Similarity in parasite communities of the teleost fish Pinguipes brasilianus in the southwestern Atlantic: Infracommunities as a tool to detect geographical patterns

Patterns of distance decay in similarity among communities of the fish Pinguipes brasilianus (Teleostei: Pinguipedidae) from five areas in the southwestern Atlantic were investigated to determine whether the rate of decay varied depending on the community level or the parasite guild analyzed (ectoparasites, adult endoparasites and larval endoparasites). Similarities in species composition were computed at both the component community and infracommunity levels. Similarity indices were calculated between all possible pairs of assemblages from different zones. Infracommunity similarity values between and within host populations were averaged. Significance of linear regressions for similarity values against distance was assessed using randomization tests. Different patterns were observed for each guild, and similarity among infracommunities within host populations varied accordingly. Decay in similarity over distance was recorded for most communities. The slopes differed significantly between infracommunities and component communities in all cases, and stronger decay was always observed for infracommunities. Different geographical patterns in parasite communities were a consequence of variability in parasite availability in the different regions, modulated by oceanographic conditions, as well as variation among species in terms of host specificity and life-cycles strategies. Infracommunities showed a stronger effect of distance than component communities, probably due to the influence of short term and local variability of oceanographic conditions.     

A critical appraisal of marginal increment analysis for assessing temporal periodicity in band formation among tropical sharks

Marginal increment ratio (MIR) analyses were conducted as part of age and growth studies on three coastal/semi-oceanic species, the smalltail shark, Carcharhinus porosus, daggernose shark, Isogomphodon oxyrhynchus and the night shark C. signatus, and two ubiquitous oceanic species, blue shark, Prionace glauca, and whitetip shark, C. longimanus, collected in equatorial areas off Brazil with the aim of establishing the interspecific temporal nature of vertebral band formation. Monthly variations in marginal bands were analyzed using mean MIR on the entire sample as the standard method for all species. Reasons for the inconclusive results regarding these species are critically appraised with respect to three main sources of bias that are associated with marginal increment analysis (MIA). Bias due to insufficient sample sizes may have hampered the analysis for I. oxyrhynchus and C. longimanus due to movements from shallow waters to seamounts for the former species and to extensive migrations for the latter. Bias due to data collection over too long a period is thought to have influenced monthly mean MIR for C. porosus and P. glauca. For the latter, individuals from different age groups lay down rings at different times, making band deposition inconsistent between individuals. Finally, bias due to births occurring over too long a period was the prevalent cause for confounding MIR values among I. oxyrhynchus and C. signatus species, whose birth period lasts several months and leads to different ages within the same cohort. Other approaches used for MIA in C. signatus and P.␣glauca led to distinct times of band formation by age-groups when compared to MIR applied on the entire sample. For the daggernose shark, delays in events related to the reproductive cycle from one year to the next were also found to confound MIR. Requirements for the use of MIR implying a band width that displays a sinusoidal cycle when temporally plotted (month or season) were not fulfilled for any of these species. The method has been of little utility for detecting the periodicity of band deposition among sharks from the tropics. This emphasizes the need for supplying information on the temporal periodicity of pair deposition based on other methods.     

Foraminiferal assemblage and reef check census in coral reef health monitoring of East Brazilian margin

Human activity is changing environmental conditions on a global scale. Among the ecosystems that are affected by human activities, coral reefs are among the most prominent. In Brazil, the coral reefs of the Corumbau Marine Extractive Reserve (CMER) and Abrolhos National Marine Park (ANMP) in Bahia state have some of the highest coral cover in the South Atlantic Ocean. Hard coral cover, algal cover, and foraminiferal population distribution patterns were used to assess the coral reef benthic environments, and define a background that can be used in worldwide comparisons in future studies. To compare these two monitoring approaches in different coral reef environments, relative frequency data for occurrence of hard coral and algal cover, using point-intercept transects as proposed by the Reef Check protocol, and foraminiferal samples were collected from Corumbau (nearshore) and Abrolhos (offshore) in April 2005. The foraminiferal assemblage was evaluated using the FORAM index (FI — Foraminifera in Reef Assessment and Monitoring), which provides a numeric diagnosis of suitability of benthic habitat to support calcifying organisms that host algal symbionts, originally developed for Caribbean reef areas. Coral cover in the surveyed areas, both in Corumbau and in Abrolhos, ranged from 13% to 37%, while high foraminiferal diversities (H') were found in all stations. Dominance of symbiont-bearing taxa of Amphistegina lessonii and Archaias angulatus only occurred at two shallow stations, Mato Verde and Siriba, both in Abrolhos, where FI > 4.00. Stations located in Corumbau and Abrolhos had FI values < 4.00. Q-mode cluster analysis showed that foraminifers have specific preferences for physical conditions, especially hydrodynamics and light availability, which influence the FI index. Although coral cover in these areas can be considered good by regional standards, foraminifer analysis showed that the benthic system was unfavorable for symbiont-bearing foraminiferal species at most stations. This discrepancy reveals that the FI must be used with caution in areas other than the northwestern Atlantic and Caribbean where it was developed, and that some coral species can thrive in muddier conditions than can most symbiont-bearing foraminifers.     

