Pseudione callianassae Kossmann, 1881

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), pp. 251-301 : 274-277

Pseudione callianassae Kossmann, 1881

Fig. 8

Pseudione callianassae Kossmann, 1881a : pl. 33, fig. 17 (type locality: Naples, Italy; type host: Callianassa subterranea ( Montagu, 1808) (misidentification of Callianassa truncata Giard & Bonnier, 1890a , see Remarks).— Giard & Bonnier, 1887a: 63, 77–78, fig. 16 (list, reproduction of Kossmann’s (1881) figure).— Giard & Bonnier, 1890b: 377 (mention).— Stebbing, 1893: 411 (list).— Calman, 1898: 280 (mention).— Bonnier, 1900: 152 (mention), 168 (list), 222 (list), 248 (mention), 293 (list, discussion of identity), 381 (list).— Bohn, 1901: 330 (list).— Gerstaecker & Ortmann, 1901: 185 (list), 238 (mention), 257 (list).— Lo Bianco, 1909: 603 (mention).— Van Name, 1920: 72 (mention).— Shiino, 1937: 482 (discussion).— Pike, 1953: 225, 229 (list).— Spooner, 1957: 204 (mention).— Danforth, 1963a: 10 (list).— Catalano & Restivo, 1965: 203 (list).—Lemos de Castro, 1965: 11 (mention).— Gruner, 1966: 329 (mention).— Bourdon, 1968: 408 (discussion of identity).— Naylor, 1972: 69 (list), 75 (mention).— Bourdon, 1976: 167 (mention).— Bourdon, 1981b: 120 – 121 (discussion of identity).— Isaac et al., 1990: 402, 404 (list).— Hayward et al., 1995: 358, 360 (list).— Astall et al., 1996: 823 (mention).— Hansson, 1998: 64 (list in possible synonymy with P. dohrni and P. caspersi Gruner, 1966 ).— Trilles,1999: 335 (mention).— Markham, 2001: 196 (mention), 198 (list), 200 (list).—van der Land, 2001: 322 (list).— Boyko & Williams, 2009: 207 (mention).

Pseudione Callianassae — Carus, 1885: 453 (list).

Palaegyge callianassae — Giard & Bonnier, 1890b: 374 (mention), 384–385 (list), 388 (mention).

Palaegyge Dohrni Giard & Bonnier, 1890b: 374 , 376, 377, 384–385 (nomen nudum).— Giard, 1905: 12 (mention).— Bouvier, 1940: 102 (mention, nomen nudum) (new synonymy).

Palaegyge Dohrnii Giard & Bonnier, 1890b: 376 , 377 (nomen nudum) (new synonymy).

Pseudione Dohrni Stebbing, 1893: 411 (list, nomen nudum) (new synonymy).

Pseudione Dohrni Bonnier, 1900: 48 , 152, 168, 293–295, pl. 21 (type locality = Gulf of Naples, infesting C. truncata ) (new synonymy).

Palaegyge Callianassae — Giard, 1905: 12 (mention).

Pseudione dohrni — Van Name, 1920: 72 (mention).— Caroli, 1931: 320 –321 (mention).— Shiino, 1937: 482 (mention).— Caspers, 1939: 236, 238, 242 (mention).— Shiino, 1951: 32, 36 (mention).— Danforth, 1963a (list).— Catalano & Restivo, 1965: 203 (list).— Shiino, 1964b: 242 (mention).— Bourdon, 1968: 173 (key), 212–215, figs. 73–75, 408 (Naples, infesting C. truncata ).— Restivo, 1970: 305 –306, 10 (key, discussion).— Bourdon, 1981a: 628 (mention).— Bourdon, 1981b: 120 –121 (mention).— Hansson, 1998: 64 (list).—van der Land, 2001: 322 (list) (new synonymy).

Pseudoione [sic] Dohrni — Reverberi, 1943a: 42 (mention).— Reverberi, 1943b: 233, 297–299 (effects on C. truncata ).

Pseudojone [sic] callianassae — Restivo, 1968: 505 (none found at Naples on Callianassa laticauda Otto, 1828 = Pestarella tyrrhena (Petagna, 1792)) .

