The order Monhysterida is highly important to freshwater environments, containing a number of genera noted for their ability to endure extreme environmental conditions, such as those found in semi‐arid regions. The genus Monhystrella is often cited in references to these regions. The present study was performed in six reservoirs in a semi‐arid region of Brazil, employing collection and identification techniques commonly used for the phylum Nematoda. Sixteen genera pertaining to the phylum were detected, although only Monhystrella was found in all the reservoirs, with a monospecific population of Monhystrella hoogewijsi identified in Olivedos Reservoir. The present study contains the first record of this genus and species in Brazil, as well as the first‐ever description of the male of the species. The main morphometric variations were a longer tail and smaller amphidial fovea of females from the Brazilian semi‐arid region. The differences in morphometric measurements and the description of the male specimen expand current descriptions and levels of knowledge regarding this species.
A new species of the genus Acantholaimus is described from the South Atlantic, in the Potiguar Basin off the continental shelf of northeast Brazil. Acantholaimus marliae sp. n. is characterized by the long body; numerous somatic setae arranged in four sublateral longitudinal rows; buccal cavity with five solid teeth (four subventral and one dorsal), with the largest tooth dorsally located and the most protuberant between the subventral teeth shaped similarly to a "bottle opener"; and spiral fovea amphidialis. Acantholaimus marliae sp. n. is the only species described for the genus that has a spiral fovea amphidialis. This is the fifth species of Acantholaimus described from shallow water. An emended diagnosis of the genus is provided.
Two new species of the genus Acantholaimus (Nematoda, Chromadoridae) are described from the South Atlantic, in the Santos Basin off the slope of southeastern Brazil. Acantholaimus pugious sp. n. is characterized by a narrow and elongated anterior end; teeth that are thin and long stylet-like (two in number), amphidial fovea located far from the anterior end and occupying most of the corresponding body diameter. Acantholaimus bidentatus sp. n. is characterized by a narrow anterior end, cuticle with more evident dots on both body extremities (up to amphidial fovea and tail); two long, protractible thin teeth (similar to stylet), with curved proximal part. The two species are similar in the shape of the teeth. The teeth morphology may be correlated to the process of adaptive convergence of these species. An emended diagnosis of the genus is provided.
A new species of the genus Cephalanticoma is described for the Atlantic Ocean in the Potiguar Basin off the continental shelf of northeast Brazil. Cephalanticoma rugatusa sp. n. is characterized by bearing head capsule ending on the level of amphideal fovea, a tubular precloacal supplement and two rows of thin precloacal setae. Cephalanticoma rugatusa sp. n. differs from all other species of the genus by having a precloacal cuticular papilla in front of the cloaca and a cuticular transversal wrinkle which extends from the papilla elevation to the conical-cylindrical portion of the tail occupying both subventral regions. An emended diagnosis and a dichotomous key to species based on both genders are provided.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.