Snails and slugs are some of the most threatened animals on our planet today and their biodiversity is still vastly uncharted. In the digital age, community science platforms such as iNaturalist pose an interesting perspective to gather new information on these organisms through user-submitted photos and data. Using Brazil as a case study, our new study explores the potential of iNaturalist as a source of biological data on rare snails and slugs. Undergrad student Rafael Masson Rosa reports on some new discoveries and recent outcomes from the study.
iNaturalist is a community science platform in which users can post photos of organisms they’ve sighted, including data on the time and place of the observation. The platform, accessible through both a mobile app and a dedicated website, musters a thriving community of people who frequently post and identify observations. It serves as a way to both educate people about their local biodiversity and generate useful data on the observed species.
Data from iNaturalist has been used in scientific research before, helping to map little-known species and even leading to the discovery of species new to science.
With that in mind, we decided to investigate which information we could gather from iNaturalist about land snails and slugs. These animals are severely endangered and still poorly understood – especially in tropical regions, where they are most diverse. So, we used Brazil as a case study and reviewed all observations on Brazilian snails and slugs posted on iNaturalist.
The study was published in the academic journal PLOS One and is freely available online. Some of our most interesting results are shown below.
Found alive for the first time
The description of snail species based only on dry empty shells is a common practice. For some species, living individuals have never been documented and nothing is known about their appearances aside from the dead shells.
Surprisingly, we identified quite a few of those cases. The most striking one is the megasnail Megalobulimus pergranulatus, which shows a unique (and previously unknown) colour pattern on its soft body.
Potential new species
Amazingly, two potentially new species were detected among the observations we analysed. While we can not say for sure they belong to new species without a thorough analysis of actual specimens, both these snails are “oddities” that don’t quite fit any other known species.
Ecology and conservation
Besides the most striking discoveries, there were also plenty of interesting records on iNaturalist. Most of the observations highlighted by us on our article consist of records of native species outside their previously known range. But some observations are new records of ecological interactions and of rare species thought to be extinct.
Potential uses elsewhere
While our study focused on the land snail fauna of Brazil, it serves as an example of how iNaturalist can bring relevant data for studies in general.
Tropical countries, where most of the biodiversity is located, are the most understudied regions in the world when it comes to terrestrial gastropods (and many other invertebrate animals). The lack of data on the fauna of these regions is particularly worrying when considering that snails are perhaps the most endangered animals nowadays, having the highest number of recorded extinctions of any animal group. As such, any new tool that can help us collect data on these animals is welcome, and iNaturalist has great potential to aid us in this.
The methods of our study can be easily applied for any terrestrial animal group and any country or region, provided that there are relevant observations for it on iNaturalist. It is clear that the platform, as well as community science in general, holds great potential to aid in inventorying biodiversity, and for this we must thank all users who take their time to take pictures of the fauna and publish them online.
I can also vouch for the potential scientific value of inaturalist. It is a great resource, with the main limitation being
that the records are photographic only. This is not a problem for taxa that are photographically definitive, but
not so good for taxa that are not. However, the photos can at least provide an alert, and their
scientific value is sometimes realized when the photographers can be persuaded to obtain voucher material.
I was fortunate in one instance where after three years specimens were obtained by some of the photographers and this effort led to verification of a new ghost moth species in northern Mexico (results available at https://zoonova.afriherp.org/documents/Grehan%20et%20al%202022%20ZN%2019%20Phassus%20NE%20Mexico.pdf).
While inaturalist may be called ‘citizen science’ the ‘science’ part may require specimen based verification, which unfortunately in many cases is not possible (some photographers do not want to get involved with specimen collection, even if something new turns up). I can also vouch for the biological information of photos sometimes being useful. There is a unique biological behavior recorded for some South African ghosts moths for which identification is not possible, but recently a moth was reared by a photographer hat should soon arrive for direct examination and identification.