Monthly Archives: January 2011

Alien species in South America

Alien species get more and more attention. In some countries, like at the moment in Brazil (, 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.

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.


Dangling snails – an update

Nearly two years ago ( / Snailblog 7 and 11 May 2009), I published some observations on dangling snails. This week, Mike Rutherford from the University of West Indies at Trinidad, draw my attention to some early papers on this topic. R.J.L. Guppy (1866) seems to earn the credits for the first publication about this phenomenon, when he described his Adamsiella aripensis. Tryon was the first to publish a figure, in his Monograph of American molluscs (1868), depicting a Chondropoma dentata Say, 1825 dangling on a leaf. 


All the known occurrences are related to Annulariidae and Cyclophoridae.

Many thanks Mike for helping me with the literature search!

Guppy, R.J.L., 1866. On the terrestrial and fluviatile Mollusca of Trinidad. Annals and Magazine of Natural History (3) 17: 42-56.

Tryon, G.W., 1868. Monograph of the terrestrial Mollusca of the United States (concluded). American Journal of Conchology 4: 5-22.

Check your sources

During the finalization of a long-delayed article on snails and spiders, I checked again the sources that I used for the first draft. One of these was a review paper by Nyffelder & Symondson (2001). According to this paper, “one of the earliest published reports on malacophagy involving a spider was by Johnson (1863). He reported that the large wolf spider Isohogna [= Lycosa] maderiana (Walkenaer), found in Madeira, fed on snails.”. 

When I looked up this paper, I found indeed a note on “Lycosa tarentuloides maderiana Walkenaer”, but this was on the colouration of a female specimen. The only reference in this paper to snails, was this text under the remarks of a newly described Lycosa species:


A possible clue to the source of this error may be found in the methodology section of Nyffelder & Symondson’s paper. “Several hundred reports on the feeding habits of spiders and harvestmen published in scientific journals, books, and in unpublished theses were searched for information on malacophagy. This search was based largely on the Liste des Travaux Arachnologiques (1968-1999), published by the International Society of Arachnology (formerly C.I.D.A.), Paris. An inquiry among fellow arachnologists was carried out via specialist Internet discussion groups”. 
It seems plausible that Nyffelder and Symondson have copied the statement on Johnson’s paper from the replies among their fellow arachnologists. Besides apparently not having checked their source, they also quote the reference to Johnson’s paper incorrectly and incomplete. Not only the authors have to be blamed for that, but also the editors of Ecological Entomology (an ISI ranked journal, current impact factor 1.697).

If Johnson’s paper is not the first recorded case of malacophagy by spiders, who has then to be given the credits? Based on Nyffelder & Symondson’s list it should be Carl W. Verhoeff. His 1900 paper mentions that he had observed in the field the co-occurrence of the harvestmen Ichrysopsalis helwigii with the snail Vitrina pellucida. When he placed them together in the lab, he found the next morning only a clean shell.  
Credit where credit is due.

But overall the lesson is: check your sources!


Johnson, J.Y., 1863. Description of a new species of Lycosa living in the island of Madeira; with some remarks on Lycosa tarentuloides maderiana Walkenaer. Annals and Magazine of Natural History (3) 12: 152-155.

Nyffeler, M. & W.O.C. Symondson, 2001. Spiders and harvestmen as gastropod predators. Ecological Entomology 26: 617-628.

Verhoeff, C.W., 1900. Zur Biologie von Ischryropsalis. Zoologischer Anzeiger 23: 106-107.

Photo of the day (114): Choanopoma

In a new journal that appears on-line since last year, Folia conchyliologica, I found a paper by C. Audibert on a trip to Mexico, Yucat??n where he highlighted one species: Chaonopoma (Choanopomops) largillierti (Pfeiffer, 1846).


I reproduce here part of Audibert’s figures. His full article may be found in Folio Conchyliogica 5: 4-6. The journal, focussing mainly on European snails, is available on this website:

WCMC archive now partly accessible

Today I found, in the latest issue of BionetBulletin, an announcement about the archive of the World Conservation Monitoring Centre (WCMC). It is the biodiversity information and assessment arm of the United Nations Environment Programme (UNEP), and has published a lot of informative reports. Nearly 400 of these have been made accessible through the internet. Although some date back to the ’80s, I found some interesting reports (e.g. on cloud forests in Latin America).


You can find the full list on available reports here All reports are available in different formats.
Another WCMC initiative is a portal for biodiversity information, called A-Zareas of biodiversity importance ( This site gives a summary of the main conservation initiatives, but links to references and publications for further details.

Photo of the day (113): Drymaeus

Some other pictures, made by Adri??n Gonz??lez in Ecuador, Prov. Imbabura, Valle de Intag. It is of a Drymaeus species, probably D. fallax (Pfeiffer, 1853) or a closely related taxon, characterized by the protruding, keeled last whorl and the aperture with a ‘pinch’. This species doesn’t look like a spectacular one at all, yet I find it charming with its grey and white tones. Adri??n writes “it was found in a very common plant, locally known as ‘chilka’, with yellow flowers that we use as guide for the social spiders in the high Andean forests”.