taxonID	type	description	language	source
050E2B38FFB2AB3B06E0FA4DFB89FC88.taxon	type_taxon	Type species. Characithecium costaricensis (Price & Bussing, 1967) Mendoza-Franco, Reina & Torchin, 2009	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFB2AB3B06E0FA4DFB89FC88.taxon	materials_examined	Type host. Astyanax aeneus (Günther) (Characidae). Type l ocality. Central America, from southeastern Mexico to Panama.	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFB2AB3B06E0FA4DFB89FC88.taxon	distribution	Other localities. The Pampasic region, Argentina.	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFB2AB3B06E0FA4DFB89FC88.taxon	diagnosis	Emended diagnosis. Body comprising cephalic region, trunk, peduncle and haptor. Tegument thin and smooth. Cephalic lobes developed, head organs and cephalic glands present. Eyespots present. Mouth midventral; pharynx muscular; esophagus short, 2 intestinal ceca confluent posterior to gonads, lacking diverticula. Gonads intercecal, overlapping; testis dorsal to germarium. Seminal vesicle as dilation of vas deferens with distal loop before reaching base of male copulatory organ (MCO); single prostatic reservoir present. Copulatory complex comprising an articulated MCO and accessory piece. MCO coiled tube with counterclockwise rings, with dilated and reel shaped base; articulation process present, lying within rings of MCO. Accessory piece, clamp shaped, comprising 2 subunits. Genital pore midventral near level of cecal bifurcation. Seminal receptacle pregermarial; vagina single, sclerotized or slightly sclerotized; opening sinistral, midventral, lateroventral, or in marginal position. Vitellaria follicular, restricted to trunk and coextensive with intestine. Haptor with 7 pairs of hooks with ancyrocephaline distribution, being pairs 1 and 5 reduced in size, 2 pairs of anchors with developed roots and U shaped bars. Hooks similar, each with depressed thumb, delicate point, and shank comprising 2 subunits (proximal subunit expanded). Ventral anchor larger than dorsal anchor. Ventral bar with dilated extremities and posterormedial projection present or absent.	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFB2AB3B06E0FA4DFB89FC88.taxon	discussion	Remarks. Characithecium was erected by Mendoza-Franco et al. (2009) to accommodate Urocleidoides costaricensis Price & Bussing, 1967, a species considered incertae sedis by Kristy et al. (1986) in their emendation of Urocleidoides. Characithecium costaricensis (Mendoza-Franco et al. 2009) has been extensively reported from southern and central Mexico and Nicaragua from different species of Astyanax. The characteristics shared by the 5 species found in O. jenynsii that allowed their inclusion in Characithecium are: (1) eyes present; (2) overlapping gonads (testis dorsal to germarium); (3) a seminal vesicle formed by a simple dilation of the vas deferens; (4) an articulated MCO and accessory piece; (5) MCO with a coiled shaft in counterclockwise direction; (6) ventral anchor larger than dorsal anchor; and (7) hook shanks, each composed of 2 subunits (proximal subunit expanded) (Mendoza-Franco et al. 2009). Additional characters observed in the 5 new species required to extend the generic diagnostic features to include the vaginal aperture position (as midventral, lateroventral or lateromarginal) and the variability in the morphology of ventral bar (posteromedial projection present or absent).	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFB1AB3D06E0FC26FB7DFBE7.taxon	description	(Figs. 1 – 8; 43 – 44)	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFB1AB3D06E0FC26FB7DFBE7.taxon	materials_examined	Type host. Cyphocharax voga (Hensel) Type locality. Chascomús Lake, 35 ° 37 ’ S, 58 ° 04 ’ W, Chascomús, Buenos Aires province, Argentina. Other host. Oligosarcus jenynsii (Günther).	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFB1AB3D06E0FC26FB7DFBE7.taxon	distribution	Other localities. Nahuel Ruca Lake, 38 ° 08´S, 57 ° 32´W, Mar Chiquita, Buenos Aires Province, Argentina.	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFB1AB3D06E0FC26FB7DFBE7.taxon	description	Prevalence. 100 %. Mean abundance (intensity range). 36 (2 – 163).	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFB1AB3D06E0FC26FB7DFBE7.taxon	materials_examined	Type material. Voucher s pecimens (MLP-He- 6803) were deposited in the Helminthological Collection of the Museo de La Plata (HCMLP), La Plata, Argentina.	