Pseudojone [sic] dohrni — Restivo, 1968: 505 (occurrence at Naples on C. truncata ).

Pseudione dorhni [sic]— Bourdon, 1968: 150, 172, 410 (new synonymy).

not Pseudione callianassae — Tattersall, 1931: 187 (Mewstone Grounds near Plymouth, England, infesting C. subterranea ).— Pike, 1953: 225, 229 (repeat of Tattersall’s (1931) record; specimen reported as lost).— Holme, 1961: 453 (English Channel, infesting C. subterranea ).— Holme, 1966: 475, 490, fig. 53 (repeat of Holme’s (1961) record); HELCOM, 2012: 140, 187 (Kattegat) (= Pseudione borealis Caspers, 1939 ).

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.

Distribution. Gulf of Naples, Italy.

Host. Callianassa truncata (Giard & Bonnier, 1890) (type host).

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. 8B ).

Maxilliped with rounded distal end and subacute spur; palp present as two setose, laterally rounded, finger-like projections ( Fig. 8C ).

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. 8D ); 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. 8E ). 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. 8F, G ), length 1.5mm, 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. 8F ). Eyes absent. Antennules of three articles each, antennae of four or five articles each ( Fig. 8G ). Small maxillipeds present, few setae on distal end ( Fig. 8G ).

Pereomeres 3 broadest, tapering slightly anteriorly and posteriorly ( Fig. 8F ). All pereomeres directed laterally, distolateral margins rounded. Pereopods not described.

Pleon with five segments plus pleotelson; segments tapering posteriorly, pleomeres directed posterolaterally ( Fig. 8F ). 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.

Remarks. Kossmann’s (1881a) 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 (1981b) 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 (1981b) 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 (1981b) showed that this was an error. Kossmann’s (1881a) 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 (1981b) 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 (1881a) 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 (1890a) 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 (1881a). 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).

Pseudione callianassae has been reported from faunal surveys only twice since Kossmann’s (1881a) original description. Tattersall (1931) reported it from C. subterranea , and this record was repeated by Pike (1953) and Spooner (1957), wherein the specimen was stated to have been lost. The second report was by Holme (1961) who reported it from “ Callianassa ” and this record was repeated in Holme (1966). These records are from northern European waters and it is very likely that they represent misidentified P. borealis , which has been reported from this region on C. subterranea (see Bourdon 1968; 1981a), and which is a species that was not included on any of these faunal lists. Pseudione borealis had been reported under the names P. tuberculata Caspers, 1939 (non P. tuberculata Richardson, 1904 ) and P. caspersi Gruner, 1966 , both of which were synonymized with it by Bourdon (1981a). The record of P. callianassae from HELCOM (2012) is merely a checked box on a faunal list and it is unclear from where that data was obtained.

We concur with the earlier speculations of Caroli (1940) and Bourdon (1981b) that P. callianassae and P. dohrni are the same species because: 1) the only bopyrid known from C. subterranea in the Mediterranean is I. thoracica , whose males have antennae of seven articles and antennae of three articles ( P. callianassae males with five antennal and three antennular articles), 2) I. vicina , herein considered a synonym of I. thoracica and known from C. truncata in the Mediterranean, also has males with seven antennal and three antennular articles and so cannot be identical with P. callianassae , 3) A. reverberii , known from C. truncata in the Mediterranean, has males which lack maxillipeds (present in P. callianassae ), and 4) P. dohrni is found on C. truncata in the vicinity of Naples which is the type locality of P. callianassae , and has males with maxillipeds as well as five antennal and three antennular segments. We therefore formally synonymize P. callianassae and P. dohrni herein, with the result being that Pseudione callianassae is now known to be restricted to the Mediterranean, currently only found in the Gulf of Naples and only on C. truncata .

Figures

FIGURE 8. Pseudione callianassae Kossmann, 1881. A, female, dorsal view; B, barbula; C, maxilliped; D, first oostegite, internal view; E, pleon, ventral view; F, male, dorsal view; G, male, head, ventral view.A–F after Bourdon 1968; G after Giard & Bonnier 1887a.Scale bar: A = 0.5 mm, rest not to scale.