A luminous land snail is the “International Mollusc of the Year 2024”

More than 6,000 people took part in the public vote

A land snail that can glow constantly is the “International Mollusc of the Year 2024”! The “living glow stick” Phuphania crossei received the most votes in the online public vote. The snail made it to the final of the international competition along with four other molluscs. The competition, which entered its fourth round this year, was launched by the Senckenberg Research Institute and Natural History Museum Frankfurt, Germany, the LOEWE Centre for Translational Biodiversity Genomics (TBG) and Unitas Malacologica, the international society for mollusc research, to raise awareness about the enormous biodiversity of molluscs and to promote their conservation.

The snail from Thailand won more than half the votes, beating two other snail species, a mussel, and a small squid. Phuphania crossei is an air-breathing land snail found only in the tropical forests of Thailand. It takes its name from the Phu Phan mountains in the north-east of the country. Its special feature is that it constantly produces its own bioluminescent light, emitting a greenish glow like a living glow stick. At first glance, Phuphania crossei is a normal looking snail, with a yellowish-brown body and a dark grey head with eyes on stalks. Its shell is brownish with distinct ribs. However, even in daylight and without stimulation, its greenish glow is visible to the human eye. The glow is produced by light cells on the foot and the mantle. The snail can switch off this glow temporarily.

Phuphania crossei was nominated for the title of “International Mollusc of the Year 2024” by Dr Arthit Pholyotha. He conducts research on taxonomy and phylogeny of Southeast Asian land snails at the Department of Biology at Chulalongkorn University in Bangkok, Thailand. “We know of a few molluscs that can glow, such as some cuttlefish or nudibranchs. However, most species with this characteristic live in the sea. So, a luminescent land snail is something special. We only discovered that Phuphania crossei is one of these few species in 2023, when we studied it more closely,” says Pholyotha. He and his colleagues published their new findings in the journal “Scientific Reports”, which is part of the “Nature” group of publications. The researchers have also shown that this species also glows with biofluorescence after a light stimulus and glows brighter under ultraviolet (UV) light. “Now, of course, we want to find out what evolutionary advantages this brings to the land snails – because in principle, living organisms have to expend a lot of energy to generate light themselves,” Pholyotha continues.

Analysis of the genetic material can help: As the winning species of the competition, the land snail will have its entire genome sequenced by the LOEWE Centre TBG. “As bioluminescence has evolved independently in several lineages of organisms, decoding the genome of Phuphania crossei can help us understand the mysterious world of glowing molluscs that live in the sea, in fresh water or on land,” explains jury member Dr Carola Greve, laboratory manager at the LOEWE Centre TBG. “The comprehensive genome sequencing of this snail species will provide insight into the processes behind bioluminescence”.

Although molluscs are the second largest animal phylum after arthropods, relatively few mollusc species have been fully sequenced. As a result, little is known about the genomic basis of species diversity, their adaptive abilities, or the natural products they produce.

After inviting scientists and the public to nominate interesting molluscs, the competition jury selected five species from the nominations received, considering also technical aspects. From 13 March to 14 April 2024, the public was invited to vote online for one of the five finalist species.

Out of a total of 6,263 votes received from all over the world, Phuphania crossei was by far the most popular – it was chosen 3,279 times. It was followed by the Wavy Sea Butterfly (Clio recurva) with 1,078 votes. The Coosa Fiveridge (Amblema elliottii) received 865 votes and the Wavy Bubble Snail (Micromelo undatus) 607 votes. The Atlantic Brief Squid (Lolliguncula brevis) was chosen 434 times.

“We are delighted that so many people from all over the world took part in this year’s competition. We are so grateful to the researchers and mollusc enthusiasts who nominated so many special species, as well as to everyone who voted for one of the finalists,” said Professor Julia Sigwart, Head of Malacology at the Senckenberg Research Institute and Natural History Museum Frankfurt. “Together, we can use this initiative to draw attention to the great biodiversity of molluscs and inspire the public to learn more about their special features. This is also important for the protection of these often underestimated organisms and their ecosystems,” emphasises Sigwart.

In addition to Prof. Dr Julia Sigwart and Dr Carola Greve, the jury for the “International Mollusc of the Year 2024” competition once again included Dr Tilman Schell, bioinformatician at the LOEWE Centre TBG, and Prof. Dr Yasunori Kano, member of Unitas Malacologica, the international society for mollusc research.
Information on the five finalist species in the “International Mollusc of the Year 2024” competition: https://www.senckenberg.de/en/molluscoftheyear2024
Nominations for the “International Mollusc of the Year 2025” are now open:
Information on the 2021 to 2023 competitions:

Press Material

The luminous land snail Phuphania crossei, native to Thailand, has been chosen as the “International Mollusc of the Year 2024”. Deciphering its genetic information could help scientists better understand the mysterious world of luminous molluscs in water and on land.
Photo: Yuichi Oba

Is it a normal snail? No! Phuphania crossei is one of only a few land snail species that can glow.

Photo: Arthit Pholyotha