Rediscovery and New Morphological Data on TwoHassalstrongylus(Nematoda: Heligmonellidae) Coparasitic in the Marsh RatHolochilus chacarius(Rodentia: Cricetidae) from Argentina

Abstract

Two species of Hassalstrongylus Durette-Desset, 1971, coparasitic in Holochilus chacarius Thomas (Rodentia, Cricetidae) and not recorded since their original description in 1937, were newly found in their type host and locality. Hassalstrongylus mazzai (Freitas, Lent and Almeida, 1937) and Hassalstrongylus argentinus (Freitas, Lent and Almeida, 1937) were obtained from Ho. chacarius from 2 different populations: one from Salta Province (northwest Argentina) and another from Chaco Province (northeast Argentina). The species described as Heligmonoides mazzai Freitas, Lent and Almeida, 1937 had been transferred to Hassalstrongylus even though its synlophe had never been studied. We provide the first descriptions and illustrations of the synlophe of males and females of Hassalstrongylus mazzai and the female of H. argentinus and account for morphological and metrical variability. We confirm, through the study of the synlophe, the placement of Hassalstrongylus mazzai in the genus Hassalstrongylus and designate neotypes for the species because the type material deposited by the authors could not be found. Females of both species were morphologically very similar, and a principal components analysis (PCA) performed on some morphometrical characters showed that the body length, uterus length, and an unexpected character as the number of eggs were useful characters in the discrimination of both species.

Guerrerostrongylus marginalisn. sp. (Trichostrongyloidea: Heligmonellidae) from the Guianan arboreal mouse (Oecomys auyantepui) from French Guiana

“…The range for these measurements is noted in parentheses in Table 1 , and it also includes the number of eggs counted in the uteri of two paratypes. Digiani et al [ 4 ] have shown that this value, as well as the length of the uterus, are reliable characters to assist in the discrimination of syntopic species of Hassalstrongylus . This suggests that the statistical analyses of meristic data may yield unexpected useful characters in species discrimination.…”

Nematodes Associated With Mammals in the Great American Biotic Interchange (Gabi)

“…These results are concordant with the origin and subsequent diversification of cricetid rodents in South America. In addition, new records for species of Hassalstrongylus and Guerrerostrongylus appear to contribute to this hypothesis (Digiani et al 2015;Weirich et al 2016), in that the majority of the species are present in defined biomes of the South American continent and the parasites are frequently found in unrelated species of cricetid rodents.…”

Cladorchis pyriformis (Diesing, 1838) (Digenea, Cladorchiidae): new rodent host and geographic records in Argentina

“…has been recorded harboring 11 nematode species (e.g. Durette-Desset et al 1997;Notarnicola 2005;Notarnicola et al 2010;Digiani et al 2013Digiani et al , 2015Robles et al 2018), and three digenean species, Cladorchis pyriformis (Diesing, 1838), Urotrema scabridum Braum, 1990, and Schistosoma mansoni Sambon, 1907(Sutton and Lunaschi 1990Picot 1992;Lunaschi and Drago 2007;Fernandes et al 2015).…”