Dactylogyrus hypophthalmichthys Achmerow, 1952

Nitta, Masato & Nagasawa, Kazuya, 2020, Alien Gill Parasites of the Silver Carp Hypophthalmichthys molitrix (Cypriniformes: Cyprinidae) in Tochigi Prefecture, Central Japan, Species Diversity 25 (1), pp. 61-73 : 64-66

Dactylogyrus hypophthalmichthys Achmerow, 1952

[New Japanese name: Hakuren-yubigata-mushi]

( Fig. 4 )

Dactylogyrus hypophthalmichthys Achmerow, 1952: 190 , fig. 3ka; Gussev 1955: 395; Long and Yu 1958: 10–11, fig. 3; Bykhovskaya-Pavlovskaya et al. 1962: 292, 294–295, fig. 683; Akmetov 1963: 462; Lee 1963: 76; Wu 1963: 112; Babayev 1964: 51; Agapova 1966: 134; Akmetov 1966: 258; Osmanov and Yusupov 1967: 212; Musselius 1969: 238, 240; Chentsov and Kirichenko 1970: 119; Osmanov 1971: 106; Kirichenko 1972: 115; Yukhimenko 1972: 154–156; Anonymous 1973a: 139, pl. 78, figs 155–156; Musselius 1973: 19–21, fig. 6a; Volovic 1973: 130–141, figs 1–3; Bauer and Hoffman 1976: 165; Belova 1977: 38–42; Gvozdev and Agapova 1977: 109; Musselius 1977: 146; Anonymous 1978: 41; Chang and Ji 1978: 355; Chen 1981: 115; Zhang 1981: 72; Ji et al. 1982: 13; Molnár 1984: 154; Gussev 1985: 166–168, fig. 241; Margaritov and Van Than 1985: 52–54, fig. 2; Huang 1986: 15; Mhaisen et al. 1988: 893; Salih et al. 1988: 371, 378, 380, fig. 6; Ali et al. 1989: 152–153; Jalali and Molnár 1990: 241; Ma and Li 1991: 3; Wu and Wang 1991: 18, 71–72, fig. 46; Li and Zhang 1992: 91; Zhang et al. 1992: 129; Jin et al. 1993: 327–328, fig. 99; Pojmańska 1995: 81; Gibson et al. 1996: 17; Blanc 1997: 497; Gelnar and Špakulová 1997: 189; Xia and Wang 1998: 19, 20; Hoffman 1999: 126; Long 2000: 92–93, fig. 40; Yao 2000: 25; Moravec 2001: 17; Xu et al. 2001: 715; Grigorovich et al. 2002: 1208; Yao and Nie 2004: 664–665; Johnson and Lunde 2005: 131; Šefrová and Laštůvka 2005: 157; Jalali and Barzegar 2006: 50–51, fig. 9; Molodozhnikova and Zhokhov 2006: 328, 334; Urazbaev and Kurbanova 2006: 537; Ký and Tề 2007: 121, 124, fig. 91; Wu et al. 2007: 653, 655, 657; Karabekova 2008: 331, 333; Zonn et al. 2009: 125; Gussev et al. 2010: 243–244, fig. 296; Singh and Chaudhary 2010: 123–126; Mhaisen et al. 2010: 96, 99–100; Tan et al. 2011: 133–134; Zhang et al. 2011: 30–34; Bozorgnia et al. 2012: 251; Davydov et al. 2012: 141; Mhaisen et al. 2012: 106, 116; Zhang 2012: 123; Pazooki and Masoumian 2012: 575; Fedorovych 2013: 242–244; Mhaisen et al. 2013: 31; Zhatkanbayeva et al. 2013: 149; Zhou et al. 2014: 18, 20, figs 2I, J; Zaichenko 2015: 73, 77; Mhaisen and Al-Rubaie 2016: 5, 7.

Neodactylogyrus hypophthalmichthys: Yamaguti, 1963a: 38 , fig. 659.

Material examined. Eleven specimens fixed in modified picrate glycerin (NSMT-Pl 6394).

Description. Body elongate, 384–554 long including haptor, width at mid-body 73–117 (104, n =5). Pharynx spherical, 14–24 long, 15–24 wide. Male copulatory organ ( Fig. 4L ) sclerotized, consisting of penis and accessory piece, length 32–34. Penis tapered, sigmoid tube, length 31–35. Accessory piece ( Fig. 4L ) rod-shaped, its tip holding middle of penis, length 28–32. Vagina unsclerotized.

