Bull. Natl. Mus. Nat. Sci., Ser. A, 33(1), pp. 1–30, March 22, 2007 Digeneans (Trematoda) of Freshwater Fishes from Nagano Prefecture, Central Japan Takeshi Shimazu Nagano Prefectural College, 8–49–7 Miwa, Nagano, 380–8525 Japan E-mail: [email protected] Abstract Examination of digeneans (Trematoda) parasitizing freshwater fishes collected in Nagano Prefecture, central Japan, revealed that 22 species including two new species occur in this prefecture. Sanguinicola ugui sp. nov. (Sanguinicolidae) is described from the blood vessels of Tribolodon hakonensis (Günther) (Cyprinidae). Azygia rhinogobii sp. nov. (Azygiidae) is described from the stomach of Rhinogobius sp. (Gobiidae, type host) and Gymnogobius urotaenia (Hilgen- dorf) (Gobiidae), and the intestine of T. hakonensis. Phyllodistomum anguilae Long and Wai, 1958, P. mogurndae Yamaguti, 1934, P. parasiluri Yamaguti, 1934 (Gorgoderidae), and Pseudex- orchis major (Hasegawa, 1935) Yamaguti, 1938 (Heterophyidae) are redescribed. The generic di- agnosis of the genus Pseudexorchis Yamaguti, 1938 is amended in part. New host and locality records are provided for 20 known species. An outline of the life cycle of Asymphylodora macro- stoma Ozaki, 1925 (Lissorchiidae) is given. A furcocystocerous cercaria, probably the cercarial stage of A. rhinogobii sp. nov., is briefly described from Sinotaia quadrata histrica (Gould) (Gas- tropoda, Viviparidae). Key words : digenean, parasite, new species, furcocystocercous cercaria, taxonomy, life cycle, freshwater fish, Nagano, Japan. ed considerable number of digeneans. The life Introduction cycle of Asymphylodora macrostoma Ozaki, Since Yamaguti (1934) recorded Allocreadium 1924 was also studied in the field and laboratory. gotoi (Hasegawa and Ozaki, 1926) (as This paper describes two new species and adds Macrolecithus) from Misgurnus anguillicaudatus new records and information on host, locality, (Cantor) (Cobitidae) caught in Komi, most pre- and morphology of 20 known species from sumably in Nagano Prefecture, central Japan, 14 Nagano Prefecture, with a brief note on the life species of adult and one species of immature di- cycle of A. macrostoma. geneans have been reported from freshwater fish- es in this prefecture (Shimazu, 2003a, b). Howev- Materials and Methods er, surveyed areas and fishes were limited, and our knowledge of the digenean fauna of freshwa- Freshwater fishes were collected in Nagano ter fishes in the prefecture is still incomplete. For Prefecture at irregular intervals and examined example, a lophocercous-brevifurcate-apharyn- fresh for digeneans under a stereoscopic micro- geate cercaria of the genus Sanguinicola Plehn, scope. Main sampling sites of the fishes and the 1905 has been known to occur in a viviparid periods were as follows: Hiroi River at Kotobuki, snail in the prefecture (Shimazu, 1979b), but the Iiyama, from 1995 to 2004; Torii River at Mure adult remains to be discovered (Shimazu, 2003b). from 1987 to 1995; Lake Kizaki at Oomachi In order to obtain further knowledge of the di- from 1976 to 1994; Nogu River at Oomachi in genean fauna, I surveyed freshwater fishes at var- 1987; Lake Suwa at Suwa from 1976 to 1999; ious sites in Nagano Prefecture, and have collect- and Tenryu River at Ina in 2000. Gobiids called 2Takeshi Shimazu “yoshinobori” in Japanese from several sites re- (Cyprinidae). main unidentified to species and are referred to Sites of infection. Blood vessels chiefly of as Rhinogobius sp. in this paper. It is uncertain the gills and rarely of the liver, kidneys, and whether they all belong to a single species. heart. Worms were found at least in the efferent Prevalence and intensity of infection of each par- branchial arteries of the gills (NSMT-Pl 5283) asite species were not counted. and the lumen of the ventricle of the heart Digenean specimens were treated as follows: (NSMT-Pl 5291). The exact site of infection in slightly flattened under coverslip pressure, fixed the other organs could not be determined. with 70% ethanol, and stained with Grenacher’s Localities. Hiroi River (type locality) at Ko- alum carmine; slightly flattened, fixed with AFA, tobuki (36°54ЈN, 138°21ЈE), Iiyama; Lake Suwa and stained with Heidenhain’s iron hematoxylin; at Suwa (36°03ЈN, 138°06ЈE); and Tenryu River or fixed with hot 10% neutralized formalin and at Ina (35°50ЈN, 137°57ЈE), all in Nagano Pre- stained with Mayer’s hematoxylin. These stained fecture, central Japan. specimens were mounted in Canada balsam. Specimens deposited. Holotype (NSMT-Pl Some were observed alive for study of the excre- 5284) and 27 paratypes (NSMT-Pl 5284–5286 tory system. Some others and some infected or- and 5288) from Hiroi River on 20 July 1996, 23 gans of hosts were fixed with 10% neutralized October 1996, 24 November 1996, and 5 Novem- formalin, made into serial paraffin sections (10 ber 2004; and many vouchers (NSMT-Pl 5283– mm thick), and