Écologie des Théidées

The Recent thecideid brachiopod Lacazella mediterranea (Risso), studied in the Mediterranean and on the Great Bahama Bank, shows a depth range of 20–150 m (optimum 50–95 m), determined by the need of subdued light. A hard substratum is essential for the cementing of the shell. Brachiopods of the genera Crania. Argyrotheca , and Megathiris belong to the same ecological niche - more or less dependence on light and substratum results in a differentiation of the species in biocoenoses as well and taphocoenoses. Several Mesozoic species are studied in coral, bryozoan, poriferan, and rudist environments. Species like Thecidea papillata (Schlotheim) and Danella recurvirostris (Defrance) seem to have acquired a free life, independent of the substratum, and others, like Praelacazella baltoviensis Barczyk stood fairly intense light in shallow water. Diptych thecideids and megathyridids occurred in bryozoan and coral environments.     

Paléoécologie des associations d'ostracodes d'une formation carbonatée à Rudistes en environnement péri-deltaïque: l'exemple du Santonien de la Cadière d'Azur (Sud-Est France)

Paleoecological studies carried out in the Carbonate bank with Rudists of La Cadière d'Azur (Southeast France) and adjacent perideltaic areas have been made in order to define some stages during the evolution of the formation. For each period, type of ostracode assemblage can be proposed. This is undertaken by analysis using both a more precised systematics and especially quantitative methodology, particularly the factorial analysis of correspondances. One purpose of this study is to justify the paleoecological interpretations and moreover to conclude on the autecology of ostracode species. Lastly, it is suggested that carbonate rate (i.e. water content in calcium), turbulence of sea-waters (influencing the grain-size of terrigenous deposits) and perhaps depth are locally important controlling factors of ostracode diversity.     

Cover Picture: J. Biophotonics 9/2011

An example of Pallasea cancelloides – benthic Baikal amphipod employed for the studies of stress conditions. (Picture: D.V. Axenov‐Gribanov et al., pp. 619–626 in this issue)     

L‘écologie et la vie sociale du Céphalophe bleu (Cephalophus monticola Thunberg), petit ruminant forestier africain

The blue duiker is a small, frugivorous, strictly diurnal ruminant that occupies forest with open undergrowth. The social group consists of a ♂-♀ pair with the young of the last two litters. Pairs seem permanent in small territories adjacent to each other, without any noticeable overlap. The population density is high. The life style adopted by the blue duiker represents an exception among forest ruminants, and appears to be a well adapted response to various ecological pressures, especially predation.