Tag Archives: distribution

Improving citizen science projects

Citizen sciences projects are becoming more and more popular with scientists to expand their capacity to collect data. Yet, there are ways to further improve this ‘tool’ as Callaghan et al. argue in their just published (open access) paper.

Their abstract reads: “Citizen science is mainstream: millions of people contribute data to a growing array of citizen science projects annually, forming massive datasets that will drive research for years to come. Many citizen science projects implement a “leaderboard” framework, ranking the contributions based on number of records or species, encouraging further participation. But is every data point equally “valuable?” Citizen scientists collect data with distinct spatial and temporal biases, leading to unfortunate gaps and redundancies, which create statistical and informational problems for downstream analyses. Up to this point, the haphazard structure of the data has been seen as an unfortunate but unchangeable aspect of citizen science data. However, we argue here that this issue can actually be addressed: we provide a very simple, tractable framework that could be adapted by broadscale citizen science projects to allow citizen scientists to optimize the marginal value of their efforts, increasing the overall collective knowledge”.


Also in malacology several projects are known that use(d) this tool of citizen science, mostly known in the northern hemisphere. While in the southern hemisphere (Neotropics, Asia, Africa) the lack of sufficient biodiversity data is more prominent and the number of professional researchers is comparatively low, the potential for well-organised citizen projects may be larger. Something to consider for malacologists out there?

Callaghan, C.T. et al., 2019. Improving big citizen science data: Moving beyond haphazard sampling. PLoS Biol 17(6): e3000357. https://doi.org/10.1371/journal.pbio.3000357


Pantepui snails

Just published: a chapter on the land snails of the Venezuelan Pantepui region. It is a slightly updated summary of what was published some years ago, while in the meantime only slight progress was made.

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For the species reported hitherto from this area the taxonomy is summarised, and data on the ecology and biogeography is presented.

The rest of the book presents a lot of information on this interesting area of South America, both general and on the flora and fauna. The illustrations are plentiful and often spectacular.

Breure, A.S.H., 2019. Land snails: an updated summary: 247-261. — In: Rull, V., Vegas-Villarrúbia, T., Huber, O. & Señaris, C. (eds.) Biodiversity of Pantepui: the pristine ‘Lost World’ of the Neotropical Guayana Highlands. Academic Press, Cambridge

Historical range information

A paper just published by Salvador provides interesting information on some distribution ranges based on a historical collection. The abstract reads “The malacological collection of the Museum of New Zealand Te Papa Tongarewa (NMNZ), despite naturally focusing on New Zealand species, also includes a variety of specimens from South America. Examination of this material revealed new distributional data for several species. All Brazilian, Uruguayan and Argentinian terrestrial gastropods from the NMNZ collection were examined and re-identified (no material from Paraguay was found). The information gathered was compiled and is presented in this article, and may contain significant data for malacologists working with the region’s fauna. In summary, 99 species are reported, 13 of which represent new records and meaningful increments in geographical distribution, either extending their known range or filling distributional gaps. Moreover, the NMNZ collection houses the type material of six species from Brazil and Argentina described by the New Zealand malacologist Henry Suter (1841–1918) in 1900“.

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The material consists of species from 17 families. “The following 13 species have significant increments in their distribution (range extension or filling of distributional ‘gaps’): Auris chrysostoma, Auris illheocola, Auris melanostoma and Thaumastus nehringi (Bulimulidae [Thaumastus belongs to the Megaspiridae]); Callionepion iheringi (Megaspiridae); Cyclodontina fusiformis, Moricandia willi and Spixia martensii (Odontostomidae); Simpulopsis decussata (Simpulopsidae); Neobeliscus calcarius (Achatinidae); Happia iheringi (Scolodontidae); Epiphragmophora hieronymi (Epiphragmophoridae); and Solaropsis punctatus (Pleurodontidae) [sic, Solaropsidae]“. The author rightly draws attention to the fact that even historical collections – although sometimes lacking from precise data – can contribute to our knowledge of distribution of species. This being said, however, it also points to the insufficient inventories being made on a detailed scale in many of the Neotropical countries which leads to insufficient insights in the distribution of many species.

Salvador, R.B., 2019. Brazilian, Uruguayan and Argentinian terrestrial gastropods in the collection of the Museum of New Zealand Te Papa Tongarewa. – Tuhinga, 30: 82-98.

New records for Brazilian Helicina

A new paper just appeared by Silva et al. “New records for Helicina schereri Baker, 1913, are reported. It was a species previously restricted to the states of Ceará, Rio Grande do Norte, Paraíba, Alagoas and Tocantins in Northeastern Brazil, and State of Santa Catarina, much further south. The new occurrences reported herein fill distribution gaps and also significantly expand the range of the species ca. 970 km westwards. The new records are from the following locations: Bahia State (Ituaçu and Itaquara municipalities) in Northeast Brazil; Mato Grosso do Sul State (Bonito Municipality) in the Midwest; and Minas Gerais (Lagoa Santa municipality) in the Southeast”.