Mycorrhizal status of some plants of the Araucaria forest and the Atlantic rainforest in Santa Catarina, Brazil

 In Brazil, the Araucaria forest and the Atlantic rainforest are two threatened ecosystems, with 10% or less of their original areas presently existing. To assess the mycorrhizal status in these forests, roots of 29 native species, belonging to 19 families, were collected throughout the year from different regions of Santa Catarina, Brazil. Roots were washed, and then cut in a cryo-microtome to seek ectomycorrhizal colonization. Other roots were stained before being examined for vesicular-arbuscular mycorrhizas (VAM). Patterns of colonization were identified and photographed. All plants presented evidence of vesicular-arbuscular mycorrhizal colonization. No evidence of ectomycorrhizal colonization was found. Vesicular-arbuscular mycorrhizal colonization patterns varied from single intracellular aseptate hyphae, coils, and/or appressoria, to vesicles and/or arbuscules. Results confirmed that VAM hosts are predominant in South American forests while ectomycorrhizas are extremely rare even among genera known as ectomycorrhizal in other regions of the humid tropics. Accepted: 27 August 2000     

Enigmatic traces in infaunal bivalves from the late Quaternary of Argentina,Southwestern Atlantic. Bioerosion,bioclaustration or nothing?

Ichnological investigations were carried out on late Quaternary shells of the intertidal deep infaunal bivalve Tagelus plebeius (Lightfoot, 1786) found along the southwestern Atlantic, between Uruguay and the southernmost Buenos Aires Province in Argentina. Analyses reveal distinctive marks that are spread on the outer shell surface only. The marks are regular-unbranched-elongate, perpendicular to the outer shell growth lines, with deflections on the margins, never interconnected, without bifurcations, conforming bottom-up constructions. They occur in hundreds of specimens from many samples taken from sediments ranging in age from the late Pleistocene to the Recent. These marks have never been reported or described for this species and their origin and formation remain elusive. We describe these traces thoroughly and we propose an explanation for their preservation on about half the shells examined. Potential destructive boring structures (excavated from outside-in) or bioerosion activities by other macro- or micro-organisms are dismissed. These antimarginal asymmetric traces point instead to a process of constructive bioclaustrations (grown from the bottom-up) produced in situ during the life of the bivalve by unknown symbiont organisms. Additionally, the regular pattern observed for the marks exclude host growth as a consequence of abiotic/extrinsic causes. From a palaeoecological perspective, these structures suggest a biotic interaction that was hitherto undescribed neither for bivalves nor for the late Quaternary of the southwestern Atlantic.     

Mayflies (Ephemeroptera) from Reserva Ecológica Michelin,Bahia, Brazil

New records and distributional notes are provided for Reserva Ecológica Michelin, an Atlantic Forest fragment near the southern coast of Bahia State, Brazil. Two families, four genera and five species are recorded for the first time in Bahia State. Additionally, one family, two genera and three species are also recorded for the first time in the Northeast Region of Brazil, resulting in nine families, 48 genera and 96 species recorded to this region. Amongst the recorded species, Hermanella mazama (Nascimento, Mariano, and Salles, 2012) has been classified as an endangered species on the official Brazilian red list.     

Plant endemism in two forests in southern Bahia, Brazil

An important factor in determining species rarity is the geographic distribution of species. Estimates were made of the level of endemism of the flora of two sites in the southern Bahian wet forest zone. Estimates were made for endemism in the Atlantic forest biome and for the much more restricted area of southern Bahia and northern Espi´rito Santo and are derived from analyses of the distributions of the species known from each area. The species checklist for each area is based on identified specimens resulting from intensive collecting in a forest near Serra Grande (40km north of Ilhe´us) and the Una Biological Reserve (40km south of Ilhe´us). Slightly less than half of the species (45.2% at Una and 47.7% at Serra Grande) have widespread distributions and 7.4% at each site are disjunct between the coastal forests and Amazonia. In the Una Reserve, 44.1% of the species are endemic to the coastal forest and 28.1% endemic to southern Bahia and northern Espi´rito Santo. At Serra Grande, 41.6% of the species are endemic to the coastal forest and 26.5% endemic to southern Bahia and northern Espi´rito Santo.     

Analysis of the marine ornamental fish trade at Ceará State, northeast Brazil

Brazil is one of the leading exporters of ornamental fishes, mostly freshwater; however, monitoring of the trade is nearly non-existent in the country. This paper provides an initial assessment of a new venture, the marine aquarium fish trade at Ceará State, northeast Brazil, aiming to document the species traded, to provide preliminary estimates of numbers of specimens traded, and to identify priorities in data collection and monitoring. A total of 143 species and 199 304 fishes were traded. From the total, 109 species were native and represented 84% of the fishes traded. Thirty-four exotic species figured on the permits and amounted to nearly 16% of the exports; however, most of them consist of misidentified native species. Nearly 90% of the fish trade was directed to the international market. Official figures represent an underestimation of the total number of captured specimens.     

First report on the dragonflies from Parque Estadual da Ilha do Cardoso,state of São Paulo,Brazil, with notes on the morphology and behavior of Lauromacromia picinguaba (Odonata: Corduliidae s.l.)

The dragonflies from the Parque Estadual da Ilha do Cardoso, municipality of Cananéia, located at the southern limit of the state of São Paulo in the Brazilian Atlantic Forest, were surveyed for the first time through a short sampling effort lasting four days in October 2011. A total of 36 species, including four new state records for species of the genera Lestes, Phyllocycla, Navicordulia and ‘Schizocordulia’, and three undescribed species of damselflies belonging to Cyanallagma, Forcepsioneura and Idioneura were identified. Some notes are also given for other species, as well as on the morphology and behavior of the intriguing corduliid Lauromacromia picinguaba (incertae sedis). The results, based on a small sample, indicate that the local dragonfly biota at Parque Estadual da Ilha do Cardoso is rich and impressive, and needs to be investigated and protected.