An annotated checklist of Planorbinae (Heterobranchia, Hygrophila, Planorbidae) from northwestern Argentina

The family Planorbidae comprises freshwater gastropods with planispiral, spiral and limpet-shaped shells. Subfamily Planorbinae sensu stricto, has a richness of almost 300 species, with some of the main genera being Biomphalaria Preston, 1910 and Drepanotrema Fischer & Crosse, 1880. Some Biomphalaria species are of concern to human health as they are intermediate hosts of blood flukes in Latin America. In Argentina, the family Planorbidae is represented by 15 species in four genera. In Northern Argentina (NOA region), records of the family are scarce, and most of them are a result of occasional collecting. We provide an updated checklist of Planorbinae in NOA resulting from fieldwork, material in malacological collections, and data in the literature. Nine species occur in the area: four species of Biomphalaria and five of Drepanotrema. Among Biomphalaria species, we recorded Biomphalaria straminea (Dunker, 1848), which is considered a natural host of the blood fluke Schistostoma mansoni Sambon, 1907, for first time in Salta province; the known geographic distribution of B. straminea is extended in the country.

The Maz Metasedimentary Series (Western Sierras Pampeanas, Argentina). A relict basin of the Columbia supercontinent?

The Maz Metasedimentary Series is part of the Maz Complex that crops out in the sierras of Maz and Espinal (Western Sierras Pampeanas) and in the Sierra de Umango (Andean Frontal Cordillera), northwestern Argentina. The Maz Complex is found within a thrust stack of Silurian age, which later underwent open folding. The Maz Metasedimentary Series mainly consists of medium-grade garnet–staurolite–kyanite–sillimanite schists and quartzites, with minor amounts of marble and calc-silicate rocks. Transposed metadacite dykes have been recognized along with amphibolites, metagabbros, metadiorites and orthogneisses. Schist, quartzite and metadacite samples were analysed for SHRIMP U–Pb zircon dating. The Maz Metasedimentary Series is polymetamorphic and records probably three metamorphic events during the Grenvillian orogeny, at c. 1235, 1155 and 1035 Ma, and a younger metamorphism at c. 440–420 Ma resulting from reactivation during the Famatinian orogeny. The sedimentary protoliths were deposited between 1.86 and 1.33–1.26 Ga (the age of the Andean-type Grenvillian magmatism recorded in the Maz Complex), and probably before 1.75 Ga. The main source areas correspond to Palaeoproterozoic and, to a lesser magnitude, Meso-Neoarchaean rocks. The probable depositional age and the detrital zircon age pattern suggest that the Maz Metasedimentary Series was laid down in a basin of the Columbia supercontinent, mainly accreted between 2.1 and 1.8 Ga. The sedimentary sources were diverse, and we hypothesize that deposition took place before Columbia broke up. The Rio Apa block, and the Río de la Plata, Amazonia and proto-Kalahari cratons, which have nearby locations in the palaeogeographic reconstructions, were probably the main blocks that supplied sediments to this basin.

Synopsis of the Genus Pentacalia (Compositae, Senecioneae) in Bolivia

The Neotropical genus Pentacalia Cass. (Compositae, Senecioneae) is distributed from southern Mexico to northwestern Argentina, plus two disjunct species that thrive in Brazil. Most species diversity occurs in the montane forests of Colombia, Ecuador, and Peru. It comprises scandent woody plants characterized by displaying alternate leaves (opposite in three species), involucres with supplementary bracts, usually yellow ray florets (when present), sagittate to caudate anther bases, and truncate to obtuse style branches with a crown of sweeping trichomes (sometimes with a tuft of longer trichomes, but not strictly penicillate). The Bolivian species were revised for the first time by Cabrera (1985), who treated the group under Senecio L. sect. Streptothamni Greenm. Because of the subsequent addition of new species and the need of taxonomic arrangements, an updated synopsis of the genus recognizing 18 species is presented. The names P. brittoniana (Hieron.) Cuatrec. and P. miguelii (Cuatrec.) Cuatrec. are synonymized with P. psidiifolia (Rusby) Cuatrec., as well as P. inquisiviensis H. Rob. & Cuatrec. with P. cardenasii (Cuatrec.) Cuatrec. and P. sailapatensis (Cuatrec.) Cuatrec. with P. urubambensis (Cabrera) Cuatrec. Seven names are lectotypified and an epitype is designated for the name P. zongoensis (Cabrera) J. Calvo. The new species P. viburnifolia J. Calvo & A. Fuentes is described. Revised nomenclature, succinct descriptions, taxonomic discussions, lists of specimens examined, and distribution maps are provided for all accepted species, in addition to an identification key. Pictures of living plants are also presented for eight species.