J. Parasitol., 94(4), 2008, pp. 793-802 ? American Society of Parasitologists 2008 FIVE NEW SPECIES OF UROCLEIDOIDES (MONOGENOIDEA) (MIZELLE AND PRICE 1964) KRITSKY, THATCHER, AND BOEGER, 1986, PARASITIZING THE GILLS OF PANAMANIAN FRESHWATER FISHES Edgar F. Mendoza-Franco* and Ruth G. Reina Smithsonian Tropical Research Institute, Apartado 0843-03092 Balboa, Ancon, Panama, Republic of Panama. e-mail: mfranco@mda.cinvestav.mx ABSTRACT: During an investigation of gill monogenoidean parasites from freshwater fishes in central Panama, 5 new species of Urocleidoides (sensu stricto) were found: Urocleidoides cultellus n. sp., Urocleidoides visiofortatus n. sp., and Urocleidoides advenai n. sp. from the gymnotiform Brachyhypopomus occidentalis (Hypopomidae); Urocleidoides neotropicalis n. sp. and Urocleidoides piriatiu n. sp. from the characiforms Saccodon dariensis (Parodontidae) and Ctenolucius beani (Ctenoluciidae), respectively. Our findings represent the first known species of Urocleidoides from these fishes in Central America and demonstrate that they are morphologically linked to their South American congeners. Urocleidoides Mizelle and Price 1964 (Monogenoidea: Dac- tylogyridae) (as amended by Kritsky et al., 1986), accommo- dates species possessing overlapping or tandem gonads, a coiled male copulatory organ with counterclockwise rings, a sinistral vaginal sclerite, unmodified anchors, and similar hooks with dilated shanks, and hooks pairs 1, 5, usually reduced in size. According to this diagnosis, 6 species of Urocleidoides {Uro- cleidoides anops Kritsky and Thatcher, 1974, from Characi- dium caucanum Eigenman 1912 [Characidae]; Urocleidoides curimatae Molnar, Hanek and Fernando, 1974 from Curimata argentea, Gill 1858 [Curimatidae]; Urocleidoides eremitus Kritsky, Thatcher and Boeger, 1986, from Hoplias malabaricus (Bloch, 1794) [Erythrinidae]; Urocleidoides hypopomi Suriano, 1997 from Hypopomus brevirostris Steindachner, 1868 [syn. Brachychypopomus brevirostris [Hypopomidae] [as Rhamphi- chthyidae in Suriano, 1997]; Urocleidoides paradoxus Kritsky, Thatcher and Boeger, 1986, from Rhytiodus microlepis Kner, 1858 [Anostomidae]; and Urocleidoides reticulatus Mizelle and Price, 1964, from Poecilia reticulata Peters 1859 [Poeciliidae]) have been reported from South American fishes (Brazil, Trini- dad, Argentina, and Colombia) (Kritsky et al., 1986; Suriano, 1997). Additionally, 3 other species (Urocleidoides flegomai Mendoza-Franco, Aguirrre-Macedo and Vidal-Martinez, 2007 from Piabucina panamensis Gill, 1877 [Lebiasinidae]; Uro- cleidoides similuncus Mendoza-Franco, Aguirrre-Macedo and Vidal-Martinez, 2007, from Poecilia gillii [Kner, 1863] [Poe- ciliidae] ; and Urocleidoides vaginoclaustrum Jogunoori, Krit- sky and Venkatanarasaiah, 2004, from Xiphophorus helleri Heckel 1848 [Poeciliidae]) of this parasite genus have been described from the Neotropics (Jogunoori et al., 2004; Men- doza-Franco et al., 2007). Herein, 3 and 2 new species of Uro- cleidoides from the gills of Brachychypopomus occidentalis (Regan, 1914) (Hypopomidae) and the characiforms Saccodon dariensis Meek and Hildebrand, 1913 (Parodontidae) and Cten- olucius beani (Fowler, 1907) (Ctenoluciidae), respectively, are described. Received 22 August 2007; revised 14 January 2008; accepted 14 Jan- uary 2008. * Also at: Laboratory of Parasitology, Centro de Investigacion y de Estudios Avanzados (CINVESTAV, Unidad Merida), Carretera Anti- gua a Progreso Km. 6, Apartado Postal 73 "Cordemex", C.P. 97310 Merida, Yucatan, Mexico. MATERIALS