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Memorias do Instituto Oswaldo Cruz Vol. 90(6), Nov./Dec. 1995 Neotropical Monogenoidea. 23. Two New Species of Gyrodactylus (Gyrodactylidae) from a Cichlid and an Erythrinid Fish of Southeastern Brazil Walter A Boeger, Flavio Popazoglo Departamento de Zoologia, Universidade Federal do Parana, Caixa Postal 19073, 81531-990, Curitiba, PR, Brasil
Code Number: OC95140
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Graphics: Line Drawings (gif) 35.8KTwo new species of Gyrodactylus Nordmann, 1832 (Platyhelminthes, Monogenoidea) are described from fishes collected from southeastern Brazil. Gyrodactylus geophagensis n. sp. was collected from the body surface of the "cara", Geophagus brasiliensis (Quoy and Gaimard, 1824) (Cichlidae), from the Rio da Guarda, State of Rio de Janeiro; its major diagnostic features are the morphology of the anchor with a short, truncate superficial root and the shape of the hooks - with a long, delicate shaft. Gyrodactylus trairae n. sp. parasitizes the body surface of the"traira", Hoplias aff. malabaricus (Bloch, 1794) (Erythrinidae), from the Rio Guandu, State of Rio de Janeiro and can be easily differentiated from other species of the genus by having a thin, dorsal bridge, connecting the superficial bar with the spathulated shield. These are the first species of Gyrodactylus formally reported from Brazil. Presently, 26 species of Gyrodactylidae are known from freshwater fishes in the Neotropical Region; a list of these species is provided. Key words: Platyhelminthes - Gyrodactylidae - Gyrodactylus geophagensis n. sp. - Gygrodactylus trairae n. sp. - Geophagus brasiliensis - Hoplias aff. malabaricus - Brazil Until recently, Gyrodactylidae were practically unknown for the Neotropical Region (Table). Kritsky and Fritts (1970) were the first to report and describe species from Neotropical freshwater fishes collected in Costa Rica, Central America. Only three additional refererences exist from 1970 to the early 80Æs: Szidat (1973), Kritsky and Thatcher (1977), and Harris (1983). Considering the species described in this paper, there are, presently, 26 gyrodactylids reported for freshwater fishes of the Neotropical Region. The majority of these forms are related to those studied in Peru and Brazil (see Table for references). Only two species are known from Neotropical marine fishes: Gyrodactylus curemae Conroy and Conroy, 1985 was described from Mugil curema Valenciennes, 1836 from Venezuela; and Gyrodactylus sp. reported by Jara (1986) from Mugil cephalus Linne, 1758 from the coast of Peru. Although many of the species of Gyrodactylidae reported from the region are not closely related to each other but to other Neartic or Eurasian species (An et al. 1991), Neotropical fishes are the only known hosts of a unique group of this family of worms. Harris (l983) proposed a new family, Ooegyrodactylidae, to include, at that time, two species of oviparous monogenoideans which depicted great morphological similarity to the Gyrodactylidae. Kritsky and Boeger (l991) described four new species of these worms. However, Boeger et al. (l994) rejected monophyly of Ooegyrodactylidae using techniques of Phylogenetic Systematics and transferred all its members to Gyrodactylidae. The Ooegyrodactylidae, according to these authors, is paraphyletic. Thus, the Gyrodactylidae is presently composed of viviparous (the tradicional composition) and of oviparous species (formely members Ooegyrodac-tylidae). Oviparous Gyrodactylidae have only been found on Neotropical Siluriformes, mainly Loricariidae. Although species of Gyrodactylus have already been reported from South America (Jara 1986, An et al. 1991), none have been previously registered from Brazil. However, during a survey of Gyrodactylidae, two new species of Gyrodactylus were collected from fishes of the Southeast Region of the country. These forms are described herein.
MATERIALS AND METHODS
Fishes were collected from two localities of the Southeast Region of Brazil, as indicated in the respective descriptions, by different types of nets. Individual or pooled hosts were placed in vials containing a 1:4000 solution of formalin (Putz & Hoffman 1963). After 1 hr, the vials were vigorously shaken and additional formalin was added to increase the concentration to about 5%. Gyrodactylids were prepared according to procedures described in Kritsky et al. (1995). lllustrations were prepared with the aid of a camera lucida. Measurements are given in micrometers; the average is given followed by the range and the number (n) of structures measured, in parenthesis; anchors were measured following method indicated by Kritsty et al. (1995). Type specimens were deposited at the Instituto Oswaldo Cruz (IOC), Rio de Janeiro, Brazil, the University of Nebraska State Museum (HWML), Lincoln, Nebraska, and the U. S. National Museum Helminthological Collection (USNM), Beltsville, Maryland, USA, as indicated in the respective descriptions. DESCRIPTIONS Gyrodactylus geophagensis n. sp.
