Asymmetrione asymmetrica ( Shiino, 1933 )

Williams, Jason D., Boyko, Christopher B. & Madad, Asma Z., 2019, Branchial parasitic isopods (Crustacea: Isopoda: Bopyridae: Pseudioninae) of hermit crabs (Crustacea: Decapoda: Diogenidae) from the western Pacific, with descriptions of a new genus and three new species, Raffles Bulletin of Zoology 67, pp. 83-118 : 86-88

Asymmetrione asymmetrica ( Shiino, 1933)

( Fig. 1A, B, E )

Pseudione asymmetrica Shiino, 1933: 249 , 273–277, figs. 9, 10 [Tanabe Bay, Japan; infesting Clibanarius bimaculatus (De Haan, 1849) Shiino, 1952: 38 , 41 [mention]; Shiino, 1958: 30 [Shirahama, Japan; infesting C. bimaculatus ]; Danforth, 1963: 11 [list]; Codreanu et al., 1965: 225, 227, 234, 242, 243 [designated as type of Asymmetrione ; implied as nominotypical subspecies]; Shiino, 1972: 7 [list]; Markham, 1978: 103 [mention]; Markham, 1985a: 107 [mention]; Harada, 1991: 201 [type specimen data]; An et al., 2010: 2068 [mention].

Asymmetrione asymmetrica — Codreanu, 1967: 209 [mention]; Markham, 1975: 264, 265 [list]; Bourdon, 1976: 366 [mention]; Markham, 1985b: 3–5, fig. 1 [ Thailand, infesting Clibanarius merguiensis de Man, 1888 ]; Haig & Ball, 1988: 163 [ Indonesia; infesting Clibanarius englaucus Ball & Haig, 1972 ]; Trilles & Hipeau-Jacquotte, 1996: 119 [mention]; Kazmi & Markham, 1999: 879 [mention]; Trilles, 1999: 326 [mention]; Saito et al., 2000: 36 [list]; Kensley, 2001: 222 [list]; Markham, 2003: 72 [list]; Saito & Kinoshita, 2004: 4, 6 [list]; Williams & Schuerlein, 2005: 101 [mention]; Madad, 2008: 2, 6, 15, 16, 19, 25, 26, 46, 47, 49, 51 [ Philippines, infesting “ Calcinus gaimardii (H. Milne Edwards, 1848) ” (misidentification of Clibanarius cf. virescens [Krauss, 1843], see below), Calcinus minutus Buitendijk, 1937 ; Japan, infesting C. bimaculatus ]; An et al., 2010: 2069 [list]; McDermott et al., 2010: 8 [list]; Trilles & Hipeau-Jacquotte, 2012: 258, 301 [mention, list]; Tudge et al., 2012: 289, fig. 70.31 [ Japan; infesting C. virescens ].

Asymmetrione asymmetrica asymmetrica — Bourdon, 1968: 313 [table of characters], 314.

Material examined. Japan: 1 dextral ovigerous ♀ (3.2 mm), 1 mature ♂ (1.2 mm) (NSMT-Cr 14402) from right branchial chamber of Clibanarius bimaculatus (De Haan, 1849) (host not in jar), Seto, Shirihama , Japan; Philippines: 1 dextral ovigerous ♀ (4.6 mm), 1 ♂ (2.2 mm) ( USNM 1493912 ) from right branchial chamber of ♀ Clibanarius cf. virescens (2.7 mm SL), Batangas, Sombrero Island , coll. JDW, 30 January 1999; 1 dextral ovigerous ♀ (4.5 mm), 1 ♂ (1.8 mm) (pers. coll.) from right branchial chamber of ♂ Calcinus minutus (3.4 mm SL), also with two externae of Dipterosaccus sp. (Rhizocephala) , Batangas, Anilao, coll. JDW, 13 February 1999; 1 dextral ovigerous ♀ (5.2 mm), 1 ♂ (3.4 mm) ( USNM 1493913 ) from right branchial chamber of ♀ C. cf. virescens (2.8 mm SL), Puerto Galera, Small Lalaguna Beach, coll. JDW, 17 June 2000; 1 dextral ♀ (5.5 mm), 1 ♂ (2.2 mm) ( USNM 1493914 ) from right branchial chamber of ♀ C. cf. virescens (3.2 mm SL), Puerto Galera, Small Lalaguna Beach, coll. JDW, 17 June 2000 .

