J. Parasitol., 93(4), 2007, pp. 761-771 ? American Society of Parasitologists 2007 NEW AND PREVIOUSLY DESCRIBED SPECIES OF DACTYLOGYRIDAE (MONOGENOIDEA) FROM THE GILLS OF PANAMANIAN FRESHWATER FISHES (TELEOSTEI) Edgar F. Mendoza-Franco*, M. Leopoldina Aguirre-Macedo, and Victor M. Vidal-Martinez Laboratory of Parasitology, Centra de Investigacion y de Estudios Avanzados (CINVESTAV, Unidad Merida), Carretera Antigua a Progreso Km. 6, Apartado Postal 73 "Cordemex," C.P. 97310 Merida, Yucatan, Mexico, e-mail: mfranco@mda.cinvestav.mx ABSTRACT: During an investigation of the diversity of metazoan parasites of 7 freshwater fish species from 3 localities in central Panama, the following gill dactylogyrid (Monogenoidea) species were found: AphanoblaStella chagresii n. sp. from Pimelodella chagresi (Heptapteridae); Aphanobla Stella travassosi (Price, 1938) Kritsky, Mendoza-Franco, and Scholz, 2000 from Rhamdia quelen (Heptapteridae); Diaphorocleidus petrosusi n. sp. from Brycon petrosus (Characidae); Gussevia asota Kritsky, Thatcher, and Boeger, 1989, from Astronotus ocellatus (Cichlidae); Sciadicleithrum panamensis n. sp. from Aequidens coeruleopunctatus (Cichlidae); Urocleidoides flegomai n. sp. from Piabucina panamensis (Lebiasinidae); and Urocleidoides similuncus n. sp. from Poecilia gillii (Poeciliidae). Consideration of the comparative morphology and distribution of these parasites along with the evolutionary history of the host fishes suggests that diversification may be associated with geotectonic events that provided isolation of the Central American fauna with the uplift of the Panamanian Isthmus during early Pliocene (3 mya). Central America comprises a tectonically dynamic part of the world that has interested biogeographers for many years (Ro- sen, 1976; Gayet et al., 1992; Iturralde and MacPhee, 1999). This diverse region has served as a corridor for organismic dispersal from South America upwards (and vice versa), and much attention has been focused on the Isthmus of Panama as a barrier to dispersal of marine organisms (Bermingham and Martin, 1998; Perdices et al., 2002). Within this scenario, knowledge of the diversity of the parasite fauna of fishes is still limited, as is the case for the monogenoidean parasites (Scholz et al., 1999; Aguirre-Macedo et al., 2001; Vidal-Martinez et al., 2001; Choudhury et al., 2002; Mendoza-Franco et al., 2003; Aguirre-Macedo and Scholz, 2005). Although species in this group of flatworms have already been extensively studied in fish from South America (Kritsky et al., 1986; Boeger and Krit- sky, 1988; Kritsky et al., 1989, 1992; Boeger et al., 1994; Krit- sky et al., 1996, 1997; Agarwal and Kritsky, 1998; Kohn and Cohen, 1998; Kritsky and Gutierrez, 1998; Boeger and Kritsky, 2003), these same species are largely unstudied in Central America. Monogenoidean species were found during a study on metazoan parasites carried out in April 2006 in freshwater en- vironments from several localities in the surroundings of Sob- erania National Park in central Panama. In the present study, 7 dactylogyrid species (5 new) are described and/or reported from the gills of 7 fish species, and a possible explanation of the origin and speciation of these parasites in Central America based on their geographical distribution is provided. MATERIALS AND METHODS Fish were collected using beach seines, hook and line, and trammel nets from Rio Frijolito (09?09'53"N, 79?45'16"W), Lago Gatun (09?06'871"N, 79?41'721"W), and Lago Alajuela (09?15'00"N, 79?34'59.88"W) in the Chagres River Basin in central Panama. Live fish were brought to the laboratory, killed by pithing the brain, and examined for monogenoids. Worms were removed from gills, examined, and measured as temporary or permanent mounts fixed with ammonium picrate (Ergens, 1969). Additional specimens were mounted unstained in glycerin jelly for study of the sclerotized structures. All other mea- Received 25 September 2006; revised 22 February 2007; accepted 22 February 2007. ' Current address: Smithsonian Tropical Research Institute, Naos Island Laboratories, Apartado Postal 0843-03092 Balboa, Ancon, Panama City, Republic of Panama. surements were obtained from unflattened specimens fixed in hot (=90 C) or ambient temperature (=30 C) formalin (4%), stained in Gomori trichrome and mounted in Canada balsam. Drawings were made with the aid of a drawing tube using an Olympus microscope with Nomarski interference contrast. Measurements, all in micrometers, represent straight-line distances between extreme points and are expressed as the mean followed by the range and number (n) of structures measured in parentheses; body length includes that of the haptor. Numbering of hook pairs follows the scheme illustrated in Mendoza-Franco, Violante-Gon- zalez, and Vidal-Martinez (2006). Type and voucher specimens are de- posited in the United States National Parasite Collection, Beltsville, Maryland (USNPC); National Helminthological Collection of Mexico (CNHE), Institute of Biology, National Autonomous University of Mex- ico, Mexico; and the helminthological collection of the Institute of Par- asitology, Ceske Budejovice, Czech Republic (IPCAS), as indicated in the respective descriptions. Host names follow those in the Food and Agriculture Organization Fish Base (http://www.fishbase.org). DESCRIPTION Aphanoblastella chagresii n. sp. (Figs. 1-8) Diagnosis: Body fusiform, greatest width near posterior trunk. Ce- phalic margin narrow; cephalic lobes poorly to moderately developed; 3 bilateral pairs of head organs; cephalic glands indistinct. Eyes 4, pos- terior pair larger, closer together than anterior pair; accessory granules usually uncommon in cephalic region. Pharynx subspherical; esophagus moderately long. Peduncle broad; haptor subhexagonal. Ventral anchor with well-developed roots, straight shaft, elongated curved point. Dorsal anchor with short deep