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFB1AB3D06E0FC26FB7DFBE7.taxon	description	Redescription. Based on 20 specimens. Body robust, 611 (480 – 754; n = 20) long; greatest width 196 (137 – 277) usually at middle of body. Two pairs of cephalic lobes, 1 lateral and 1 anterior pair divided into 3 lobules. Five pairs of head organs and cephalic glands present. Four eyespots, frequently dissociated, accessory granules often present in cephalic region and anterior to pharynx. Pharynx ovate, muscular 43 (33 – 48) in greatest width; esophagus short to moderately long. Haptor sub-hexagonal, 85 (71 – 89) long, 113 (100 – 132) wide. Ventral anchor 40 (31 – 44) long, base 26 (20 – 28) wide; with elongate superficial root, short deep root, straight shaft and curved distal point. Dorsal anchor 36 (27 – 42) long; base 22 (16 – 23) wide; with well-developed roots, straight shaft and curved distal point. Ventral bar 36 (30 – 46) long, with medial suture with expanded ends. Dorsal bar widely Ushaped, 40 (37 – 49) long, with slightly enlarged ends. Hooks similar in shape; pairs 1 and 5 reduced in size 16 (13 – 19) long, hooks (excluding pairs 1 and 5) 23 (16 – 28) long, with protruding thumb and delicate point; shank comprised of 2 subunits; proximal subunit expanded, filamentous hooklet (FH) loop extending anterior to union of shank subunits. MCO a coiled tube with 3 – 4 counterclockwise coils, 237 (216 – 254) long; base of MCO reelshaped, connected to articulation process of accessory piece. Accessory piece 33 (29 – 40) long, clamp-shaped, comprising 2 subunits connected by a muscular ligament, distal subunit claw-like, proximal subunit larger, subtriangular, with short and slightly concave free distal extreme serving as guide for MCO. Articulation process of accessory piece twisted. Gonads overlapping; testis dorsal to germarium; seminal vesicle a distal dilation of vas deferens, looping before entering base of MCO; single, prostatic reservoir present. Vitellaria moderately dense throughout trunk, except in regions of reproductive organs; oviduct, ootype and uterus not observed. Vaginal aperture strongly sclerotized and sinistral; vagina a long and tortuous sclerotized tube, directed posteriorly and convoluted before connecting with seminal receptacle. Seminal receptacle, medial and anterior to germarium. Eggs not observed.	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFB1AB3D06E0FC26FB7DFBE7.taxon	discussion	Remarks. A detailed morphological examination of the specimens newly collected from O. jenynsii from both, the type locality and Nahuel Rucá Lake, and their comparison with the descriptions provided by Suriano (1981; 1997) showed that all are members of the same taxon by having identical morphology of MCO, accessory piece, hooks and internal organs. It is noteworthy that no type material is available for this species, which was originally described as Androspira chascomusensis by Suriano (1981) and later transferred to Palombitrema chascomusense by the same author (Suriano 1997). However, the morphology of the MCO and hooks does not agree with the diagnosis of Palombitrema Price & Bussing, 1968 to which the species was assigned by Suriano (1997). Palombitrema is characterized by having the MCO directly articulated to the accessory piece, pairs 6 and 7 of hooks different in shape than hooks 1 – 5, being the pair 7 also considerably larger, and dorsal anchors with little developed roots and larger than ventral anchors. (Price & Bussing 1968; Kritsky & Leiby 1972; Kritsky & Thatcher 1974; Mendoza Franco et al. 1999; 2003; 2009). In contrast, in our specimens, the MCO is articulated by a ligament to accessory piece, hooks are of similar shape and length and anchors have developed roots. These characteristics that clearly differentiate Palombitrema from Characithecium, were not considered in the resurrection of Palombitrema by Suriano (1997), indicating that the inclusion of specimens from C. voga and O. jenynsi in this genus was erroneous. Consequently, this species is transferred to Characithecium as C. chascomusensis n. comb. Characithecium chascomusensis n. comb. can be readily differentiated from C. costaricensis, the only member of the genus, by the morphology of the accessory piece, the number of coils in the MCO (3 – 4 in C. chascomusensis n. comb. vs ½ – 1 in C. costaricensis), the position of vaginal aperture (lateral in C. chascomusensis vs midventral in C. costaricensis) and the absence of a posterior ventral projection in the ventral bar as present in C. costaricensis. Furthermore, C. chascomusensis n. comb. can be distinguished from its other congeners herein described by possessing a higher number of coils in the MCO; by having the vaginal aperture located anteriorly, at level of the prostatic reservoir; and by the shape of the accessory piece, with a pointed claw-like distal subunit and a subtriangular proximal subunit, latter with short and slightly concave free distal extreme.	