Type locality. Tanabe Bay , Seto, Japan ( Shiino, 1933) .

Distribution. Tanabe Bay, Seto, Shirihama, Japan ( Shiino, 1933); Thailand ( Markham, 1985b); Irian Jaya, Indonesia ( Haig & Ball, 1988); Batangas, Puerto Galera, Philippines ( Madad, 2008, herein).

Hosts. Diogenidae : Calcinus minutus Buitendijk, 1937 , Clibanarius bimaculatus (De Haan, 1849) , C. englaucus Ball & Haig, 1972 , C. merguiensis de Man, 1888 , C. virescens (Krauss, 1843) , C. cf. virescens and Dardanus lagopodes (Forskål, 1775) .

Size range (length). Females to 5.5 mm, males to 3.4 mm. Mean length of adult female specimens was 4.6 ± 0.9 mm (n=5) and mean length of male specimens was 2.2 ± 0.8 (n=5).

Remarks. The Japanese specimens examined here are the ones reported by Shiino (1958).

The Philippine females (e.g., Fig. 1A ) most closely match Markham’s (1985b) specimens of A. asymmetrica from Thailand. One specimen (USNM 1493914) exhibited more pronounced tergal projections than others, but is generally consistent with Shiino’s (1933) description of A. asymmetrica as well. The males (e.g., Fig. 1B ) are as described and illustrated by Shiino (1933); however, their pleons are more elongate than that of the one illustrated by Markham (1985b).

Prior to the present study, there were 11 well-described recognised species of Asymmetrione , five of which are found within in the Indo-West Pacific: A. asymmetrica , A. foresti ( Bourdon, 1968) , A. globifera An, Markham & Yu, 2010 , A. nossibensis Bourdon, 1976 , and A. sallyae Williams & Schuerlein, 2005 . A sixth species of Indo-West Pacific Asymmetrione is described below. Kazmi & Khatoon (2016) described an additional species, Asymmetrione imarani Kazmi & Khatoon, 2016 infesting Diogenes violaceus Henderson, 1893 collected from an unspecified locality in Pakistan. Although identifiable as a member of Asymmetrione , the description is incomplete and lacking in male and female diagnostic characters to distinguish it from other species in the genus; thus, we consider this taxon a species inquirenda. A second species mentioned in their text ( Asymmetrione sp. 1 ) remains to be described.

Clibanarius virescens was not previously known as a host of A. asymmetrica prior to the record of Tudge et al. (2012). Some of the specimens examined by Madad (2008) were originally identified as Calcinus gaimardii but have been reidentified herein as C. cf. virescens . Dardanus lagopodes (Forskål, 1775) was not previously reported as a host of A. asymmetrica .

Ecology. Mean prevalence of A. asymmetrica was 0.72 ± 0.32% over the two collections in which the parasite was found (n=309 total hermits examined). A total of four female and male pairs of A. asymmetrica was extracted from C. minutus and C. cf. virescens in the Philippines. One of the C. minutus hosts was also parasitised by a rhizocephalan, identified as Dipterosaccus sp. (fide R. Yoshida, pers. commun) ( Fig. 1E ). Calcinus minutus Buitendijk, 1937 , is also known to be parasitised by Peltogaster latus Van Baal, 1937 , in Indonesia ( Van Baal, 1937; Fransen et al., 1997), although the host was identified in Van Baal (1937) only as “ Calcinus spec ” (repeated as “ Calcinus sp. ” in McDermott et al., 2010). Peltogaster latus occurs on its hosts as a single externa, while species of Dipterosaccus , while sometimes occurring singly may also occur with two or three externae per host ( Van Baal, 1937; Yoshida et al., 2013).

Figures

Fig. 1. Asymmetrione asymmetrica (Shiino, 1933), USNM 1493912 (A, B), JDW pers. coll. (E), and Asymmetrione harmoniae new species, USNM 1493917 (C, D). A, mature female, dorsal view; B, male paired with female shown in A, dorsal view; C, immature female, dorsal view; D, male paired with female shown in C, dorsal view; E, lateral view of Calcinus minutus doubly infested with Asymmetrione asymmetrica and Dipterosaccus sp. (two externae indicated by *). Scale bars = 1 mm (A, B, E); 500 µm (C, D).