root, protruding superficial root, straight shaft moderately elongated, elongate curved point. Ventral bar, delicate, broadly V-shaped, with a poorly developed posteromedial protuberance; dorsal bar broadly V-shaped, bulbous ends directed laterally. Hooks similar, each with, protruding thumb, delicate shaft and point, fine shank; hook pair 1, reduced in size; FH loop about 40% shank length (pairs 2?7), 50% shank length (pair 1). Male copulatory organ (MCO) a coil of ~2.5 counterclockwise rings, base of male copulatory organ with small sclerotized plate. Accessory piece, comprising variable sheath along distal shaft of copulatory organ. Testis subspherical; sem- inal vesicle as dilation of vas deferens, indistinct, fusiform; one prostatic reservoir. Germarium subspherical to ovate, comprising comparatively few cells, slightly overlapping gonads; oviduct, ootype not observed; uterus delicate. Vaginal aperture sinistroventral, simple; vaginal canal tubular, straight to slightly slanted posteriorly into pyriform seminal receptacle. Measurements of 21 specimens studied from this host pro- vided in Table I. Taxonomic summary Type host: Catfish Pimelodella chagresi (Steindachner, 1877) (Sil- uriformes: Heptapteridae). 761 762 THE JOURNAL OF PARASITOLOGY, VOL. 93, NO. 4, AUGUST 2007 1 20 ? *. Tti **" m *. ** .??**?? \* .*??*'? t/* *, M' #^ ? * * *?? #* *? i? m 8 9 x FIGURES 1?8. Aphanoblastella chagresii n. sp. (1) Whole mount (composite, ventral view). (2) Ventral bar. (3) Hook (pair 1). (4) Dorsal bar. (5) Hook (pairs 2?7). (6) Copulatory complex (dorsal view). (7) Ventral anchor. (8) Dorsal anchor. All figures are drawn to the 20-u.m scale, except 1 (100-u.m). MENDOZA-FRANCO ET AL?DACTYLOGYRIDS FROM PANAMA 763 TABLE I. Measurements of species of Aphanoblastella from species of Pimelodella and Rhamdia (Siluriformes) in the tropics.* A. chagresiif A. travassosi^. A. travassosi^ A. travassosi\\ A. travassosi f P. chagresi P. laticeps R. guatemalensis R. quelen R. quelen Body length 236 (175-350; n = 16) 295 (180-375) 282 (204-364; n = 34) 390 (321-472) 364 (295-432; n = 11) Greatest width 63 (42-82; n = 12) 85 (65-100) 104 (77-127; n = 32) 85 (75-91) 95 (80-112; n = 11) Pharynx width 19 (14-22; n = 15) 20 (15-25) 28 (21-33; n = = 23) 26 (24-28) 24 (21-29; n = 10) Haptor width 50 (40-60; n = 8) ? 55 (45-63; n = = 31) 55 (42-61) 56 (51-74; n = 9) Ventral anchor length 20 (19-20; n = 28) 18 (15-20) 22 (21-24; n = = 13) 20 (19-21) 26 (24-29; n = 27) Ventral anchor width 10 (9-15; n = 11) ? 16 (14-17; n = = 11) 14 (13-14) 15 (14-17; n = 8) Dorsal anchor length 16 (16-17; n = 21) 15 (14-20) 24 (21-27; n = = 11) 17 (16-17) 27 (25-30; n = 20) Dorsal anchor width 8 (8-10; n = 13) ? 16 (14-18; n = = 12) 13 (12-14) 16 (14-18; n = 7) Ventral bar length 23 (20-28; n = 18) 29 (23-40) 32 (29-37; n = = 10) 30 (29-31) 30 (26-33; n = 17) Dorsal bar length 24 (20-28; n = 11) 30 (25-42) 37 (31-44; n = = 9) 23 (22-25) 35 (31-39; n = 9) Hooks pairs 1, 3?7 14 (13-14; n = 21) 15 (10-17) 13 (12-14; n = = 23) 9 (8-10) 12 (11-13; n = 20) Hooks pair 2 10 (10-11; n = 7) ? ? ? ? MCO# length 16 (15-17; n = 5) 85 (70-110) 41 (38-45; n = = 5) ? Accessory piece 18 (15-22; n = 14) 30 (25-35) 31 (28-36; n = = 4) 29 (24-32) 32 (32-33; n = 3) Germarium length 24 (19-28; n = 8) ? 28 (20-44; n = = 23) 390 (321-472) 30 (22-37; n = 8) Germarium width 25 (20-44; n = 9) ? 22 (18-25; n = = 23) ? 21 (11-30; n = 8) Testis length 29 (28-31; n = 7) ? 51 (40-59; n = = 19) ? 58 (50-66; n = 6) Testis width 27 (20-40; n = 7) ? 35 (25-46; n = = 18) ? 28 (24-37; n = 5) * Measurements (in u,m) are mean, with range in parentheses; n = number of measurements. f Present study. ? Measurements of A. travassosi from Argentina (Suriano, 1986). ? Measurements of A. travassosi from southeast Mexico (Kritsky et al., 2000). | Measurements of A. travassosi from Trinidad (Molnar et al., 1974). # Male copulatory organ. Site of infection: Gills. Type locality/collection date: Rio Frijolito (09?09'53"N, 79?45'16"W), Republic of Panama, April 2006. Specimens deposited: Holotype (CNHE 5784); 10 paratypes (CNHE 5786), 5 paratypes (IPCAS M-431), and 5 paratypes (USNPC 99625). Etymology: The specific name is derived from its host. Remarks Aphanoblastella was erected by Kritsky et al. (2000) to accommodate dactylogyrid species possessing tandem gonads, a coiled MCO with counterclockwise rings, unmodified anchors, a ventral bar with postero- medial projection, a nonarticulated MCO, and accessory piece simple and similar hooks with undilated shanks. Since then, 3 species of Aphanoblastella have been recognized from the gills of neotropical cat- fish species of Rhamdia (Siluriformes). These include: Aphanoblastella travassosi (Price, 1938) Kritsky, Mendoza-Franco, and Scholz, 2000 (type species) from Rhamdia rogersi (Regan, 1907), R. sebae (Valen- ciennes, 1840), and R. quelen (Quoy and Gaimard, 1824) (= R. gua- temalensis in Perdices et al., 2002) in Costa Rica and Trinidad, respec- tively, and from R. guatemalensis (Giinther, 1864) in Mexico; from Pimelodella laticeps Eigenmann, 1917 in Argentina; A. robustus (Miz- elle and Kritsky, 1969) Kritsky, Mendoza-Franco and Scholz, 2000 from Rhamdia sp. in the Amazon River of Brazil, and A. mastigatus (Suriano, 1986) Kritsky, Mendoza-Franco and Scholz, 2000 from R. sapo (Valenciennes, 1840) in Argentina (see Molnar et al., 1974; Sur- iano, 1986; Kritsky et al., 2000). Based on comparative haptor mor- phology, A. chagresii n. sp. most closely resembles the type species, A. travassosi (as redescribed on the basis of specimens found in R. gua- temalensis [Kritsky et al., 2000]). Aphanoblastella chagresii n. sp. dif- fers from A. travassosi by having hooks of different size and an ex- panded accessory piece (rod-shaped in A. travassosi) and by lacking a posteromedial process on the ventral bar. Additionally, it differs in its shorter ventral (length 19?20 vs. 21?24 in