PARATICINELLA N. GEN. AND TAXONOMIC REVIS
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摘要

Based on examination of the type material deposited by Jacques Sigal at the Musée National d’Histoire Naturelle in Paris, we have validated the hypothesis of Randrianasolo and Anglada (1998) that the holotype and paratype of m>Ticinella bejaouaensism> Sigal 1966 belong to two different species, the distributions of which do not overlap. Indeed, the holotype is of late Albian age and from Madagascar whilst the paratype is of a latest Aptian age and from Tunisia. Sigal’s paratype is here confirmed to be the holotype of the species m>eubejaouaensism> Randrianasolo and Anglada, 1998. It displays a distinctive wall texture bearing perforation cones that coalesce to form irregularly arranged rugosities and ridges, which tend to parallel the periphery. In addition, flaps may cover the umbilical area. However, it lacks true umbilical supplementary apertures and therefore cannot be included in the genus m>Ticinellam> Reichel, 1950. The new genus m>Paraticinellam>, with m>Paraticinella eubejaouaensism> as the type species, is here formalized to accommodate uppermost Aptian trochospiral individuals with a wall texture bearing perforation cones, rugosities, and ridges in patterns paralleling the margin, and possessing an umbilical cover-plate.

m>Paraticinella eubejaouaensism> evolved from m>Hedbergella trocoideam> in the upper Aptian. The evolutionary trend is exemplified by the increasing number of chambers, by flattening of the spire height, by widening of the umbilicus with the appearance of a cover-plate, by acquisition of well-developed ridges on wall surfaces, and by the appearance of weakly developed infralaminal accessory apertures in later specimens of m>P. eubejaouaensism>.

A close study of the holotype of m>Ticinella bejaouaensism> Sigal, 1966 reveals a substantial similarity in morphology and wall structure with m>Ticinella robertim> and a lack of distinguishing criteria between the two species. Consequently, the species m>Ticinella bejaouaensism> is invalidated and is considered to be a junior synonym of m>T. robertim>.

A third species was observed associated with m>Ticinella robertim> and m>Biticinella breggiensism> in Madagascar and Spain, and it is attributable to the genus m>Ticinellam> based on the presence of true umbilical supplementary apertures and a typical m>Ticinellam> wall structure (muricate to coarsely pustulose), while in gross morphology, it resembles m>Paraticinella eubejaouaensism>. We have named this new taxon m>Ticinella moulladeim>. It differs from m>T. robertim> by its thinner test, more numerous chambers, and wider umbilicus.

Finally, the last zone of the uppermost Aptian must be renamed the m>Paraticinella eubejaouaensism> Zone to replace m>Ticinella bejaouaensism>, which is now considered to be an invalid taxon.

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