Rhipidocotyle danai Bray & Palm, 2009, n. sp.

Rhipidocotyle danai n. sp. (Figure 1)

Type-host: Thyrsitoides marleyi Fowler (Gempylidae: Perciformes), black snoek Site: intestine.

Type locality: Pelabuhan Ratu, Java, Indonesia (06°59S, 106°32’E, March 2008).

Deposition of specimens: Holotype ZMB Generalkatalog Entozoa, E.7453, paratypes ZMB Generalkatalog Entozoa, E.7454, BMNH 2009.5.22.3, NBC MZBTr 204.

Etymology: The species is named after Dr. Darnas Dana (04.01.1947 – 27.08.2007), former Vice Rector of Planning and Development (1999–2003), Bogor Agricultural University, Indonesia, and Director of Fish Health and Environment, Directorate General of Aquaculture, Ministry of Marine Affairs and Fisheries (2004–2006), who invited the second author to carry out fish parasitological research at IPB.

Description: Based on 10 whole-mount preparations. Measurements and ratios in Table 1. Body elongate, widest at level of anterior post-testicular region, tapering anteriorly (Figure 1). Tegument spinous; spines squamous, tiny, reach to posterior extremity. Rhynchus broader anteriorly, aperture ventral; hood smooth. Mouth just anterior to ovary or at level of anterior part of ovary, inside anterior half of body. Pharynx globular. Caecum irregularly oval, small.

Testes 2, oval, tandem, in anterior part of posterior half of body, contiguous or slightly separated. Cirrussac elongate, more-or-less parallel sided, reaching anterior testis. Seminal vesicle elongate-oval, in proximal cirrus-sac. Pars prostatica long, in 2 distinct parts; proximal part straight narrow; distal part, wider, straight, surrounded by dense layer of gland-cells, lining of filaments in chevron arrangement pointing distally. Ejaculatory duct narrow, opening on large, curved genital lobe, inside genital atrium. Genital atrium large. Genital pore distinctly separated from posterior extremity.

Ovary oval, pretesticular, contiguous with anterior testis. Mehlis’ gland overlapping ovary and anterior testis. Uterine seminal vesicle occasionally seen in proximal uterus. Laurer’s canal apparently opens dorsally at level of Mehlis’s glands, not usually detectable. Uterus reaches distinctly anterior to vitelline fields, fills most of available space to level of genital pore. Eggs numerous, tanned, operculate. Metraterm not detected, obscured by eggs. Vitellarium consists of 2 lateral fields of 13–18 follicles, more or less symmetrical, but with one slightly longer than other, anterior extremity distinctly posterior to rhynchus and anterior extent of uterus, but always anterior to caecum and gonads; posterior extremity at about level of ovary or slightly anterior.

Excretory pore terminal; anterior extent of vesicle obscured by eggs.

Taxonomic comparison: Comparison of Rhipidocotyle danai n. sp. using the visual keys discussed above shows that in the comparison diagram (Figure 2) 6 species have no black squares against their names, namely R. anguillae Wang, 1985, R. coiliae Wang, 1980, R. longleyi Manter, 1934 R. microovatum Zhukov, 1977, R. scombropsis (Yamaguti, 1938) and R. sphyraenae Yamaguti, 1959. Six have one black square against their name: R. fluminensis Vicente & dos Santos, 1973, R. ghanensis Fischthal & Thomas, 1968, R. karthai Hafeezullah & Siddiqi, 1970, R. khalili Nagaty, 1937, R. pentagonum (Ozaki, 1924), R. pseudorhombi Nahhas, Sey & Nakahara, 2006.

Rhipidocotyle anguillae was described from the eel Anguilla mauritiana (now considered the giant mottled eel Anguilla marmorata Quoy & Gaimard - Anguillidae) from off Fujian Province, China and (Wang 1985) differs from R. danai n. sp. in the distinct five-lobed rhyncheal hood, and probably the pre-uterine distance (about 26% of body-length vs 16–20 (19)%) and cirrus-sac reach (about 28% of body-length vs 34– 42(39)%).

