Mexico. The host, U. spinigera, was previously known to bear Orthione mesoamericana Markham, 2004, in Costa Rica and Colombia.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF94FF8F4DCEFA1DFE399D58.taxon	description	P. upogebiae — Van Name, 1920: 72 (mention). P. urogebiae [sic] — Popov, 1929: 13 (mention). Ps. urogebiae [sic] — Popov, 1929: 14 (mention).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF94FF8F4DCEFA1DFE399D58.taxon	description	“ bopyrid ” Williams, 1993: 44 (Barra del Tordo, Mexico, infesting U. felderi). not Pseudione upogebiae — Pearse, 1947: 326 (in part, Beaufort, North Carolina, U. S. A., infesting Upogebia affinis) (= Orthione furcata).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF94FF8F4DCEFA1DFE399D58.taxon	materials_examined	Material examined. United States: Two ovigerous female paratypes of Pseudione upogebiae (9.8 – 11.1 mm), mature male paratype (3.1 mm), ex branchial chambers of Upogebia affinis (sizes and sexes unknown), Beaufort, North Carolina, coll. W. P. Hay, 17 Aug 1915, (USNM 48370); mature holotype female of Pseudione panopei (12.1 mm), ex branchial chamber of “ Panopeus herbstii ” [erroneous identification; see Remarks; size and sex of host unknown], Beaufort, North Carolina, coll. A. S. Pearse, 22 Aug. 1946 (USNM 82669; body excepting most of abdomen in EtOH, abdomen mounted on slide); mature allotype male of P. panopei, same data as holotype (USNM 82670; mounted on slide); paratype female of P. panopei, same data as holotype (USNM 82671; mounted on slide); mature female (likely ovigerous but no eggs currently present in vial) (9.9 mm), ex branchial chamber of “ Uca pugilator ” (Bosc, 1801) [incorrect host identification; see below], Beaufort, North Carolina, coll. A. S. Pearse, 20 Jul 1946 (USNM 84047; also present in vial was a mature male Probopyrus pandalicola (Packard, 1879) (3.0 mm); mature male (4.5 mm, USNM 1424905) and single first oostegite), ex branchial chamber of “ Panopeus herbstii ” [incorrect host identification; see below], Beaufort, North Carolina, coll. A. S. Pearse, 22 Aug 1946 (USNM 84049; also present in vial was an ovigerous female (11.8 mm) of Orthione furcata, now USNM 1424906); unidentifiable fragments, ex U. affinis (as per label; host not in vial), Beaufort, North Carolina, coll. A. S. Pearse, 13 Jun 1946 (USNM 84050); mature female (likely ovigerous but no eggs currently present in vial) (8.3 mm), mature male (3.2 mm), ex branchial chamber of U. affinis (as per label; host not in vial), Beaufort, North Carolina, coll. A. S. Pearse, 17 Jun 1946 (USNM 84051); ovigerous female (10.0 mm), mature male (3.3 mm), ex right branchial chamber of U. affinis, Goose Cove sand spit, Cedar Key, Levy County, Florida, 29.133 ° – 83.037 °, 0 – 1 m depth, coll. G. F. Paulay & UF Invertebrate Zoology class (UF 044634). Mexico: Ovigerous female (9.0 mm, part sacrificed for molecular work), mature male (2.7 mm), ex right branchial chamber of female paratype of Upogebia felderi (8.0 mm CL), Stn 6, Barra del Tordo, mouth of Rio Carrizal, Tamaulipas, inshore of grass beds, yabbby pump, coll. D. L. Felder & R. Tinnin, 24 May 1982 (ULLZ 3019); mature female (7.0 mm, ½ sacrificed for molecular work), ex left branchial chamber of female U. felderi (8.0 mm CL), Stn 6, Rio Carrizal, Barro del Tordo, Tamaulipas, coll. D. L. Felder & R. Tinnin, 24 May 1982 (ULLZ 10200); ovigerous female (7.8 mm), mature male (2.5 mm), ex branchial chamber of U. felderi (sex and CL unknown), Barra del Tordo, mouth of Rio Carrizal, Tamaulipas, oyster covered beaches near grass beds, shallow and intertidal, coll. D. L. Felder, Rabalais et al., 14 Jun 1978 (USNM 1084297 ex ULLZ 3071).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF94FF8F4DCEFA1DFE399D58.taxon	distribution	Distribution. Virginia, U. S. A to Brazil, and northern Gulf of Mexico west to Tamaulipas, Mexico.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF94FF8F4DCEFA1DFE399D58.taxon	biology_ecology	Hosts. Upogebia affinis (Say, 1818) (type host), and U. felderi Williams, 1993. The record of Panopeus herbstii H. Milne Edwards, 1834, as host of the type specimens of Pseudione panopei is in error; see below.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF94FF8F4DCEFA1DFE399D58.taxon	discussion	Remarks. Pseudione panopei has always been a puzzle because it is the only species in Pseudioninae, outside those of Gigantione Kossmann, 1881, that has been reported from a brachyuran host. Markham (1975) examined Pearse's type material of Pseudione panopei and stated that “ this species is definitely assignable to Pseudione, but there is some reason to believe that the host was incorrectly recorded. ” Markham (1975) did not, however, indicate why he thought the host was not Panopeus herbstii as given by Pearse (1947). We have examined all of the type material of Pseudione panopei (Fig. 7) and concur with Markham’s (1975) conclusion that the host was recorded in error. The morphological characters of the holotype female of Pseudione panopei are identical with those of Progebiophilus upogebiae (compare Fig. 6 herein with Fig. 3 in Markham 1988). The allotype male (USNM 82670) and the immature paratype female (USNM 82671) are both mounted on slides and in poor condition; both are highly distorted and their length cannot be measured accurately. The