Nematophila argentinum ( Cordero & Vogelsang, 1940 ) Cordero & Vogelsang, 1940

Lenis, Carolina & Vélez, Imelda, 2011, Digeneans in Trachemys callirrostris callirostris and Podocnemis lewyana (Testudinata) from the Magdalena River, Colombia: description of Pseudonematophila n. gen. and amendment of Nematophila Travassos, 1934 (Cladorchiidae: Schizamphistominae), Zootaxa 3095, pp. 49-62 : 57-59

Nematophila argentinum ( Cordero & Vogelsang, 1940) n. comb.

( Fig. 6 )

(Syn. Paramphistomum argentinum Cordero & Vogelsang, 1940 )

Host: Podocnemis lewyana , Trachemys callirostris callirostris

Site of infection: Large intestine

Localities: San Nicolás (9° 8'17.20"N; 74°38'59.42" O); Coyongal (8°55'11.00"N; 74°29'25.26" O).

Accesion numbers: CCH.116 (112; 129) in P. lewyana ; CCH.116 (128) in T. c. callirostris .

Redescription: based on 13 individuals. Body large, oval, maximum width at level of testis, 10.14–15.62 (12.40 ± 1.68) long by 4.06–5.38 (4.58 ± 0.44) wide. Pharynx 0.82–1.57 (1.17 ± 0.20) long by 0.82–1.20 (1.06 ± 0.10) wide; extramural pharyngeal sacs. Esophagus medium, 0.62–1.41 (1.01 ± 0.28) long by 0.16–0.20 (0.19 ± 0.01) wide; esophageal bulb 0.58–0.84 (0.74 ± 0.09) long by 0.22–0.38 (0.29 ± 0.06) wide. Testes lobed, oblique, overlap caeca laterally, anterior testis preequatorial 0.22–0.71 (0.42 ± 0.18) long by 0.19–0.86 (0.45 ± 0.21) wide; posterior testis postequatorial, 10.2–0.78 (0.40 ± 0.18) long by 0.26–0.64 (0.44 ± 0.14) wide. Cirrus–sac circular, small, immediately postbifurcal, 0.16–0.23 (0.20 ± 0.02) long by 0.17–0.26 (0.21 ± 0.03) wide. Vitelline follicles in two lateral extracaecal fields from level of oesphageal bulb to level of acetabulum. Ovary round to oval, small to medium, smooth contour to slightly lobed, intercaecal to level of caecal ends, 0.31–0.63 (0.39 ± 0.10) long by 0.24–0.59 (0.43 ± 0.11) wide. Uterus intercaecal, passes between testes. Eggs numerous, 124–169 (146 ± 12) long by 82–119 (96 ± 10) wide. Acetabulum round, medium compared to the body, subterminal, 11.83–2.49 (2.29 ± 0.22) long by 1.91–2.75 (2.31 ± 0.23) wide.

Remarks: The original descriptions of Nematophila ovalis , Allassostoma venezuelensis and Paramphistomum argentinum are based on one or two flukes, are incomplete, and there is no evidence found of type specimens. Additionally their authors mention that these species were assigned to known genus, only provisionally, because the morphological characters are not entirely congruent with the genus assigned (see Cordero & Vogelsang 1940). Later, Caballero et al. (1959) synonymized these species with Nematophila grandis (Diesing, 1839) Travassos, 1934 , based on similarities of the oral sucker, pharynx and pharyngeal sacs, cirrus–sac, shape and distribution of reproductive organs and vitelline follicles. The most recent works of parasites of Southamerican turtles, recognizes to N. grandis as the only species of genus ( Dyer & Carr, 1990; Salízar & Sánchez, 2004; Lunaschi & Drago, 2007).

During this taxonomic survey of Schizamphistominae from the Colombian specimens, we founded that N. ovalis , A. venezuelensis and P. argentinum ( Cordero & Vogelsang, 1940) are valid species, and as a result we suggest transfer N. ovalis to Pseudonematophila n. gen., and transfer A. venezuelensis and P. argentinum to Nematophila genus. Therefore, we emended here the subfamily diagnosis to include the traits of Pseudonematophila new genus and Nematophila . We suggest the creation of Pseudonematophila n. gen. from the Colombian flukes, because have a genital sucker bifurcal ( Fig 2 a – b), and numerous tegumental papillae from the posterior level of the genital sucker to the posterior end of the body ( Fig 3 c–d). A new genus was necessary because these traits had not been described before for this subfamily. The genital sucker is a trait present in different subfamilies of Cladorchiidae Fischoeder, 1901 , and the presence of tegumental papillae on anterior extremity has been reported in Schizamphistominae, in the genus Stunkardia Bhalerao, 1931, Elseyatrema Rohde, 1984, Halltrema Lent & Freitas, 1939, Parachiorchis Caballero, 1934 and Schizamphistomoides Stunkard, 1925 (see Jones 2005). The generic name of Pseudonematophila n. gen., is given because the type species (P. o v a l i s n. comb.), shares more morphological features with Nematophila than with any other genus of Schizamphistominae (distribution of the reproductive organs, oral sucker, acetabulum and vitelline follicles).

