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Biologically-controlled mineralization in the hypercalcified sponge Petrobiona massiliana (Calcarea, Calcaronea)
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Hypercalcified sponges, endowed with a calcium carbonate basal skeleton in addition to their spicules, form one of the most basal metazoan group engaged in extensive biomineralization. The Mediterranean species Petrobiona massiliana was used to investigate biological controls exerted on the biomineralization of its basal skeleton. Scanning and transmission electron microscopy (SEM, TEM) confirmed that basopinacocytes form a discontinuous layer of flattened cells covering the skeleton and display ultrastructural features attesting intense secretory activity. The production of a highly structured fibrillar organic matrix framework by basopinacocytes toward the growing skeleton was highlighted both by potassium pyroantimonate and ruthenium red protocols, the latter further suggesting the presence of sulfated glycosaminoglycans in the matrix. Furthermore organic material incorporated into the basal skeleton was shown by SEM and TEM at different structural levels while its response to alcian blue and acridine orange staining might suggest a similar acidic and sulfated chemical composition in light microscopy. Potassium pyroantimonate revealed in TEM and energy electron loss spectroscopy (EELS) analysis, heavy linear precipitates 100–300 nm wide containing Ca2+ and Mg2+ ions, either along the basal cell membrane of basopinacocytes located toward the decalcified basal skeleton or around decalcified spicules in the mesohyl. Based on the results of the previous mineralogical characterization and the present work, an hypothetical model of biomineralization is proposed for P. massiliana: basopinacocytes would produce an extracellular organic framework that might guide the assemblage of submicronic amorphous Ca- and Mg-bearing grains into higher structural units.
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Contexte chronostratigraphique et paléoenvironnemental de la séquence de la grotte Walou : synthèse et perspectives
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Ce chapitre propose une synthèse de l’ensemble des disciplines présentées dans les deux premiers volumes consacrés aux fouilles 1996-2004 à la grotte Walou (volume 1 : sciences de la terre ; volume 2 : sciences de la vie et datations). Il livre un cadre précis aux données archéologiques analysées dans le troisième et dernier volume de cette monographie, ainsi que des perspectives relatives tant aux recherches qui restent à entreprendre à Walou qu’à celles qui concernent les remplissages des autres grottes du bassin mosan.
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On the use of endosteal layers and medullary bone from domestic fowl in archaeozoological studies
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The very high incidence of medullary bone in two archaeozoological assemblages of the Roman period was believed to reflect systematic slaughtering of older hens at the end of the egg laying season. In an attempt to test this hypothesis, histological analyses were carried out. Histological data in the literature on ageing of modern fowl and on the development of medullary bone in hens are insufficient for application to archaeozoological material. Bones of modern fowl of known age were analysed with the aim of validating the use of endosteal layers for ageing. In addition, hens with known egg laying stage were studied in order to try and document differences in medullary bone development that could be related to the time of slaughtering (just before, during, or just after the egg laying season).
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An Industrial Site at al Shaykh Sa’id/Wadi Zabayda
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The status of the northeastern Atlantic and Mediterranean small mussel drills of the Ocinebrina aciculata complex (Mollusca: Gastropoda: Muricidae) with the description of a new species
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The northeastern Atlantic and Mediterranean small mussel drills of the Ocinebrina aciculata complex are here revised and consist of at least 3 species. The type species, Ocinebrina aciculata (Lamarck, 1822), characterized by a slender shell with rounded whorls and primary and secondary spiral cords of approximately similar size, lives throughout the northeastern Atlantic and Mediterranean Sea at depths usually ranging between 0 and 105 m. Its synonymy is here stabilized by a neotype selection for Murex corallinus Scacchi, 1836. Ocinebrina corallinoides Pallary, 1912 (=Ocinebrina buzzurroi Cecalupo and Mariani, 2008, new synonymy), characterized by a strongly elongate and weakly convex shell and primary and secondary spiral cords of approximately similar size, is endemic to the Gulf of Gabès and is here considered a distinct species, pending genetic studies. Ocinebrina reinai n. sp. is here described from the central Mediterranean Sea (where it is sympatric with O. aciculata) on the basis of morphological diagnostic features of shell (rarest presence of labral tooth, commoner presence of infrasutural apertural denticle, dark spots on the ribs and spiral sculpture with differently sized primary and secondary cords and smaller threads) and radula, confirmed by genetic data. Divergence in COI sequences with sympatric samples of O. aciculata (>7%), confirm their status as a distinct species. A comparative table reporting diagnostic features of the congeneric species of the complex and those with which the new species was previously misidentified is offered.
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Description of a new species of Lataxiena (Gastropoda: Muricidae) from India
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A new species of the genus Lataxiena is described from Madras, India, with range extension to Thailand, strait of Malacca.
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Description of Two New Species of Trophoninae s.l. and Typhinae (Gastropoda: Muricidae) from New Caledonia and Comments on Litozamia Iredale, 1929 and Siphonochelus Jousseaume, 1880
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Abstract: Litozamia acares n. sp. and Siphonochelus (Trubatsa) wolffi n. sp. are described from New Caledonia. The radula and the operculum of Litozamia acares are illustrated and described. The classification of Litozamia in Trophoninae is maintained awaiting molecular data to either confirm or modify this decision. Litozamia longior (Verco, 1909) is reinstated as a valid species. The use of the subgenus Choreotyphis Iredale, 1936 is reinstated in Siphonochelus for a single species from eastern Australia, based on differences in shell morphology
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A molecular phylogenetic framework for the Ergalataxinae (Neogastropoda: Muricidae)
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The Timbellus richeri complex (Gastropoda: Muricidae) in the southwest Pacific
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Cenozoic evolution of Muricidae (Mollusca, Neogastropoda) in the Southern Ocean, with the description of a new subfamily
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Gastropods are among the most studied group in Antarctica, and taxa with an advanced status of systematic knowledge can be used as a model to study how oceanographic and climatic patterns shaped Recent faunal assemblages. Within the ongoing study of the muricid phylogeny, we have analysed molecular and morphological data from species traditionally ascribed to the muricid subfamily Trophoninae. Particularly, the availability of specimens collected in the Southern Ocean and surrounding basins allowed to demonstrate as the genera Pagodula, Xymenopsis, Xymene and Trophonella, which are traditionally classified in the Trophoninae, actually belong to a distinct lineage, for which the new subfamily Pagodulinae is herein introduced. We propose and discuss a possible framework for the origin and radiation of Antarctic muricids.
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