Monika Inés Hamann

Species affinity and infracommunity ordination of helminths of Leptodactylus chaquensis (Anura: Leptodactylidae) in two contrasting environments from Northeastern Argentina

One hundred seventy-two frogs (Leptodactylus chaquensis) were collected from November 2002 to November 2003, in agricultural (n = 132) and nonagricultural (n = 40) areas. Both sites are near the city of Corrientes, Argentina. The main goals of this study were as follows: (1) to determine the helminth parasite community in agricultural and nonagricultural habitats; (2) to analyze the relationships between helminth parasites and site of infection, frog body size, and gender; (3) to identify and examine covariation and association of helminth communities; and (4) to determine the mean richness and diversity of parasite communities. The helminth compound community of this amphibian species consisted of 24 species: 19 in agricultural habitats and 18 in nonagricultural habitats. The mean richness, mean diversity, and evenness of helminths were significantly different between the habitats (P < 0.05). The body size of the host was the important factor in determining parasite richness. Both habitats exhibited differences in community ordination. The helminth species in the 2 habitats exhibited the same interspecific relationships, although differences were observed in the intensity of infection.

Helminth community structure of the oven frog Leptodactylus latinasus (Anura, Leptodactylidae) from Corrientes, Argentina

A total of 36 adult individuals of Leptodactylus latinasus were collected near the city of Corrientes, Province of Corrientes in Argentina. The main goals of this study were: (1) to determine the helminth parasite fauna of L. latinasus; (2) to determine the richness and diversity of parasites at the component and infracommunity levels; (3) to analyze the relationships between helminth, frog body size and sex, and (4) to identify and examine species affinity of helminth communities. The helminth component community of this frog’s population consisted of 17 species. The predominant groups of parasites were the trematodes (adults: Glypthelmins repandum, Catadiscus inopinatus and Haematoloechus longiplexus; larvae: Travtrema aff. stenocotyle, Bursotrema aff. tetracotyloides, Styphlodora sp., unknown opisthogonimid species, Petasiger sp. and unknown strigeid species), followed by the nematodes (Cosmocerca podicipinus, C. parva, C. rara, C. cruzi, Schrankiana schranki and Aplectana hylambatis); other groups of parasites were represented by only one species (unknown larval cestode species and Centrorhynchus sp.). All parasite helminth species showed an aggregated pattern of distribution. The most infected organs were kidneys, small intestine, large intestine and pharyngeal zone. The host body size was important in determining the parasites abundance of G. repandum. At the level of component community G. repandum was the species with highest prevalence of infection and Bursotrema aff. tetracotyloides was the dominant species. Helminth species showed four significant pairs of covariation and two significant pairs of association in the infracommunities of Leptodactylus latinasus.

First Report of Nematodes in the Common Lesser Escuerzo Odontophrynus americanus (Duméril and Bibron, 1841) (Amphibia: Cycloramphidae) from Corrientes, Argentina

Abstract The common lesser escuerzo, Odontophrynus americanus, from Corrientes, Argentina, was found to harbor 3 species of Nematodes: Rhabdias elegans, Cosmocerca podicipinus, and Cosmocerca parva. Cosmocerca podicipinus was the most prevalent nematode species (22.7%), whereas C. parva had the highest mean intensity of infection (5.5 ± 2.12). These 3 nematode species are reported for the first time from O. americanus and members of the Cycloramphidae from Corrientes, Argentina.

Cosmocercid Nematodes of Three Species of Frogs (Anura: Hylidae) from Corrientes, Argentina

Abstract We collected 142 hylid frogs representing 3 species, chaco treefrog Hypsiboas raniceps, dwarf treefrog Dendropsophus nanus, and sanborn treefrog Dendropsophus sanborni, near the city of Corrientes, Corrientes Province, Argentina, between January 2002 and December 2003, and we examined them for nematodes. Two species of cosmocercid nematodes were found infecting the large intestine of these hosts. Cosmocerca parva was found infecting H. raniceps and D. sanborni, whereas Cosmocerca podicipinus was found infecting D. nanus. These nematode species are reported for the first time from these hylids from Corrientes, Argentina.

