Tag Archives: conservation

Cuban Red List

It had escaped my attention, but already in 2016 a Red List of terrestrial invertebrates for Cuba was published. It deals with Mollusca, Insecta and Arachnida.

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The chapter on molluscs contains species of Cerionidae, Annulariidae, Cepolidae, Helicinidae, Urocoptidae, Orthalicidae, and Pleurodontidae. In total 88 (sub)species are listed and assessed according to the IUCN criteria. This < 10% of the species known from the island.

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A very useful source of information and a good basis for further research.

Hidalgo-Gato González, M.M. et al., 2016. Libro Rojo de invetrebrados terrestres de Cuba. – Editorial Academia, La Habana, 241 pp. Link

Internet trade and conservation

In the just published number of Tentacle, one of the interesting articles is about shell trade via the internet. It is to be applauded that Chinese authors have taken this hot topic to the open as shell trade is definitely a threat to molluscan diversity. The normal reaction from traders will be that they trade shells they found empty, but this has in most cases to be considered incorrect (as the perfect state of shells on offer tells otherwise). Unfortunately, even professional malacologists fall sometimes for the temptation of describing new species from material collected by traders, thereby reinforcing this questionable practice of dealers and their collectors.

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As the article shows a picture of Neotropical shells taken from a nature reserve in Florida, this is clearly a practice not limited to eastern Asia.

Zhang, G. & Wu, M., 2020. Internet trade, a new threat to malacodiversity. – Tentacle, 28: 12-14.

Land cover change in NE Mexico

Land-cover change and protected nature areas is not a subject that is well-studied. Vázquez-Reyes et al. recently published about it related to a region in northeastern Mexico.

Protected areas (PAs), priority terrestrial regions (PTRs) and priority terrestrial sites (PTSs) are strategies for conserving natural resources. However, loss of coverage on the peripheries can lead to isolation between these conservation areas. The present study analyzed the association of the change of coverage inside and outside 2 PAs, 5 PTRs and 128 PTSs in Tamaulipas with the richness and geographic distribution of 5 species groups (strict, semi-aquatic and tolerant hydrophiles, as well as gastropods and pteridophytes in 3 periods (1986, 2002 and 2011). In addition, we identified areas with similar species composition and socioeconomic-environmental factors related to the change in coverage. The highest richness and geographic distribution of aquatic plants occurred outside the conservation areas, while the greatest richness of ferns and gastropods was present inside them. The greatest loss of coverage occurred outside the El Cielo Biosphere Reserve and the Sierra de Tamaulipas PA. The loss of native cover increased in the last 30 years and is greater outside the conservation areas, therefore is necessary to propose and implement strategies to reduce the isolation of these areas“.

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Although no list is given of the gastropods studied, assumingly they were terrestrial species. This is a policy study rather than a taxonomical one, but for conservation purposes it may be of interest.

Vázquez-Reyes, C.J. et al., 2019. Biodiversity risk from land-cover change in terrestrial priority regions and protected natural areas in northeastern Mexico. – Revista Mexicana de Biodiversidad 90: e902726 (16 pp.).

Demography Tikoconus

Due to oversight I missed the recent paper by Barrientos on the biology one of the new euconulid species; time to report it now.

Introduction: Ecology and natural history of neotropical land snails is almost unknown. Objetive: In this paper, I analyse the population dynamics of Tikoconus (Tikoconus) costaricanus Barrientos, an understory endemic euconulid.
Methods: I compared T. costaricanus’ demography patterns in tropical montane forests in central Costa Rica in three habitats with different restoration techniques: a mature forest, a secondary forest and a Cuppressus lusitanica plantation. I collected data in three month periods during a year. I analysed population size in relation with habitat, sampling date, leaf litter humidity, depth and quantity; and specimen size in relation with habitat and sampling date. I also kept some specimens in terraria and described part of their natural history.
Results: The species is more abundant in mature forest (Ø = 0.174 ind/m2). The number of specimens in each habitat was constant throughout the year (Kruskall-Wallis = 2.0118, p = 0.57, NS) and hatching occurs in the middle and last months of the rainy season (Kruskall-Wallis = 17.3061, P = 0.00061, **). Number of specimens is related with leaf litter humidity (Spearman correlation, r = 0.3524, n = 232, P < 0.001, **), quantity (Spearman correlation, r = 0.3922, n = 232, P < 0.001, **) and depth (Spearman correlation, r = 0.2543, n = 232, P < 0.001, **). This relationship is explained by the high and stable humid environment provided by leaf litter. Some specimens migrate from foliage to leaf litter during the drier months. Eggs (Ø = 1mm) are laid on moss or soil and the young spend the first 2 or 3 weeks of their life on moss. Egg masses are small (Ø = 4 eggs), and shells look bubbly. Egg development time (20 days) was longer than in other tropical species. Adult pigmentation appears around two months after hatch. In the only case observed, egg laying began 5 months after hatching and the specimen lived 9 months.
Conclusions: Restorations techniques should consider leaf litter features in order to protect endemic neotropical humid dependent diversity

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This is an excellent ecological study of one of the new species recently described by her. And although the resulting data are not completely unexpected given the (very scarce) literature data, this study may have wider application than just the Costa Rican case. Albeit these studies are difficult to execute (especially if species are small and not occurring in abundant numbers), I hope that more Neotropical malacologists with endeavour them during field work.