It should be noted that in the original description of Pseudonematophila ovalis n. gen., n. comb. did not include tegumental papillae, pharyngeal sacs and eggs, and was performed on one immature individual ( Cordero & Vogelsang, 1940). It differ from Colombia specimens the length of the caeca and in the shape and location of the ovary. In the Venezuelan specimen the caeca ends close to the anterior margin of the acetabulum and the ovary is small, irregular and intercaecal ( Fig. 1 ), while in the Colombian specimens, the caeca ends in the second third of the body, the ovary is small, oval to lobed shaped, and is located between the posterior testis and the acetabulum, to the level where the caeca ends ( Fig. 3 b). Our observations in individuals from different ages suggest that the level where the caeca ends can be variable, especially between the anterior and posterior region of the ovary ( Fig. 3 a-b), additionally the testes are branched in threadlike extensions in immature specimens, and lobed with few threadlike extensions in adult specimens.

The diagnosis of Nematophila ( Jones 2005) is emended by transfering A. venezuelensis and P. argentinum ( Fig.

4), and by including in the diagnosis the following features: tegument thick, without spines, acetabulum small or medium compared to body, terminal or subterminal ventral; extramural pharyngeal sacs; testes in tandem or oblique, lobed or branched ( Fig 4 ), external seminal vesicle ( Fig. 5 a, 6a) and excretory vesicle V – shaped with pore dorsal to anterior margin of the acetabulum. It should be noted that in Allassostoma the testes and the ovary are restricted to the middle third of the body, and the vitelline follicles are extracaecal from the anterior testis to the caecal ends and are intercaecal at the postovarian level. In the same way, Paramphistomum neither shows pharyngeal sacs nor esophageal bulb, and is a parasite of ruminants (see Jones, 2005). Here, we provided the first key to Nematophila , which includes N. grandis , N. venezuelensis n. comb. and N. argentinum n. comb.

Figures

FIGURE 1. Pseudonematophila ovalis n. gen., n. comb., adapted from Cordero & Vogelsang, (1940) Inmature specimen, ventral view. Scale 2 mm.

FIGURE 2. Pseudonematophila ovalis n. gen. n. comb. from Podocnemis lewyana, Colombia. a. Specimen adult, ventral view. Scale 1 mm. b. Details of genital sucker and genitalia with the cirrus everted, sagital section. Scale 0.25 mm. c. Details of genitalia and tegumentary papillae. Scale 0.25 mm.

FIGURE 3. Pseudonematophila ovalis n. gen. n. comb. a. Adult specimen, testes lobed with few threadlike extensions and numerous vitelline follicles, ventral view, scale 1 mm. b. Immature specimen, testes branched in numerous threadlike extensions and few vitelline follicles, ventral view, scale 1 mm. c. Ventral papillae in middle region of body, its number and size increase towards the acetabulum, sagital section. d. Papillae distribution in hindbody, ventral view. e. Detail of genital sucker, sagital section. f. Genitalia with the cirrus everted, oesophageal bulb, sagital section. Scale 0.25 mm.

FIGURE 4. Species of Nematophila Travassos, 1934. a. N. grandis adapted from Caballero et al. 1959. b. N. venezuelensis n. comb. adapted from Cordero & Vogelsang (1940). c. N. argentinum n. comb. adapted from Cordero & Vogelsang (1940). Scale 2 mm.

FIGURE 5. Nematophila venezuelensis n. comb. a. Mature specimen collected from P. l e w y a n a, Colombia; pharyngeal sacs intramural and testes in tandem. Scale 2 mm. b-c. Details of genitalia, sagital section, scale 0.8 mm.

FIGURE 6. Nematophila argentinum n. comb. a. Mature specimen collected from T. c. callirostris, Colombia; pharyngeal sacs extramural and testes oblique. Scale 2 mm. b-c-d. Details of genitalia, sagital section, scale 0.25 mm.