Tag Archives: conservation

Ecology and conservation of Plectostylus

A recent paper by Barahona-Segovia et al. discusses the details of the ecology of a Chilean Plectostylus species. Their abstract is “Terrestrial mollusks are one of the least studied groups of terrestrial invertebrates, especially in the Neotropics. In Chile, there is scarce biological and ecological information about many genera, even though the group is quite diverse and occupies different habitats along the country. Plectostylus araucanus is the most recently described species and one of the few arboreal species found only in the coastal native forest of central-south of Chile. In this study, we recorded a new locality for P. araucanus in the del Maule Region and described ecological and physiological characteristics. The new locality is placed 204 km northwards of the type locality. Based on different records, Plectostylus araucanus is proposed as an endangered (EN) species under the distribution criterion of IUCN. Most of the specimens of P. araucanus were found living in tree cavities and away from the edge of native forest fragments. Physiological measures showed monthly differences, especially between some months of summer and fall and between months of the same season (i.e., summer). We discuss the implications of our results in the microhabitat selection, thermoregulation and habitat use by this tree snail, and the importance of this data in management and conservation for other native malacofauna”.

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This is an interesting study, as detailed ecological research on Neotropical snails is scarce and the available data gives a very partial view on the requirements of the malacofauna; the handles for conservation management are thus also extremely limited, which is a concern with the increasing threats of anthropogenic influences.

Barahona-Segovia, R.M. et al., 2019. Shelter, ecophysiology and conservation status of Plectostylus araucanus (Pulmonata: Bothriembryontidae) in the fragmented Bosque Maulino, central Chile. – Revista Mexicana de Biodiversidad, 90: e902703 (12 pp.).


Belize land snails

A new book by Dourson et al. on the non-marine malacofauna of Belize is a peculiar case, which shows that privately publishing a book including new taxa might be a tricky case.

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The non-marine malacofauna of Mexico and Central America is seemingly well-known through the work of the late Fred G. Thompson. His checklist, of which the final version appeared in 2011, listed all the currently accepted (sub)species and synonyms known from that area. It was a major milestone after the previous works by Crosse & Fischer’s Mission au Mexique et Guatemala, …Mollusques (1870-1902) and Von Martens’ molluscan part of the Biologia Centrali-Americana (1890-1901). Thompson’s publication, listing ca. 1250 taxa for this enormous area, stated that this number possibly only reflects one third of the actual malacofauna, due to the fact that most countries have only partially been surveyed for molluscs. 

Dourson et al. have concentrated on Belize, a relatively small country which borders southern Mexico and Guatemala. During the period 2006-2016 they surveyed all the seven physiographic regions of the country. And where Thompson only listed 24 species they enumerate 158 in total, of which 17 newly described in this book, with three others recently described in journals and a further eight still not formally described. This constitutes an increase of 658% for the biodiversity of non-marine snails in this country!

The authors have set up this book in such a way that it is aimed for a broad public, both scientists and laymen. After the introductory chapter, two chapters are dealing with general information on land snails and the value of snails in ecosystems respectively. The next chapter ‘Collecting and Identifying Land Snails’ also explains the organisation of the book. Chapters 5-12 treat land snails according to their shape and size, followed by a chapter on slugs and one on freshwater snails. The final chapter is dealing with exotic snails occurring in Belize. The book is concluded by a glossary, a species list per family, a bibliography, and an index of scientific names.

The first version of this book (Dourson et al., 2018a) was unintentionally published while the authors were still updating the text on the basis of reviews they had asked to specialists. Nevertheless, the book was distributed by several commercial companies, and the new species descriptions are thus validly available according to the International Code on Zoological Nomenclature. This date was 10 January 2018; the final, ‘official’ version came out just before Christmas on 21 December (Dourson et al., 2018b). 