stained with hematoxylin and 5295, 5296 and 5297, and 5298) from Hiroi eosin. River from 1996 to 2004, Lake Suwa on 2 Au- For comparison, institutional specimens were gust 1996 and 5 October 1996, and Tenryu River borrowed from the Collections of Dr. Satyu Yama- on 9 September 2000, respectively. guti and Dr. Yoshimasa Ozaki deposited in Me- Etymology. The specific name “ugui” is the guro Parasitological Museum (MPM), Tokyo; Japanese common name of the type host. National Museum of Nature and Science, Tokyo Description. Based on holotype (NSMT-Pl (NSMT); U.S. National Parasite Collection 5284) and 9 paratypes (NSMT-Pl 5284–5286 and (USNPC), Beltsville, Maryland, U.S.A.; and the 5288). Body flat, elongate, widest at level of an- Parasite Collection of the National Museum of terior part of testis, pointed at anterior end, grad- Nature (NMNPC), Ottawa, Canada. ually narrowing posteriorly and rounded at poste- Drawings were made with the aid of a camera rior end, 1.29–1.67 by 0.19–0.35, possibly bear- lucida. Measurements (length by width) are given ing fine setae (Figs. 1 and 2). Anterior proboscis in millimeters unless otherwise stated. Represen- absent. Tegumental spines lanceolate, weakly tatives of the specimens studied have been de- curved, arranged in ventrolateral transverse rows posited in the NSMT and USNPC. from near anterior end of body to middle level of The life cycle of Asymphylodora macrostoma cirrus pouch; 1 each in anterior 1st–4 th to 6 th Ozaki, 1924 was studied in the Torii and Hiroi rows, thick, 6–8 mm long; 2–5 (usually 4) each in rivers and in the laboratory. remainder, slender, 14–22 mm long (Fig. 3). Nerve chords conspicuous; transverse nerve Class Trematoda commissure 0.14–0.19 or 10–12% of body length from anterior end. Oral and ventral suckers ab- Subclass Digenea sent. Mouth small, only slightly subventral, close Family Sanguinicolidae to anterior tip of body. Small globular sphincter- Sanguinicola ugui sp. nov. or sucker-like structure about 6–9 mm in diameter (Figs. 1–6) encircling esophagus immediately adjacent to mouth aperture (Fig. 3). Esophagus narrow, slen- Type host. Tribolodon hakonensis (Günther) der, forming thick-walled fusiform structure (Fig. Digeneans of Freshwater Fishes 3 o cvd sd od cp pc sv fgp u mgp ot gc Figs. 1–6. Sanguinicola ugui sp. nov. 1, holotype, entire body, dorsal view; 2, holotype, entire body, excretory organs added from free-hand sketches, vitelline follicles omitted, ventral view; 3, paratype, anterior part of body, showing tegumental spines, a sphincter- or sucker-like structure encircling esophagus, and a thick- walled, fusiform structure of esophagus, ventral view; 4, paratype, tegumental spines, ventral view; 5, holo- type, terminal genitalia, dorsal view; 6, fully-embryonated egg detected in host’s liver. cvd, common vitelline duct; cp, cirrus pouch; fgp, female genital pore; gc, gland cells; mgp, male genital pore; o, ovary; od, oviduct; ot, ootype; pc, prostatic cells; sd, sperm duct; sv, seminal vesicle; u, uterus. Scale bars: 0.5 mm in Figs. 1 and 2; 0.2 mm in Figs. 3 and 5; 0.025 mm in Figs. 4 and 6. 3) 0.06–0.08 by 0.02–0.04 in front of transverse to cirrus pouch, ventral to ovary (Fig. 5). Cirrus nerve commissure. Intestine X-shaped; ceca very pouch fusiform or club-shaped, thin-walled, short, usually 4 or rarely 5 or 6 in number, 0.14–0.16 by 0.05–0.07, directed posteriorly, 0.28–0.36 or 21–23% of body length from anteri- slightly diagonal, surrounded by small gland or end. Testis single, median, between ovary and cells (Fig. 5). Male genital pore dorsal, sinistro- intestinal ceca, 0.44–0.60 by 0.09–0.19, with submedian, some distance from posterior end of 21–25 lateral lobes on either side (Figs. 1 and 2). body, lined with cuboidal cells arranged in a sin- Spermatozoa flowing posteriorly in dorsal medi- gle layer, surrounded by small gland cells (Figs. an bundle within testis from anterior end of testis 1, 2, and 5). Seminal vesicle very thin-walled. to posterior; several similar short bundles from Small globular pars prostatica may be differenti- lateral lobes joining this bundle in places; these ated immediately before cirrus. Cirrus very bundles apparently lacking any kind of duct (Fig. short, eversible. Prostatic cells large. Ovary 1). Single diagonal sperm duct running posterior- bilobed laterally in shape of butterfly, 0.12–0.17 ly from median point of posterior margin of testis by 0.09–0.14, median, just behind testis; isthmus 4Takeshi Shimazu 0.85–1.16 or 65–71% of body length from anteri- canals each with flame cell; right flame cells be- or end (Figs. 1, 2, and 5). Oviduct originating tween transverse nerve commissure and intestinal from posterior margin of ovarian isthmus, pass- ceca, but left near cirrus pouch; flame cell for- ing posteriorly, making loop, dorsal to sperm mula 2 [(1ϩ1)]ϭ4. duct, including spermatozoa (or acting as oviduc- Discussion.