AND METHODS Fishes were collected with the use of electrofishing and trammel nets from Aguas Claras River at its confluence with the Bayano Lake (09?15'05.1"N, 78?41'11.2"W) and Rio Piriati River (09?03'36"N, 78?39'57"W) at its confluence with the Chagres River Basin in central Panama. Methods of collection, preparation of helminths for study, and measurement and illustration follow Mendoza-Franco et al. (2007). To study sclerotized structures, some specimens were mounted unstained in glycerin jelly. Measurements, all in micrometers (p,m), 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 the haptor. Numbering (distribution) of hook pairs follows Mizelle (1936; see Mizelle and Price, 1963). Type and vouchers specimens are deposited in the United States National Parasite Collection, Beltsville, Maryland (USNPC) and in the National Helminthological Collection of Mexico (CNHE), Institute of Biology, National Autonomous University of Mexico, Mexico, as indicated in the respective descriptions. Names and hosts follow those provided in FishBase (Froese and Pauly, 2004). DESCRIPTION Urocleidoides cultellus n. sp. (Figs. 1-10) Diagnosis: Body fusiform 385 (165?712; n = 4) long, robust; great- est width 64 (41?76; n = 5) usually at level of testis. Cephalic margin broad; cephalic lobes moderately developed; 3 bilateral pairs of head organs; cephalic glands indistinct. Eyespots absent; accessory granules scattered in cephalic region and anterior trunk. Pharynx spherical 13 (12?18; n = 4) in diameter; esophagus moderately long. Peduncle broad; haptor subrectangular, 72 (65?85; n = 3). Ventral anchor 40 (39? 43; n = 10) long, with elongate tapered superficial root, short deep root, proximally bent shaft, short point; base 23 (23?24; n = 5) wide. Dorsal anchor 24 (23?25; n = 7) long, poorly differentiated deep root, curved shaft, with bifurcate points; base 15 (15?16; n = 7) wide. Ventral bar 44 (42?47; n = 6) long, wide U-shaped with enlarged terminations; dorsal bar 37 (35?42; n = 4) long, with enlarged ends. Hooks similar, each with recurved point, depressed thumb, dilated shank; hook pairs 1, 5 reduced in size; filamentous booklet (FH) loop half shank length (pairs 1, 5), one-quarter shank length (pairs 2, 3, 4, 6, 7); hook pair 1? 27 (26-29; n = 4) long; hook pair 2?45 (45-46; n = 4) long; hook pairs 3, 4 and 6?37 (36-37; n = 10) long; hook pair 5?17 (n = 4) long; hook pair 7?52 (51?52; n = 4) long. Male copulatory organ a coil of about 5 counterclockwise rings, base with lateral flange, 22 (n = 2) diameter of the first ring. Accessory piece tripartite, 35 (n = 2) long. Vagina ventral, a convoluted tube opening at the level of left intestinal caecum; seminal receptacle midventral, small. Gonads over- lapping, testis dorsal, slightly visible at end of germarium; seminal ves- icle a distal enlargement (expansion) of vas deferens; 1 prostatic res- ervoir; oviduct, ootype, uterus not observed. Vaginal sclerite 24 (23? 27; n = 4) long, composed of grooved rod distally hooked. Vitellaria scattered throughout trunk, absent in regions of reproductive organs. 