The ‘unofficial’ first version was based on old classifications for several families (e.g., Orthalicidae contained both Orthalicus [Orthalicidae] and Bulimulus and Drymaeus [Bulimulidae]; no distinction was being made between Urocoptidae and Epirobiidae; Subulinidae were not included in Achatinidae). The classification of Ampullariidae is not in accordance with the authoritative papers of Cowie. In June 2018, after receiving a further draft of the book, I send a long list with additional comments to the authors. Thus it is regrettable that this version was published at all. Unfortunately part of the suggested corrections were not applied (e.g., p. 11: Morlet’s crocodile should be Morelet’s crocodile; p. 26: the ‘escargot’ of the French is not Cornu aspersum but Helix pomatia; p. 227: the correct name for the species is Brachypodella speluncae (L. Pfeiffer, 1852), and the syntype figured on p. 226 is Cylindrella costulata Morelet, 1851 [Pfeiffer’s name being a replacement name for this junior homonym]). Some figures have been updated and the list of references is somewhat extended but still contains typos and flaws, while recent literature on several groups are missing.

The following new species have been described (publication date thus January 2018), with the holotypes deposited in the Florida Museum of Natural History, Gainesville:

Family Helicinidae: Lucidella caldwelli
(Note that since authorship has not been restricted, Caldwell is co-author of his own eponym)

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Family Bulimulidae: Drymaeus tzubi
(N.B. in this version incorrectly classified as belonging to Orthalicidae)

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Family Spiraxidae: Euglandina fosteri

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Family Spiraxidae: Pseudosubulina juancho

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Family Spiraxidae: Rectaxis breweri

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Family Achatinidae: Opeas marlini
(N.B. in this version still under the family Subulinidae)

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Family Achatinidae: Leptopeas corwinii
(N.B. in this version still under the family Subulinidae)

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Family Achatinidae: Lamellaxis matola
(N.B. in this version still under the family Subulinidae)

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Family Achatinidae: Leptinaria doddi
(N.B. in this version still under the family Subulinidae)

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Family Urocoptidae: Brachypodella levisa

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Family Thysanophoridae: Thysanophora meermani

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Family Scolodontidae: Miradiscops striatae

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Family Scolodontidae: Miradiscops youngii

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Family Scolodontidae: Miradiscops bladensis

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Family Charopidae: Rotadiscus saqui

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Family Charopidae: Chanomphalus angelae

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Family Ferussaciidae: Cecilioides dicaprio

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This book is an extremely nice contribution to our knowledge of the Central American malacofauna. It is suitable both for both the ‘serious’ malacologist and for a layman, thanks to the very accessible way the book was designed. But, as the authors communicated to me, the prime audience is the general public. The lay-out will appeal to this target group, although the silly cartoons could be missed without making the book less informative.

As far as I know, the authors are now giving workshops to people in Belize to bring this fauna more to their attention. They will also develop a laminated snail card for quick identifications in the field. All this sounds as wonderful initiatives.

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Update: The final version of the book came meanwhile available, and this post has been updated. It is unfortunate that the authors have not grasped the opportunity to correct some of the errors in Thompson’s checklist and that the classification is not up-to-date. It is clear that the first, unofficial version will become a collector’s item for bibliophiles!

Dourson, D.C., Caldwell, R.S. & Dourson, J.A., 2018a. Land snails of Belize, Central America. A chronicle of remarkable diversity and function. — Goatslug Publications, Stanton, Kentucky, U.S.A. Hardcover, 338 pp. ISBN 978 0999 802304. [no longer available]

Dourson, D.C., Caldwell, R.S. & Dourson, J.A., 2018b. Land snails of Belize, Central America. A chronicle of remarkable diversity and function. — Goatslug Publications, Stanton, Kentucky, U.S.A. Softcover, 339 pp. ISBN 978 0999 802311. € 69. 

New Tentacle

Just published, a new issue of the Tentacle, the newsletter on conservation issues edited by Rob Cowie.

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Full of interesting new short notices, the following are related to the Neotropics:

Outerbridge, M., Ovaska, K. & Garcia, G. – Back from the brink: recovery efforts for endemic land snails of Bermuda (p. 16-18): on a captive breeding programme and translocation of Poecilozonites snails.

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Torres, S. & Darrigan, G. – Distribution and conservation status of freshwater Bivalvia (Unionida, Mytilida, Venerida) in Argentina (p. 19-21): containing results of a recently published paper and a plea for creating new protected habitats for freshwater environments in the country.

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Kostick, H.L. – Interesting finds in Jamaica. Report from the field 2018 (p. 26-27): report on range extensis for two species, and the observation of a predatory New Guinea flatworm.