pleotelson of the male has lateral lobes that were folded somewhat when the specimen was mounted on a slide and Pearse (1947) inaccurately drew them as if they were segmented uropods. Now that the identity of Pseudione panopei has been clarified and it is actually a species that is only known from gebiidean hosts, this leaves the following explanations for its occurrence on a brachyuran: 1) Progebiophilus upogebiae does, in fact, occur on Panopeus herbstii in Beaufort, North Carolina (and perhaps elsewhere in the host’s range) and this is an unique case of a bopyrid species found on both gebiidean and brachyuran hosts or 2) the host identity was recorded in error and the types of Pseudione panopei were actually obtained from a Upogebia host. If the former is true, then it is hard to explain why no one has subsequently found this parasite on Panopeus herbstii, which is a common and well-studied crab. Given the clear evidence of Pearse mixing multiple bopyrid species within lots (see Material Examined above), the most parsimonious explanation is that Pearse mixed up his lots with respect to host identity as well. All of Pearse’s samples except USNM 84047 (see below) include a label hand-written by Pearse (confirmed based on comparison with Pearse journals); labels include locality, date and host identification data. It is unclear why he described Pseudione panopei as a new species, but he may have been influenced by the now-discredited theory of Giard & Bonnier (1890 b) that each parasite discovered on a novel host must be specifically distinct from all other previously described species. USNM 84047 contains a female Progebiophilus upogebiae and a male Probopyrus pandalicola (Packard, 1879) (now USNM 1424905, Fig. 5 C), a species also mentioned by Pearse (1947) and providing another example of Pearse’s co-mingling of taxa and poor labeling of specimens. The host recorded on another label as “ Uca pugilator ” (now Leptuca pugilator (Bosc, 1801 )) is also clearly in error. The original Pearse identification label for USNM 84047 is missing and the two labels in the vial indicate identification of the parasites as Pseudione upogebiae by Roland Bourdon. However, given that USNM 84046 and 84048 are both lots of Leidya distorta (Leidy, 1855) found parasitizing L. pugilator, we suspect that the original Pearse identification label for USNM 84047 also read L. distorta and this was changed when Bourdon examined the specimens. Both USNM 84046 and 84048 were cited in Bourdon & Bowman’s (1970) paper on Leidya but 84047, conspicuously, was not. Apparently, Bourdon did not look at the male in 84047 closely as he did not notice it belonged to Probopyrus pandalicola, but this is perhaps not surprising as he was likely focusing on the fact that the lot did not contain any Leidya specimens. The fragmentary specimen (USNM 84050) was identified on the label as “ Pseudodione [sic] upogebia [sic]. ” Based on the poor condition of the specimen and Pearse’s confusion between Progebiophilus upogebiae and Orthione furcata (Richardson, 1904) (see also Markham 1988); this vial may or may not contain fragments of P. upogebiae. Although Hay & Shore (1918) misspelled the genus name and Markham (1988) correctly noted this fact, Markham’s citation erroneously showed the genus name as spelled correctly. The first author to report Progebiophilus upogebiae from Upogebia felderi was Williams (1993). An additional paratype lot of U. felderi (ULLZ 3017) was cited by Williams (1993) as containing a host parasitized by Progebiophilus upogebiae and there is a note to that effect in the vial, but no parasitized specimen is present; the parasite is actually deposited as USNM 1084297 (see material examined). Both the female and male from the Florida Gulf coast show no differences from the material described and figured by Markham (1988) from North Carolina (Figs. 5 D, E) except that the present male has broad midventral tubercles on pereomeres 5 – 7, however, these structures are rather low and can only be seen in lateral view. The specimens examined from Cedar Key, Florida (Fig. 6) are only the second record of Progebiophilus upogebiae under that name from the northeastern Gulf of Mexico; the first was that of Pearse (1953, as the type locality of the synonym Phyllodurus robustus). However, Kaestner’s (1970) record of “ Pseudoione ” [sic] furcata Richardson, 1904, from the “ Gulf coast ” is almost certainly based on misidentified Progebiophilus upogebiae. Protozoans similar in morphology to members of the genus Cothurnia (Vaginicolidae) were attached to the pereopods of Progebiophilus upogebiae from the Gulf of Mexico (Fig. 6 C, D). In addition, these bopyrid specimens had mesomycetozoeans (Class Mesomycetozoea, Order Eccrinales) attached to the cuticle (Fig. 6 C). Such ectosymbionts have previously been reported from other bopyrids (Williams & An 2009) and their hosts (Shields et al. 2015).