79.3 794 THE JOURNAL OF PARASITOLOGY, VOL. 94, NO. 4, AUGUST 2008 MENDOZA-FRANCO AND REINA? NEW SPECIES OF UROCLEIDOIDES 795 Taxonomic summary Type host: Knifefish B. occidentalis (Regan, 1914) (Gymnotiformes: Hypopomidae). Site of infection: Gills. Type locality/collection date: Aguas Claras River at its confluence with the Bayano Lake (09?15'05.1"N, 78?41'11.2"W), Republic of Pan- ama, September 2006. Specimens deposited: Holotype, CNHE 6019; 4 paratypes, CNHE 6020; 3 paratypes, USNPC 100679. Etymology: The specific name is from Latin (cultellus = a little knife) and refers to the common name of its host, the knifefish. Taxonomic summary Type host: Dormilon Saccodon dariensis Meek and Hildebrand, 1913 (Characiformes: Parodontidae). Site of infection: Gills. Type locality/collection date: Piriati River at its confluence with the Chagres River Basin (09?03'36"N, 78?39'57"W), Republic of Panama, September 2006. Specimens deposited: Holotype, CNHE 6021; 18 paratypes, CNHE 6022; 10 paratypes, USNPC 100680. Etymology: This species is named for the geographical area from which it was collected. Remarks Based on comparisons of the haptor, reproductive organs, and cop- ulatory complex morphology, U. cultellus n. sp. most closely resembles Urocleidoides carapus Mizelle and Kritsky, 1969, and Urocleidoides gymnotus Mizelle, Kritsky and Crane, 1968 from Gymnotus carapo (Linnaeus, 1758) (Gymnotiformes: Gymnotidae) from the Amazon Riv- er in Brazil (both considered by Kritsky et al. [1986] as being members of the Urocleidoides sensu lato group) and U. hypopomi from H. bre- virostris (syn. B. brevirostris) (Hypopomidae) in Argentina (see Mizelle et al., 1968; Suriano, 1997). Urocleidoides cultellus n. sp. differs from these 3 latter monogenoidean species by having a coiled male copula- tory organ with 5 rings (ranging from 2 to 3 rings and from 7 to 9 rings in U. carapus and U. gymnotus, respectively), dorsal bar with enlarged ends (arched posteriorly with hooked ends in U. gymnotus), and dorsal anchors with bifurcate points (absent in U. gymnotus and U. hypopomi). Additionally, it differs in the size of its hooks; hook pair 2 (length 45? 46 vs. 31?36 in U. carapus and 26?30 in U. gymnotus), and hook pair 7 (length 51?52 vs. 42?44 in U. carapus and 26?30 in U. gymnotus) (see Mizelle et al., 1968; Suriano, 1997; present study). Urocleidoides neotropicalis n. sp. (Figs. 11-19) Diagnosis: Body fusiform 202 (150?275; n = 16) long; greatest width 73 (57?85; n = 12) at various points along the trunk. Cephalic margin broad; cephalic lobes moderately developed; 3 bilateral pairs of head organs; cephalic glands distinct, posterolateral to pharynx. Eye- spots absent; accessory granules scattered in cephalic region and ante- rior trunk. Pharynx spherical, 14 (9?15; n = 19) in diameter; esophagus moderately long. Peduncle broad; haptor globose, 49 (41?56; n = 14) wide. Ventral anchor 29 (28?30; n = 18) long, with well-differentiated roots, elongate superficial root, distally round deep root, curved shaft, elongate point; base 16 (15?17; n = 19) wide. Dorsal anchor 26 (25? 27; n = 11) long, with poorly differentiated deep root, straight shaft, elongate point; base 13 (12?13; n = 7) wide. Ventral bar 24 (21?27; n = 14) long, broadly U-shaped with enlarged terminations and a slight indentation; dorsal bar 28 (26?32; n = 16) long, broadly U- or V-shaped, with posteromedial projection. Hooks similar, each with pro- truding thumb, delicate shaft and point, dilated shank; hook pairs 1, 5 reduced in size; filamentous booklet (EH) loop of hook extending to union of shank subunits; hook pairs 2, 3, 4, 6, 7?16 (14?17; n = 19) long; hook pairs 1, 5?10 (10?11; n = 12) long. Male copulatory organ a coil of about 5% counterclockwise rings, bulbous base with lateral flange, tube delicate, first ring 17 (13?19; n = 11) in diameter. Acces- sory piece simple, 30 (29?33; n = 4) long, terminating in a perpendic- ular opening. Vagina sinistral, a corrugated, bulb shaped, slightly