Samples of macrobenthic organisms were obtained at seven stations on a presumed pollution gradient from the head of Vancouver Harbour through to outer Howe Sound. Polychaetes (83 apparent species) and molluscs (43 apparent species) were the most abundant faunal groups numerically (44.8 and 47.9%, respectively). Molluscs accounted for most of the biomass (87.9%). The following univariate and mul...

Bivalve, ammonite and snail shells are described by a small number of geometrical parameters. Raup noted that the vast majority of theoretically possible shell forms do not occur in nature. The constraint factors that regulate the biased distribution of natural form have long since been an open problem in evolution. The problem of whether natural shell form is a result of optimization remains u...

Departamento de Zoologia, Universidade do Estado do Rio de Janeiro, Av. São Francisco Xavier, 524, Maracanã, CEP 20550-900, Rio de Janeiro, RJ, Brasil División de Recursos Acuáticos, Centro de Investigaciones Ecologicas Guayacán, Universidad de Oriente, Cumaná, 6101, Venezuela *e-mail: [email protected] Received November 17, 2005 – Accepted June 12, 2006 – Distributed November 30, 2007 (...

Spatial and temporal variations in relation to environmental and biological parameters were carried out from three stations in Sands pit backwater along the coast of Karachi, Pakistan from January 1999 to December 1999. Various meiofauna taxa were identified from the sample procured during low tide. The total mean densities of meiofaunal were (30.42 ±6.81) and (3628 ± 5958) individuals per10 cm...

Limestone hills are now gaining global conservation attention as hotspots for short-range endemic species. Levels of land snail endemism can be high at limestone hills, especially at hill clusters that are geographically isolated. In the State of Perak, Peninsular Malaysia, limestone hills have been opportunistically surveyed for land snails in the past, but the majority have yet to be surveyed...

Arousal states strongly influence behavioral decisions. In general, arousal promotes activity and enhances responsiveness to sensory stimuli. Earlier work has emphasized general, or nonspecific, effects of arousal on multiple classes of behaviors. However, contemporary work indicates that arousal has quite specific effects on behavior. Here we review studies of arousal-related circuitry in moll...

Predation is arguably one of the main driving forces of early metazoan evolution, yet the fossil record of predation during the Ediacaran-Early Cambrian transition is relatively poor. Here, we present direct evidence of failed durophagous (shell-breaking) predation and subsequent shell repair in the Early Cambrian (Botoman) epibenthic mollusc Marocella from the Mernmerna Formation and Oraparinn...

In addition to regular photoreceptors, some invertebrates possess simple extraocular photoreceptors. For example, the central ganglia of mollusks contain photosensitive neurons. These neurons are located on the dorsal surface of the ganglia and based on their electrophysiological properties, it has been postulated that they are the internal photoreceptors. However, besides the eye, transduction...