Wiwaxia is a bizarre metazoan that has been interpreted as a primitive mollusc and as a polychaete annelid worm. Extensive material from the Burgess Shale provides a detailed picture of its morphology and ontogeny, but the fossil record outside this lagerstätte is scarce, and complete wiwaxiids are particularly rare. Here we report small articulated specimens of Wiwaxia foliosa sp. nov. from th...

The impacts of climate change on the structure and functioning estuaries is a major focus concern, even more when affected species support important fisheries as bivalves Ruditapes decussatus , philippinarum Venerupis corrugata Cerastoderma edule in Europe. Their reproductive performance, context stressors, had not been investigated so far. Our objective was to experimentally evaluate acute str...

Larvae of the abalones Haliotis rufescens, H. corrugata, and H. (ulgens displayed most rapid growth and best survival at 15°_18°, 18°_21°, and 20°·23°C, respectively. Survival oflarvae and postlarvae was poor above these optimal ranges. However, juveniles 3 mo to 1 yr old were tolerant of a broader temperature range. The warm-water species, H. fulgens, increased in shell length at an average ra...

Chemical communication is fundamental to sexual reproduction, but how sperm search for and find an egg remains enigmatic. For red abalone (Haliotis rufescens), a large marine snail, the relationship between chemical signaling and fluid motion largely determines fertilization success. Egg-derived attractant plumes are dynamic, changing their size and shape in response to unique combinations of p...

Abalone sperm lysin is a 16 kDa acrosomal protein used by sperm to create a hole in the egg vitelline envelope. Lysins from seven California abalone exhibit species-specificity in binding to their egg receptor, and range in sequence identity from 63 % to 90 %. The crystal structure of the sperm lysin dimer from Haliotis fulgens (green abalone) has been determined to 1.71 A by multiple isomorpho...

Species of Haliotis (abalone) show high variety in structure and mineralogy of the shell. One of the European species (Haliotis tuberculata) in particular has an unusual shell structure in which calcite and aragonite coexist at a microscale with small patches of aragonite embedded in larger calcitic zones. A detailed examination of the boundary between calcite and aragonite using analytical mic...

Failure to account for interactions between endangered species may lead to unexpected population dynamics, inefficient management strategies, waste of scarce resources, and, at worst, increased extinction risk. The importance of species interactions is undisputed, yet recovery targets generally do not account for such interactions. This shortcoming is a consequence of species-centered legislati...