Abstract: The re-examination of nematodes collected decades ago from a spiny rat, Proechimys roberti (Echimyidae) from Pará State, revealed the presence of Acanthostrongylus acanthostrongylusTravassos, 1937, and two coparasitic species of Pudica (Heligmonellidae: Pudicinae), one of them new to science. Pudica minima n. sp. mostly resembles Pudica tenuaDurette-Desset, 1970, described from Proechimys semispinosus in Colombia. Nevertheless, it differs from P. tenua by having a synlophe with 12 ridges with poorly developed careen, bursal pattern of type 2-2-1 on the right lobe, bursal rays 2 and 3 similar in length, and spicules longer with spoon-shaped tips. Pudica evandroi (Travassos, 1937) was already described from Pr. roberti but its synlophe remained undescribed and the original description lacked some details. A detailed study of the synlophe is provided and the range of morphometric data for males and females is enlarged. The study of the synlophe allowed ratifying the placement of this species within Pudica, as early suggested by previous authors. The species list and identification key to species of Pudica are updated with the inclusion of three species. The status of Heligmosomum alphaTravassos, 1918, which was transferred to Pudica in 1990, is emended and the species is considered a Nippostrongylinae incertae sedis.

Paraheligmonella lamothei n. sp. (Heligmonellidae: Heligmonellinae) is described from the small intestine of a cottontail, Sylvilagus floridanus (Allen, 1890) (Leporidae), from Costa Rica. New morphological data on the synlophe and caudal bursa of Paraheligmonella romerolagi (Gibbons and Kumar, 1980), the most similar species, are also provided. The new species differs from P. romerolagi, parasitic of Romerolagus diazi (Ferrari-Pérez, 1893) from Mexico, mainly by the characters of the caudal bursa and the synlophe of the female within the posterior region of body. Males of P. lamothei n. sp. possess a caudal bursa not bell-shaped, with a pattern of type 2-2-1 for right lobe and 2-3 with a tendency to type 2-2-1 for left lobe, whereas males of P. romerolagi possess a bell-shaped caudal bursa, with a pattern of type 2-2-1 with a tendency to type 4-1 for both lobes. In P. lamothei n. sp. rays 3 are slightly longer than rays 2 and the genital cone is poorly developed, whereas in P. romerolagi rays 3 are much longer than rays 2 and the genital cone is large and bulbous. Females of P. lamothei n. sp. possess, at ovejector level, ventral and latero-ventral ridges hypertrophied and dorsal ridges reduced, whereas at the same level, females of P. romerolagi possess lateral ridges hypertrophied and dorsal and ventral ridges reduced. Additionally, hypertrophied cuticular ridges posterior to the vulva are present in P. lamothei n. sp., but absent in P. romerolagi.

Se describe Paraheligmonella lamothei n. sp., parásita del intestino delgado de Sylvilagus floridanus (Allen, 1890) (Leporidae) de Costa Rica. Se aportan además datos nuevos morfológicos sobre el synlophe y la bolsa caudal de Paraheligmonella romerolagi (Gibbons y Kumar, 1980), la especie morfológicamente más parecida. La especie nueva se diferencia de P. romerolagi, parásita de Romerolagus diazi (Ferrari-Pérez, 1893) de México, principalmente por caracteres de la bursa caudal y el synlophe de la hembra en la región posterior del cuerpo. Los machos de P. lamothei n. sp. poseen una bursa caudal sin forma de campana, con un patrón de tipo 2-2-1 para el lóbulo derecho y 2-3 con tendencia a tipo 2-2-1 para el lóbulo izquierdo, mientras que los machos de P. romerolagi poseen una bursa en forma de campana, con un patrón de tipo 2-2-1 con tendencia a tipo 4-1 para ambos lóbulos. En P. lamothei n. sp. los rayos 3 son ligeramente más largos que los rayos 2 y el cono genital está poco desarrollado, mientras que en P. romerolagi los rayos 3 son mucho más largos que los rayos 2 y el cono genital es grande y bulboso. Las hembras de P. lamothei n. sp. poseen, a la altura del oviyector, las crestas cuticulares ventrales y latero-ventrales hipertrofiadas y las dorsales y laterales reducidas, mientras que a la misma altura, las hembras de P. romerolagi poseen las crestas laterales hipertrofiadas y las dorsales y ventrales reducidas. Adicionalmente, las crestas cuticulares hipertrofiadas posteriores a la vulva en P. lamothei n. sp., están ausentes en P. romerolagi.

A new genus and a new species of Heligmonellidae nematodes are described parasiting the stomach of three agoutis (two Dasyprocta fuliginosa and one D. leporina) captured in the middle and high Negro river microregion, state of Amazonas, Brazil. The new genus, as well as its type-species, are closely related to the trichostrongylids included in Fuellebornema, particularly on what concerns the pattern of the caudal bursa, but differing from them by the characteristics of the synlophe, that presents a poorly developed carene, when compared to the referred number of body ridges in Freitastrongylus n. gen. and consequently in F. angelae n. sp.,in which the ridges are well developed and the carene at mid-body has a similar size when compared to the ridge situated in front of the right field (ridge no. 5). Caudal bursa is of the type 1-4, with rays 9 shorter than rays 10, with a very long genital cone.

Description of four new species of Oswaldocruzia parasitizing Iguanidae and Leptodactylidae from Ecuador, demonstrate that they are morphologically close to each other. Like most of the other neotropical and holarctic Oswaldocruzia , they are characterized by spicules with three main branches: blade, shoe and fork; the division of the fork within the distal third of the spicule length appears to be characteristic of the neotropical species. - Oswaldocruzia bainae n. sp. parasitizing Anolis chrysolepis and Anolis fuscoauratus possesses a synlophe visible only on transversal sections of the body. It is composed of rounded and not pointed ridges. - Oswaldocruzia tcheprakovae n. sp. parasitizing Eleutherodactylus altamazonicus is closely related to O. bainae , but the synlophe is present only in the anterior and posterior extremities of the body. - Oswaldocruzia cassonei n. sp. parasitizing Eleutherodactylus lanthanites is closely related to O. taranchoni, Ben Slimane and Durette-Desset, 1995, a parasite of Bufo marinus from Brazil. It is differentiated by the synlophe and the measurements. - Oswaldocruzia petterae n. sp. parasitizing Leptodactylus pentadactylus is closely related to O. chambrieri, Ben Slimane and Durette-Desset, 1993, parasitizing Bufo and Eleutherodactylus in the same region. It is differentiated since, for an equivalent length of the body, the ridges are almost two times fewer and the spicules smaller.

A new nematode, the type of a new genus and a new species Laurostrongylus hoineffae, parasitic in the cricetid rodent Gymnuromys roberti in Madagascar, is described. The species belongs to the Graphiidinae subfamily of Trichostrongylidae but some features point to its affinity to certain Libyostrongylinae, especially to two monospecific genera endemic in Madagascar Pararhabdonema and Cnizostrongylus. This ensemble of relict species seems thus to support the concept of a common ancestor for the Libyostrongylinae and Graphidiinae. The two subfamilies were supposed to originate in the Ethipian region. The presence of the three generain Madagascar could either indicate their Madagascan origin or, more likely, a continental origin with an insular niche allowing the preservation of the species.