Barrientos, Z., 2019. Demography of the land snail Tikoconus (Tikoconus) costaricanus (Stylommatophora: Euconulidae) in tropical low montane and premontane forests, Costa Rica. – Revista de Biología Tropical, 67(6): 1449-1460.

A rare Guadeloupe species

In the flush of the ‘end-of-the-year’ papers, a brief note was published by Lenoble & Charles on a rare species from Guadeloupe. Their abstract is “A shell of Laevaricella guadeloupensis (L. Pfeiffer, 1856) (Gastropoda, Oleacinidae) was found on Mahault Ridge, within the Guadeloupe National Park. This locality is the second where this endemic species to Basse-Terre has been identified since it was listed as extinct by IUCN in 1996“.

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Besides an interesting record, it shows that one should be careful to list species as extinct, but at the same time it is clear that this specific species is extremely vulnerable.

Lenoble, A. & Charles, L., 2019. Nouvelle station de Laevaricella guadeloupensis (L. Pfeiffer, 1856), une espèce endémique rare de Guadeloupe (Mollusca, Gastropoda). – MalaCo, 15: 11-13.

Non-native South American species

An extensive analysis just appeared from Darrigan et al. (advance online) about the occurrence of non-native molluscs throughout South America. Their abstract is “Non-native species have been introduced at escalating rates during the last decades, mainly due to the dispersion generated by the increasing trade and transport worldwide. Mollusks, the second largest metazoan phylum in terms of species richness, are no exception to this pattern, but, to date, a comprehensive synthesis of non-native mollusk species (NNMS) in South America was not available. For this purpose, an e-discussion group was formed with malacologists and taxonomists from South America, where we exchanged and analyzed bibliography, databases and information about NNMS, providing expert opinion to this assessment. The first list of non-native mollusk species for South America, considering terrestrial, freshwater and marine environments, includes 86 NNMS distributed in 152 ecoregions (terrestrial, freshwater and marine) of the 189 recognized for the South American continent. Information on their native region, vectors, first record for South America and distribution, are also provided. In the analysis of the distribution of the NNMS and the entry points of each species (e.g., ports, cargo and passenger airports, cities) and status of conservation of the ecoregions, four hot spots were recognized: Subtropical-Atlantic, Northern Andes, Central Andes and Southern Andes. This work, thus, sets the baseline on NNMS for South America, a key piece of information regarding the development of policies targeting the management of biological invasions and their socio-ecological impacts“.

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An interesting study that was totally done by South American malacologists. The paper contains a number of graphs and figures that illustrates the rapid increase over the past decades of non-native species in this understudied continent. It will be a good basis for further studies.

Darrigan, G. et al., 2020. Non-native mollusks throughout South America: emergent patterns in an understudied continent. – Biological Invasions (advance online): 19 pp. https://doi.org/10.1007/s10530-019-02178-4.

Priority conservation areas

A few years ago a species catalogue was published for Argentina (Superfamily Orthaicoidea only), which now forms the basis for a paper on conservation by Ovando et al.

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Their abstract reads “Mollusca is a megadiverse phylum with an estimated number of 70,000–76,000 described species which can inhabit a wide variety of environments. Among them, land snails are a main component of terrestrial ecosystems and they play a pivotal role in ecosystem functioning. They are suffering habitat loss, overexploitation and competition from introduced species, but are regarded as a “non-charismatic” group for conservation purposes. Orthalicoidea is a dominant faunal element in the Neotropics and in Argentina includes 104 species that inhabit a variety of environments. Their abundance, diversity, comprehensive taxonomy and widespread representation in different ecoregions makes this molluscan group an excellent model for biodiversity assessments. The database used here consisted of 985 unique geographic records of 104 species. Species distribution models were generated using the Maximum Entropy method and Zonation v 3.1 was used to evaluate the proposed conservation goals. Three analyses including species distributions, the current protected areas system (PAs) and the Human print layer were carried out. This allowed the identification of priority areas for conservation, the percentage of the species distribution under PAs and analysis of the potential impacts under current land use and in the priority areas detected above. Sixty-one species were modeled, and 59 of them were included in the priority area selection process due to their high area under curve (AUC) scores. Five high priority areas located in the different ecoregions, were identified: 1-dry Chaco, 2-humid Pampas, 3-Southern Andean Yungas, 4-Alto Paraná Atlantic Forests and 5-high Monte. A small percentage of the average distribution range of Orthalicoidean species (3%) was within the current protected areas. Highest-ranked priority areas for land snails are outside the current protected areas system. When human impact is considered, the priority areas are reduced in size and appear as small patches. However, highest priority areas for conservation continue being those detected in the above analyses. Most of the areas detected are used for economic purposes, creating conflicts of interest between the development of human activities and conservation. This study represents one of the first attempts to identify ecoregion level priority areas for a terrestrial invertebrate group. Further analyses, including new predictors and other molluscan taxa, would improve planning the conservation of poorly known invertebrate groups“.

