Do recreational activities affect macrofauna distribution pattern in Amazonian macrotidal sandy beaches?

Recreational activities are important source of disturbance on sandy beaches and have a negative effect on benthic communities as they alter species abundance, diversity, and/or distribution. Here, we report for the first time the effects of the recreational activities on the distribution pattern of macrobenthic communities of Amazonian sandy beaches. Sampling was performed during three consecutive months with different beach use intensity in 2017 (before, during vacation, and one month after the vacation period) on two contrasting beaches regarding disturbance (Urban: Atalaia; and Protected: Corvinas) in the intertidal zone along two equidistant transects at seven equidistant sampling stations: from the high-tide water mark to the swash zone. At each sampling station, four biological and sediment samples were randomly collected. Also, in each station, the sediment compaction was determined using a manual penetrometer. Physical sediment variables remained constant over time in both beaches, whereas differences were found in sediment compaction over the periods. Sediment compaction was considered the most important factor for the differences observed in macrobenthic community structure in the study beaches, and it was related to intensity of recreational activities. Variations in density and changes in richness between periods and sampling stations were observed in Atalaia beach. On the other hand, Corvinas beach remained the same throughout the study. Overall, three faunal zones were distinguished: upper intertidal, intermediate intertidal, and low-intertidal, whereas in the vacation period, only two faunal zones were distinguished: upper-intertidal and intermediate-low intertidal.

Description of Pseudosteineria longisetis sp. n. from northeastern Brazil with a review of the genus Pseudosteineria Wieser, 1956 (Nematoda: Xyalidae).

A new free-living marine nematode of the family Xyalidae is described from Armação Beach, northeastern Brazil, and the genus Pseudosteineria is reviewed. Pseudosteineria longisetis sp. n. is characterized by having six groups of long subcephalic setae, amphids situated slightly anterior to the groups of subcephalic setae or at the level of the first subcephalic setae, long somatic setae located posteriorly to subcephalic setae and distributed along the body, one papiliform precloacal supplement, and gubernaculum with dorso-caudal apophysis. An emended diagnosis of the genus, an updated list of species and dichotomous identification key, and a pictorial key are given. A comparative table including the main characters of all Pseudosteineria species is also provided.

A new species of Pomponema Cobb, 1917 (Nematoda: Cyatholaimidae) from Northeast of Brazil, with reference to the taxonomic status of the genera Parapomponema Ott, 1972 and Propomponema Ott, 1972.

A new species of free-living marine nematode is described from Itapuã beach, northeast of Brazil. Pomponema veronicae sp. n. differs from other species of Pomponema by having buccal cavity with large pointed dorsal tooth, two subventral teeth and pairs of denticles, gubernaculum with two L-shaped lateral plates and having a membrane at its distal end that connects to L-shaped plate, and presence of a ventral orifice at distal end of L-shaped plates. It also differs from other species in the size of spicules and gubernaculum. The new species is considered most closely related to Parapomponema species because of the L-shaped lateral plates of gubernaculum, but the taxonomic status of Parapomponema was reviewed and Parapomponema and Propomponema are now synonymized with Pomponema. Pomponema cyatholaimoides is considered as a species inquirendum and Pomponema carinatum is accepted as Pomponema loticum. An updated identification key to species of Pomponema is included.

The state of the art of Chromadoridae (Nematoda, Chromadorida): a historical review, diagnoses and comments about valid and dubious genera and a list of valid species.

Chromadoridae is a widespread family of mostly free-living marine nematodes. This systematic review provides for each genus: a historical background, an updated diagnosis and a list of species. Our review recognizes 37 valid genera, 395 valid species, 57 descriptions without enough morphological information for accurate identification (species inquirenda) and 10 species incerta sedis. We also recognize 21 species as nomena nuda. Additionally, polytomous keys were constructed for the subfamilies and for the genera of the three major subfamilies (Chromadorinae, Euchromadorinae and Hypodontolaiminae) using the most important diagnostic characters. A phylogenetic analysis based on rDNA sequences of species available in the GenBank was also conducted. Phylogenetic trees based on the 18S and 28S rDNA confirmed the classification into three subfamilies (Spilipherinae, Hypodontolaiminae and Chromadorinae), despite the absence of defined synapomorphies. Phylogenetic relationships at lower taxonomic level are problematic given the large number of sequences not identified to species level.

Updates on information about free-living marine nematodes in Brazil: new records and comments on problems in taxonomic studies.

New records of nematode species in Brazil, which appeared after or were not mentioned in the last review, are shown in this paper. All environments were considered, including the continental margin. In addition, all studies on marine nematodes in Brazil, including grey literature, ecological papers and book chapters, are listed. Furthermore, information on genera/species richness, dominant genera, and densities is also presented. A total of 11 orders, 72 families, 372 genera, and 450 species of nematodes were recorded in Brazilian marine environments by April 2017. Following problems are discussed: taxonomic lists available only in grey literature, use of outdated identification keys (leading to incorrect identifications), and identifications mostly to putative species or to the genus level.

Parasphaerolaimus magdolnae sp. n. (Nematoda, Sphaerolaimidae) with intra-uterine development of its offspring from a Brazilian estuarine system.

One new species of Parasphaerolaimus is described from a Brazilian estuarine system with intra-uterine development of its offspring. Parasphaerolaimus magdolnae sp. n. is distinguished from other species of the genus by the presence of only one anterior testis, spicules morphology and size and a gubernaculum without dorsal apophysis. The cuticle of the new species is striated and the position of the vulva is far posterior on the body, almost reaching the anus. The taxonomy of Parasphaerolaimus was also re-examined and two other species were transferred from Sphaerolaimus to Parasphaerolaimus after the last revision: P. pentasetus (Pastor de Ward, 1984) comb. n. and P. striatus (Allgén, 1935) comb. n. An updated identification key for all valid species of Parasphaerolaimus is included.