Rhipidocotyle coiliae reported from the Japanese grenadier anchovy Coilia nasus Temminck & Schlegel (Engraulidae) and the snake eel Cirrhimuraena chinensis Kaup (Ophichthidae), off Fujian, China (Wang 1980) can be distinguished from R. danai n. sp. by the lobed rhyncheal hood and the cirrus-sac restricted to the post-testicular region. It is also probably distinguished by its greater pre-uterine difference (about 26% vs 16–20 (19)%), length (1,120–2,080 vs 2,117–2,715), relatively width (about 22–31% vs 12–20 (17)%), cirrussac reach (about 30% vs 34–42 (39)%) and egg-length (22–26 vs 19–23).

Rhipidocotyle longleyi was originally reported from the blackmouth bass Synagrops [= Hypoclydonia] bellus (Goode & Bean) (Acropomatidae) from off Tortugas, Florida (Manter 1934) and can be distinguished from R. danai n. sp. by its rhynchus which has a distinctly seven-lobed hood. This observation is based on the original description, but other descriptions of the species from geographically distant regions (Reimer 1985; Szuks 1981; Yamaguti 1938) also indicate this distinctive feature. R. longleyi may possibly be slightly broader generally (width about 15–25% of body length vs 12–20 (17)%).

Species Rhipidocotyle danai n. sp. Rhipidocotyle jayai n. sp. Prosorhynchus platycephali Host (s) Thysitoides marleyi Johnius macropterus Sunagocia otaitensis n 4 5 13

Length 2,117–2,715 (2,439) 2,340–3,297 (2,740) 2,823–4,468 (3,856) Width 318–489 (409) 415–560 (479) 254–456 (356) Pre-vitelline distance 440–652 (567) 492–684 (593) 613–890 (766) Pre-caecal distance 809–1,030 (922) 991–1,423 (1,140) 1,145–1,790 (1,558) Pre-uterine distance 386–540 (465) 647–1,015 (805) 440–1,339 (711) Pre-mouth distance 883–1,117 (1,018) 1,152–1,513 (1,321) 1,570–2,220 (1,934) Pre-testicular distance 1,071–1,314 (1,195) 1,476–1,962 (1,645) 1,377–2,408 (2,066) Pre-ovarian distance 931–1,176 (1,046) 1,327–1,687 (1,444) 1,297–2,302 (1,962) Rhynchus 165–176 × 116–132 (170 × 124) 175–213 × 152–202 (188 × 180) 151–193 × 108–143 (168 × 122) Rhynchus to vitellarium 268–483 (399) 318–498 (407) 408–831 (606) Rhynchus to uterus 210–382 (297) 449–817 (623) 281–1,336 (592) Rhynchus to caecum 720–873 (791) 785–1,436 (993) 1,154–1,686 (1,457) Long vitelline field 424–528 (483) 832–1,419 (992) 765–1,662 (1,276) Short vitelline field 399–606 (493) 645–1,177 (814) 711–1,453 (1,030) Caecum 309–382 × 67–132 (344 × 98) 431–567 × 130–238 (500 × 196) 198–369 × 87–124 (107 × 103) Pharynx 79–88 × 92–108 (84 × 100) 105–140 × 110–156 (125 × 133) 83–117 × 61–105 (103 × 87) Ovary 160–204 × 136–179 (183 × 160) 162–225 × 132–204 (194 × 177) 105–195 × 126–171 (150 × 144) Ovary to anterior testis 0 0–85 (27) 0