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF90FF8E4DCEF8D6FBA39C55.taxon	diagnosis	Diagnosis. Female: Body elongate; all segments distinct. Frontal lamina weakly developed, smooth. Barbula with single pair of smooth lateral projections; median region with series of low lobes. Maxilliped usually with dual palp, both lobes setose on distal margins. First oostegites with tapered posterolateral point; internal ridge with few low projections. Coxal plates moderately developed on pereomeres 1 – 4 on at least one side; tergal projections not present; lateral margins of pereomeres 1 – 4 rounded, 5 – 6 tapered or rounded and resembling pleomeres. Pereopods with short carpi, smooth outer surface of meri, and relatively smooth dorsal surface of bases. Six pleomeres, first five produced into moderately to greatly developed lateral plates, directed posterolaterally; five pairs of biramous, lanceolate pleopods, edges and surfaces smooth; uropods lanceolate, uniramous or biramous, edges and surfaces smooth. Male: Body gradually tapered anteriorly and posteriorly from widest pereomere; all body regions distinct. Anterior pereopods not markedly larger than others. Pleon of six pleomeres, usually all distinct but last two or three fused in some species; pleopods uniramous, tuberculiform; posteriolateral margins of pleotelson slightly to strongly produced into posterolateral lobes; no uropods. Worldwide distribution, infesting hosts in Axiidea and Astacidea (Nephropidea).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF90FF8E4DCEF8D6FBA39C55.taxon	discussion	Remarks. 82 species and subspecies have been described in Pseudione, but after varied synonymizing and transfer to other genera, 53 currently remain in the genus (Boyko et al. 2011). These 53 taxa are, however, a morphologically heterogeneous assemblage, with essentially only one unifying feature: the number of pairs of pleopods. Females of all Pseudione species have 5 pairs of biramous pleopods and males have 5 pairs of ovate uniramous pleopods. Clearly, other morphological characters need to be examined to sort these taxa into monophyletic groupings. A significant impediment to clear delineation of this genus has always been the question of identifying the characters of the type species, Pseudione callianassae Kossmann, 1881, due to the poor quality of the original description. In the present work, we provide evidence that P. dohrni Bonnier, 1900, is identical to P. callianassae (see Remarks under P. callianassae, below), thereby providing a suite of characters that can be used to define the genus, restrict it to a group of similar taxa, and identify those species of “ Pseudione ” that belong in other existing genera or for which new genera should be established. The characters given above in the diagnosis restrict the concept of Pseudione to 8 species: P. callianassae Kossmann, 1881 (type species, = P. dohrni Bonnier, 1900), P. atlantica Bourdon, 1971, P. borealis Caspers, 1939, P. hanseni Nierstrasz & Brender à Brandis, 1923, P. longicauda Shiino, 1937, P. murawaiensis Page, 1985, P. nephropsi Shiino, 1951 and P. tanimbarensis Markham, 1999. Of these, five (P. callianassae, P. borealis, P. hanseni, P. longicauda, and P. murawaiensis) parasitize hosts in Axiidea whereas three (P. atlantica, P. nephropsi, and P. tanimbarensis) parasitize hosts in Astacidea. Among the other 45 species previously considered to belong to Pseudione, none are known from astacidean hosts, whereas only three are known from axiidean hosts. Because the focus of this paper is on parasites of axiidean and gebiidean hosts, we do not deal with the 41 “ Pseudione ” species that are found on anomuran or caridean hosts. They will be arranged in natural groups as relevant material becomes available for revisionary work; we hope this will include molecular studies to test the monophyly of the groups and that Pseudione sensu lato can act as a testing ground for host / parasite co-evolutionary hypotheses. We have analyzed the sole species of Pseudione purportedly described from a brachyuran host, P. panopei Pearse, 1947, because it is a synonym of a species in a genus whose other species are known from gebiidean hosts (see Remarks under Progebiophilus upogebiae). The three species that are found on axiidean hosts but do not share characters with Pseudione sensu stricto are also analyzed and transferred to other genera herein. Two of these species (P. brattstroemi Stuardo, Vega & Cespedes, 1986, and P. overstreeti Adkison & Heard, 1995) are placed in a new genus (see Remarks for Robinione n. gen.), whereas the third (P. compressa Shiino, 1964) appears to be a species of Ionella Bonnier, 1900 (see Remarks for Ionella compressa, n. comb.).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF91FF824DCEF9C7FDEE9AAA.taxon	description	Palaegyge callianassae — Giard & Bonnier, 1890 b: 374 (mention), 384 – 385 (list), 388 (mention).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF91FF824DCEF9C7FDEE9AAA.taxon	description	Pseudojone [sic] dohrni — Restivo, 1968: 505 (occurrence at Naples on C. truncata). Pseudione dorhni [sic] — Bourdon, 1968: 150, 172, 410 (new synonymy).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF91FF824DCEF9C7FDEE9AAA.taxon	materials_examined	Material examined. None; we attempted to borrow the “ paratypes ” (actually syntypes) of P. dohrni that were cited by Bourdon (1968) from MNHN but they could not be located in the collections.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF91FF824DCEF9C7FDEE9AAA.taxon	distribution	Distribution. Gulf of Naples, Italy.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF91FF824DCEF9C7FDEE9AAA.taxon	biology_ecology	Host. Callianassa truncata (Giard & Bonnier, 1890) (type host).