A. travassosi) and dorsal (length 16?17 vs. 21?27) anchors and accessory piece (length 15?22 vs. 28?36) (see Table I). It is noteworthy that A. chagresii n. sp. from P. chagresi appears to be morphometrically similar to A. travassosi reported from P. laticeps in Argentina (Suriano, 1986; Kritsky et al., 2000). Aphanoblastella chagresii n. sp. and A. travassosi occur on the same geographic range of their hosts, Pimelodella spp., and both are relatively similar in the size of their ventral (length 19?20 vs. 15?20 in A. travassosi from P. laticeps) and dorsal (length 16?17 vs. 14?20) anchors (see Table I) and in the morphology of the accessory piece (compare figures 6 [present study] and 15 from the original redescrip- tion of A. travassosi in Suriano, 1986). Further, the hook measurements (length 10?17) provided by Suriano for A. travassosi fit into the ranges (length 10?14) of A. chagresii n. sp. All above mentioned suggests that A. travassosi from P. laticeps may be a synonym of A. chagresii n. sp., in other words, the same parasite species (A. chagresii n. sp.) on Pi- melodella spp. If so, then a split between Pimelodella and Rhamdia resulted in speciation of A. chagresii n. sp. and A. travassosi, respec- tively (see phylogeny of Rhamdia in Perdices et al., 2002). Confirmation of the synonymy of A. travassosi from P. laticeps in Argentina with respect to A. chagresii n. sp. from P. chagresi in Panama will require further study of new specimens collected from P. laticeps and/or mo- lecular research. Aphanoblastella travassosi (Price, 1938) Kritsky, Mendoza-Franco and Scholz, 2000 Diagnosis: Comparative measurements by host presented in Table I. Taxonomic summary Host: Silver catfish, Rhamdia quelen (Quoy and Gaimard, 1824) (Sil- uriformes: Heptapteridae). Site of infection: Gills. Locality/collection date: Lago Alajuela (09?15'00"N, 79?34'59.88"W), Republic of Panama, April 2006. Specimens deposited: 3 reference specimens (CNHE 5786), 5 in IPCAS (M-353), and 5 in USNPC (99626). Remarks The specimens fit the diagnosis of A. travassosi, the type species of the genus, which was redescribed by Kritsky et al. (2000) on the basis of specimens found in R. guatemalensis from cenotes (= sinkholes) in southeastern Mexico. Comparison of the present material with a vouch- er of A. travassosi from R. guatemalensis from the Parasitology Labo- 764 THE JOURNAL OF PARASITOLOGY, VOL. 93, NO. 4, AUGUST 2007 ratory, CINVESTAV, Merida, Mexico (CHCM 314), did not reveal any differences. The present finding of A. travassosi on R. quelen in Panama is a new geographical record. Diaphorocleidus petrosusi n. sp. (Figs. 9-15) Diagnosis: Body 298 (242?337; n = 8) long, fusiform; greatest width 68 (57?75; n = 8) near midlengfh. Cephalic margin broad; cephalic lobes moderately developed; 3 bilateral pairs of head organs; cephalic glands indistinct. Eyes 4; members of posterior pair with conspicuous lens, larger, closer together than members of anterior pair; eye granule variable in size, usually elongate ovate; accessory granules in cephalic, anterior trunk regions. Pharynx spherical 17 (15?18; n = 7) diameter; esophagus short. Peduncle broad; haptor subhexagonal 66 (58?73; n = 7) wide. Anchors similar; each with poorly defined deep root, elongate superficial root, straight shaft, point short; ventral anchor 32 (30?34; n = 26) long, base 18 (16?20; n = 17) wide; dorsal anchor 22 (21?23; n = 15) long, base 12 (11-13; n = 11) wide. Ventral bar 24 (22-26; n = 15) long, straight to broadly U-shaped, ends enlarged, usually with anteromedial indentation; dorsal bar 20 (22?26; n = 15) long, broadly U-shaped. Hook 17 (15?18; n = 32) long, with 2 subunits; FH loop about 30% shank length. Copulatory organ a coil with about one and half counterclockwise rings, coil diameter of the first ring 16 (13?20; n = 12). Accessory piece 18 (16?20; n = 3) long, comprising a pincer shape distally that appears as 2 supporting processes. Gonads overlap- ping; testis elongate, fusiform, dorsoposterior to germarium, 12 (10?15; n = 3) long, 6 (5?8; n = 3) wide, ovate; seminal receptacle as expansion of vas deferens, sigmoid, pyriform; one prostatic reservoir. Germarium slightly oval, elongated, 44 (32-67; n = 6) long, 16 (13-20; n = 7) wide; oviduct, ootype not observed; submarginal sinistral vaginal ap- erture, a nondilated sclerotized tube into large medial seminal receptacle lying anterior to germarium; vitellaria limited in trunk, absent in regions of reproductive organs. Taxonomic summary Type host: Sabalo pipon Biycon petrosus Meek and Hildebrand, 1913 (Characiformes, Characidae). Site of infection: Gills. Type locality/collection date: Rio Frijolito (09?09'53"N, 79?45'16"W), Republic of Panama, April 2006. Specimens deposited: Holotype (CNHE 5787); 3 paratypes (CNHE 5788), 4 paratypes (IPCAS M-432), and 3 paratypes (USNPC 99627). Etymology: This species is derived from the specific name of its host. Remarks Placement of this new species in Diaphorocleidus is based on the generic diagnosis provided by Jogunoori et al. (2004), i.e., species with overlapping gonads, a coiled copulatory organ with counterclockwise rings, submarginal sinistral vaginal aperture, and hook shank with 2 subunits. The morphology of the features of the haptor and the copu- latory complex distinguish Diaphorocleidus petrosusi n. sp. from the other 4 species of the genus that occur on fish of the Characidae (Dia- phorocleidus affinis (Mizelle, Kritsky, and Crane, 1968) Jogunoori, Kritsky, and Venkatanarasaiah, 2004, from Bryconops affinis (Gunther, 1864); Diaphorocleidus armillatus Jogunoori, Kritsky, and Venkatan- arasaiah, 2004, (type species) from Gymnocorymbus ternetzi (Boulen- ger, 1895); Diaphorocleidus kabatai (Molnar, Hanek, and Fernando, 1974), Jogunoori, Kritsky and Venkatanarasaiah, 2004, from Astyanax bimaculatus (Linnaeus, 1758), and Diaphorocleidus microstomus (Miz- elle, Kritsky