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Silva, F. dos Santos et al., 2019. New records of Helicina schereri (Gastropoda: Helicinidae) from the states of Bahia, Minas Gerais, and Mato Grosso do Sul, Brazil. – Papéis Avulsos de Zoologia, 59: e20195903 (3 pp.).

New record for Gulella bicolor in Mexico

A specimen of Huttonella bicolor = Gulella bicolor (Hutton, 1834) was collected from clayey-sandy soil in Tabasco, Mexico, which constitutes its second record in the state and the third in Mexico. This small gastropod is a predator that has mainly spread through tropical and island regions as an exotic species. Its introduction to Asian and Caribbean Islands is noteworthy. Its pupiform shell and the lamella or tooth complex were compared against previous descriptions. In Mexico, this species has been found in northern Veracruz and Tabasco, which confirms that it is spreading along the Gulf of Mexico from the United States towards Brazil. The features of this streptaxid as a potential hazard through its preferred prey are discussed”.

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An additional record to the ones given in the paper is the recent mentioning of this species for Belize by Dourson et al. (2018: 315).

Introduced species are often problematic with regard to the native malacofauna, but in this case the authors argue that also additional reasons may be present for keeping a close eye on the further spread of this species. Which is related to exotic species always a good idea to follow and document their distribution.

Costillo-Rodriguez, Z.G. et al., 2018. A new record of Huttonella bicolor (Hutton, 1834) (Mollusca, Gastropoda, Streptaxidae) in Mexico. – Acta Zoológica Mexicana (n.s.) 34: e3411181 (6 pp.).

More on Argentinian Bostryx

María José Miranda has recently published a new study on several Bostryx species from central western Argentina. As always, this is a thorough paper with lots of anatomical data.


The abstract reads: “The genus Bostryx Troschel, 1847 is endemic to South America, extending from Ecuador to Chile and Argentina. The southernmost Argentinian species of the genus that inhabit San Luis, San Juan and Mendoza provinces, specially the pre-Andes, Andes and Sierras Pampeanas mountain ranges, were examined. This is the first time the anatomy of Bostryx pastorei (Holmberg, 1912), Bostryx reedi (Parodiz, 1947) and Bostryx strobeli (Parodiz, 1956) has been described. Bostryx cordillerae (Strobel, 1874) is re-described regarding shell and anatomy due to new morphological data. The main differences among the species examined are based on shell characters. The distribution of Bostryx mendozanus (Strobel, 1874) and Bostryx cuyanus (Pfeiffer, 1867), other species found in this region, was also discussed”.

As she cited my publication about the subfamily Bostrycinae (Breure, 2012), I feel entitled to correct a possible misinterpretation. From her text it gives the impression that I have a very restricted view of this subfamily, leaving out all species not listed in my 2012 paper. The contrary is true. Page 3 of my paper explicitly stated that the list presented is incomplete, and further research should show which other species belong to this monophyletic clade. As the shell shape may be very misleading, which is corroborated in Miranda’s paper, I invited further research using anatomical and molecular data. Miranda’s paper is a welcome contribution to this end, although she has not presented phylogenetic data which could supplement the available data in GenBank. Hence there is room for further additions…

Breure, A.S.H., 2012. The status of the genus Bostryx Troschel, 1847, with description of a new subfamily (Mollusca, Gastropoda, Bulimulidae). – ZooKeys 216: 1-3.
Miranda, M.J., 2015. The genus Bosoryx in central western Argentina: anatomical and distributional description of four of its southernmost species (Gastropoda, Bulimulidae). – Iheringia, Zoologia 105: 484–498.

Epiphragmophora distribution

Geographical distributions of snails sometimes remain a bit puzzling, and Cuezzo (2015) has delivered another case where both a geographic gap and an altitudinal gap seem to exist.

“This is the first record of Epiphragmophora estella in Argentina, a species traditionally of Bolivian distribution. Specimens were found during several field trips conducted in the northern patch of the Southern Andean Yungas forest of Salta province. Morphometrics and qualitative shell characters are described in order to validate the taxonomic identification. Current species distribution is also reported”.

Cuezzo 2015 f2

This disjunct distribution calls for additional field work in Bolivia, a country which malacofauna remains poorly known.

Cuezzo, M.G., 2015.  First record of occurrence of Epiphragmophora estella (d’Orbigny, 1837) (Mollusca, Gastropoda, Stylommatophora) in Argentina. – Check List 11: 1496. Available at http://biotaxa.org/cl/article/view/11.1.1496/10873