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Agudo-Padrón, I. – Conservation of non-marine molluscs in Central southern Brasil: Recent additions to the inventory of Santa Catarina State ((p. 29-30): recent additions in land snails were Peltella palliolum, Gastrocopta servilis, Omalonyx matheroni, Streptaxis tumescens, and one alien, viz. Ovachlamys fulgens. Also 4 freshwater native to the region and one alien were new additions.

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Agudo-Padrón, I. – Molluscs included in the new version of the Red Book of Brasilian fauna threatened with exinction (p. 32-33).

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Agudo-Padrón, I. – The non-marine endemic gastropod molluscs of Santa Catarina State, Central southern Brasil: a brief update (p. 33-34).

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When the cure kills

Today something about policy. Often boring and uninteresting (seemingly), but sometimes politicians take decisions which are affecting the work of taxonomists. Therefore the recent paper by Prathapan et al. which appeared in the journal Science is worth mentioning.

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The Convention on Biological Diversity (CBD) commits its 196 nation parties to conserve biological diversity, use its components sustainably, and share fairly and equitably the benefits from the utilization of genetic resources. This last objective was further codified in the Nagoya Protocol (NP).

The authors state that the NP mechanism seem to work out counter-productive, leading to all sorts of national legislature in biodiverse countries which hamper the study of its biodiversity by biologists. Conservation approaches are very strict and deny that effective conservation also demands the scientific understanding of species. In practice, legislative processes have been tightened in many countries to such extent that biological research has been hampered by permits. Permitting processes are sometimes becoming vulnerable to fraud and corruption, the responsible persons using their for their own benefit and blocking permits to foreign colleagues who are not their favourites. While some South American countries are playing these games and EU-based museum curators adhere strictly to the official rules, it leads to a total stand-still of taxonomic research which needs e.g. live collected animals for molecular study.

The authors, supported by 172 co-signatories from 35 countries, make a strong plea to the CBD to “do more to raise the legal curtain that has fallen between biodiversity scientists and the biodiversity that they strive to discover, document, and conserve”.

Prathapan, K.D. et al., 2018. When the cure kills–CBD limits biodiversity research. – Science, 360 (6396): 1405-1406.

New Tentacle issue available

Tentacle issue 26 is available now via this link. As always a very interesting overview of short papers and notes related to the conservation of molluscs.

The issue starts with an In Memoriam for Tony Whitten (1953-2017) who, although mainly involved with conservation in Asia, has been of importance for stimulating malacologists for conservation issues. This is best illustrated by a quote from 2001 which was added by the editor: “I would venture to suggest that the majority of malacologists need to poke their heads out from the security of their shells and slither rapidly to be heard and become involved in the issues that threaten the organisms on which their careers are based. This does not mean that this topic take over your own particular speciality and distract your research programme, but it does recognize that you have a profound responsibility to do something [my italics]. The actual and potential threats to many mollusc species, and the trends, can’t get much worse”.

Related to the Neotropics, the following notes are included:

1. Espinosa, A. Measures to control Lissachatina fulica: impact on native terrestrial molluscs in the Dominican Republic.
This papers tells the story how an area of secondary forest, where in August 2017 nine endemic species were found, plus the achatinid, was a few months later completely ‘treated’ with molluscicides and deforestation.

2. Santos, S.B. dos & Miyahira, I.G. Evaluation of the list of endangered non-marine molluscs in Brasil in progress.

3. Agudo-Padron, I. Conservation of non-marine molluscs in Central Southern Brasil: revised and updated inventory of species of Santa Catarina State.

4. Salvador, R.B. et al. Presumed extinct land snail Megalobulimus cardosoi found again in Pedra Talhada Biological Reserve, north-east Brasil.

Molluscs in the news

Two news items came to my attention today. The first has been taken from the Conch-L list and is about conservation of Florida land snails. “Florida Fish and Wildlife [Conservation Commission] has just sent out a posting regarding endangered and threatened species. There are two proposed rulings on Tree snails. The one  is Liguus and the other is Orthalicus. Here is the Liguus and other species  link. http://myfwc.com/wildlifehabitats/imperiled/species-action-plans/”. Only Liguus fasciatus is mentioned, together with more than 50 species of other phyla.

