A record of Permian subaqueous vent activity in southeastern Brazil.

The remarkable occurrence of more than 4,500 conical siliceous mounds in an area of less than 1.5 square kilometres has been reported in the Paraná basin, near Anhembi, São Paulo, in southeastern Brazil. These structures, which are up to two metres high, are thought to have been formed at the margin of a very shallow, broad but waning internal sea, and it was originally suggested that they are stromatolites. Yet their restricted occurrence, unusual abundance and nearly pure siliceous composition have never been satisfactorily explained by this hypothesis. Here we report field and laboratory observations on their shape, construction, composition and mineralogy. On the basis of our data we suggest that the conical mounds are the result of subaqueous Late Permian vent activity in southwestern Gondwana. The present siliceous cone field differs considerably from other Palaeozoic siliceous hot spring deposits, such as those at Rhynie, Scotland, and the Drummond basin, Australia, and therefore represents an unusual occurrence of vent activity.

Phlebotomines (Diptera, Psychodidae) in caves of the Serra da Bodoquena, Mato Grosso do Sul State, Brazil

The present paper deals with the phlebotomine species captured during the period from January 1998 to June 2000 in 12 caves located in the Serra da Bodoquena, situated in the south central region of Mato Grosso do Sul State, Brazil. Three of the caves are situated further north (in Bodoquena county), seven in the central area (Bonito county) and two in the south (Jardim county). These last two caves and three of those in Bonito are located at the west side of the ridge. Eighteen species of phlebotomines were captured within the caves: Brumptomyia avellari (Costa Lima, 1932), Brumptomyia brumpti (Larrousse, 1920), Brumptomyia cunhai (Mangabeira, 1942), Brumptomyia galindoi (Fairchild & Hertig, 1947), Evandromyia corumbaensis (Galati, Nunes, Oshiro & Rego, 1989), Lutzomyia almerioi Galati & Nunes, 1999, Lutzomyia longipalpis (Lutz & Neiva, 1912), Martinsmyia oliveirai (Martins, Falcão & Silva, 1970), Micropygomyia acanthopharynx (Martins, Falcão & Silva, 1962), Micropygomyia peresi (Mangabeira, 1942), Micropygomyia quinquefer (Dyar, 1929), Nyssomyia whitmani (Antunes & Coutinho, 1939), Psathyromyia campograndensis (Oliveira, Andrade-Filho, Falcão & Brazil, 2001), Psathyromyia punctigeniculata (Floch & Abonnenc, 1944), Psathyromyia shannoni (Dyar, 1929), Pintomyia kuscheli (Le Pont, Martinez, Torrez-Espejo & Dujardin, 1998), Sciopemyia sordellii (Shannon & Del Ponte, 1927) and Sciopemyia sp. A total of 29,599 phlebotomine sandflies was obtained. Lutzomyia almerioi was absolutely predominant (91.5 per cent) over the other species on both sides of the Bodoquena ridge, with the exception of the southern caves in which it was absent. It presents summer predominance, with nocturnal and diurnal activities. The species breeds in the caves and was captured during daytime both in the dark area and in the mouth of the caves. Martinsmyia oliveirai, the second most frequent sandfly, also presents a summer peak and only predominated over the other species in one cave, in which there were human residues.