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF91FF824DCEF9C7FDEE9AAA.taxon	description	Redescription (translated and modified from Bourdon, 1968). Female (Fig. 8 A – E), body length 3.5 mm, maximal width 1.9 mm, head length 0.63 mm, head width 0.72 mm. No body pigmentation. Pereon weakly sinistral (8 °) with coxal plates and pereomeres of left side slightly larger on segments 1 – 4 (Fig. 8 A). Head wider than long, with thin frontal lamina (Fig. 8 A), moderately embedded medially in first pereomere; eyes lacking. Antennules of three articles each, antennae of four articles each, basal articles enlarged, especially of antennae. Barbula with 1 pair of lanceolate lateral projections, medial margin with series of rounded tubercles, outermost pair slightly larger (Fig. 8 B). Maxilliped with rounded distal end and subacute spur; palp present as two setose, laterally rounded, finger-like projections (Fig. 8 C). First oostegite anterior lobe rounded, inner ridge with 6 small rounded finger-like projections on proximal half, distal lobe subtriangular, tip with tuft of setae (Fig. 8 D); fifth oostegite with fringe of setae on posterior margin. Pereon composed of 7 pereomeres, first 4 laterally straight, last 3 wider and posterolaterally tapered to points, broadest across pereomere 6, gradually tapering anteriorly and posteriorly; pereomere 1 with convex posterior margin. Posterior margins of pereomeres 2 – 4 with straight to slightly concave posterior margins (Fig. 8 A). Pereomeres 1 – 4 weakly bilobed laterally, with rounded coxal plates, no dorsolateral bosses. Pereomeres 5 – 7 weakly bilobed on posterior margin approximately 12 % of length in from distal edge, pereomeres 5 – 7 similar in morphology to lateral plates of pleon, posterior indentation located more mesially in posterior pereomeres and pleomeres. First pair of pereopods at anterolateral margin of head; pereopods evenly spaced. Pereopods increasing in size posteriorly, each with strong dorsal lobe on ischium. Pleon with 5 distinct pleomeres plus pleotelson (Fig. 8 A, E), pleomeres resembling posterior four pereomeres, posterolaterally tapered. Pleomeres with foliaceous, biramous pleopods, not extending beyond lateral plates and not visible in dorsal view, endopod and exopod both with tuberculate, thickened margins, tapered distally, posterior pairs decreasing in size (Fig. 8 E). Uniramous lateral plates, overlapping and posterolaterally tapered (Fig. 8 A); lateral plates slightly smaller posteriorly and more concave on posterior margins. Pleotelson (Fig. 8 A) rounded with pair of biramous uropods, endopod longer than exopod, exopod resembling lateral plates of pleomeres (Fig. 8 A, E). Male (Fig. 8 F, G), length 1.5 mm, maximal width 0.59 mm, head length 0.19 mm, head width 0.49 mm, pleon length 0.38 mm. Head suboval, widest medially, distinct from first segment of pereon (Fig. 8 F). Eyes absent. Antennules of three articles each, antennae of four or five articles each (Fig. 8 G). Small maxillipeds present, few setae on distal end (Fig. 8 G). Pereomeres 3 broadest, tapering slightly anteriorly and posteriorly (Fig. 8 F). All pereomeres directed laterally, distolateral margins rounded. Pereopods not described. Pleon with five segments plus pleotelson; segments tapering posteriorly, pleomeres directed posterolaterally (Fig. 8 F). First 5 pleomeres distinctly segmented, pleotelson partly fused with fifth pleomere. First pleomere narrower than pereomeres, gradually becoming narrower posteriorly, rounded distolateral margins. Five pairs of low rounded pleopods; no midventral tubercules. Pleotelson distal margins of lobes with setae; uropods absent.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF91FF824DCEF9C7FDEE9AAA.taxon	discussion	Remarks. Kossmann’s (1881 a) description of the type species of Pseudione, based on material collected from Naples on Callianassa subterranea (Montagu, 1808), is not only extremely brief but was entirely based on characters of the male and only the ventral surface of a male’s head was figured. Markham (2001) concluded that this rendered the name a nomen nudum, but we consider the figure of the male’s head as sufficient to make the name available (IZCN Article 12.2.7). No subsequent authors have reported a valid P. callianassae, although some have indicated that they collected the species (e. g., Tattersall 1931; Holme 1961), but, as shown below, these are misidentificatons of P. borealis Caspers, 1939. Caroli (1940) thought that the host of P. callianassae might be C. truncata Giard & Bonnier, 1890 because he could not find bopyrids on any C. subterranea collected from the Mediterranean. Bourdon (1968) suggested that P. callianassae might be identical to either P. dohrni Bonnier, 1900 or P. borealis, but refrained from synonymizing either species with the type species. Bourdon later (1981 b) suggested that P. callianassae might be identical with either P. dohrni or P. reverberii Restivo, 1970 and that the host might not actually be C. subterranea but rather C. truncata, because that species was often found to bear both of these parasites, whereas C. subterranea in the Mediterranean has never been found parasitized by any bopyrid. In the same paper, Bourdon (1981 b) transferred P. reverberii to the new genus Acrobelione (type