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A useful study, the more as the authors have embraced the ecosystems approach widely used in conservation policies, and with interesting results concerning this group. Their conclusions that conflicts of interests between economic development and conservation continue is nor new nor re-assuring. We all know that conservation is likely to draw the shortest straw in this battle…

Ovando, X.M.C. et al., 2019. Identifying priority areas for invertebrate conservation using land snails as models> Journal for Nature Conservation 50: 125707 (10 pp.).

Rediscovered Bermuda species

When we consider Bermuda on the outskirts of the Neotropics, this information might be relevant:

Bermuda land snail: An animal ‘back from the dead’

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Thousands of critically endangered snails have been released into the wild after being rescued from the edge of extinction, with a little help from a British zoo.

The greater Bermuda land snail was thought to have disappeared for many years until an empty shell turned up in the territory’s capital city, Hamilton.

Live snails were then found among litter in a nearby alleyway.

Some were flown to Chester Zoo for a unique breeding programme.

More than 4,000 snails raised at the zoo have now been taken back to the island and released.

Many more captive snails will soon be returned to their homeland to help give the species a new lease of life.

Mark Outerbridge, a wildlife ecologist for the Bermuda government, said the snail was a “Lazarus species”, which was considered extinct not so long ago.

Then, in 2014, a man walked into his office in the capital, Hamilton, holding a fresh snail shell.


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“It turned out that, yes, this was in fact the greater Bermuda land snail, a species that we thought had gone extinct 40 years earlier,” he said.

“He came back the next day with a fresh one, a live one in his hand, and that’s how I was thrust into this conservation project.”

A small but thriving population of land snails was discovered behind a restaurant. The gastropods were living among litter – specifically inside thrown-away plastic bags – in a “dank wet alley”, surrounded by four-storey buildings.

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Water dripping from air conditioning units had created an environment where the animals could survive unnoticed.

“It turned out that the plastic bags were one of the favourite places for these snails to hang out, because of course it retained the moisture the best – and the snails are very vulnerable to drying out,” said Dr Outerbridge.

“And when we started picking up these plastic bags and unfolding them – literally they contained hundreds of juveniles and hatchling-sized snails.”

Some of the hatchlings were taken into captivity for breeding. Their offspring were later sent to Chester Zoo and the Zoological Society of London, where scientists were able to establish colonies.

It turns out that the snails are prolific breeders in captivity, with thousands of snails bred in a matter of years.

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“At the last count we’ve got somewhere around 13,000 snails – we’ve probably got more than that, they’ve had a lot of babies since then,” said Amber Flewitt, of Chester Zoo, who cares for the snails.

The secret of breeding success, she said, was nice soil and their favourite foods, which include sweet potato and lettuce.

Thousands of the Chester Zoo snails have now been sent back to Bermuda for release in nature reserves.

The snails are thought to be doing well in their new home.

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Dr Gerardo Garcia of Chester Zoo said that, following three years of intensive work, the zoo was proud to see the snails heading home.

“This is an animal that has been on this planet for a very long time and we simply weren’t prepared to sit back and watch them become lost forever when we knew we might be able to provide a lifeline,” he said.

The greater Bermuda land snail is unique to Bermuda and is part of an ancient lineage of land snail that dates back in time over one million years.

Once abundant on the islands that make up the territory of Bermuda, the population went through a dramatic decline during the 20th Century after being preyed on by invading killer snails.

The snails have been released on a nature reserve on the northern Nonsuch Island, which has snail-friendly habitats and no evidence of the main predators that nearly caused the animal’s demise.

They will join a small wild population, estimated at a few hundred individuals. This makes the species more rare in the wild than the likes of the giant panda or mountain gorilla, according to Chester Zoo.

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Some captive individuals have been fitted with fluorescent tags to monitor their recovery in the wild.

“Not only did they escape the axe of extinction but they have rebounded so well in captivity through breeding that now what we’re doing is we’re identifying islands in Bermuda that don’t have the predators and reintroducing them to those islands, and our expectations are very high that they’ll do well,” said Dr Outerbridge.

In the case of this species, it was a matter of having to look literally under every rock and every log before writing the animal off, he added.

The original article, including some videos, can be found here.

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.