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFB7AB3F06E0FB06FED4FB84.taxon	description	(Figs. 9 – 17; 45 – 46)	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFB7AB3F06E0FB06FED4FB84.taxon	materials_examined	Type host. Oligosarcus jenynsii (Günther) Type locality. Nahuel Rucá Lake, 38 ° 08´S, 57 ° 32´W, Mar Chiquita, Buenos Aires Province, Argentina.	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFB7AB3F06E0FB06FED4FB84.taxon	description	Prevalence. 100 %. Mean abundance (intensity range). 20.8 (2 – 98).	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFB7AB3F06E0FB06FED4FB84.taxon	materials_examined	Type material. Holotype (MLP-He- 6795) and paratypes (MLP-He- 6796) are deposited in the Helminthological Collection of the Museo de La Plata (HCMLP), La Plata, Argentina.	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFB7AB3F06E0FB06FED4FB84.taxon	etymology	Etymology. The specific name is refers to the large size of ventral anchors.	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFB7AB3F06E0FB06FED4FB84.taxon	description	Description. Based on 20 specimens. Body small and delicate, 450 (351 – 540; n = 20) long; greatest width 144 (104 – 181) usually at middle of body. Two pairs of cephalic lobes, 1 lateral and 1 anterior. Four pairs of head organs observed. Cephalic glands present. Four eyespots, frequently dissociated, accessory granules often present in cephalic region and anterior to pharynx. Pharynx spherical, muscular 32 (25 – 38) in diameter; esophagus short. Haptor 110 (93 – 134) wide, 60 (50 – 70) long. Ventral anchor 56 (51 – 61) long, base 24 (20 – 26) wide; with welldeveloped roots, superficial root elongate, deep root shorter, shaft long and curved, curvature more pronounced at distal tip; anchor filament conspicuous. Dorsal anchor 34 (30 – 38) long, base 22 (19 – 25) wide, with well-developed roots, straight shaft and curved distal point. Ventral bar 43 (39 – 56) long, with slight antero-medial projection, medial suture and expanded ends. Dorsal bar curved, 33 (28 – 43) long, with expanded ends. Hooks similar in shape; pairs 1 and 5 reduced in size 18 (16 – 19) long, hooks (excluding pairs 1 and 5) 26 (18 – 37) long, with protruding thumb and delicate point; shank comprised of 2 subunits; proximal subunit expanded, FH loop extending anterior to union of shank subunits. MCO a coiled tube with 2 counterclockwise coils, 144 (123 – 176) long, base of MCO reel shaped, connected to articulation process of accessory piece. Accessory piece 26 (24 – 28) long, clamp-shaped, comprising 2 subunits with sharp distal ends, proximal subunit larger and serving as guide for MCO. Gonads overlapping; testis dorsal to germarium; seminal vesicle as a distal dilation of vas deferens, looping before entering base of MCO. Prostatic reservoir present. Vitellaria moderately dense throughout trunk, except in regions of reproductive organs. Oviduct, ootype and uterus not observed. Vaginal aperture poorly sclerotized, sinistroventral; vagina as a sclerotized tube connecting with large and globose seminal receptacle. Seminal receptacle, medial and anterior to germarium. Egg 55 long, 45 wide, spherical yellow brown bearing a short polar filament with bifurcate end.	