species: Pleurocrypta langi Van Name, 1920) because females of the two species were quite similar in many characters and the males of both species lacked maxillipeds. Although Restivo (1970) described the male of P. reverberii as having maxillipeds, Bourdon (1981 b) showed that this was an error. Kossmann’s (1881 a) illustration clearly shows that males of P. callianassae possess maxillipeds. With the elimination of P. reverberii as a possible synonym of P. callianassae, it is unclear why Bourdon (1981 b) did not follow through and make P. dohrni a synonym of P. callianassae but it may be because he was unsure of the identity of the host for P. callianassae. Part of the problem in determining the identity of the host of P. callianassae is that, for many years, the Mediterranean species of Callianassa were often lumped together under C. subterranea. Abed-Navandi & Dworschak (1997) noted that most early records of C. subterranea from the Mediterranean were probably misidentified C. truncata. In fact, there are three species of Callianassa occurring in the Mediterranean (fide Ngoc- Ho 2003): C. acanthura Caroli, 1946, C. subterranea, and C. truncata. Callianassa subterranea is found in deeper waters in the Mediterranean (35 – 500 m) than is typical in the rest of its range (Ngoc-Ho 2003). It is likely that Kossmann’s (1881 a) material came from a much shallower collection. Callianassa acanthura and C. truncata have also been at times placed in Necallianssa Heard & Manning, 1998, but we follow Ngoc-Ho (2003) here in retaining them in Callianassa Leach, 1814 senu stricto, as her paper is the last to have dealt with their generic placement. Note that Giard & Bonnier (1890 a) described C. truncata by comparing it with material they identified as C. subterranea. However, Ngoc-Ho (2003) showed that this comparative material was actually Pestarella candida (Olivi, 1792), a species from which no bopyrids have been reported. No bopyrids have been recorded from C. acanthura either, whereas C. truncata is known to bear three species of these parasites: P. dohrni, Acrobelione reverberii, and Ione vicina (= I. thoracica; see above). Callianassa subterranea has been reported to host three species as well: Ione thoracia, P. borealis and P. callianassae, but only the latter has been reported from this host in the Mediterranean, and only by Kossmann (1881 a). Pseudione dohrni, P. borealis, A. reverberii, and I. thoracia are well described species that have been found on their reported hosts numerous times. Ione vicina is purportedly separated from I. thoracica by a single character (endopod of the first pleopod) that does not hold up to scrutiny and, therefore, as shown elsewhere in the present paper (see Remarks under I. thoracica), they are synonyms (see also Bourdon, 1968).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF9DFF824DCEFED7FC469F29.taxon	materials_examined	Material examined. Japan: Ovigerous female (10.5 mm, right 1 / 3 of body sacrificed for molecular work), mature male (2.8 mm), ex left branchial chamber of Nihonotrypaea japonica (7 mm CL, lacking gonopores), Stn 4, 32 ° 47 ' N 130 ° 36 ' E, Shirakawa River, Kumamoto, coll. A. Tamaki, 5 Apr 2004 (ULLZ 5471); ovigerous female (8.5 mm, left ½ sacrificed for molecular work), mature male (2.7 mm), ex right branchial chamber of Nihonotrypaea cf. petalura (10.6 mm CL, lacking gonopores), Sample # 14, Ariakemachi, coll. A. Tamaki (ULLZ 11653).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF9DFF824DCEFED7FC469F29.taxon	distribution	Distribution. Japan; Hong Kong; Shandong, Fujian, and Hainan Provinces, China.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF9DFF824DCEFED7FC469F29.taxon	biology_ecology	Hosts. Nihonotrypaea harmondi (Bouvier, 1901, N. japonica (Ortmann, 1891) (type species), N. petalura (Stimpson, 1860), and Paratrypaea bouvieri (Nobili, 1904).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF9DFF824DCEFED7FC469F29.taxon	discussion	Remarks. This species belongs to Pseudione sensu stricto (as defined by the resolution of the identity of the type species herein). An et al. (2009) included Saito & Kinoshita (2004: 1 – 7, figs. 3, 4) in their synonymy list for P. longicauda; however, Saito & Kinoshita (2004) correctly identified their material as Ione cornuta Bate, 1864. Both of the females discussed herein were used to generate 18 S rDNA data for the phylogenetic analysis of Boyko et al. (2013) but were erroneously reported in the Supplemental File as being from the same lot. The specimens studied by Wardiatno (2004) were never named or figured; they are likely either this species or I. cornuta, as these are the only species known from Nihonotrypaea japonica.