scler- otized connected to small medial seminal receptacle anterior to ger- marium. Gonads overlapping, germarium 25 (19?31; n = 7) long, 18 (15?30; n = 6) wide; testis dorsal, slightly visible at end of germarium; seminal vesicle a distal enlargement (expansion) of vas deferens; 1 pros- tatic reservoir; oviduct, ootype, uterus not observed. Vaginal sclerite 34 (33?36; n = 12) long, robust, a grooved rod distally hooked. Vitellaria scattered throughout trunk, except absent in regions of reproductive organs. Remarks This species is easily differentiated from other congeneric species by having a male copulatory organ with 5% rings (ranging from 2 to 2% rings in U. piriatiu n. sp., U. eremitus, U. visiofortatus n. sp., and U. paradoxus), a corrugated bulb shaped of the sinistral vaginal aperture (convoluted vaginal tube in U. cultellus n. sp. and as a short tube in midventral position in U. visiofortatus n. sp.) and by having a robust vaginal sclerite (length 34 vs. 24 and 23 in U. cultellus n. sp. and U. visiofortatus n. sp., respectively). Urocleidoides piriatiu n. sp. (Figs. 20-29) Diagnosis: Body 258 (215?307; n = 9) long, broad, robust, foliform; greatest width 95 (87?105; n = 8) usually at level of gonads. Cephalic margin broad; cephalic lobes moderately developed; 3 bilateral pairs of head organs; cephalic glands indistinct. Eyespots absent; small acces- sory granules present in cephalic region. Pharynx spherical 15 (13?18; n = 9) in diameter; esophagus inconspicuous. Haptor hexagonal, 53 (48-65; n = 8). Ventral anchor 32 (30-34; n = 8) long, with depressed superficial root, distally tapered deep root, proximally bent shaft, short recurved point; base 15 (14?16; n = 6) wide. Dorsal anchor 25 (23? 26; n = 10) long, with well-differentiated roots, curved shaft, moder- ately elongate point; base 12 (11?12; n = 6) wide. Ventral bar 28 (26? 30; n = 5) long, rod-shaped with enlarged extremities; dorsal bar 27 (26?29; n = 5) long, broadly V-shaped with posteromedial projection. Hooks similar, each with depressed thumb, delicate shaft and point, dilated shank composed of two subunits; hook pairs 1, 5 reduced in size; filamentous booklet (EH) loop Vi shank length (pairs 2, 3, 4, 6, 7), Vi shank length (pair 1); hook pairs 2, 3, 4, 6?17 (n = 3) long; hook pair 7?21 (20-21; n = 8) long; hook pairs 1, 5?15 (14-15; n = 5) long. Male copulatory organ a coil of about 2 rings, base with lateral flange, tube delicate, first ring 20 (19?22; n = 3) in diameter. Accessory piece, 24 (20?29; n = 5) long, comprising 2 subunits; dextral subunit terminally acute; sinistral subunit bottle-shaped. Vagina sinistral, a del- icate tube with a distal ovate bulb guarding aperture; seminal receptacle midventral, anterior to germarium. Gonads overlapping, germarium 52 (50-62; n = 5) long, 22 (20-23; n = 5) wide; testis dorsal, slightly visible at end of germarium; seminal vesicle a distal enlargement (ex- pansion) of vas deferens; 1 prostatic reservoir; oviduct, ootype, uterus not observed. Vaginal sclerite 31 (29?32; n = 3) long, delicate, slender with distal hook, subterminal short projection. Vitellaria scattered throughout trunk, absent in regions of reproductive organs. Taxonomic summary Type host: Ctenolucius beani (Fowler, 1907) (Characiformes: Cten- oluciidae). Site of infection: Gills. Type locality/collection date: Piriati River at its confluence with the Chagres River Basin (09?03'36"N, 78?39'57"W), Republic of Panama, September 2006. Specimens deposited: Holotype, CNHE 6023; 8 paratypes, CNHE 6024; 6 paratypes, USNPC 100681. FIGURES 1?10. Urocleidoides cultellus n. sp. (1) Whole mount (composite, ventral view). (2) Vagina. (3) Copulatory complex (ventral). (4) Ventral anchor. (5) Dorsal anchor. (6) Vaginal sclerite. (7) Hook (pair 5). (8) Hook (pair 7). (9) Ventral bar. (10) Dorsal bar. All figures are drawn to the 25-u.m scale, except 1 (50-u.m), 2 (20-jxm), and 3 (30-jxm). 