Tag Archives: uruguay

New fossil Pupoides

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”.

Reference:
Cabrera, F. & Martinez, S., 2017. Late Cretaceous Pupoides Pfeiffer 1854 (Gastropoda: Pupillidae) from  Uruguay (Queguay Formation). – Journal of Conchology, 42 (5):333-338.

New fossil Bahiensis species

Fossil species are the highlights in Neotropical malacology, as they are rare finds and provide glimpses into the distant past. A new species of Bahiensis (Odontostomidae) has recently been described from the Paleocene in Uruguay (Cabrera & Martínez, 2012).

The abstract of their paper reads: The land snail family Odontostomidae has a poor fossil record, mainly from the middle Paleogene and early Neogene of Argentina. In this paper a new species of Odontostomidae from the Paleocene of Uruguay (Queguay Formation) is described. Bahiensis priscus n. sp. represents the first record of the genus Bahiensis Jousseaume 1877, and the oldest record for an Odontostomidae. The new species is characterized by a pupoid fusiform shell and an oval aperture with a single axial columellar fold. Present distribution of the genus indicates a tropical–subtropical environment, in high humidity rate areas.

Although one extant species – B. guarani (d’Orbigny, 1835) – lives in adjacent areas in Argentina, Paraguay and Brazil, the major diversity of extant species is now found in NE Brazil.

Reference:
Cabrera, F. & Martínez, S., 2012. The oldest Odontostomidae (Mollusca: Gastropoda): Bahiensis priscus n.sp. (Paleocene, Uruguay). – Palaontologische Zeitschrift 86: 451-456.

Modeling on Giant African Snail invasion

An Argentinan group of colleagues has elaborated the potential areas where the Giant African Snail (GAS) might occur or invade (Vogler et al., 2013). Using the same methodology as Borrero et al. (2009), they have detailed now the potential distribution areas for all South American countries. The abstract reads:

The best way to reduce problems related to invasive species is by preventing introductions into potentially susceptible areas. The purpose of this study was to create distribution models for the invasive gastropod Achatina fulica Bowdich, 1822 in South America in order to evaluate its potential geographic distribution and identify areas at potential risk. This mollusc, considered one of the 100 world’s worst invasive alien species, is the focus of intense concern due to its impact on agriculture, human health, and native fauna. We tested two commonly used ecological niche modeling methods: Genetic Algorithm for Rule-Set Prediction (GARP) and Maximum Entropy (MaxEnt). Models were run with occurrence points obtained from several sources, including the scientific literature, international databases, governmental reports and newspapers, WorldClim bioclimatic variables, and altitude. Models were evaluated with the threshold-independent Receiver Operating Characteristic (ROC) and Area Under the Curve (AUC). Both models had consistent performances with similar areas predicted as susceptible, including areas already affected and new potentially susceptible areas in both tropical and temperate regions of South America.

This new study is more detailed and much more elaborated than Borrero et al. (2009), and uses two modeling methods, (A) GARP and (B) Maxent, of which the latter is generally performing best in comparative studies. The relevance of presenting country maps for potential distribution of this species in each South American country is clear: the responsible authorities now have a handle to focus their attention to areas most under threat. Generally, the Amazon basin is most infected or theathened, but certain areas in Ecuador, Colombia and Venezuela are across the Andes but have already been invaded. The following table shows that none of the South American countries can escape to the threat of GAS, although there are gradual differences.

References:
Borrero F.J. et al., 2009. Into the Andes. Three new introductions of Lissachatina fulica (Gastropoda, Achatinidae) and its potential distribution in South America. – Tentacle 17: 6-8.
Vogler, R.E., Beltramino, A.A., Sede, M.M., Gutiérrez Gregoric, D.E., Nuñez, V. & Rumi, A., 2013. The Giant African Snail, Achatina fulica (Gastropoda: Achatinidae): using bioclimatic models to identify South American areas suspectible to invasion. – American Malacological Bulletin 31: 39-50.

Alien species in South America

Alien species get more and more attention. In some countries, like at the moment in Brazil (http://tudoglobal.com/blog/editorias/73850/pais-se-preocupam-com-surto-de-meningite.html?doing_wp_cron), Lissachatina fulica is a real pest, causing public health problems, and under public debate. However, there are several other species which remain less noticed because they have less economic impact. 

Rumi et al. (2010) have made a summary of all records in literature from a number of South American countries. They found 42 species of terrestrial gastropods recorded. On the basis of museum collections, they were able to add several records for 8 species from Argentina, one from Colombia, and one from Peru. Thus, although the title of their paper focusses on Theba pisana in Argentina, it is of a much wider scope.

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Reference:
Rumi, A., S??nchez, J., & Ferrando, N.S., 2010. Theba pisana (M??ller, 1774) (Gastropoda, Helicidae) and other alien land molluscs species in Argentina. – Biological Invasions 12: 2985-2990.

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