NICHE SPECIFICITY OF TWO GLYPTHELMINS (TREMATODA) CONGENERS INFECTING LEPTODACTYLUS CHAQUENSIS (ANURA: LEPTODACTYLIDAE) FROM ARGENTINA

Abstract Sixty-five specimens of the frog Leptodactylus chaquensis were infected by 2 Glypthelmins species (Glypthelmins repandum: 41%, and Glypthelmins palmipedis: 38%) in the small intestine. This study was designed to determine the site specificity of both species along the length of the small intestine by analyzing the distribution, niche overlap, morphological characteristics, and population dynamics. The location of G. palmipedis is very restricted, with the core infection site in the anterior small intestine. In contrast, G. repandum can be characterized as having an expanded niche within the small intestine. In single infections and with different intensities, individuals of both parasitic species showed preference for the anterior small intestine. In concurrent infections and with different intensities, the distribution of G. palmipedis did not change when G. repandum was present; however, displacement of G. repandum toward the middle of the small intestine was observed. Glypthelmins species used the same microhabitat and presumably the same food resource and were generally found to overlap more than expected by chance. This finding suggests the possibility of different feeding mechanisms given by differences in their pharynx size by 37%. Also, the coexistence of these could be associated with the differentiation of realized niches.

Helminth communities in the burrowing toad, Rhinella fernandezae, from Northeastern Argentina

The main goals of this study were to determine the richness and diversity of helminth parasites of Rhinella fernandezae at the component and infracommunity levels and determine the ecological implications of different biotic and abiotic factors. Specimens were collected near the city of Corrientes, Corrientes Province, Argentina. Prevalence of infection was 94% in the specimens examined (n = 65). The helminth component community in R. fernandezae in this area was comprised a total of 22 species. Of all helminth species, only three (Catadiscus inopinatus, Cosmocerca podicipinus and C. parva) were dominant (importance value: I > 1.0) in the community. The most abundant species were B. tetracotyloides (d = 0.43) among the larvae and C. podicipinus (d = 0.09) among adult worms. At the infracommunity level, the mean individual species richness (2.28 ± 1.48) (mean ± SD) was no more than 3 helminth species per infected host; the diversity and equitability of helminths were 0.23 ± 0.21 and 0.48 ± 0.38, respectively. The host body size was the main factor in determining the parasite abundance. Species richness was significantly and positively correlated with host body size. The parasite helminth species predominantly showed an overdispersed pattern of distribution. Helminth species showed two negative and significant pairs of covariation and one significant pair of association (P < 0.05). R. fernandezae has a wide variety of parasites relating to the host microhabitat, mobility and feeding habits.

Schrankiana chacoensis sp. nov. (Nematoda: Atractidae) from Leptodactylus bufonius Boulenger, 1894 (Anura: Leptodactylidae) from Argentina

Here we describe a new atractid nematode, Schrankiana chacoensis sp. nov., from the large intestine of Leptodactylus bufonius (Anura: Leptodactylidae), from Chaco Province, Argentina. This is the first atractid nematode described for L. bufonius. The new species is distinguished from the remaining species of the genus by its cephalic morphology: S. chacoensis sp. nov. possesses four large papillae on the lips (two on the dorsal lip and one on each subventral lip) without any other small papillae (present in the remaining Schrankiana species) and forked amphids; by having a shorter vagina; tips of the lateral alae located well anterior to the anus in both sexes, one additional pair of postcloacal papillae compared with other species, and a “fringe” in the posterior and anterior margins of the excretory pore. Schrankiana chacoensis sp. nov. represents the eighth species assigned to the genus. A key to the species of the genus is provided. http://www.zoobank.org/urn:lsid:zoobank.org:pub:D4B643AF-1F5D-4E36-83EE-C204AB2067B3

First report of Schulzia travassosi (Nematoda, Trichostrongylina, Molineoidea) for amphibians of the Chaco region in Argentina and proposal of Oswaldocruzia melanostictusi nov. comb.

