New species of Hassalstrongylus (Trichostrongyloidea: Heligmonellidae) in the large-headed rice rat Hylaeamys seuanezi, in the Atlantic Forest of northeast Brazil.

Natália Alves Costa,Maíra Guimarães Kersul,Arnaldo Maldonado Junior,Martin Roberto Del Valle Alvarez,Rosana Gentile

doi:10.1590/s1984-29612021031

Abstract

A new species of Trichostrongyloidea (Nematoda: Heligmonellidae), Hassalstrongylus lauroi n. sp., is described from specimens collected from the small intestine of the rodent Hylaeamys seuanezi in the Atlantic Forest of northeastern Brazil (Igrapiúna, state of Bahia). The genus Hassalstrongylus includes 17 species, which parasitize rodents occurring in the Neotropical and Nearctic regions. It differs from the genus Stilestrongylus through its smaller number of ridges in the synlophe and through the size of the genital cone. The main taxonomic characteristics of this new species are the subsymmetrical caudal bursa of type 2-2-1, ray 8 branching out at the base of the dorsal trunk, right lobe smaller than the left, and rays 4 and 5 of robust nature. In addition, the ornamental ray 5 and the robustness of ray 4 on the male caudal bursa, along with the modification of the ridges of the posterior end of the female, allow us to consider the specimens found to be a new species.

Highlights

Heligmonellidae (Skrajabin & Schikhobalova, 1952 tribe) Durette-Dessete & Chabaud, 1977 is a large family of small nematodes
The large-headed rice rat, Hylaeamys seuanezi (Weksler, Geise & Cerqueira, 1999), is a sigmodontine rodent endemic to the Brazilian Atlantic Forest. It occurs in forested areas and agroforestry systems in northeastern and southeastern Brazil, in the states of Bahia, Espírito Santo, Minas Gerais and Rio de Janeiro (Brennand et al, 2013; Silva et al, 2020)
The main taxonomic characteristics of this new species comprise a subsymmetrical caudal bursa of type 2-2‐1, ray 8 arising from the base of the dorsal trunk, left lobe larger than the right lobe and rays 4 and 5 of robust nature, the latter presenting a corrugated shape in both lobes

Summary

Introduction

Heligmonellidae (Skrajabin & Schikhobalova, 1952 tribe) Durette-Dessete & Chabaud, 1977 is a large family of small nematodes. Hassalstrongylus Durette-Desset, 1971, includes 17 species with 19 to 24 cuticular longitudinal ridges that vary in body size and body sagittal plane This genus has a symmetrical or subsymmetrical caudal bursa and a non-hypertrophied genital cone, and mainly parasitizes cricetid rodents (Anderson, 2000; Durette-Desset, 1985). The large-headed rice rat, Hylaeamys seuanezi (Weksler, Geise & Cerqueira, 1999), is a sigmodontine rodent endemic to the Brazilian Atlantic Forest It occurs in forested areas and agroforestry systems in northeastern and southeastern Brazil, in the states of Bahia, Espírito Santo, Minas Gerais and Rio de Janeiro (Brennand et al, 2013; Silva et al, 2020). We describe a new species of the genus Hassalstrongylus that was found parasitizing the rodent H. seuanezi in the Brazilian Atlantic Forest, in the municipality of Igrapiúna, in the state of Bahia

Materials and Methods

Discussion