and Crane, 1968), Jogunoori, Kritsky and Venkatanara- saiah, 2004, from Hemigrammus microstomus Durbin, 1918) (Jogunoori et al., 2004). Diaphorocleidus petrosusi n. sp. most closely resembles D. armillatus from which it differs by having a distally pincer-shaped accessory piece (tortuous in D. armillatus), and by the comparative morphology of the dorsal anchors. Four dactylogyrid species have been described in South America: 3 from Biycon melanopterus (Cope, 1872) (Jainus amazonensis Kritsky, Thatcher, and Kayton, 1980; Tereancis- trium kerri Kritsky, Thatcher, and Kayton, 1980, and Trinibaculum bra- ziliensis Kritsky, Thatcher and Kayton, 1980) and 1 from Biycon ce- phalus (Gunther, 1869) (Annulotrematoides biyconi Cuglianna, Silva Cordeiro, and Luque, 2003) (Kritsky et al., 1980; Cuglianna et al., 2003), but none of these parasite species show similarity with Dia- phorocleidus petrosusi n. sp. Cussevia asota Kritsky, Thatcher, and Boeger, 1989 Diagnosis: Ventral anchor 25?26 long. Dorsal anchor 26 (n = 2) long; base 10?11 wide. Ventral bar 30 long; dorsal bar 28 long. Hook 10?11 long. Proximal ring diameter of the MCO 16 long. Accessory piece 31 long. Taxonomic summary Host: Red oscar, Astronotus ocellatus (Agassiz, 1831) (Perciformes: Cichlidae). Site of infection: Gills. Locality/collection date: Lago Gatun (09?06'871"N, 79?41'721"W), Republic of Panama, April 2006. Specimens deposited: 1 reference specimen (CNHE 5789). Remarks Measurements and the morphology of the sclerotized structures of the present specimen do not differ significantly from that figured in the original description. Gussevia asota is 1 of 3 originally described spe- cies (G. astronoti Kritsky, Thatcher, and Boeger, 1989 and G. rogersi Kritsky, Thatcher, and Boeger, 1989) on native A. ocellatus in South America (Brazil) and also reported from the same host species held in an aquarium in the United States (Kritsky et al., 1989). The finding of a single specimen of G. asota suggests that A. ocellatus has lost their original monogenoids since its colonization to Panama from South America. Astronotus ocellatus from Lago Gatun in Panama had only 2 specimens (one measured) on 6 fish. Thus, probably seasonality, i.e., low infection prevalences, could help to explain the absence of these South American monogenoids on A. ocellatus in Panama. Sciadicleithrum panamensis n. sp. (Figs. 16-22) Diagnosis: Body fusiform; greatest width near midlengfh. Cephalic margin broad; cephalic lobes moderately developed; 3 bilateral pairs of head organs; cephalic glands indistinct. Eyes 4; members of posterior pair closer together than members of anterior pair; eye granule usually elongate ovate. Pharynx spherical; esophagus short to moderately long. Peduncle broad; haptor subhexagonal. Ventral anchor 25 (23?27; n = 15) long, with slightly appressed roots, evenly curved shaft, short point; base 11 (11?13; n = 11) wide. Dorsal anchor 23 (22?27; n = 13) long, with slightly depressed superficial root, poorly differentiated deep root, evenly curved shaft, short point; base 9 (8?9; n = 8) wide. Ventral bar 26 (23?28; n = 9) long, broadly V-shaped, with small enlarged ends; dorsal bar 23 (22?27; n = 8) long, yoke-shaped, with slightly enlarged ends, prominent anteromedial expansion. Hooks similar, each 12 (11? 13; n = 34) long, with upright thumb, delicate point, shank; FH loop about 80% shank length. Gonads overlapping; testis ovate, dorsopos- terior to germarium; seminal vesicle as expansion of vas deferens, fu- siform; one prostatic reservoir, fusiform. MCO a coiled tube comprising 1.5 rings, base with slight flange. Accessory piece with broad basal portion terminating in diagonal opening, distal portion slightly pointed, lying within second shaft of the copulatory organ. Germarium with irregular margin; oviduct, ootype, uterus not observed. Vagina dextro- ventral, a slight sclerotized tube opening into small medial seminal re- ceptacle; vitellaria dense throughout trunk, except absent in regions of reproductive organs. Taxonomic summary Type host: Chogorro Aequidens coeruleopunctatus (Kner, 1863) (Per- ciformes: Cichlidae). Site of infection: Gills. Type locality/collection date: Rio Frijolito (09?09'53"N, 79?45'16"W), Republic of Panama, April 2006. Specimens deposited: Holotype (CNHE 5790); 2 paratypes (CNHE 5791) and 3 paratypes (USNPC 99628). Etymology: This species is named for the country from which it was collected. MENDOZA-FRANCO ET AL?DACTYLOGYRIDS FROM PANAMA 765 10 14 25 15 FIGURES 9?15. Diaphorocleidus petrosusi n. sp. (9) Whole mount (composite, ventral view). (10) Hook. (11) Copulatory complex (ventral view). (12) Ventral anchor. (13) Dorsal anchor. (14) Ventral bar. (15) Dorsal bar. All figures are drawn to the 25-u.m scale, except 9 (100-u.m). 766 THE JOURNAL OF PARASITOLOGY, VOL. 93, NO. 4, AUGUST 2007 17 25 19 20 22 FIGURES 16-22. Sciadicleithrum panamensis n. sp. (16) Whole mount (composite, ventral view). (17) Ventral anchor. (18) Ventral bar. (19) Hook. (20) Dorsal bar. (21) Dorsal anchor. (22) Copulatory complex (ventral view). All figures are drawn to the 25-u.m scale, except 16 (100-(xm). MENDOZA-FRANCO ET AL?DACTYLOGYRIDS FROM PANAMA 767 Remarks Features of the haptor (ventral bar with cavities, hook with slender shank and upright thumb) and copulatory sclerites (MCO with clock- wise rings) clearly indicate that present specimens comprise an unde- scribed species of Sciadicleithrum. This species resembles its 9 con- geners from South America by sharing the following features: a sinis- troventral vaginal aperture, overlapping gonads, absence of longitudinal lateral grooves on shaft and point of anchors, no disjunction between roots of ventral and dorsal anchors, and a copulatory organ comprising less than 2 rings (see Mendoza-Franco and Vidal-Martinez, 2005). While 2 other species of Sciadicleithrum (S. aequidens (Price and Schlueter, 1967) Kritsky, Thatcher