Tag Archives: varia

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.

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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”.

journal.pbio.3000357.g001

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?

Reference:
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

How ‘lefties’ are initiated

In some snails it occasionally occurs, in others it is more frequent, and in a few families (e.g. Clausiliidae) it is the norm: sinistral shells or ‘lefties’.

Also in the Neotropics this can be found. Clausiliids occur mainly in the Andean countries, and groups with some genera where sinistrality more or less frequent does occur are e.g. Corona and Drymaeus. But the genetic mechanism behind this phenomenon is now slowly unraveled. See the story behind the link below…

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Roeters van Lennep (1820-1879)

Freshly pressed: a new paper on the history of malacology, i.e. about the 19th Century Dutch cabinet collector H.C. Roeters van Lennep.

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H.C. Roeters van Lennep was one of the most famous Dutch shell collectors during the mid-19th century, for whom we here present new and additional biographical information. His collection was auctioned in 1876, but so far only a limited amount of information has been published on this topic. The details of the auction are reconstructed on the basis of his correspondence with H. Crosse. Such new information provides an insight into who buyers were during the auction, which prices were realised, and where parts of the material ended up. There ap- pears to have been a second auction in 1879 where possibly a large part of the remainder of the first auction was sold.

Reference:
Breure, A.S.H. & Backhuys, W. Herman Christiaan Roeters van Lennep (1820-1879) and the auction of his collection. – Spirula, 418: 10-16.

New edition of ‘2400 years’

Today an updated version of Coan & Kabat’s ‘2400 years’ appeared:

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“Gene Coan and I are pleased to announce that the 2019 edition of “2,400 Years of Malacology” – a catalog of biographical and bibliographical articles about those who studied and collected mollusks and related files – is now on the website of the American Malacological Society:
Please note that the home of the AMS website has recently changed, so any links or bookmarks will need to be updated.
The 2019 edition is 1,710 pages.  It includes four additional documents containing (1) collations of a number of important references for malacological systematists (111 pages); (2) collation of the Systematisches Conchylien-Cabinet (1837-1920) (65 pages); (3) collations of significant malacological journals (62 pages), and (4) an updated version of the “Annotated Catalog of Malacological Meetings, Including Symposia and Workshops in Malacology” (145 pages)”.
As usual, this is a very useful work for those who want to know who is behind all those names that are dispersed in the malacological literature, either as authors or as collectors or other persons of interest.

L / XL / XXL

In the latest Shell-O-Gram newsletter of the Jacksonville Shell Club, I found this article about record-breaking Euglandina shells:

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It would be interesting to know if there is any specific reason why in this population these snails become bigger than everywhere else. Plenty of food supply or just a gene going wild and producing mutants?