Zuschin m (4 risultati)

Exceptionally well-preserved feeding traces on shells of two species of helicid snails, are reported from a protected wooden barn. In Helix pomatia Linnaeus, 1758, widely gapping traces follow the spirally winding shell for usually one, sometimes two, occasionally more whorls. Feeding traces on the smaller Cepaea hortensis (O. F. M?ller, 1774) shells are generally restricted to a lateral sector through the shell, often leaving the aperture unaffected. Fractured edges in both species have a jagged outline, and small rodents are considered as the most likely predators. Shells with such distinct breakage pattern are certainly very fragile, and the fossilisation potential is therefore small. 4 pp., 4 figs, 4.…

Bivalve species richness in the Northern Bay of Safaga, northern Red Sea, was assessed through original collecting activity in water depths from the intertidal to >50 m and by incorporating selected literature records. One-hundred-and-ninety-three samples, yielding 16,320 shells (dead and living), were taken from a coral-dominated coastal area that covers approximately 75 km2. Two-hundred-and-forty-three bivalve species were recognized; this is the highest number of species reported to date for any coastal area of comparable size. This high species richness can be related to the great habitat variety in the bay and the major sampling effort, including quantitative and qualitative samples from hard and soft substrata, which enabled us to detect many rare species. Species accumulation curves suggest that the full range of species in the bay was considerably under-estimated. Additional species would most likely be detected at depths from 20?50 m, where sampling intensity was much lower than in shallower parts of the bay. Additional species are also likely to be small and rare; they will probably have unusual life habits and will probably be detected in bulk samples from soft substrata, from systematic sampling in cryptic habitats and from commensal associations. The consideration of dead shells in this survey helped us to recognize species that were rare or that colonize very specialized habitats. The probability of finding them alive within a reasonable time was low, with a reasonable number of samples, or without destructive sampling methods. Surveys of this type may help to identify areas of conservation importance, especially where living bivalves are only present in low numbers. 15 pp., 10 figs, 4. …

Hardcover. Condizione: New. Conservation palaeobiology tracks the history of ecosystems based on the fossil record to guide conservation decisions and contribute to the theoretical foundations of conservation biology. The accelerating pace of global change requires better understanding of the long-term resilience and adaptive capacities of ecosystems. Fossil assemblages in outcrops and cores, together with surface accumulations of skeletal remains, represent unique archives of past ecosystem dynamics and baseline community states prior to anthropogenic impacts. However, as biological data retrieved from fossil and death assemblages cannot be treated in isolation, conservation palaeobiology integrates palaeontological and geological tools to account for the nature of the stratigraphic record. This volume brings together studies that demonstrate how combining marine palaeoecological records with other types of geohistorical data (taphonomic, sedimentological, geochronological, geochemical) can inform biodiversity conservation and ecosystem management. The papers highlight novel approaches and challenges in applying geohistorical data to conservation problems, discuss the limitations imposed by time averaging, and offer both deep- and near-time perspectives on conservation palaeobiology of marine ecosystems.…

The Northem Bay of Safaga is a shallow-water bay with highly structured bottom topography extending down to more than 50 m water depth. The authors studied more than 18000 individuals from 100 quantitative samples (13 from sediments, 87 from hard substrata), 37 qualitative samples (36 from sediments, 1 from hard substrata) and numerous unsystematic collections, and extracted 218 species; for most of them they provide detailed habitat information. A quantitative analysis shows that bivalve death assemblages in sediments and bivalve life assemblages on hard substrata match very well with bottom facies. In contrast, bivalve death assemblages on hard substrata have a very low spatial resolution pattem. Major differences between bivalve life and death assemblages on hard substrata are therefore evident. These differences can be attributed to the logistics of the sampling method, which provided a strong bias against dead bivalves that lived in close association with living corals. 357 pp., 57 (6 color) plates, 12 tabs, hardcover gr. 8 [19.5 x 27.5 cm].…