and Boeger, 1989 and S. cavanaughi (Price, 1966) Kritsky, Thatcher, and Boeger, 1989) have apparently spe- ciated from the South American species of Aequidens maroni (= Cleith- racara maroni) (Steindachner, 1881) (Kritsky et al., 1989), speciation of S. panamensis n. sp. seems to have occurred through its host geo- graphic range, A. coeruleopunctatus in Central America (the Atlantic slope of Panama and Pacific slope of Costa Rica [Food and Agriculture Organization Fish Base, http://www.fishbase.org]). Additionally, it has been demonstrated that Aequidens is a secondary fish (i.e., ability of the host to survive high salinities), with populations not genetically isolated from each other in Panama. Similarly, that ability in the com- mon ancestor of A. coeruleopunctatus to cross short distances (e.g., to Panama from South America) through salt water could have allowed isolated populations of this host species with the consequent speciation of its monogenoid, S. panamensis n. sp. Urocleidoides flegomai n. sp. (Figs. 23-31) Diagnosis: Body fusiform 256 (200?357; n = 15) long, with parallel lateral margins; greatest width 55 (45?72; n = 13) usually at level of testis. Cephalic margin broad; cephalic lobes well developed; 3 bilateral pairs of head organs; cephalic glands distinct. Eyes 4; subequal; eye granules frequently dissociated, small, usually ovate; accessory granules (granules not associated with the eyes) present in cephalic region and anterior trunk. Pharynx spherical 16 (11?20; n = 16) in diameter; esophagus moderately long. Peduncle broad; haptor hexagonal, 59 (51? 74; n = 13). Ventral anchor 31 (28?36; n = 20) long, with elongate slightly depressed superficial root, short deep root, curved shaft, elon- gate point; base 16 (15?18; n = 13) wide. Dorsal anchor 25 (22?29; n = 18) long, with well-differentiated roots, curved shaft, elongate point; base 13 (12-15; n = 14) wide. Ventral bar 29 (24-36; n = 15) long, broadly V-shaped with enlarged terminations and a slight anteromedial indentation; dorsal bar 25 (21?32; n = 15) long, broadly U- or V-shaped, with terminations directed laterally. Hooks similar, each with protruding thumb, delicate shaft and point, dilated shank; hook pairs 1, 5 reduced in size; FH loop about 30% shank length (pairs 2, 3, 4, 6, 7), 50% shank length (pair 1); hook pairs 2, 3,4,7 ? 23 (21-25; n = 14) long; hook pairs 1,5 ? 15 (14?15; n = 10) long; hook pair 6 ? 19 (17?20; n = 19) long. Male copulatory organ a coil of ~4.5 rings, base with lateral flange, tube delicate, 13 (11?14; n = 9) diameter of the first ring. Accessory piece flabellate, 17 (15?20; n = 3) long. Vagina sinistral, a tortuous tube with distal coil connecting to a bulb prior to discharching into small medial seminal receptacle anterior to germar- ium. Gonads overlapping, germarium 13 (10?20; n = 10) long; testis dorsal, slightly visible at end of germarium; seminal vesicle a distal enlargement (expansion) of vas deferens; 1 prostatic reservoir; oviduct, ootype, uterus not observed. Vaginal sclerite 21 (20?25; n = 14) long, composed of grooved rod with distal hook, subterminal short projection. Vitellaria scattered throughout trunk, except absent in regions of repro- ductive organs. Taxonomic summary Type-host: Candela Piabucina panamensis Gill, 1877 (Characifor- mes: Lebiasinidae). Site of infection: Gills. Type locality/collection date: Rio Frijolito (09?09'53"N; 79?45'16"W), Republic of Panama, April 2006. Specimens deposited: Holotype (CNHE 5792); 5 paratypes (CNHE 5793), 5 paratypes (IPCAS M-433), and 5 paratypes (USNPC 99629). Etymology: The specific name is from Greek (flegomai = blaze, flame) and refers to the vernacular Spanish name of its host, candela. Remarks Based on the presence of sinistral vaginal sclerite, overlapping go- nads, MCO with counterclockwise rings, and hooks with enlarged shanks (pairs 1, 5 usually reduced in size), this species is considered a new member of Urocleidoides (Mizelle and Price, 1964) Kritsky, Thatcher, and Boeger, 1986. Urocleidoides includes a group of 7 trop- ical species, which parasitize fishes of the Characidae (Characidium caucanum Eigenmann, 1912), Anostomidae (Rhytiodus microlepis Kner, 1858), Curimatidae (Curimata argentea [= Steindachnerina argentea\ [Gill 1858]), and Erythrinidae (Hoplias malabaricus (Bloch, 1794)) within Characiformes and Poeciliidae (Poecilia reticulata (Peters, 1859) and Xiphophorus helleri (Heckel, 1848)) of the Cyprinodontiformes (Kritsky et al., 1986; Suriano, 1997; Jogunoori et al., 2004). Uroclei- doides flegomai n. sp. found in P. panamensis represents the first record of Urocleidoides in another family (Lebiasinidae) within Characiformes. Based on the comparative morphology of the copulatory complexes and bars, the closest relatives of U. flegomai n. sp. are U. vaginoclaustrum Jogunoori, Kritsky, and Venkatanarasaiah, 2004 from X. helleri; U. er- emitus Kritsky, Thatcher, and Boeger, 1986 from H. malabaricus; and U. anops Kritsky and Thatcher, 1974 from C. caucanum from the Neo- tropics (compare Figs. 24?28 [present study] and figs. 18, 22?25 for U. vaginoclaustrum in Jogunoori et al. [2004]; figs. 3, 6, and 7 for U. eremitus in Kritsky et al. [1986]; and 14, 16, and 17 for U. anops in Kritsky and Thatcher [1974]). Considering that the Characiformes (200 species in Africa and more than 1,200 species in the Neotropics in about 14?16 families) and Cyprinodontiformes (850 species in about 110 gen- era) comprise the most speciose assemblages of fishes in the tropics and North America (Costa, 1998), high diversification of Urocleidoides on these potential host species is to be expected. Urocleidoides similuncus n. sp. (Figs. 32-40) Diagnosis: Body 177 (168?192; n = 4) long, robust; greatest width 85?110 usually at level of testis. Cephalic margin broad; cephalic lobes well developed; 4 bilateral pairs of head organs; cephalic glands