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF9DFF854DCEFA5CFD6D9F50.taxon	diagnosis	Diagnosis. Female: Body ovate; all segments distinct. Frontal lamina weakly to moderately developed, smooth. Barbula with pair of lateral projections, either smooth or tuberculate; median region smooth or with series of low lobes. Maxilliped usually with setose palp (Fig. 9 A). First oostegites with tapered posterolateral point; internal ridge with numerous fimbriate projections. Coxal plates moderately developed on pereomeres 1 – 4 on both sides, margins crenulate; tergal projections present; lateral margins of pereomeres 1 – 4 crenulate, blunt, 5 – 6 not distinctly different from 1 – 4 (Fig. 9 A). Pereopods with elongate carpi, bases with large irregular, infolded mass on dorsal surface (Fig. 9 C, D). Six pleomeres, first five produced into moderately to greatly developed lateral plates with crenulate edges, directed posterolaterally; five pairs of biramous pleopods, lanceolate, edges crenulate, external surfaces strongly tuberculate; uropods lanceolate, uniramous, margins crenulate and external surface tuberculate. Male: Body gradually tapered anteriorly and posteriorly from widest pereomere (Fig. 10 A); all body regions distinct. Anterior pereopods not markedly larger than others (Fig. 10 A – C). Pleon of six pleomeres, usually distinct but last two fused in one species; pleomeres either similar in shape to pereomeres or becoming progressively thinner and with tapered, posteriorly directed, lateral margins (Fig. 10 D); pleopods uniramous, low, tuberculiform (Fig. 10 D); posteriolateral margins of pleotelson slightly to strongly produced into posterolateral lobes; resembling uropods of the female in the type species (Fig. 10 A, D); true uropods lacking. Currently known only from the Americas (east coast of North America, Gulf of Mexico and west coast of South America), infesting hosts in Axiidea.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF9DFF854DCEFA5CFD6D9F50.taxon	materials_examined	Type species. Pseudione overstreeti Adkison & Heard, 1995. Other included species. Pseudione brattstroemi Stuardo, Vega & Céspedes, 1986.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF9DFF854DCEFA5CFD6D9F50.taxon	etymology	Etymology. The genus is named in honor of Dr. Robin Overstreet for his many contributions to the field of parasitology. Because the type species epithet was based on Dr. Overstreet’s surname, we felt it appropriate to form the generic name based on his given name (combined with the bopyrid genus name Ione). The gender is feminine.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF9DFF854DCEFA5CFD6D9F50.taxon	discussion	Remarks. Robinione n. gen. can be distinguished from Pseudione sensu stricto by the following character states of the females (those of Pseudione in parentheses): 1) body outline ovate (elongate), 2) coxal plates with crenulated and tuberculate margins (margins smooth), 3) first oostegite with numerous filamentous projections along nearly all of inner ridge (inner ridge smooth or with only a few small rounded projections in proximal region), 4) bases of pereopods with large dorsal, irregular, infolded mass, larger and more complex sculpture in posterior pereopods (pereopods without dorsal mass), and 5) lateral plates and distolateral margins of pereomeres greatly expanded, lateral plates as broad as associated pleomeres (lateral plates and pereomeres not so expanded, lateral plates narrower than their respective pleomeres). The females of R. overstreeti n. comb. and R. brattstroemi n. comb. are nearly identical. Based on the specimens examined herein and the descriptions of Stuardo et al. (1986 a, b), the only obvious difference between the females is that the barbula of R. brattstroemi n. comb. has lateral lobes with crenulate margins (barbular lobes of R. overstreeti n. comb. are smooth). The males of the two species, however, are remarkably different. The males of R. brattstroemi n. comb. have few taxonomically important features at the species level, although Stuardo et al. (1986 b) used SEM and found setae and other morphological characters that were useful for distinguishing this species from those in other genera. The male of R. overstreeti n. comb. is distinct in having the lateral margins of pleomeres 2 – 5, as well as those of the pleotelson becoming tapered and extended posteriorly. This is reminiscent of the condition of males in Ione; however, in Ione, which belongs to a different bopyroid family than Robinione n. gen., the males have all the segments of the pleon fused (separate in R. overstreeti n. comb.) and all the pleon segments are modified (only 2 – 5 modified in R. overstreeti n. comb.). This pleonal condition was found in all males of R. overstreeti n. comb. examined in this study. The males of R. overstreeti n. comb. have rounded medial lobes on the pleomeres (Fig. 10 A, D), which may represent reduced pleopods. Finally, Stuardo et al. (1986 b; Fig. 13) documented cephalic slits on the males of R. brattstroemi n. comb. and these were also found in the males of R. overstreeti n. comb. examined in the present study.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF9AFF864DCEFAC4FACC9BA8.taxon	description	Pseudioniinae [sic] sp. A. Rakocinski et al., 1993: 102 (list).