Liguus Florida

The ‘Science in the news’ site had an item on natural history museums and how these institutions, behind the scenes, are centers of cutting-edge research. One example is the recent discovery of a Plekocheilus species, collected back in the 1800s. More brushing off the dust than cutting the edge, but anyway…

Extinction of land snails

My gut feeling about the IUCN Red List, the stringent and bureaucratic procedure involved, and the few land snails listed on it, have given me an uneasy feeling for quite some years. Now Régnier et al. (2015) have published a study in which they offer an alternative approach, viz. with a mixture of a model study and expert opinions.

Their abstract is brief: “Since the 1980s, many have suggested we are in the midst of a massive extinction crisis, yet only 799 (0.04%) of the 1.9 million known recent species are recorded as extinct, questioning the reality of the crisis. This low figure is due to the fact that the status of very few invertebrates, which represent the bulk of biodiversity, have been evaluated. Here we show, based on extrapolation from a random sample of land snail species via two independent approaches, that we may already have lost 7% (130,000 extinctions) of the species on Earth. However, this loss is masked by the emphasis on terrestrial vertebrates, the target of most conservation actions. Projections of species extinction rates are controversial because invertebrates are essentially excluded from these scenarios. Invertebrates can and must be assessed if we are to obtain a more realistic picture of the sixth extinction crisis”. But their summarizing figure shows the following picture:

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From their discussion I derive the following quotes: “The current Red List underestimates the actual number of extinct and threatened invertebrate species: there are almost seven times as many extinctions in our sample as would have been listed following the IUCN criteria, and we suggest that discrepancies of this order of magnitude, or greater, given that mollusks are one of the better known invertebrate groups, should be expected for other invertebrate groups. (…) a number of studies and our own work suggest that invertebrate extinctions are mostly overlooked: we suggest that we have probably already lost 7% of described living species of the world. On oceanic islands, there is evidence that this percentage is much higher”. This is really alarming!

Their method involved a random selection of taxa that have been assessed. For the Neotropical realm the following species were involved: Amphistemma pilsbryanum, Arangia aequatoris, Bostryx apertus, Bostryx baeri, Bostryx dentaxis, Bostryx gayi, Bostryx haasi, Brachypodella collaris, Bulimulus erectus, Bulimulus inermis, Callocoptis vesperalis, Capillacea angustior guamaensis, Cochlodinella variegata, Dentellaria chemnitziana, Drymaeus albolabiatus, Drymaeus chaperi, Drymaeus combinai, Drymaeus icterostomus, Drymaeus mexicanus, Drymaeus picturataEucalodium moussonianum, Eurytus ameghinoi, Eurytus glandiformis, Eurytus pirriensis, Gongylostomella fortis, Guestieria martinida, Hispaniolana gigantea, Labyrinthus stolzmanni, Leiostracus coxiranus, Leiostracus spiritualis, Liparotes obesulus, Liparotes obesulus obesus, Lyobasis binneyi, Martirelix huertai, Obeliscus pattalus, Plagioptycha duclosiana abacoensis, Plekocheilus appuni, Praticolella berlandieriana, Radiodiscus ditzleri, Stenostylus meleagris, Streptostyla chiriquiana, Streptostyla flavescens boucardi, Streptostyla irrigua, Streptostyla potosiana, Thaumastus integer, Thaumastus yanamensis, Torrecoptis polita, Trilamellaxis parallela culebrensis, Urocoptis producta, Varicella angiostoma ingallsiana, Zachrysia auricoma. Species that were rated as ‘probably extinct’ in the model assessment are printed in bold. Both in the model and the expert approach the number of species that are qualified as ‘unable resp. not possible to assess’ is relatively high. So the lack of knowledge about the conservation status of land molluscs is still at an alarming level. Given the methodology used this is also a pregnant result of this important study.

Régnier, C., Achaz, G., Lambert, A., Cowie, R., Bouchet, P. & Fontaine, B., 2015. Mass extinction in poorly known taxa. – Proceedings of the National Academy of Sciences of the United States of America. Published online before printJune 8, 2015, doi:10.1073/pnas.1502350112  (see Full Text (PDF)).