Anterior testis 217–264 × 167–236 (240 × 203) 233–337 × 206–305 (287 × 261) 136–223 × 143–206 (194 × 179) Distance between testes 0–23 (6) 0 121–290 (180) Posterior testis 217–242 × 180–233 (229 × 202) 178-275 × 169–254 (243 × 217) 160–285 × 167–237 (225 × 192) Posterior testis to cirrus-sac 0 0 10–440 (251) Cirrus-sac 718–952 × 92–130 (803 × 108) 459–781 × 104–161 (588 × 133) 467–707 × 109–149 (590 × 133) Seminal vesicle 164 × 51 56–100 × 44–84 (76 65) 110–257 × 41–78 (186 × 63) Pars prostatica 502–758 × 56–86 (588 × 68) 366–591 × 39–80 (479 × 51) 418–977 × 47–84 (513 × 66) Post-testicular region 566–864 (735) 423–768 (554) 770–1,481 (1,165) Post-vitelline region 1,009–1,591 (1,281) 988–1,276 (1,115) 1,003–2,202 (1,771) Cirrus-sac reach 889–1,016 (940) 68–1,069 (855) 735–1,074 (899) Post-ovarian region 961–1,366 (1,160) 844–1,376 (1,094) 1,276–2,122 (1,673) Genital pore to posterior 46–89 (77) 49–93 (70) 58–302 (236) extremity

Eggs 19–23 × 9–13 (21 × 11) 25–30 × 13–20 (27 × 16) 22–29 × 17–24 (26 × 20) Width%* 12–20 (17) 17–18 (18) 8.1–12 (9.3)

Pre-vitelline distance%* 18–26 (23) 17–24 (22) 16–27 (20)

Pre-caecal distance%* 37–38 (38) 38–44 (42) 35–45 (41)

Pre-uterine distance%* 16–20 (19) 26–35 (29) 13–30 (18)

Pre-mouth distance%* 41–43 (42) 46–51 (49) 45–56 (50)

Pre-testicular distance%* 46–51 (49) 56–64 (60) 48–57 (54)

Pre-ovarian distance%* 41–44 (43) 46–51 (53) 45–54 (51)

Rhynchus length%* 6.1–7.9 (7.0) 5.3–8.3 (7.0) 3.9–5.4 (4.4)

Rhynchus width as % 70–76 (73) 83–102 (95) 67–78 (73)

rhynchus length

.....continued on the next page Rhipidocotyle microovatum from the barred queen fish Scomberoides [= Chironemus] tala Cuvier (Carangidae) off Chennai, India (Zhukov 1977) is distinguished from R. danai n. sp. by its 7-lobed hood. It also can probably be distinguished by the length of the pre-vitelline region (about 32% of body-length vs 18– 26 (23)%), relative width (about 23–28% of body length vs 12–20 (17)%), length of pre-uterine region (about 23% of body-length vs 16–20 (19)%) and egg length (16–19 vs 19–23 (21)).

Rhipidocotyle scombropsis was originally reported from the gnomefish Scombrops boops (Houttuyn) (Scombropidae) from off Japan (Yamaguti 1938) and can be distinguished from R. danai n. sp. by its gonads always being distinctly separated by uterine slings, the cirrus-sac reaches to the posterior testis, or into the anterior post-testicular region and, apparently, by a weakly incised hood. R. scombropsis may possibly be slightly broader generally (width about 17–25% of body length vs 12–20 (17)%), and have a relatively shorter cirrus-sac reach (about 30% vs 34–42 (39)), and slightly shorter pre-vitelline (about 18.5% vs 18–26 (23)%) and pre-uterine (about 14% vs 16–20 (19)%) distances.

Rhipidocotyle sphyraenae was originally reported in the red barracuda Sphyraena pinguis Günther (Sphyraenidae) off Japan (Yamaguti 1959) and differs from R. danai n. sp. in the seven double papillae on the rhyncheal hood. It also probably differs in its pre-uterine distance (about 8% of body-length vs. 16-20 (19)%). This comparison is based on the original description only, not on the redescription by Reimer (1985) from the sombre splitfin Neoscombrops annectens Gilchrist (Acropomatidae) from off Mozambique.

Rhipidocotyle fluminensis from the little tunny Euthynnus alletteratus (Rafinesque) (Scombridae) off Rio de Janeira State, Brazil (Vicente & Santos 1973) was distinguished from R. danai n. sp. in the visual key by pre-uterine distance (about 33% of the body-length vs 16–20 (19)%). The rhyncheal hood is illustrated as distinctly angular and the body is notably wider in the mid-region, making the worm distinctly fusiform in outline.