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF9AFF864DCEFAC4FACC9BA8.taxon	materials_examined	Material examined. United States: Immature female (5.5 mm), ex right branchial chamber of female Callichirus islagrande (10.9 mm CL), Gulf Beach, Isle Dernière, Louisiana, coll. R. B. Griffis & T. Zimmerman, 27 Jul 1993 (ULLZ 10206); immature female (5.5 mm, on SEM stub, USNM 1459847 ex ULLZ 10205), mature male (3.0 mm), ex right branchial chamber of female C. islagrande (8.0 mm CL), mid-intertidal pool and low intertidal, bay side, Isle Dernièrs, Louisiana, coll. R. B. Griffis, D. L. Felder & T. McTigue, 19 Oct 1993 (ULLZ 10205); ovigerous female (11.0 mm), mature male (4.0 mm), ex left branchial chamber of female C. islagrande (11.4 mm CL), Gulf side, Isle Dernièrs, Louisiana, coll. D. L. Felder, P. Klerks & D. Griffis, 22 Jan 1995 (ULLZ 10207); immature female (11.0 mm), mature male (4.0 mm), ex left branchial chamber of female C. islagrande (10.8 mm CL), Gulf side of beach, Isla Dernièrs, Louisiana, coll. R. B. Griffis & T. Zimmerman, 27 Jul 1993 (ULLZ 10199); female (11.0 mm), ex left branchial chamber female C. islagrande (10.1 mm CL), Gulf side of beach, Isle Dernièrs, Louisiana, coll. R. B. Griffis, D. L. Felder & T. McTigue, 19 Oct 1993 (ULLZ 10209); immature female (3.0 mm), ex left branchial chamber of immature C. islagrande (5.0 mm CL), immature female (3.7 mm), mature male (2.3 mm, on SEM stub, USNM 1459848 ex ULLZ 10198), ex left branchial chamber of immature C. islagrande (5.0 mm CL), immature female (3.5 mm), mature male (2.0 mm), ex right branchial chamber of female C. islagrande (6.5 mm CL), immature female (3.5 mm), mature male (2.2 mm, on SEM stub, USNM 145 9848 ex ULLZ 10198), ex right branchial chamber of female C. islagrande (5.0 mm CL), access road # 3, near Fish Pass, low tide, morning, Mustang Island, Texas, coll. D. L. Felder & L. Bilodeau, 1 Mar 2000 (ULLZ 10198); ovigerous female (12.0 mm), mature male (4.5 mm), ex C. islagrande (host not in vial with parasites), Gulf side, Isle Dernièrs, Louisiana, coll. D. L. Felder & R. B. Griffis, 24 Jul 1992 (ULLZ 10210); ovigerous female (11.0 mm), mature male (4.5 mm), ex left branchial chamber of female C. santarosaensis Sakai and Türkay, 2012 (11.4 mm CL), bay side, Isle Dernièrs, Louisiana, coll. A. Christian, D. Badgwill, R. B. Griffis & I. A. Griffis, 22 Jan 1993 (ULLZ 10204).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF9AFF864DCEFAC4FACC9BA8.taxon	distribution	Distribution. Gulf of Mexico from west coast of Florida to Texas, U. S. A., and Tabasco, Mexico.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF9AFF864DCEFAC4FACC9BA8.taxon	biology_ecology	Hosts. Callichirus islagrande (Schmitt, 1935) (type species) and C. santarosaensis Sakai & Türkay, 2012.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF9AFF864DCEFAC4FACC9BA8.taxon	discussion	Remarks. The present material of R. overstreeti n. comb. (Figs. 9, 10) matches that of Adkison & Heard (1995), who provided a detailed description of the species. Although they did not show the ventral view of the male, Adkison & Heard (1995) indicated that the pleopods were “ vestigial or absent, represented by low mounds mesal to lateral processes of pleomeres ” as we found in our samples (Fig. 10 D). The male pleomeres documented in Adkison & Heard (1995; Fig. 2 A) are slightly more elongate and acute than in the present specimens, but this variation is typical for pleopodal morphology in bopyrids. Each male pereopod of R. overstreeti n. comb. has a recurved dactylus, the distal end of which touches the base of the propodus and is surrounded by a low ridge of tooth-like projections (Fig. 10 B, C). The female R. overstreeti n. comb. examined with SEM (Fig. 9) is not fully mature, thus has reduced oostegites and, proportionally, somewhat longer and thinner pleopods and uropods than the holotype (Adkison & Heard, 1995; Fig. 1 B). Female and male antennae (Figs. 9 B, 10 B) have the same numbers of articles as in the original description (3 and 4 for females; 3 and 5 for males). Female R. overstreeti n. comb. have pereopods with elongate carpi and a large irregular, infolded mass on the dorsal surface of each of the bases (Fig. 9 C, D), all pereopodal segments covered with scales (Fig. 9 C – F). Felder & Dworschak (2015) discussed in detail the nomenclatural issues surrounding the name C. santarosaensis, which is now used for Gulf of Mexico populations of the Callichirus species formerly called C. major (Say, 1818), but which is distinct from that Atlantic coastal species. This is the first record of “ Pseudione ” overstreeti from C. santarosaensis (either under that name or as C. major). Adkison & Heard (1995) examined several hundred C. santarosaensis (as C. major) and found no bopyrids on them; it is not clear where their specimens were collected from, but based on the material examined list for P. overstreeti, they probably came from Alabama or Mississippi.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF99FFB84DCEFC8AFB279BD5.taxon	materials_examined	Material examined. United States: 2 worms (7.4, 8.2 mm), ex gill tissue of ovigerous female Lepidophthalmus louisianensis (13.0 mm CL), Grande Terre, Lousiana, coll. unknown, 25 May 1988 (ULLZ 3531); 8 worms (3 extracted: 7.5, 9.7, 11.5 mm; one specimen on SEM stub, USNM 1459849 ex ULLZ 10208), ex ventral thorax and base of third pereopods of female L. louisianensis (8.8 mm CL), inshore, Bay St. Louis, Mississippi, coll. unknown, 18 Jul 1990 (ULLZ 10208); 1 worm (not extracted), ex gill tissue of female L. louisianensis (8.9 mm CL), outer beach, Bay St. Louis, Mississippi, coll. R. Griffis & D. L. Felder, 26 Jan 1991 (ULLZ 10203).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF99FFB84DCEFC8AFB279BD5.taxon	distribution	Distribution. Mississippi and Louisiana, U. S. A.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF99FFB84DCEFC8AFB279BD5.taxon	biology_ecology	Host. Lepidophthalmus louisianensis (Schmitt, 1935).	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