indis- tinct. Four eyes poorly developed, subequal; members of posterior pair usually farther apart than those of anterior pair; eye granules usually ovate. Pharynx spherical 19 (17?22; n = 5); esophagus short (contracted specimens). Peduncle broad; haptor subhexagonal. Anchors similar; each with robust base, truncate superficial root, well-developed deep root, angular bends at junctions of base and shaft and shaft and point; short point; ventral anchor 21 (20?22; n = 5) long; base 14 (14?15; n = 4) wide; dorsal anchor 19 (18-20; n = 6) long; base 15 (14-15; n = 5) wide. Ventral bar 25 (23?26; n = 3) long, with bulbous termina- tions; dorsal bar 22 (20?25; n = 3) long, rod-shaped to slightly arced, with enlarged ends. Hooks similar, each 10 (9?10; n = 7) long, with delicate shaft and point, protruding thumb, slightly dilated shank; FH loop about 80% shank length. Male copulatory organ a coil of ?3.25 rings, 19 (18?20; n = 3) diameter of the first ring, base with lateral flange, tube delicate. Accessory piece 20?22 long, flabellate. Gonads overlapping, germarium ovate; testis dorsal, ovate (lateral margins in- distinct); seminal vesicle a distal enlargement (expansion) of vas defer- ens; 1 prostatic reservoir; oviduct, ootype, uterus not observed. Vagina sinistral, an elongate narrow sclerotized tube coiled prior to opening into irregular medial seminal receptacle; vaginal sclerite 23 (22?26; n = 4) long, a robust rod with distal hook, subterminal short projection, proximal portion with longitudinal groove. Vitellaria dense throughout trunk, except absent in regions of reproductive organs. Taxonomic summary Type host: Molly Poecilia gillii (Kner, 1863) (Cyprinodontita, Poe- ciliidae). Site of infection: Gills. Type locality/collection date: Rio Frijolito (09?09'53"N, 79?45'16"W), Republic of Panama, April 2006. Specimens deposited: Holotype (CNHE 5794); 4 paratypes (CNHE 5795) and 2 paratypes (USNPC 99631). Etymology: The specific name is from Latin (simil/is = similar + uncus = hook) and refers to the similar size of hooks. 768 THE JOURNAL OF PARASITOLOGY, VOL. 93, NO. 4, AUGUST 2007 FIGURES 23?31. Urocleidoides flegomai n. sp. (23) Whole mount (composite, ventral view). (24) Ventral anchor. (25) Copulatory complex (dorsal view). (26) Ventral bar. (27) Dorsal anchor. (28) Dorsal bar. (29) Hook. (30) Vaginal sclerite. (31) Vagina. All figures are drawn to the 25-fj.m scale as Figure 29, except 23 (100-(jLm) and 25 (25-u.m). MENDOZA-FRANCO ET AL?DACTYLOGYRIDS FROM PANAMA 769 O FIGURES 32?40. Urocleidoides similuncus n. sp. (32) Whole mount (composite, ventral view). (33) Ventral anchor. (34) Vaginal sclerite. (35) Copulatory complex (ventral view). (36) Dorsal anchor. (37) Ventral bar. (38) Hook. (39) Dorsal bar. (40) Vagina. All figures are drawn to the 25-fj.m scale, except 32 (50-^.m) and 40 (30-(jLm). Remarks Urocleidoides similuncus n. sp. differs from congeneric species by possessing similar anchors, each with a robust base, superficial root with truncate tip, and by having hooks of similar size. It resembles U. fle- gomai n. sp., U. eremitus, and U. anops in the general morphology of the copulatory complex. Specimens of U. similuncus n. sp. from P. gillii were strongly contracted, apparently a result of premature fixation while the worms were still alive (see Fig. 32). That contraction is reflected in the comparatively shorter body lengths, measuring only 168?192 in specimens from P. gillii in the Frijolito River compared with those of U. flegomai n. sp. (length 200?357) from P. panamensis in the same locality. This is the only described species of Urocleidoides with hooks of similar size. DISCUSSION In the present study, 7 species (5 new) of monogenoids in- festing the gills of fish species of 5 families within the Chara- ciformes (Characidae and Lebiasinidae), Cyprinodontiformes (Poeciliidae), Perciformes (Cichlidae), and Siluriformes (Pi- melodidae = Heptapteridae) were found. Molecular and mor- phological comparisons suggest that South American fish taxa are the most basal groups in characid, cichlid, and pimelodid phylogeny, followed by its Neotropical forms, creating putative monophyletic sister groups (Perdices et al., 2002). Based on this conclusion and considering the morphology and host range of the monogenoidean species found in this study (species of Urocleidoides on Characiformes, species of Sciadicleithrum and Aphanoblastella on Cichlidae and Pimelodidae) the hy- pothesis of a common evolutionary history with the South American clade is supported. The current zoogeographical dis- tribution of monogenoidean species (except for G. asota) from different genera found in Panama may be initially explained by dispersal of a common ancestor of each genus to this region, i.e., by primary and/or secondary host species from parent 770 THE JOURNAL OF PARASITOLOGY, VOL. 93, NO. 4, AUGUST 2007 drainages in South America. This ability of hosts to invade new geographical areas could have allowed sufficient evolutionary time for them to overlap into different biogeographic regions to produce their own endemic lineages along with their para- sites in Central America. For instance, based on molecular data, it has been suggested that Rhamdia sp. colonized Central Amer- ica (late Pliocene, 5 mya), much later than Rivulus spp. (Cy- prinodontiformes) (15.9?18.4 mya) and the heroine cichlids (11.3-13 mya) (Perdices et al., 2002; Chakrabarty, 2006). The 2 latter groups are secondary freshwater fishes, which may have dispersed through brackish or marine water before the uplift of the Isthmus of Panama (Perdices et al., 2002). This could result in loss of the monogenoids due to a lack of tolerance to high salinities experienced during colonization. Consistent with this hypothesis, only 1 of the 3 monogenoidean species (G. asota, G. astronoti, and G. rogersi) from the gills of A. ocellatus from native habitats in South America (Brazil) was found in Panama. Furthermore, Cichla ocellaris harbors 3 species of Gussevia in South America, but none of them was found on the 5 C. ocel- laris individuals we examined. Although this also could be ex- plained by sampling error, parasitological studies on Mexican cichlids conducted since 1987 have showed only 4 species of Sciadicleithrum compared to its 9 congeners from South Amer- ica (Vidal-Martinez et al., 2001; Mendoza-Franco and Vidal- Martinez, 2005). Therefore, the possibility exists that the low number and/or absence of monogenoidean species in native cichlids from Central America and the Greater Antilles (e.g., Cuba) (Mendoza-Franco, Vidal-Martinez et al., 2006) by in- vasion of its secondary host species or its derivatives to these areas from South America (Chakrabarty, 2006) could be a result of loss of parasites (Mendoza-Franco and Vidal-Martinez, 2005). Historical factors such as geotectonic events within Cen- tral America would help to explain how these fish groups have radiated from basal lineages within Central America exhibiting their own distinct fauna and probably endemic species of mon- ogenoids, e.g., Brycon petrosus as the probable original host for those monogenoidean species (e.g., D. kabatai) infesting Astyanax spp. in the Neotropics. ACKNOWLEDGMENTS We acknowledge the Smithsonian Tropical Research Institute (STRI) for financial and logistical support. We thank R. G. Reina (STRI) for assistance with the fish collections and identifications. The final prep- aration of this contribution was conducted during the postdoctoral stay of E.F.M.F. at STRI, Republic of Panama. LITERATURE CITED AGARWAL, N, AND D. C. KRITSKY. 1998. Neotropical Monogenoidea. 33. Three new species of Ancistrohaptor n. g. (Dactylogyridae, Ancyrocephalinae) on Triportheus spp. (Teleostei, Characidae) from Brazil, with checklist of ancyrocephalines recorded from Neo- tropical characiform fishes. Systematic Parasitology 39: 59?69. AGUIRRE-MACEDO, M. L., AND T SCHOLZ. 2005. Culuwiya cichlidorum n. sp. (Digenea: Haploporidae) from the Black belt cichlid Vieja maculicauda (Pisces: Cichlidae) from Nicaragua. lournal of Para- sitology 91: 1379-1384. , , D. GONZALEZ-SOLIS, V. M. VIDAL-MARTINEZ, P. POSEL, G. ARJONA-TORRES, E. SIU ESTRADA, AND S. DUMAILO. 2001. Larval helminths parasitizing freshwater fishes from the Atlantic Coast of Nicaragua. Comparative Parasitology 68: 42?51. BERMINGHAM, E., AND A. P. MARTIN. 1998. Comparative mtDNA phy- logeography of Neotropical freshwater fishes: Testing shared his- tory to infer the evolutionary landscape of lower Central America. Molecular Ecology 7: 499-517. BOEGER, W A., AND D. C. KRITSKY. 1988. Neotropical Monogenoidea. 12. Dactylogyridae from Serrasalmus nattereri (Cypriniformes, Serrasalmidae) and aspects of their morphologic variation and dis- tribution in the Brazilian Amazon. Proceedings of the Helminthol- ogical Society of Washington 55: 188?213. , AND . 2003. Parasites, fossils and geologic history: His- torical biogeography of the South American freshwater croakers, Plagioscion species (Teleostei, Sciaenidae). Zoologica Scripta 32: 3-11. , , AND E. BELMONT-IEGU. 1994. Neotropical Monoge- noidea. 20. Two new species of oviparous Gyrodactylidea (Polyon- choinea) from Loricariid catfishes (Siluriformes) in Brazil and the phylogenetic status of Ooegyrodactylidae Harris, 1983. lournal of Helminthological Society of Washington 61: 34?44. CHAKRABARTY, P. 2006. Systematics and historical biogeography of Greater Antillean Cichlidae. Molecular Phylogenetic and Evolution 39: 619-627. CHOUDHURY, A., R. HARTVIGSEN-DAVERDIN, AND D. R. BROOKS. 2002. Wallinia chavarriae sp n. (Trematoda: Macroderoididae) in Asty- anax aeneus (Gunther, 1860) and Bryconamericus scleroparius (Regan, 1908) (Osteichthyes: Characidae) from the area de conser- vacion, Guanacaste, Costa Rica. lournal of Parasitology 88: 107? 112. COSTA, W I. E. M. 1998. Phytogeny and classification of the Cypri- nodontiformes (Euteleostei: Atherinomorpha): A reappraisal. In Phylogeny and classification of Neotropical fishes, L. R. Malabar- ba, R. E. Reis, R. P. Vari, Z. M. Lucena, and C. A. S. Lucena (eds.). Edipucrs, Porto Alegre, Brazil, p. 537?560. CUGLIANNA, A. M., N. DA SILVA CORDEIRO, AND I. L. LUQUE. 2003. Annulotrematoides biyconi sp. n. (Monogenea: Dactylogyridae) parasitic on Brycon cephalus (Osteichthyes: Characidae) from Bra- zil. Folia Parasitologica 50: 272?274. ERGENS, R. 1969. The suitability of ammonium picrate-glycerin in pre- paring slides of lower Monogenoidea. Folia Parasitologica 16: 320. GAYET, M., J. C. RAGE, T SEMPERE, AND P. Y. GAGNIER. 1992. Mode of interchanges of continental vertebrates between North and South America during the late Cretaceous and Paleocene. Bulletin de la Societe Geologique de France 6: 781?791. ITURRALDE-VINENT, M. A., AND R. D. E. MACPHEE. 1999. Paleogeog- raphy of the Caribbean region: Implications for Cenozoic bioge- ography. Bulletin of the American Museum of Natural History 238: 1-95. IOGUNOORI, W, D. C. KRITSKY, AND I. VENKATANARASAIAH. 2004. Neo- tropical Monogenoidea. 46. Three new species from the gills of introduced aquarium fishes in India, the proposal of Heterotylus n. g. and Diaphorocleidus n. g., and the reassignment of some pre- viously described species of Urocleidoides Mizelle & Price, 1964 (Polyonchoinea: Dactylogyridae). Systematic Parasitology 58: 115-124. KOHN, A., AND S. C. COHEN. 1998. South American Monogenea ? List of species, hosts and geographical distribution. International lour- nal for Parasitology 28: 1517-1554. KRITSKY, D. C, W A. BOEGER, AND M. IEGU. 1996. Neotropical Mon- ogenoidea. 28. Ancyrocephalinae (Dactylogyridae) of piranha and their relatives (Teleostei, Serrasalmidae) from Brazil and French Guiana: Species of Notozothecium Boeger and Kritsky, 1988, and Mymarothecium gen. n. lournal of the Helminthological Society of Washington 63: 153-175. , , AND . 