Cabrera et al. published a paper on Late Cretaceous molluscs from Uruguay. Their abstract reads: “Paleoecological studies of continental gastropods give valuable information about the depositional environment of the fossil assemblages. In South America, these assemblages from the Late Cretaceous/ Paleocene are scarce and poorly studied. Most works focuses on taxonomy, but a paleoecological approach is still missing. We analyzed the assemblages present in the Queguay limestones from Uruguay. The total fossil content consists in freshwater and terrestrial gastropods, characean gyrogonites, ostracods, Neosauropoda eggshells, vegetable remains, insect nests, and pupal chambers. As the precise age and sedimentary environment of the Queguay limestones have been discussed for almost nine decades, a paleoecological study was conducted in order to answer these questions from this point of view. Diversity (Simpson, Shannon-Wiener, equitability) and similarity (Jaccard and Kulczynski) indices were calculated; the analyses showed a close relationship among all locations, and therefore we conclude that there are not differences in fossil content among the localities. Moreover, the data allows to consider them basically of the same environment and age. The presence of Neosauropoda eggshells in several outcrops indicate unquestionably a Late Cretaceous age, and establish the oldest record worldwide for Pupillidae, Orthalicoidea and Biomphalaria”.
The fact that the fossils mentioned establish the oldest known facies for several genera (Pupoides, Bulimulus, Bahiensis, and Biomphalaria) is an important result of this study. This might be useful data for future use when one needs fossil species for calibrating phylogenetic data.
Cabrera, F. et al., 2018. Continental Late Cretaceous gastropod assemblages from Uruguay. Paleoecology, age, and the oldest record for two families and a genus. – Historical Biology, advance online. DOI: 10.1080/08912963.2018.1471478.
Based on a small collection already made in 1982, Araya et al. have just published a paper on the snail fauna near Antofagasta.
“New records for Bostryx holostoma (Pfeiffer, 1846), Pupoides minimus (Philippi, 1860), Stephacharopa calderaensis Miquel & Araya, 2013 and an unidentified charopid species are presented on the basis of specimens collected near the city of Antofagasta, in northern Chile. This is the first record for S. calderaensis after its description, extending its known distribution about 350 km northwards. Details on the protoconch of B. holostoma are presented for the first time, and this species extends its distributional range 145 km southwards. The microhabitat of these species in litho-refugia may explain the presence of these minute terrestrial mollusks in hyper arid northern Chile, further highlighting the need of additional studies of this neglected fauna”.
Especially the protoconch structure of Bostryx holostoma is interesting, as this reveals a spiral structure which is not present in other Chilean Bostryx species. As unpublished DNA results of species from this genus from different countries reveal, this genus may well be polyphyletic.
Araya, J.F. et al., 2017. New records of terrestrial mollusks (Gastropoda: Stylommatophora) from Antofagasta, northern Chile. – Revista Mexicana de Biodiversidad, 88: 769-772.
Cabrera & Martinez (2017) have just published a paper on minute pupillids. “A new species of Pupoides Pfeiffer 1854, subgenus Ischnopupoides Pilsbry 1926, is described for the Late Cretaceous of Uruguay (Queguay Formation), being the oldest record of the genus and subgenus. Pupoides (I.) gnocco new species is characterized by a small dextral fusiform shell, constituted by a spire comprising five slightly convex whorls, oblicuous axial ornamentation, subrounded aperture, and an expanded outer lip that lacks dentition”.
Cabrera, F. & Martinez, S., 2017. Late Cretaceous Pupoides Pfeiffer 1854 (Gastropoda: Pupillidae) from Uruguay (Queguay Formation). – Journal of Conchology, 42 (5):333-338.
Today a paper was published about the Chilean Atacama region. This is in the coastal desert and is a harsh environment for snails. The authors, Araya & Catalán, have made a laudable effort to chart the species and provide a key for easy identification. This paper is limited to the non-bulimulid terrestrial snails, i.e. the families Bothriembryontidae, Charopidae, Ellobiidae, Pupillidae, Strophocheilidae, and Helicidae.
Terrestrial mollusca are sparsely studied in Chile and, for the first time, a formal record of the diversity of land snails in northern Chile is reported. Coastal and desertic areas in the Region of Atacama, in the border of the Atacama desert and the Pacific Ocean, were surveyed with the aim to describe the presence and distribution of this poorly known fauna. Of the fourteen species recorded, the geographic distribution records for nine species are extended, and some taxa are recorded for the first time since their original descriptions. All, except one, of the fourteen terrestrial molluscan species occurring in the area are endemic to Chile; they are all terrestrial species, most of them have a restricted geographic distribution, and none of them is currently protected by law. The results reveal that the region of Atacama has one of the most diverse terrestrial snail biodiversity in Chile, ranking only after the Juan Fernandez Archipelago. Distribution records of all the studied species and a taxonomic key are also provided.
Araya, J. F. & Catalán, R. (2014): A review of the non-bulimulid terrestrial Mollusca from the Region of Atacama, northern Chile — ZooKeys 398: 33–51. http://bit.ly/1mI5w4r.