This is the first record of the nematode parasite Schulzia travassosi (Trichostrongylina, Molineidae) in two Argentinean amphibians, Leptodactylus bufonius and Rhinella major, collected in two localities of the Chaco region, Las Lomitas (Formosa Province) and Taco Pozo (Chaco Province). The species was observed using light and scanning electron microscopy (SEM) and compared with previous studies of Paraguayan specimens. Regarding metric characters, the measurements found in Argentinean specimens generally did not differ from those of Paraguayan specimens; some differences were observed in the total length of males and females (some longer and some shorter than Paraguayan specimens), length of the oesophagus (in almost all specimens shorter than in Paraguayan ones) and position of the vulva (nearer to posterior end in Argentinean specimens). The branches and sphincter of ovejector are slightly longer than in Paraguayan female specimens. In males, ray 4 is almost the same length as rays 2, 3 and 5, 6. Cephalic end, cephalic vesicle, synlophe and vulvar depression were viewed under SEM. Schulzia melanostictusi Chopra, Shing and Kumar, 1986 is reassigned as Oswaldocruzia melanostictusi (Chopra, Shing and Kumar, 1986) nov. comb.

Nematode Parasites of Leptodactylus elenae and Leptodactylus podicipinus (Anura: Leptodactylidae) from Corrientes, Argentina

ABSTRACT:  Two species of leptodactylid frogs, the marbled white-lipped frog, Leptodactylus elenae, and the pointed belly frog, Leptodactylus podicipinus, collected in Corrientes Province, Argentina, were examined for nematode parasites. Four adult species of nematodes belonging to 2 families (Cosmocercidae and Rhabdiasidae) were found parasitizing lungs and intestines: Aplectana delirae and Cosmocerca podicipinus in L. elenae; and Cosmocerca parva, Cosmocerca podicipinus, and Rhabdias sp. in L. podicipinus. This is the first report of nematode parasites for L. elenae and the second for L. podicipinus in Argentina. Aplectana delirae and Rhabdias sp. represent new host records.

New larval trematodes in Biomphalaria species (Planorbidae) from Northeastern Argentina.

Larval trematodes infecting Biomphalaria tenagophila and B. occidentalis were surveyed in a suburban and semipermanent pond of Corrientes province, Northeastern Argentina. A total of 1,409 snails were examined between spring 2011 to winter 2013, and 8 different larval trematodes were studied morphologically. Three of these species—Echinocercaria sp. IV, Ribeiroia sp. and Echinocercaria sp. XIV–have been previously found in Corrientes province. Six other trematodes belonging to Strigeidae (Furcocercaria sp. III), Clinostomidae (Cercaria Clinostomidae sp.), Spirorchiidae (Cercaria Spirorchiidae sp.) and Echinostomatidae (Echinocercaria sp. 1, Echinocercaria sp. 2, Echinocercaria sp. 3) are new species parasitizing Biomphalaria snails. Cercaria Spirorchiidae sp. is the third larval trematode related to Spirorchiidae recorded in South America and the first one for Argentina. Cercaria Clinostomidae sp. is the first one related to Clinostomidae in northeastern Argentina. The prevalence of larval trematodes infecting B. tenagophila and B. occidentalis in the environment studied was low (<5%) with the echinostome group better represented in terms of prevalence and species richness. Drought periods could affect the dynamics of parasitic transmission due to the absence of trematodes in the autumn and winter of the first seasonal cycle. However, in humid periods parasite transmission can occur throughout the year due to the presence of larvae in all seasons of the second seasonal cycle, although the less-warm seasons showed higher prevalence than the summer period probably related to the subtropical climate of Corrientes province.