No abstract

The current taxonomy of the Teredinidae (shipworms) is wholly based on morphology and up to now no molecular studies of the phylogeny of this group have been published. In the present study the relationships between four genera of the subfamilies Teredininae and Bankiinae were established and the efficiency of the 16S rRNA gene in characterizing four Teredinidae species was tested. Phylogenetic trees support the grouping of Bankia fimbriatula with Nausitora fusticula and of Neoteredo reynei with Psiloteredo healdi, but the genetic distances do not justify the classification of these species into two distinct subfamilies. The results show that B. fimbriatula, N. reynei and P. healdi specimens from the coast of the Brazilian state of Pará have five distinct 16S rRNA haplotypes, with one N. reynei haplotype differing from the other haplotypes in respect to at least seven sequences sites, indicating the existence of two very distinct sympatric lineages.

The objective of this work was to propose a nondestructive method to identify and quantify the damage caused by marine borers in wood structures. First, a test specimen was submerged in an estuarine environment for 120 days. Radiography was then applied to detect and evaluate the attack by marine borers. Two methods of evaluation were performed with the images to compare them. The first assessment was carried out using the QGIS® geoprocessing program for the treatment of images as a tool, which made it possible to identify and quantify the damage (in cm²). The second evaluation followed the method indicated in EN 275 (1992), which suggests a visual assessment, based on X-ray images, classified according to a template provided in the standard. Although the method using the image treatment by QGIS® is an estimate, it has the advantage of providing a numerical result, in contrast to the visual analysis, which is not as accurate due to its subjectivity. Besides this, the treatment of the images allowed good visualization of the damage to the specimen. The findings indicated that QGIS® can be used as a complement to the method proposed by EN 275 (1992).

Wood in marine environments requires protection against xylophagous, and to increase the effectiveness of the preservatives, it is first necessary to know environmental conditions and species of wood borers present. The durability of treated Pinus taeda wood against the attack of marine borers in different environments was investigated, with (1) burnt oil, by the hot-cold bath method; (2) paraffin, by the Bethell method; (3) superficial burning of the wood with oil application, known as shou sugi ban technique; and (4) impermeable rubber, with and without the addition of silica, by immersion. The experiment was adapted from the standard EN 275 (1992) and carried out in three areas, one located in a river and two in estuarine coastal areas of the Paranaguá Bay (Brazil). Based on the percentage of lost wood area, the treatment with impermeable rubber with the addition of silica showed the best performance at the local 1 site (26.3%). At the local 2 site, treatments with impermeable rubber with and without the addition of silica had the lowest percentages of loss, with mean values of 13.95 and 12.65%, respectively. The other treatments had losses above 30%, being classified as severe damage, meaning they are not suitable for this use.