Rhipidocotyle ghanensis from the spottail spiny turbot Psettodes belcheri Bennett (Psettodidae) from off Ghana (Fischthal & Thomas 1968) was distinguished from R. danai n. sp. in the visual key by the position of the mouth (about 60–67% of the body-length from the anterior extremity vs 41–43 (42)%) and can also be distinguished by its 7-lobed rhyncheal hood and the inflated excretory vesicle in the anterior part of the body. R. ghanensis probably has a relatively slightly longer rhynchus (about 8.2–10.7% vs 6.1–7.9 (7.0)%), longer pre-vitelline (about 29–33% vs 18–26 (23)%) and pre-uterine (about 25–28% vs 16–20 (19)%) regions, shorter cirrus-sac reach (about 29–33% vs 34–42 (39)) and post-testicular region (about 23% vs 26–35 (30)%).

Rhipidocotyle karthai from the Indian spiny turbot Psettodes erumei (Bloch & Schneider) (Psettodidae) off Visakhapatnam, India (Hafeezullah & Siddiqi 1970) was distinguished from R. danai n. sp. in the visual key by the position of the mouth (about 57% of the body-length from the anterior extremity vs 41–43 (42)%) and can also be distinguished by its 7-lobed rhyncheal hood. R. karthai probably has a relatively slightly longer rhynchus (about 8.8–9.1 % vs 6.1–7.9 (7.0)%), and shorter cirrus-sac reach (about 31% vs 34–42 (39)) and post-testicular region (about 24% vs 26–35 (30)%). Madhavi (1974) considered R. karthai a synonym of R. ghanensis.

Rhipidocotyle khalili was originally described from the milkfish Chanos chanos (Forsskål) (Chanidae) off the Egyptian Red Sea coast at Koseira (Nagaty 1937) and is distinguished from R. danai n. sp., according to the visual key, by its pre-vitelline distance (about 54% of body-length vs 18–26(23)%). Apparently, there is a ‘crown-shaped structure’ around the rhynchus. Other differentiating features may be the pre-uterine distance (about 26% of body-length vs 16–20(17)%), the pre-mouth distance (about 51% of body-length vs 41– 43(42)%) and the cirrus-sac reach (about 28% of body-length vs 34–42 (39)%). This species has also been reported in Indonesian waters by Yamaguti (1953b), from a barracuda Sphyraena sp. (Sphyraenidae off Sulawesi. The worm was described, but not illustrated. Subsequently, it has been reported in other Sphyraena spp. in the Bay of Bengal (Madhavi 1974) and off Mozambique (Reimer 1985).

Rhipidocotyle pentagonum, originally reported from the contradictorily named Japanese Spanish mackerel Scomberomorus niphonius (Cuvier) (Scombridae) off Shikoku Island, Japan (Ozaki 1924, 1928), differs from R. danai n. sp. in the visual key by pre-uterine distance (about 49% vs 16–20(19)%). Based on Ozaki’s descriptions this species differs from R. danai n. sp. by its seven-lobed rhynchus hood and possibly in cirrus-sac reach (about 24% vs 34–42 (39)%). The species is widely reported in scombrids, including records from the Mediterranean Sea (Eckmann 1932), Japan (Yamaguti 1938), the Bay of Bengal (Madhavi 1974), the Pacific coast of Mexico (Castillo-Sánches et al. 1997) and the Atlantic Ocean off Rio de Janeiro State, Brazil (Fernandes et al. 2002).

Rhipidocotyle pseudorhombi, from the largetooth flounder Pseudorhombus arsius (Hamilton) (Paralichthyidae) in the Arabian Gulf (Nahhas et al. 2006), differs from R. danai n. sp. in the visual key by the pre-vitelline distance (about 37% of body-length vs 18–26(23)%). The rhynchus is said to have a ‘smooth poorly developed hood and 7 thin papillae, 2 lateral, one dorsal, one ventral and 3 median.’

As far as we are aware this is the first report of a fully identified bucephalid in a member of the Gempylidae.