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFB7AB3F06E0FB06FED4FB84.taxon	discussion	Remarks. Characithecium longianchoratum n. sp. can be differentiated from C. costaricencis by the morphology of accessory piece, the number of coils of the MCO (2 in C. longianchoratum n. sp. vs ½ – 1 in C. costaricensis), the position of the vaginal aperture (latero ventral vs midventral), the sclerotization of the vaginal canal and the absence of a posterior ventral projection in ventral bar. Furthermore, C. longianchoratum differs from its congeners herein described by having a poorly sclerotized and sinistroventral vaginal pore; by the shape of the accessory piece with both distal and proximal subunits with pointed tips; by having a ventral bar with sub-quadrate elongated ends; and by having a long and curved shaft in the ventral anchor. The distally pincer-shaped accessory piece and the shape of anchors of the new species show some resemblance to Urocleidoides strombicirrus (Price & Bussing, 1967) Kritsky & Thatcher, 1974. This species was considered as incertae sedis by Kritsky et al. (1986) in their revision of Urocleidoides. Since then, no generic reassignment has been made for U. strombicirrus, despite it has been reported later parasitizing Astyanax spp. from Colombia, Nicaragua and Panama (Mendoza-Franco et al. 2003, 2009). Mandoza-Franco et al. (2003) suggest that it species may constitute a new genus. The extended diagnosis of Characithecium could now include U. strombicirrus, however more studies are necessary for confirm their generic status, especially because the MCO is apparently directly articulated to the accessory piece (see Price & Bussing 1967; Kritsky & Thatcher 1974; Mendoza-Franco et al. 2003; 2009). Nevertheless, although U. strombicirrus could in the future be transferred to Characithecium, being readily distinguished from C. longianchoratum by its smaller size and by having a lateral and heavily sclerotized vaginal aperture (Price & Bussing 1967; Kritsky & Thatcher 1974; Mendoza-Franco et al. 2003; 2009).	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFB5AB3106E0FBD7FC47FED5.taxon	description	(Figs. 18 – 26; 47 – 48)	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFB5AB3106E0FBD7FC47FED5.taxon	materials_examined	Type host. Oligosarcus jenynsii (Günther). Type locality. Nahuel Rucá 38 ° 08´S, 57 ° 32´W, Mar Chiquita, Buenos Aires Province, Argentina.	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFB5AB3106E0FBD7FC47FED5.taxon	description	Prevalence. 70 %. Mean abundance (intensity range). 1.8 (1 – 7).	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFB5AB3106E0FBD7FC47FED5.taxon	materials_examined	Type material. Holotype (MLP-He- 6797) and paratypes (MLP-He- 6798) are deposited in the Helminthological Collection of the Museo de La Plata (HCMLP), La Plata, Argentina.	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFB5AB3106E0FBD7FC47FED5.taxon	etymology	Etymology. The specific name is derived from Latin robustus (= robust) and refers to the larger size of this species in relation to the other species in the genus.	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFB5AB3106E0FBD7FC47FED5.taxon	description	Description. Based on 11 specimens. Body robust 842 (606 – 1000; n = 10) long; greatest width 236 (186 – 282) usually at middle of body. Cephalic lobes developed. Five pairs of head organs and cephalic glands present. Four eyespots in cephalic region and anterior to pharynx, accessory granules present in cephalic regions posterior to pharynx. Pharynx spherical, 47 (40 – 59) in diameter; esophagus moderately long. Haptor hexagonal, 81 (67 – 92) long, 114 (100 – 128) wide. Ventral anchor 43 (39 – 48) long, base 29 (26 – 32) wide, with superficial root well developed and elongated, short deep root, straight shaft and curved distal point; anchor filaments conspicuous. Dorsal anchor 35 (32 – 37) long, base 25 (21 – 27) wide, with developed roots, similar in shape to ventral anchor. Ventral bar 30 (27 – 34) long, V-shaped, with medial suture and slightly dilated extremes. Dorsal bar 35 (31 – 38) long, U-shaped, with curved convex margin, straight concave margin and expanded ends. Hooks similar in shape, pairs 1 and 5 reduced in size 17 (11 – 20) long, hooks (excluding pairs 1 and 5) 22 (17 – 24) long, with protruding thumb and delicate point; shank comprised of 2 subunits; proximal subunit expanded, FH loop short. MCO a coiled tube with 2 ½ counterclockwise coils, 231 (216 – 240) long; base of MCO reel- shaped, connected to articulation process of accessory piece. Accessory piece 28 (22 – 30) long, pincer-shaped, comprising 2 subunits connected by a muscular ligament, distal subunit with bifurcate end; proximal subunit larger, with concave free distal extreme serving as guide of MCO. Gonads overlapping; testis dorsal to germarium; seminal vesicle as a distal dilation of vas deferens, looping before entering base of MCO. Prostatic reservoir present. Vitellaria dense throughout trunk, except in regions of reproductive organs. Oviduct, ootype and uterus not observed. Vaginal aperture ventro-sinistral sclerotized and funnel-shaped. Vagina a sinuous sclerotized tube connecting with a sclerotized vaginal vestibule leading to a seminal receptacle anterior to germarium. Egg 78 long x 50 wide, brownish, triangular, bearing short bipolar filament.	