03F54574FF99FFB84DCEFC8AFB279BD5.taxon	discussion	Remarks. Three specimens of Lepidophthalmus louisianensis (Schmitt, 1935) were parasitized by juvenile non-encysted nematodes (Fig. 11). One of the parasitized hosts (ULLZ 3531) was an ovigerous female and contained two worms extending into the gills and thorax. The other two hosts were non-ovigerous females and contained one worm (ULLZ 10203) in the gill tissue and eight worms (ULLZ 10208) in the ventral thorax and bases of third legs. The extracted nematodes ranged in length from 7.4 to 11.5 mm (8.9 ± 1.7, n = 5). Based on the morphology of the nematodes, particularly the structure of the mouth (Fig. 11 B, C), they are members of Physalopteridae, most closely matching the genus Heliconema Travassos, 1919. The oral aperture of each of our specimens has two pseudolabia; each pseudolabium has a pair of cephalic papillae, a large median conical tooth and ridged teeth (Fig. 11 B) while the amphids are indistinct. These characters are similar to those of H. brooksi Crites & Overstreet, 1991, which was described from the shrimp eel, Ophichthus gomesii (Castelnau, 1855), collected in Mississippi Sound, Gulf of Mexico. Crites & Overstreet (1991) also found a juvenile nematode in a shrimp, Penaeus setiferus (Linnaeus, 1767), and suggested that the juvenile specimen may also be H. brooksi but noted that additional research was required for verification. In addition to H. brooksi, an undescribed species of Heliconema from the sharptail eel, Myrichthys acuminatus (Gronow, 1854), also exists in the Gulf of Mexico (Moravec, pers. comm.). Larvae of other Heliconema species are known from crustacean intermediate hosts. Those of Heliconema anguillae Yamaguti, 1935, are known to occur in the brachyurans Hemigrapsus sp. and Perisesarma bidens (De Haan, 1835) in Japan (Katahira & Nagasawa 2015) and it is possible that the “ Ascarophis ” third-stage larvae described by Moravec et al. (2003) from the brachyuran Macrophthalmus hirtipes (Heller, 1865) (= Hemiplax hirtipes (Jacquinot, in Hombron & Jacquinot, 1846 )) in New Zealand were also larvae of a species of Heliconema (Moravec, pers. comm.). Species of nematodes from other families also use callianassids as intermediate hosts and are trophically transmitted to elasmobranchs or bony fish as definitive hosts (Poinar & Thomas, 1976). For example, two unidentified species of Ascarophis van Beneden, 1871, were found in Neotrypaea californiensis (Dana, 1854) from California (Poinar & Thomas 1976). There are no reports on the specific diet of the shrimp eel, O. gomesii, but it is likely an opportunistic feeder, based on the stomach contents of congeners (Casadevall et al. 1994) and has been reported to feed “ heavily on shrimps ” (Crites & Overstreet 1991); L. louisianensis is therefore a potential prey item. Based on stomach content analyses, potential definitive hosts in the Gulf of Mexico for this species of Heliconema are bottom feeding fish predators of L. louisianensis, including croaker (Menticirrhus sp., Sciaenidae) and unspecified catfish (Felder & Rodrigues 1993). Stingrays are also possible predators of L. louisianensis based on observations of their feeding habits (Felder & Rodrigues 1993). Anguilliform fish host the highest diversity of Heliconema species but nematodes in this genus are also known from four other actinopterigian orders, as well as two orders of elasmobranchs (see Akram 1996; Li et al. 2013). Although two species of Heliconema have been reported from snakes, Moravec et al., (2007) summarized the persistent doubts as to the identity of the type hosts for H. longissimum (Ortlepp, 1923). The host of this nematode was originally identified as “ snakes ” (in quotation marks as originally given by Ortlepp, 1923) but this species has subsequently been reported several times from eel hosts. Interestingly, only one species of Heliconema was ever described from adult worms extracted from a host verified as a snake: H. serpens Fusco & Palmieri, 1980, described from Cerberus rynchops (Schneider, 1799) and found in only a single host individual (Fusco & Palmieri 1980). Because these snakes are well-known consumers of eels (Gorman et al. 1981) it is possible that the snake picked up the nematodes through parasitized prey and thus served as a postcyclic host (sensu Odening 1976) for H. serpens; the snake was not a paratenic host because the worms were mature. If true, this would be analogous to the situation reported by Goldberg et al. (2002) who found mature lizard-parasitizing nematodes in the lumen of the digestive tract of snakes who preyed on parasitized lizards. Indeed, Goldberg et al. (2002) cautioned that any finding of adult nematodes in a snake must consider the possibility that the nematodes entered via the snake’s prey, their definitive host, and not because the snake ingested an intermediate host of the parasite.	en	Boyko, Christopher B., Williams, Jason D., Shields, Jeffrey D. (2017): Parasites (Isopoda: Epicaridea and Nematoda) from ghost and mud shrimp (Decapoda: Axiidea and Gebiidea) with descriptions of a new genus and a new species of bopyrid isopod and clarification of Pseudione Kossmann, 1881. Zootaxa 4365 (3): 251-301, DOI: 10.11646/zootaxa.4365.3.1