(Figs 1-5) Host: Geophagus brasiliensis (Quoy and Gaimard, 1824) (Cichlidae) Site of infestation: body surface Type locality: Rio da Guarda, ltaguai, State of Rio de Janeiro, Brazil; December 1990 Holotype: IOC 33144a. Paratypes: (4 specimens) IOC 33144b-e; (2 specimens) USNM 84078; (2 specimens) HWML 37095 Description (based on 9 specimens): body elongate, 418 (390-455, n=3) long; greatest width 103 (89-117; n=4) near midlength. Cephalic lobes moderately developed, head organs conspicuous. Pharynx 44 (38-53; n=6) in diameter; pharyngeal process inconspicuous. Testis not observed. Copulatory organ 6-7 (n=2) in diameter, ovate, armed with 8 spinelets, 1 spine. Germarium ovate. Uterus with up to 2 embryos. Syncytial post-germarian mass of cells. Haptor 79 (71-88; n=3) long, 84-96 (n=3) wide. Anchor 57 (55-58; n=5) long; with slightly curved shaft 40 (37-41, n=5) long; point 25 (22-28; n=5) long; truncate, robust superficial root; inconspicuous deep root- base 22 (l9-24; n=5) long; angle shaft/point 45 degrees (40-49 degrees; n=5). Superficial bar 20-23 (n=2) long, 9-19 (n=2) wide, robust with short antero-lateral projections; shield of superficial bar extending to middle of anchor shaft, tapering posteriorly, 13-14 (n=2) long; deep bar relatively robust, flexible. Hooks with straight shaft, shelf with small proximal elevation, straight thumb, conspicuous heel, slender shank; hooklet 7-8 (n=5) long; FH loop not observed. Remarks: the morphology of the anchor and bar of G. geophagensis n. sp. is very similar to those of G. masu Ogawa, 1986 and G. derjarvini Mikailov, 1975. All three species depict robust anchors with short, truncate superficial root, and superficial bar with shield and anterolateral processes relatively short. Gyrodactylus geophagensis n. sp. can be differentiated from these species by having: (1) hooks with delicate, proportionally longer shaft and a straight non depressed toe; (2) copulatory organ with spinelets of about equal size - in G. masu and G. derjarvini the spinelets lateral to the cirral spine are larger than the remaining ones. The specific name refers to the generic name of the host of this species. Gyrodactylus trairae n. sp. (Figs 6-10) Host: Hoplias aff. malabaricus (Bloch, 1794) (Erythrinidae) Site of infestation: body surface Type locality: Rio Guandu, Nova lguacu, State of Rio de Janeiro, Brazil; April and June 1991 Holotype: IOC 332l5a. Paratypes: (8 specimens) IOC 332l5b-i; (8 specimens), USNM 84079; (8 specimens) HWML 37096 Description (based on 25 specimens): body elongate, 608 (530-667; n=8) long; greatest width 127 (90-175; n=8) near midlength. Cephalic lobes well developed; head organs conspicuous. Distal pharynx 42 (38-47; n=6) in diameter; proximal pharynx 47 (44-49; n=6) in diameter; pharyngeal processes not observed. Testis post germarian, laterally elongate. Copulatory organ 17-18 (n=4) in diameter, ovate, armed with 1 spine and spinelets arranged in two rows; external row with 4 large spinelets; internal row with 4-5 small intermediate spinelets; base of large spinelets large, truncate. Germarium ovate. Uterus with up to 4 generations of embryos. Vitelline follicles not observed. Numerous unicellular glands in peduncle with ducts directed posteriorly. Haptor 108 (97-123; n=l2) long, 78 (71-93; n=l2) wide. Anchor 107 (l02-114; n=l1) long, with straight shaft, 46 (41-51; n=11) long; straight point 41 (38-45; n=11); elongate, evenly curved superficial root; base 67 (61-79; n=11) long; inconspicuous deep root; angle shaft/point 52 dehrees (46-60 degrees; n=11). Superficial bar 32 (29-38; n=11) long, 12 (10-18; n=11) wide, with two lateral, anterior processes; processes of superficial bar 34 (27-43; n=11) long; shield of superficial bar 33 (29-38; n=10) long, 16 (l4-18; n=7) wide, distally spathulated, connected to bar by thin, dorsal bridge. Deep bar thin, flexible. Hooks long, with evenly curved shaft, point, depressed thumb, convex shelf, conspicuous heel; hooklet 6 (5-8; n=18) long; FH loop 1/2 shank length. Remarks: Gyrodactylus trairae n. sp. resembles species included in the subgenus G. (Mesonephrotus) Malmberg, 1964 (see Malmberg 1970) and G. katherineri Malmberg, 1964 by the presence of long anterolateral processes on the superficial bar. Although, the presence of two arched rows of spinelets on the copulatory organ and the shape of the hooklets suggest proximity of the new species with those included in the subgenus Gyrodactylus (Gyrodactylus) (sensu Malmberg 1970). Independently of the subgeneric placement, however, the new species can be easily differentiated from all known Gyrodactylus by the morphology of the anchor and shield of the superficial bar. Additionally, the embryos of G. trairae, unlike those of other species in the genus, lie almost unfolded within the uterus. The specific name refers to the local name of the fish host ("traira"). TABLE