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFB5AB3106E0FBD7FC47FED5.taxon	discussion	Remarks. Characithecium robustum n. sp. is the largest member of the genus and can be distinguished from C. costaricensis, by the morphology of accessory piece, the number of coils of MCO (2 ½ in C. robustum n. sp. vs ½ – 1 in C. costaricensis), the position of the vaginal aperture (latero ventral vs midventral), the sclerotization of the vaginal canal and the absenceof a posterior ventral projection in ventral bar. Furthermore, C. robustum differs from the new species here described by having a sclerotized vaginal vestibule, as well as a V-shaped ventral bar, and by the shape of the accessory piece, with distal subunit with bifurcate end.	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFBBAB3106E0FE1DFD96F9C3.taxon	description	(Figs. 27 – 34; 49 – 50)	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFBBAB3106E0FE1DFD96F9C3.taxon	materials_examined	Type host. Oligosarcus jenynsii (Günther). Type locality. Nahuel Rucá 38 ° 08´S, 57 ° 32´W, Mar Chiquita, Buenos Aires Province, Argentina.	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFBBAB3106E0FE1DFD96F9C3.taxon	description	Prevalence. 60 %. Mean abundance (intensity range). 1 (1 – 4).	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFBBAB3106E0FE1DFD96F9C3.taxon	materials_examined	Type material. Holotype (MLP-He- 6799) and paratypes (MLP-He- 6800) are deposited in the Helminthological Collection of the Museo de La Plata (HCMLP), La Plata, Argentina.	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFBBAB3106E0FE1DFD96F9C3.taxon	etymology	Etymology. The specific name is derived from Latin quadratum (= square) and refers to the shape of the accessory piece of the copulatory complex.	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFBBAB3106E0FE1DFD96F9C3.taxon	description	Description. Based on 10 specimens. Body robust 631 (498 – 752; n = 10) long; greatest width 174 (144 – 223) usually at middle of body. Cephalic lobes developed. Five pairs of head organs and cephalic glands present. Two pair of eyespots in cephalic region and anterior to pharynx, accessory granules present in cephalic regions at level of pharynx. Pharynx spherical, 36 (32 – 40) in diameter; esophagus short. Haptor hexagonal, 78 (71 – 90) long, 100 (87 – 114) wide. Ventral anchor 43 (40 – 46) long, base 28 (23 – 31) wide, with well-developed elongate superficial root, shorter deep root, straight shaft and curved distal point, anchor filaments conspicuous. Dorsal anchor 34 (32 – 36) long, base 20 (18 – 23) wide, with developed roots, superficial root fusiform, straight shaft with curved distal point. Ventral bar 34 (29 – 37) long, with medial suture flanked by 2 blunt small protrusions at posterior margin and dilated extremes. Dorsal bar curved 39 (36 – 41) long with ends slightly expanded. Hooks similar in shape pairs 1 and 5 reduced in size 16 (12 – 19) long, hooks (excluding pairs 1 and 5) 22 (19 – 27) long, with protruding thumb and delicate point; shank comprised of 2 subunits; proximal subunit expanded, FH loop short. MCO a coiled tube with 2 counterclockwise coils, 163 (156 – 171) long; base of MCO reel-shaped, connected to articulation process of accessory piece. Accessory piece large, 40 (37 – 45) long, comprising 2 subunits connected by a muscular ligament, distal subunit a hook-shaped; proximal subunit elongate, with expanded and cup-shaped distal end serving as guide for male copulatory organ. Gonads overlapping; testis dorsal to germarium; seminal vesicle as a distal dilation of vas deferens. Prostatic reservoir present. Vitellaria dense throughout trunk, except in regions of reproductive organs. Oviduct, ootype and uterus not observed. Vaginal aperture marginal sinistral and slightly sclerotized, opening at level of anterior border of testicle. Vagina as a sinuous sclerotized tube connecting with a seminal receptacle anterior to germarium.	