796 THE JOURNAL OF PARASITOLOGY, VOL. 94, NO. 4, AUGUST 2008 16 18 in 17 o MENDOZA-FRANCO AND REINA? NEW SPECIES OF UROCLEIDOIDES 797 Etymology: This species is named for the locality from which it was collected. Remarks This species resembles U. neotropicalis n. sp. from S. dariensis in the general morphology of its bars, especially by the presence of a posteromedial projection on dorsal bar. Urocleidoides piriatiu n. sp. differs from U. neotropicalis n. sp. in having a coiled male copulatory organ with 2 rings (4% in U. neotropicalis n. sp.) and by having ventral anchors with depressed superficial roots (tapered superficial root in U. neotropicalis n. sp.). These are the only described species of Uroclei- doides possessing a medial projection on posterior margin of its dorsal bars. Urocleidoides visiofortatus n. sp. (Figs. 30-38) Diagnosis: Body fusiform 208 (175?238; n = 8) long, with irregular margins; greatest width 63 (52?75; n = 8) usually at level of testis. Cephalic margin broad; cephalic lobes moderately developed; 3 bilateral pairs of head organs; cephalic glands indistinct. Eyespots absent; ac- cessory granules present in cephalic region and anterior trunk. Pharynx spherical 13 (11?15; n = 7) in diameter; esophagus moderately long. Peduncle almost inconspicuous; haptor subrectangular, 52 (48?58; n = 6). Ventral anchor 40 (37?44; n = 17) long, strong, with prominent superficial root, distally rounded deep root, evenly curved shaft, elon- gate point; base 19 (18?22; n = 9) wide. Dorsal anchor 25 (23?26; n = 5) long, strongly tapered superficial root, poorly developed deep root, curved shaft, elongate point; base 12 (n = 2) wide. Ventral bar 34 (30? 38; n = 9) long, with bulbous extremities, a slight anteromedial inden- tation; dorsal bar 17 (16?19; n = 6) long, slightly V-shaped. Hooks similar, each with protruding thumb, delicate shaft and point, dilated shank; filamentous booklet (FH) loop of hook extending to union of shank subunits; hooks 1,2,3, 4, 6, 7?20 (20?22; n = 11) long; hook pair 5?16 (15?17; n = 5). Male copulatory organ a delicate tube of about Wi rings, base with subrectangular flange, 21 (18?23; n = 4) diameter of the first ring. Accessory piece, an arched grooved rod, 19 (19?20; n = 3) long. Vagina ventral, a shorter delicate tube opening in a sclerotized atrium at level of a small bulb lying left to intestinal cecum; seminal receptacle midventral, small, anterior to germarium. Gonads overlapping, germarium 26 (20?30; n = 3) long, 16 (15?17; n = 3) wide; 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 23 (20? 25; n = 4) long, composed of grooved rod with distal hook. Vitellaria scattered throughout trunk, absent in regions of reproductive organs. Taxonomic summary Type host: Knifefish B. occidentalis (Regan, 1914) (Gymnotiformes: Hypopomidae). Site of infection: Gills. Type locality/collection date: Aguas Claras River at its confluence with the Bayano Lake (09?15'05.1"N, 78?41'11.2"W), Republic of Pan- ama, September 2006. Specimens deposited: Holotype, CNHE 6025; 4 paratypes, CNHE 6026; 4 paratypes, USNPC 10682. Etymology: The specific name is from Latin (visio = appearance + fortis = robust) and refers to the robust ventral anchors of this species. Remarks This species differs significantly from other congeneric forms by the relative size of the ventral and dorsal anchors and by having an arched rod-shaped accessory piece. Urocleidoides visiofortatus n. sp. resembles U. cultellus n. sp. in having a vagina in midventral position but it differs from this latter species by having shorter vaginal tube (a convoluted tube in U. cultellus n. sp.) and a wider vaginal aperture (small opening in U. cultellus n. sp.). Urocleidoides advenai n. sp. (Figs. 39-45) Description: Body fusiform 185 (128?242; n = 12) long, with par- allel lateral margins; greatest width 48 (27?60; n = 10) usually at level of testis. Cephalic margin broad; cephalic lobes moderately developed; 3 bilateral pairs of head organs; cephalic glands indistinct. Eyespots absent. Pharynx spherical 10 (9?15; n = 12) in diameter; esophagus short to nonexistent. Peduncle inconspicuous; haptor hexagonal, 39 (35? 47; n = 7). Ventral anchor 11 (10?12; n = 15) long, with elongate slightly depressed superficial root, short deep root, curved shaft, elon- gate point; base 7 (6?8; n = 6) wide. Dorsal anchor 25 (23?26; n = 7) long, with poorly differentiated deep root, evenly curved shaft, point; base 10 (n = 3) wide. Ventral bar 19 (17?22; n = 11) long, usually straight, rod shaped with slightly enlarged ends; dorsal bar 16 (14?18; n = 7) long, rod shaped with slight terminal enlargements. Hooks sim- ilar, each with protruding thumb, delicate shaft and point, dilated shank; filamentous booklet (FH) loop of hook extending to union of expanded shank; hooks 11 (9?12; n = 8) long. Male copulatory organ a delicate tube of about 1 ring, base with subrectangular flange, 15 (13?17; n = 6) diameter of the first ring. Accessory piece 14 (13?15; n = 4) long, comprising delicate sheath enclosing distal portion of the copulatory organ. Vagina sinistral, submarginal, a delicate tube leading to medial seminal receptacle anterior to germarium. Gonads overlapping, germar- ium 24 (20-30; n = 3) long, 10 (9-12; n = 3) wide; testis dorsal, slightly visible at end of germarium; seminal vesicle a distal enlarge- ment (expansion) of vas deferens; 1 prostatic reservoir; oviduct, ootype, uterus not observed. Vitellaria scattered throughout trunk, except absent in regions of reproductive organs. Taxonomic summary Type host: Knifefish B. occidentalis (Regan, 1914) (Gymnotiformes: Hypopomidae). Site of infection: Gills. Type locality/collection date: Aguas Claras River at its confluence with the Bayano Lake (09?15'05.1"N, 78?41'11.2"W), Republic of Pan- ama, September 2006. Specimens deposited: Holotype, CNHE 6027; 6 paratypes, CNHE 6028; 6 paratypes, USNPC 100683. Etymology: The specific name is from Latin (advena = a stranger, foreigner) and refers to the fact that this species lives with 2 species of Urocleidoides (U. cultellus n. sp. and U. visiofortatus n. sp.) on the gills of same host species. Remarks Urocleidoides advenai n. sp. differs from all congenitors in lacking a vaginal sclerite. In all other features this species resembles notably, in some details, the morphology of the species of Urocleidoides being described herein. All species share the unusual morphology of the base (i.e., with presence of a flange) of the MCO, the general morphology of the MCO itself and of the accessory piece; the general distribution of organs and even the morphology of the hook. The only major dif- ference is the absence, in this species, of the vaginal sclerite and