Abstract This study aimed to describe the occurrence, morphology and prevalence of Spirocamallanus krameri, a parasite of Hoplerythrinus unitaeniatus collected in state of Pará, Brazil. The morphological and morphometric characteristics are consistent with the species S. krameri, by having a hexagonal mouth opening, 16 cephalic papillae and two lateral papillae on the amphids. The buccal capsule is internally different in both sexes, with (11–13) spiral ridges in males and (13–17) spiral ridges in females. The basal ring is well developed, and three teeth are present in males and absent in females. Ten sessile caudal papillae and a pair of phasmidial pores occur in males. The spicules are small, subequal, 81–101 µm in length and the tail is tapered. The vulva in females is postequatorial, the tail is conical with lateral phasmidial pores. Among the species of Spirocamallanus that have short spicules, the general morphology of S. krameri most resembles that of S. inopinatus, but differs from that species, which have two cephalic teeth visible (absent in S. krameri) and specimens of S. inopinatus do not have sexual dimorphism in the buccal capsule of present in S. krameri.

Abstract During a helminthological survey on freshwater turtles from the Brazilian Amazon, we collected fresh and well-preserved nematodes from the stomach of Podocnemis unifilis Troschel, 1848, that resembled Orientatractis leiperi. The morphology and morphometry of specimens described herein fits those from the original description. We also observed important morphological characters not reported previously or not properly described, and those are reported here for the first time: the structure of the excretory pore (surrounded by radial cuticle striations), structure and position of deirids, phasmids, oral papillae and the presence of a dorsolateral pair of papilla in caudal region. The present work provides a detailed redescription for O. leiperi, 50 years after its original description, adding a new host and locality for this species.

Resumen Durante el análisis helmintológico de tortugas de agua dulce en la Amazonía brasileña, fueron extraídos del estómago de Podocnemis unifilis Troschel, 1848, nemátodos que parecían pertenecer a la especie Orientatractis leiperi; estos ejemplares fueron utilizados para realizar la redescripción de esta especie mediante microscopía óptica y microscopía electrónica de barrido. La morfología y morfometría de los ejemplares analizados en este estudio se ajustaron a la descripción original. Importantes caracteres morfológicos que no fueron considerados previamente o que no fueron descritos adecuadamente, se detallan por primera vez en este trabajo: la estructura del poro excretor (rodeado de estrías radiales cuticulares), estructura y posición de las papilas cervicales, fasmidios y papilas orales, distribución y disposición de las papilas caudales en los machos y la presencia de un par de papilas dorsolaterales en la región caudal. Este trabajo presenta una redescripción detallada de O. leiperi, 50 años después de su descripción original, adicionando un nuevo hospedador y nueva localidad para la misma.

Angiostrongylus cantonensis is the etiologic agent of eosinophilic meningoencephalitis in humans. Cases have been recorded in many parts of the world, including Brazil. The aim of this study was to compare the differences in the biology and morphology of two different Brazilian haplotypes of A. : ac8 and ac9. A significantly larger number of L1 larvae eliminated in the faeces of rodents at the beginning of the patent period was observed for ac9 haplotype and compared to the total of L1 larvae eliminated, there was a significant difference between the two haplotypes. The ac9 haplotype showed a significant difference in the proportion of female and male specimens (0.6:1), but the same was not observed for ac8 (1.2:1). The morphometric analysis showed that male and female specimens isolated from ac8 haplotype were significantly larger with respect to body length, oesophagus length, spicule length (male) and distance from the anus to the rear end (female) compared to specimens from ac9. The morphological analysis by light microscopy showed little variation in the level of bifurcations at the lateral rays in the right lobe of the copulatory bursa between the two haplotypes. The biological, morphological and morphometric variations observed between the two haplotypes agree with the observed variation at the molecular level using the cytochrome oxidase subunit I marker and reinforce the possible influence of geographical isolation on the development of these haplotypes.

Mesocoelium lanfrediaesp. nov. (Digenea: Mesocoeliidae) inhabits the small intestine of Rhinella marina (Amphibia: Bufonidae) and is described here, with illustrations provided by light, scanning electron microscopy and molecular approachs. M. lanfrediae sp. nov. presents the typical characteristics of the genus, but is morphometrically and morphologically different from the species described previously. The main diagnostic characteristics of M. lanfrediae sp. nov. are (i) seven pairs of regularly-distributed spherical papillae on the oral sucker, (ii) ventral sucker outlined by four pairs of papillae distributed in a uniform pattern and interspersed with numerous spines, which are larger at the posterior margin and (iii) small, rounded tegumentary papillae around the opening of the oral sucker, which are morphologically different from those of the oral sucker itself, some of which are randomly disposed in the ventrolateral tegumentary region of the anterior third of the body. Addionally, based on SSU rDNA, a phylogenetic analysis including Brachycoeliidae and Mesocoeliidae taxa available on GenBank established the close relationship between M. lanfrediae sp. nov. and Mesocoelium sp.