1997. Neotropical Monogenoidea. 29. Ancyrocephalinae (Dactylogyridae) of piranha and their relatives (Teleostei, Serrasalmidae) from Brazil: Species of Amphitecium Boeger and Kritsky, 1988, Heterothecium gen. n. and Pithanothe- cium gen. n. lournal of the Helminthological Society of Washington 64: 25-54. , , , AND L. R. VAN EVERY. 1992. Neotropical Monogenoidea. 17. Anacanthorus Mizelle and Price, 1965 (Dac- tylogyridae, Anacanthorinae) from characoid fishes. lournal of the Helminthological Society of Washington 59: 25?51. , AND P. A. GUTIERREZ. 1998. Neotropical Monogenoidea. 34. Species of Demidospermus (Dactylogyridae, Ancyrocephalinae) from the gills of pimelodids (Teleostei, Siluriformes) in Argentina. MENDOZA-FRANCO ET AL?DACTYLOGYRIDS FROM PANAMA 771 Journal of the Helminthological Society of Washington 65: 147? 159. , E. F. MENDOZA-FRANCO, AND T. SCHOLZ. 2000. Neotropical Monogenoidea. 36. Dactylogyrids from the gills of Rhamdia gua- temalensis (Siluriformes: Pimelodidae) from cenotes of the Yucatan Peninsula, Mexico, with proposal of Ameloblastella gen. n. and Aphanoblastella gen. n. (Dactylogyridae: Ancyrocephalinae). Com- parative Parasitology 67: 76?84. , AND V. E. THATCHER. 1974. Monogenetic Trematodes (Mono- pisthocotylea: Dactylogyridae) from freshwater fishes of Colombia, South America. Journal of Helminthology 48: 59?66. , , AND W. A. BOEGER. 1986. Neotropical Monogenea. 8. Revision of Urocleidoides (Dactylogyridae, Ancyrocephalinae). Proceedings of the Helminthological Society of Washington 53: 1? 37. , , AND . 1989. Neotropical Monogenoidea. 15. Dactylogyrids from gills of Brazilian Cichlidae with proposal of Sciadicleithrum gen. n. (Dactylogyridae). Proceedings of the Hel- minthological Society of Washington 56: 128?140. -, AND R. J. KAYTON. 1980. Neotropical Monogenoidea. 3. Five new species from South America with the proposal of Ter- eancistrium gen. n. and Trinibaculum gen. n. (Dactylogyridae: An- cyrocephalinae). Acta Amazonica 10: 411?417. MENDOZA-FRANCO, E. E, P. POSEL, AND S. DUMAILO. 2003. Monogeneans (Dactylogyridae, Ancyrocephalinae) of freshwater fishes from the Caribbean coast of Nicaragua. Comparative Parasitology 70: 1?11. , AND V. M. VIDAL-MARTINEZ. 2005. Phylogeny of species of Sciadicleithrum (Monogenoidea: Ancyrocephalinae), and their his- torical biogeography in the Neotropics. Journal of Parasitology 91: 253-259. , , Y. CRUZ-QUINTANA, AND F L. PRATS-LEON. 2006. Monogeneans from freshwater fishes from Cuba with description of Salsuginus cubensis sp. n. from the Limia vittata. Systematic Parasitology 64: 181-190. , J. VlOLANTE-GONZALEZ, AND V. M. VlDAL-MARTINEZ. 2006. Cornutohaptor nigrescensi n. gen. and n. sp. (Monogenoidea: Di- plectanidae) from the gills of the black snook Centropomus ni- grescens (Perciformes, Centropomidae) of the Pacific coast of Mex- ico. Journal of Parasitology 92: 481?485. MIZELLE, J. D., AND D. C. KRITSKY. 1969. Studies on monogenetic Trematodes. XXXIX. Exotic species of Monopisthocotylea with the proposal of Archidiplectanum gen. n. and Longihaptor gen. n. American Midland Naturalist 81: 370-386. , , AND J. W CRANE. 1968. Studies on monogenetic Trem- atodes. XXXVIII. Ancyrocephalinae from South America with the proposal of Jainus gen. n. American Midland Naturalist 80: 186? 198. , AND E. W PRICE. 1964. Studies on monogenetic trematodes. XXVII. Dactylogyrid species with the proposal of Urocleidoides gen. n. Journal of Parasitology 50: 579?584. MOLNAR, K., G. HANEK, AND C. H. FERNANDO. 1974. Ancyrocephalids (Monogenea) from freshwater fishes of Trinidad. Journal of Para- sitology 60: 914-920. PERDICES, A., E. BERMINGHAM, A. MONTILLA, AND I. DOADRIOB. 2002. Evolutionary history of the genus Rhamdia (Teleostei: Pimelodi- dae) in Central America. Molecular Phylogenetics and Evolution 25: 172-189. PRICE, E. W 1938. The monogenetic trematodes of Latin America. Liv- ro Jubilar Professor Travassos, Rio de Janeiro, Brazil, 3: 407?413. . 1966. Urocleidus cavanaughi, a new monogenetic trematode from the gills of the keyhole cichlid, Aequidens maroni (Stein- dachner). Bulletin of the Georgia Academy of Science 24: 117? 120. , AND E. A. SCHLUETER. 1967. Two new monogenetic Trematodes from South America. Journal of the Tennessee Academy of Science 42: 23-25. ROSEN, D. E. 1976. A vicariance model of Caribbean biogeography. Systematic Zoology 24: 431-464. SCHOLZ, T, M. L. AGUIRRE-MACEDO, G. SALGADO-MALDONADO, J. VAR- GAS-VAZQUEZ, V M. VIDAL-MARTINEZ, R. WOLTER, R. KUCHTA, AND W KORTING. 1999. Redescription of Pseudoacanthostomum panamense Caballero, Bravo-Hollis and Grocott, 1953 (Digenea: Acanthostomidae), a parasite of Siluriform fishes of the family Ari- idae, with notes on its biology. Journal of the Helminthological Society of Washington 66: 146-154. SURIANO, D. M. 1986. El genero Urocleidoides Mizelle y Price, 1964 (Monogenea: Ancyrocephalidae). Anatomia y posicion sistematica. Urocleidoides mastigatus sp. nov. y U. travassosi (Price, 1934) Molnar, Hanek y Fernando, 1974 parasitas de Rhamdia sapo (Va- lenciennes, 1840) Eigenmann y Eigenmann, 1888 y Pimelodella laticeps Eigenmann, 1917 (Pisces: Siluriformes) de la Laguna de Chascomus, Republica Argentina. Physis (Buenos Aires), Seccion B 44: 73-80. . 1997. The genus Urocleidoides Mizelle and Price, 1964 (Monogenea: Ancyrocephalidae) parasitizing characoidei fishes in Argentina. Physis (Buenos Aires), Section B 53: 1?6. VIDAL-MARTINEZ, V. M., M. L. AGUIRRE-MACEDO, T SCHOLZ, D. GON- ZALEZ-SOLIS, AND E. F MENDOZA-FRANCO. 2001. Atlas of the hel- minth parasites of cichlid fishes of Mexico. Academy of Sciences, Prague, Czech Republic, 185 p. , T SCHOLZ, AND M. L. AGUIRRE-MACEDO. 2001. Dactylogyridae of cichlid fishes from Nicaragua, Central America with descriptions of Gussevia herotilapiae and three new species of Sciadicleithrum (Monogenea: Ancyrocephalinae). Comparative Parasitology 68: 76-86.