Gyrodactylidae from freshwater fishes of the Neotropical Region ACKNOWLEDGMENTS To Dr Heraldo A Britsky (Museu de Zoologia, Universidade de Sao Paulo) for identification of the host species; Dr Delane C Kritsky (ldaho State University) and two anonymous referees for comments and suggestions. REFERENCES An L, Jara CA, Cone DK 1991. Five species of Gyrodactylus Nordmann, 1832 (Monogenea) from freshwater fishes of Peru. Can J Zool 69: 109-202. Boeger WA, Kritsky DC, Belmont-Jégu E 1994. Neotropical Monogenoidea. 20. Two new species of oviparous Gyrodactylidea (Polyonchoinea) from loricariid catfishes (Siluriformes) in Brazil and the phylogenetic status of Ooegyrodactylidae Harris, 1983. J helminth Soc Wash 61: 30-40. Conroy G, Conroy DA 1985. Gyrodactylosis in silver mullet (Mugil curema Val.) from Venezuelan coastal waters, and a description of Gyrodactylus curemae n. sp. Riv ital Ittioparasit 20: 140-147. Ferraz E, Shinn AP, Sommerville C 1994. Gyrodactylus gemini n. sp. (Monogenea: Gyrodactylidae), a parasite of Semaprochilodus taeniurus (Steindachner) from the Venezuelan Amazon. Syst Parasitol 29: 217-222. Harris PD 1983. The morphology and the life-cycle of the oviparous Oögyrodactylus farlowellae gen. et sp. nov. (Monogenea, Gyrodactylidea). Parasitology 87: 405-420. Harris PD, Lyles AM 1992. Infections of Gyrodactylus bullatarudis and Gyrodactylus turnbulli on gupies (Poecilia reticulata) in Trinidad. J Parasitol 78: 913-914. Jara CA 1986. Finding of Gyrodactylus sp. and Anacanthocotyle sp. (Monogenea, Gyrodactylidae) in fishes from the Moche River, Trujillo, Peru. Hydrobios 10: 8-13. Jara CA, Cone DK 1989. Scleroductus yuncensi gen. et sp. n. (Monogenea) from Pimelodella yuncensis (Siluriformes, Pimelodidae) in Peru. Proc helm Soc Wash 56: 125-127. Jara CA, An L, Cone DK 1991. Accessorius peruensis gen. et sp. n. (Monogenea, Gyrodactylidea) from Lebiasina bimaculata (Characidae) in Peru. J helm Soc Wash 58: 164-166. Kritsky DC, Boeger WA 1991. Neotropical Monogenea 16. New species of oviparous Gyrodactylidea with proposal of Nothogyrodactylus gen. n. (Ooegy-rodactylidae). J helm Soc Wash 58: 7-15. Kritsky DC, Boeger WA, Popazoglo F 1995. Neotropical Monogenoidea 22. Variation in Scleroductus species (Gyrodactylidae, Gyrodactylidea) from siluriform fishes of Southeastern Brazil. J helm Soc Wash 62: 53-56. Kritsky DC, Fritts TH 1970. Monogenetic trematodes from Costa Rica with the proposal of Anacan-thocotyle gen. n. (Gyrodactylidea: lsancistrinae). Proc helm Soc Wash 37: 63-68. Kritsky DC, Thatcher VE 1977. Phanerothecium gen. nov. and Fundulotrerna gen. nov. two new genera of viviparous Monogenoidea (Gyrodactylidae), with a description of P. caballeroi sp. nov, and a key to the subfamilies and genera of the family. Excerta Parasitologica en memoria del doctor Eduardo Caballero y Caballero. Inst Biol Publ Esp 4: 53-60. Malmberg G 1970. The excretory systems and the marginal hooks as a basis of the systematics of Gyrodactylus (Trematoda: Monogenea). Ark Zool 23: 1-235. Putz RE, Hoffman GL 1963. Two new Gyrodactylus (Trematoda: Monogenea) from cyprinid fishes with synopsis of those found on North American fishes. J Parasit 49: 559-566. Szidat L 1973. Morphologie un Verhalten von Paragyodactylus superbus n. g., n. sp. Erregener eines Fischsterbens in Argentinien. Angew Parasitol 14: 1-10. This work received financial support from the Fundacao de Amparo e Pesquisa do Estado do Rio de Janeiro (Proc. E-291170-033/90) and Conselho Nacional de Desenvol-vimento Cientifico e Tecnologico (Proc. 406184/90 and 500711190-9), Brazil. This is the contibution number 899 from the Departamento de Zoologia, Universidade Federal do Parana. Research fellow's CNPq Received 20 March 1995 Accepted 26 July 1995 Copyright 1995 Fundacao Oswaldo Cruz, FIOCRUZ
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