does not support proposal of a new genus for this unique species. DISCUSSION The present study represents the first report of species of Urocleidoides (sensu stricto) (U. cultellus n. sp., U. neotropi- calis n. sp., U. piriatiu n. sp., U. visiofortatus n. sp., and U. advenai n. sp.) parasitizing freshwater fishes (B. occidentalis FIGURES 11?19. Urocleidoides neotropicalis n. sp. (11) Whole mount (composite, ventral view). (12) Vaginal sclerite. (13) Copulatory complex (ventral). (14) Ventral anchor. (15) Dorsal anchor. (16) Ventral bar. (17) Hook (pair 5). (18) Hook (pair 2). (19) Dorsal bar. All figures are drawn to the 20-(jLm scale, except 11 (50-u.m) and 13 (25-u.m). 798 THE JOURNAL OF PARASITOLOGY, VOL. 94, NO. 4, AUGUST 2008 FIGURES 20?29. Urocleidoides piriatiu n. sp. (20) Whole mount (composite, ventral view). (21) Ventral anchor. (22) Copulatory complex (ventral). (23-24) Dorsal anchors. (25) Ventral bar. (26) Vaginal sclerite. (27) Dorsal bar. (28) Hook (pair 5). (29) Hook (pair 2). All figures are drawn to the 25-u.m scale, except 20 (50-uzn). FIGURES 30?38. Urocleidoides visiofortatus n. sp. (30) Whole mount (composite, ventral view). (31) Ventral anchor. (32) Dorsal anchor. (33) Vaginal sclerite. (34) Ventral bar. (35) Dorsal bar. (36) Hook (pair 27). (37) Hook (pair 5). (38) Copulatory complex (dorsal). All figures are drawn to the 25-u.m scale, except 30 (50-uzn). MENDOZA-FRANCO AND REINA? NEW SPECIES OF UROCLEIDOIDES 799 33 36 37 34 35 800 THE JOURNAL OF PARASITOLOGY, VOL. 94, NO. 4, AUGUST 2008 o 41 43 44 45 MENDOZA-FRANCO AND REINA? NEW SPECIES OF UROCLEIDOIDES 801 [Gymnotiformes], S. dariensis, and C. beani [Characiformes]) from Central America. Gymnotiformes includes 5 tropical fam- ilies (Apteronotidae, Gymnotidae, Hypopomidae, Rhamphi- chthyidae, and Sternopygidae) (see Albert and Crampton, 2005; Loureiro and Silva, 2006) and the current knowledge on diver- sity of the Monogenoidea (5 species [present study] plus 3 con- sidered incertae sedis in Urocleidoides and 1 species of Gyrodactylus\) (Mizelle and Price, 1968; Vianna et al., 2007; present study), on fishes from these families is undoubtedly insufficient to understand the parasite diversification in this re- gion. Urocleidoides (sensu stricto) includes a group of 9 trop- ical (South and Central America [Panama]) species, generally more displayed on a wide range of Characiformes (Characidae, Anostomidae, Curimatidae, Erythrinidae, and Lebiasinidae) compared to those fishes within Cyprinodontiformes (Poecili- idae) and Gymnotiformes (Hypopomidae) (Kritsky et al., 1986; Suriano, 1997; Jogunoori et al., 2004; Mendoza-Franco et al., 2007). In the present study, 5 new species of Urocleidoides were found on host species within Characiformes and Gym- notiformes. A phylogenetic analysis of otophysan fishes using morphological and molecular data has suggested that Characi- formes is a sister group of Gymnotiformes (Briggs, 2005). However, the parasite data is still incipient to support if diver- gence between these 2 latter fish groups in South America may also represent the earliest phylogenetic split of Urocleidoides in the tropics. Alternatively, fossil evidence suggests that gym- notiforms spread into Central America from South America during late Miocene (5 mya) (Saitoh et al., 2003; Briggs, 2005). Our morphological evidence strongly suggests a morphological link between the monogenoidean fauna of Urocleidoides from South American freshwater fishes and that from Central Amer- ica on gymnotiforms, probably as a result of