Hypogene Gypsum Caves in Piedmont (N-Italy)

Piedmont (N-Italy) is one of Italy\u2019s regions where Messinian gypsum outcrops most extensively. Some gypsum caves have been explored in the past, but no detailed speleogenetic studies have been carried out. The discovery of unexpected large underground voids in a gypsum quarry near Moncalvo has demonstrated the presence of intrastratal karst systems with an origin at least partly linked to rising groundwater flow. A detailed look at one of the gypsum caves near Alba (Monticello cave) has revealed this labyrinth to be another classical example of intrastratal gypsum karst, clearly formed by the rising of undersaturated groundwater through a confined Messinian gypsum bed. This chapter deals with the typical hypogene morphologies in these caves and also reports some new results on the geochemistry of the waters of the Moncalvo area

Redescription of Mactra bonariensis Philippi, 1893 and designation of a neotype

During an ongoing revision of the Paraná Formation fauna of Argentina, the taxonomic status of Mactra bonariensis Philippi, 1893, was reassessed. The morphological characters of M. bonariensis provided in the original description and illustration do not allow clear delimitation of the species. The absence of type material of this species, coupled with difficulties in resampling the type locality due to urbanization, necessitates designation of a neotype. No records of this taxon were found in palaeontological and malacological collections. However, material collected from the Paraná Formation at 'La Juanita' (Entre Ríos, Argentina) comes from beds equivalent to those exposed at the locality from which Philippi described the original material. As this species may be confused with Quaternary and extant species from the region, a redescription is provided and a neotype designated.Fil: Pérez, Leandro Martín. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleozoología Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Signorelli, Javier Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; Argentin

Panopea abbreviata (Bivalvia: Hitellidae) in the southwestern Atlantic ocean, taxonomic revision and anatomy

The taxonomy and anatomy of the southwestern Atlantic geoduck, Panopea abbreviata Valenciennes, 1839, are revised. Materials from several institutions, as well as new living specimens collected from the coast of Argentina were studied. Type materials of all related nominal species are illustrated. The shell morphology, shell ultrastructure, hinge, ligamentand mantle cavity organs are described. The symbiotic relationship with the nemertean Malacobdella arrokeana, attached to host mantle tissues, is mentioned. Panopea abbreviata is abundant in the gulfs of northern Patagonia. It occurs in the subtidal zone from 8 to 25 meters deep, deeply buried in the sediment. It has a large thick shell, shortener at the posterior end, with exposed siphons covered by a dark brownish periostracum; a hinge plate characterized by a single cardinal tooth in each valve; and shell ultrastructure with three layers: an outerlayer of nearly vertical and composite prisms, a middle, true homogeneous layer, and an inner layer of alternating sublayers of fine complex crossed lamellar and irregular simple prisms. The fused mantle is only interrupted in the pedal gape. Ctenidia and labial palps associationbelongs to the Category III and ctenidia type C(1). Panopea antarctica is its only synonym. The fossil taxa Panopea truncata, P. inferior, P. hauthali, P. coquimbensis and P. guayacanensis are excluded from the synonymy.Fil: Signorelli, Javier Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; ArgentinaFil: Alfaya, José E. F.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; Argentin