Nyctotheroides sp.

Piñeiro, M. & González, E. Sanabria C., 2023, Protozoa And Nematodes Infecting Odontophrynus Occidentalis (Anura, Odontophrynidae) From The Monte Desert Of Argentina, Zoodiversity 57 (2), pp. 171-180 : 173-175

Nyctotheroides sp. ( fig. 2 )

Prevalence: 57.14 % (12/21)

Site of infection: Large intestine

Specimens deposited: CECOAL 17021403 (10 specimens)

Remarks: The genus Nyctotheroides have very close morphological and genetic similarities with the genus Nyctotherus Leidy, 1849 , making its distinction difficult. However, until now, there is consensus that the individuals belonging to Nyctotheroides are found only parasitizing amphibians, while Nyctotherus can parasitize arthropods, reptiles and fish, among others, but not anurans ( Albaret, 1975; Affa’a et al., 2004; Lynn & Wright, 2013; Suzuki et al., 2020). Specimens found in this study present an oval completely ciliated body, with well-defined peristome and infundibulum, presence of a kidney-shaped macronucleus, a small micronucleus, a posterior contractile vacuole and a cytoproct.

Nematoda

Order Ascaridida

Superfamily Cosmocercoidea

Family Cosmocercidae Railliet, 1916

Aplectana hylambatis (Baylis, 1927) Travassos, 1931 ( fig. 3 )

Prevalence; mean intensity; total number of parasite: 9.52 % (8/21); 0.42 ± 0.70; 9.

Site of infection: Large intestine.

Specimens deposited: CECOAL 17021401 (6 females, 3 males)

Remarks: A. hylambatis is a cosmocercid species that presents considerable intraspecific variation. However, is easily identifiable by two morphological characters: the specific shape of spicule when extruded out of the body — in its last portion it possess an articulation that gives the appearance of a sickle or a hockey stick, and the possession of three pairs of adcloacal papillae on the anterior lip of the cloaca, with a large unpaired papilla between them ( González et al., 2019). Both these characters were clearly observed in the specimens of this study ( fig. 3 , D). In males, the number of pairs of cloacal papillae and their arrangement coincide with the specimens of A. hylambatis collected in Rhinella major (Müller & Hellmich, 1936) from Chaco and Formosa provinces, Argentina: 4: 5: 5 + 1; likewise, in females, the mamelon-like structures anterior to the vulva coincides, in size, number and disposition, with the specimens collected in R. major from Chaco: two considerable protuberances separated and covering partially the vulva ( fig. 3 , G) ( González et al., 2019).

Family Kathlaniidae Lane, 1914

Falcaustra sanjuanensis González, Sanabria & Quiroga, 2013 ( fig. 4 )

Prevalence; mean intensity; total number of parasite: 38.09 % (8/21); 0.85 ± 1.27; 18. Site of infection: large intestine

Specimens deposited: CECOAL 17021402 (8 females, 6 males, 4 juveniles)

Remarks: Of the 104 species of Falcaustra described so far ( Bursey et al., 2020), this is the only species described from specimens collected from Argentinean amphibians. F. sanjuanensis differs from the rest of the known species by a set of characters such as: presence of pseudosucker, distribution pattern of caudal papillae (6 precloacal, 5 adcloacal, 12 postcloacal), unpaired papilla anterior to cloaca located on a protuberance, and triangular gubernaculum. All of these characters were observed in the specimens examined in the present study ( fig. 4 , B, C, F).

Figures

Fig. 2. Nyctotheroides sp. A — Light microscopic image; B — Schematic drawing; Abbreviations: Ci — cilia; CV — contractile vacuole; Cp — cytoproct; If — infundibulum; Ma — macronucleus; Mi — micronucleus; Pe — peristome.

Fig. 3. Aplectana hylambatis. A — female, general view; B — male, general view; C — male, anterior extremity, lateral view; D — male, posterior extremity, ventral view; E — female, posterior extremity, lateral view; F — gubernaculum, lateral view; G — vulva, ventral view.

Fig. 4. Falcaustra sanjuanensis. A — female, anterior extremity, lateral view; B — male, posterior extremity, lateral view; C — gubernaculum, ventral view; D — spicules, ventral view; E — female, posterior extremity, lateral view; F — male, posterior extremity, ventral view.