Morphometric study of the nereidid Laeonereis acuta (Annelida : Polychaeta)

In order to find the Most suitable parameter for measuring the nereidid Laonereis acuta, correlations between total length or weight and eight morphological measurements: width of prostomium and 2nd, 6th, 13th and 19th setigers, length of the prostomium, length through segment 6th and length through segment 13th, were established. The width measurements showed the highest values of r, and were the most reliable indicators of size. Comparisons between weight and morphological measurements showed a similar pattern as well its negative allometric growth.o TEXTO COMPLETO DESTE ARTIGO, ESTARÁ DISPONÍVEL À PARTIR DE AGOSTO DE 2015.81342342

Sandy beach morphodynamic and the polychaete fauna in southeast Brazil

This study was aimed to examine the influence of beach morphodynamic on polychaete intertidal fauna from protected sandy beaches. The spatial distribution of polychaete from four beaches of different slopes and grain sizes were analyzed at Sao Sebastiao Channel in the northern coast of Sao Paulo State. The beaches were divided into three levels (high, low and middle) across the intertidal zone by 10 m wide transects. Five random corers (0.01 m(2)) were collected monthly from August/ 1995 until December/1997 in an area of 100 m(2) for each level. Grain size, organic matter, slope profile and moisture content from the three levels were analyzed. Differences in overall faunal density were observed among the four study sites as well as along the intertidal levels. Enseada and Barra Velha, fine sand beaches, showed significantly higher density than Siriuba and Garapocaia where coarser grains predominated. The higher levels of the beaches had higher faunal density than the middle and lower ones. The numerically dominant species on fine sediments sites, were Laeonereis acuta and Capitella capitata, whereas on coarse ones the spionid Scolelepis squamata predominated. Highest diversity values were found at sites with the greatest organic matter and silt-clay content, Siriuba and Barra Velha. The structural parameters studied here, such as density, diversity and evenness were affected by grain size properties as well as tide range, slope profile and moisture content variation. The present results showed that even under sheltered conditions beach morphodynamics can influence intertidal polychaete fauna.3543143