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFBBAB3106E0FE1DFD96F9C3.taxon	discussion	Remarks. Characithecium quadratum n. sp. differs from its congeners mainly by having the largest accessory piece, which is also different in shape, being rectangular with hook-shaped distal subunit and elongate proximal subunit ending in a cup-shaped anterior extreme. The position of vaginal aperture (at level of anterior margin of testicle) is also unique among congeners.	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFBBAB3506E0F916FF33FC30.taxon	description	(Figs. 35 – 42; 51 – 52)	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFBBAB3506E0F916FF33FC30.taxon	materials_examined	Type host. Oligosarcus jenynsii (Günther) Type locality. Nahuel Rucá 38 ° 08´S, 57 ° 32´W, Mar Chiquita, Buenos Aires Province, Argentina.	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFBBAB3506E0F916FF33FC30.taxon	description	Prevalence. 50 % Mean abundance (intensity range). 8.5 (2 – 65).	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFBBAB3506E0F916FF33FC30.taxon	materials_examined	Type material. Holotype (MLP-He- 6801) and paratypes (MLP-He- 6802) are deposited in the Helminthological Collection of the Museo de La Plata (HCMLP), La Plata, Argentina.	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFBBAB3506E0F916FF33FC30.taxon	etymology	Etymology. The specific name is derived from Latin chela (= claw) and refers to the pincer shape of the accessory piece of the copulatory complex.	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFBBAB3506E0F916FF33FC30.taxon	description	Description. Based on 10 specimens. Body small and delicate, 337 (270 – 426; n = 10) long; greatest width 99 (61 – 131) usually at middle of body. Two pair of cephalic lobes well developed 1 anterior and 1 lateral. Four pairs of head organs observed. Cephalic glands present. Two pair of eyespots in cephalic region, frequently dissociated, accessory granules often present in cephalic region. Pharynx spherical, 22 (17 – 28) in diameter; esophagus short. Haptor 75 (54 – 96) wide, 58 (49 – 70) long. Ventral anchor 44 (41 – 46) long, base 20 (18 – 23) wide; with welldeveloped and elongate superficial root, shorter deep root, curved shaft and curved distal point, anchor filaments conspicuous. Dorsal anchor 29 (26 – 31) long, base 16 (13 – 17) wide, with developed roots, superficial root elongated, straight shaft with curved distal point. Ventral bar 30 (20 – 33) long, V-shaped, with medial suture and dilated extremes. Dorsal bar curved 32 (28 – 36) long, posterior ends slightly expanded. Hooks similar in shape, hooks excluding pairs 1 and 5 and length with protruding thumb, delicate point; hooks pairs 1 and 5 reduced in size 15 (14 – 18) long, longer hooks 20 (18 – 21); shank comprised of 2 subunits; proximal subunit expanded, filamentous booklet (FH) loop short. MCO a coiled tube with 1 ½ counterclockwise coils, 93 (85 – 108) long; base of MCO reel shaped, connected to articulation process of accessory piece. Accessory piece 17 (15 – 23) long, pincer shaped, comprising 2 subunits articulated at proximal ends, both with bifurcate extremes, the shorter serving as guide for MCO. Gonads overlapping; testis dorsal to germarium; seminal vesicle as a distal dilation of a vas deferens, looping before junction to MCO. Prostatic reservoir present. Vitellaria extended throughout trunk, except in regions of reproductive organs. Oviduct, ootype and uterus not observed. Vaginal aperture heavily sclerotized, coup-shaped plate at midbody, lateral and sinistral. Vagina almost straight connecting with a seminal receptacle. Seminal receptacle medial and anterior to germarium. Eggs not observed.	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
050E2B38FFBBAB3506E0F916FF33FC30.taxon	discussion	Remarks. Characithecium chelatum n. sp. is one of the smallest member of the genus; It resembles C. longianchoratum n. sp. in the general morphology and relative size of anchors as well as by having ventral anchors protruding from haptor. However, C. chelatum n. sp. can be distinguished from its congeners by the shape of the accessory piece, with 2 subunits articulated at base and with bifurcate extremes, by having 1 ½ coils in the MCO, by the shape and sclerotization of the vaginal aperture and by the absence of a posterior medial projection in ventral bar.	en	Rossin, María Alejandra, Timi, Juan Tomás (2014): Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus. Zootaxa 3893 (3): 382-396, DOI: 10.11646/zootaxa.3893.3.4, URL: https://doi.org/10.11646/zootaxa.3893.3.4
