Functional morphology of Petricola (Rupellaria) typica (Bivalvia: Petricolidae)

The bivalve Petricola typica occurs from North Carolina (USA) to Brazil where, according to Rios (1970), its range extends to Rio Grande do Sul. The species can be found in coral blocks of Mussismilia hispida, inside colonies of Schizoporella unicornis (a calcarean bryozoan) and, more frequently, inside the sandy reefs built by the polychaete Phragmatopoma lapidosa (intertidal zone). Initial settlement probably occurs in a pre-existing cavity, which is enlarged to form a hole into which the bivalve fits exactly when its valves open. The shell, mantle, and siphons are described in detail. Special attention was paid to the ctenidia, labial palps, and stomach.     

Between uncertainty and hope: Young leaders as agents of change in sustainable small-scale fisheries

The path to sustainable small-scale fisheries (SSF) is based on multiple learning processes that must transcend generational changes. To understand young leaders from communities with sustainable SSF management practices in Mexico, we used in-depth interviews to identify their shared motivations and perceptions for accepting their fishing heritage. These possible future decision-makers act as agents of change due to their organizational and technological abilities. However, young people are currently at a crossroads. Many inherited a passion for the sea and want to improve and diversify the fishing sector, yet young leaders do not want to accept a legacy of complicated socioenvironmental conditions that can limit their futures. These future leaders are especially concerned by the uncertainty caused by climate change. If fishing and generational change are not valued in planning processes, the continuity of fisheries, the success of conservation actions, and the lifestyles of young fishers will remain uncertain.Graphical abstract Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01639-2.     

On the functional morphology of Hiatella solida (Hiatellidae: Bivalvia)

Hiatella solida (Sowerby, 1834) is the only species of the genus Hiatella represented in Southern Brazilian waters. It occurs on the coast of São Paulo and Rio Grande do Sul. The bivalves were found nestling or attached by byssus threads to specimens of the sea squirt Polyandrocarpa zorritensis or between the tubes of the polychaete Phragmatopoma lapidosa in the intertidal zone. The structure, adaptation and functional morphology were studied in detail, including the functioning of the stomach. H. solida were found with mature ova in August.     

The life cycle of the commensal hydromedusa Eutima sapinhoa n. sp.

Eutima sapinhoa n. sp. is a small hydroid, which lives attached by a basal disc to the mantle, foot, gills and labial palps of the bivalve Tivela mactroides (Born, 1778), found on the northern littoral of São Paulo State, Brazil. This bivalve, locally known as “sapinhoá”, is used as food by the coastal inhabitants. The hydroid produces a leptomedusa which belongs to the family Eutimidae. The medusa bud develops as a small knob-like protuberance near the base of the polyp and, after 61/2 days, reaches the free-swimming stage in covered preparation dishes containing about 200-ml filtered sea water at a temperature of 20° to 22°C. After 25 days the medusa is 4 mm high, 4-mm in diameter, and possesses 4 radial tentacles —each about 2 to 3 times as long as the bell diameter, 8 marginal vesicles — 2 in each quadrant, and 28 small marginal swellings — 7 in each quadrant. The peduncle is as long as the height of the bell, 4 single long gonads develop on the subumbrella on each radial canal. The nematocysts are small atrichous isorhizae, with capsules averaging 7 μm in length.