the dispersal his- tory of these fishes. Morphological similarities that support a clade of these monogenoidean species on gymnotiforms from Central and South America include: (1) ventral anchors with elongate tapered superficial roots and bent shaft; (2) dorsal an- chors with bifurcate points (present in U. carapus and U. cul- tellus n. sp.); (3) hooks with robust shanks; (4) absence of eye- spots; and (5) vaginal aperture in midventral position (present in U. cultellus n. sp., U. gymnotus, U. visiofortatus, and U. hypopomi) (see Mizelle et al., 1968; Suriano, 1997; present study). Additionally, this hypothesis is supported by the fact that U. cultellus n. sp. from B. occidentalis (present study) most closely resembles U. hypopomi from H. brevirostris (syn. B. brevirostris) and 2 species currently considered incertae sedis in Urocleidoides Mizelle and Price, 1964: U. gymnotus and U. carapus from the gymnotiform G. carapo (Gymnotidae) from Brazil. Urocleidoides gymnotus and U. carapus are in incertae sedis because available specimens of these species are highly cleared and flattened, which precluded verification of the di- agnostic features, i.e., presence of a vaginal sclerite, of Uro- cleidoides (sensu stricto) to be included within it (see Kritsky et al., 1986). However, comparisons of the haptor and copula- tory complex morphology from the original descriptions of these species showed that they are markedly similar to those of U. cultellus n. sp. On the basis of this strong resemblance, we consider that the taxonomic position of U. gymnotus and U. carapus from the South American gymnotiform fishes may be accepted within Urocleidoides (sensu stricto). In fact, U. ad- venai n. sp. from B. occidentalis (present study), as a unique species by lacking a vaginal sclerite (this character not reported in the original description of the former South American spe- cies), may be part of Urocleidoides group species lacking a vaginal sclerite. Furthermore, U. advenai n. sp. exhibit some similarity to another species currently considered incertae sedis in Urocleidoides Mizelle and Price, 1964, i.e., Urocleidoides virescens Mizelle, Kritsky and Crane, 1968, from the gymno- tiform Eigenmannia virescens (Valenciennes, 1842) (Sterno- pygidae) from Brazil (Mizelle et al., 1968; Kritsky et al., 2000). Similarly, the original description of this latter monogenoidean species is insufficient to consider it within the current bound- aries of Urocleidoides (see Mizelle et al., 1968; present study). Considering all the above, an emendation on Urocleidoides and/ or a phylogenetic analysis, i.e., cladistic, is pending in order to include members lacking a vaginal sclerite. In conclusion, the absence of a phylogenetic hypothesis for all known species of Urocleidoides also limits our ability to determine satisfactorily if species of Urocleidoides on species of Hypopomidae in Cen- tral America could have originated from an invasion of para- sites along with their hosts from South America. ACKNOWLEDGMENTS The authors are grateful to A. Castillo, A. Terrero, C. Schloeder, and E. Thompson for field and laboratory assistance during this study. Mark E. Torchin (Smithsonian Tropical Research Institute?STRI) provided useful comments on this manuscript prior to submission for publication. This study was financially supported by the STRI. This work was con- ducted while EFMF was Postdoctoral Fellowship at the STRI. LITERATURE CITED ALBERT, J. S., AND W. G. R. CRAMPTON. 2005. 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