Haptor 55–77 long, 88–125 wide. Dorsal anchor ( Fig. 4A ) total length 33–40; length to notch 29–34; outer root length 4–6, inner root length 11–18 (13, n =6), point length 9–11 (10, n =6). Dorsal bar ( Fig. 4B ) broadly V-shaped, total length 24–27, total width 4–9, median width 3–5. Ventral bar ( Fig. 4C ) T-shaped, total length, total width 8–12, median width 5–11. Marginal hooks 7 pairs; hook length: pair I ( Fig. 4D ) 27–31; pair II ( Fig. 4E ) 31–38; pair III ( Fig. 4F ) 28–35; pair IV ( Fig. 4G ) 26–33; pair V ( Fig. 4H ), 30–34, pair VI ( Fig. 4I ) 33–44; pair VII ( Fig. 4J ) 26–43. Pair of needles ( Fig. 4K ) located near second hooks, length 9–11.

Host. Silver carp Hypophthalmichthys molitrix ( Cypriniformes : Cyprinidae )

Site of infection. Gill filaments.

Remarks. This species was originally described by Achmerow (1952) from the gills of H. molitrix in Lake Petropavlovsk, Lakes Bolon and Udyl, Far-East Russia. Subsequently, Yamaguti (1963a) transferred the species to the genus Neodactylogyrus Price, 1938 , but this genus had already been synonymized with Dactylogyrus by Mizelle and Donahue (1944). As a native parasite, D. hypophthalmichthys was reported from the same host in Jiangsu, Anhui, Hubei, Zhejiang, Wuzhou, Chongqing, Liaoning, Jiangxi, Fujian, and Heilongjiang provinces, and Shanghai, China ( Long and Yu 1958; Lee 1963; Wu 1963; Anonymous 1973a; Chang and Ji 1978; Zhang 1981; Huang 1986; Ma and Li 1991; Wu and Wang 1991; Li and Zhang 1992; Xia and Wang 1998; Yao 2000; Wu et al. 2007; Zhou et al. 2014) and the Amur River, Russia ( Gussev 1955; Chentsov and Kirichenko 1970). Yao (2000) reported this monogenean from the gills of the grass carp Ctenopharyngodon idellus (Valenciennes, 1844) (Cyprinidae) in Jiangxi Province, China. The life cycle and development of D. hypophthalmichthys were described by Volovic (1973).

The specimens examined in this study conform to the descriptions and illustrations of D. hypophthalmichthys by Achmerow (1952), Bykhovskaya-Pavlovskaya et al. (1962), Long (2000), and Gussev et al. (2010): the tip of accessory piece holding the middle of the sigmoid penis is one of the features in D. hypophthalmichthys .

The present collection represents the first record of D. hypophthalmichthys from Japan. This monogenean has been reported from H. molitrix in its invading areas: the European region of Russia ( Musselius 1969), Turkmenistan ( Babayev 1964; Osmanov 1971), Hungary ( Molnár 1984), Iraq ( Salih et al. 1988; Ali et al. 1989), Iran ( Jalali and Molnár 1990; Jalali and Barzegar 2006), Czech and Slovak Republics ( Gelnar and Špakulová 1997), Warszawa ( Pojmańska 1995), the Aral Sea ( Urazbaev and Kurbanova 2006), Vietnam (Ký and Tề 2007), Kyrgyzstan ( Karabekova 2008), Kazakhstan ( Zhatkanbayeva et al. 2013), and Ukraine ( Fedorovych 2013; Zaichenko 2015).

Japanese name. In the new Japanese name, “hakuren” means the host, silver carp in Japanese, and “yubigatamushi” means the genus Dactylogyrus .

Figures

Fig. 4. Dactylogyrus hypophthalmichthys Achmerow, 1952. NSMT-Pl 6394. A, dorsal anchors; B, dorsal bar; C, ventral bar; D, marginal hook of pair I; E, marginal hook of pair II; F, marginal hook of pair III; G, marginal hook of pair IV; H, marginal hook of pair V; I, marginal hook of pair VI; J, marginal hook of pair VII; K, needle; L, male copulatory organ. Scale bars: 10µm. Abbreviations: ap, accessory piece; p, penis.