A large scale study of nearly 700 species reveals the evolutionary relationships and history of Neogastropoda, a diverse group of marine snails. The findings provide new evidence for their single origin, identify four new families and reveal a previously undetected burst of diversification in the early Cenozoic.
Biological diversity is fascinating and inspiring, yet much of it remains poorly known. This is particularly true of marine invertebrates, many of which are small, have cryptic lifestyles or live in environments that remain underexplored.
One such group is the Neogastropoda, an order of marine snails that includes around 16,000 known species, with many more still undescribed. These small predators and scavengers of the seafloor are perhaps best known for their often striking shells. But despite their diversity and long evolutionary history, fundamental questions about the group have remained unresolved: how are many Neogastropoda species related to one another, and when did the major groups emerge?
A new study involving researchers from the Swedish Museum of Natural History and a large international team now provides new answers to these questions. By combining material from natural history collections around the world with phylogenomic analyses, the researchers have assembled a dataset comprising nearly 700 species – providing a solid basis for reconstructing the evolutionary history of the group.
The study provides, for the first time, strong evidence that all the diverse groups currently placed within Neogastropoda share a single evolutionary origin. In other words, the many different lineages of these marine snails are indeed relatives.
The researchers also identify four new families of Neogastropoda. Together with a newly proposed classification, these findings provide a framework for future taxonomic research and species descriptions.
Such work is important because a large proportion of biodiversity remains undocumented. Species that are small, cryptic or difficult to access are particularly likely to remain unknown to science. Without a clear understanding of how species are related, it is also difficult to interpret their evolutionary history or place newly discovered species within it.
The study also changes the picture of when the major Neogastropoda lineages emerged.
It has long been known that the rise of Neogastropoda was associated with the major changes in marine environment that took place towards the end of the Mesozoic Era, around the time when non-avian dinosaurs declined. However, a critical revision of the Neogastropoda fossil record reveals additional complexity in this history.
The researchers found evidence of a previously undetected major burst of lineage diversification in the early Cenozoic, during the Danian.
One possible explanation lies in changes in the marine predator community. Early Cenozoic seas became a more dangerous environment for shelled snails as crustaceans and cephalopods emerged that specialised in crushing shells. This may have placed new selective pressure on neogastropods, favouring animals with novel and more resistant shell architectures. Lineages that failed to adapt went extinct, while those that evolved more resistant shells survived and eventually gave rise to the modern-type Neogastropoda families known today. These modern groups may therefore look familiar to us while being quite different from their ancient Mesozoic ancestors.
The study illustrates how taxonomy, natural history collections, fossil evidence and genomic data can be combined to reconstruct evolutionary history.
Natural history collections from around the world provided the crucial samples needed to compare hundreds of species. The resulting dataset allowed the researchers to investigate relationships across a large part of Neogastropoda and combine this information with evidence from the fossil record.
The results demonstrate the importance of zoological systematics not only for describing new species, but also for revising existing knowledge of biodiversity.
There are still many species of Neogastropoda waiting to be described. A robust classification provides a necessary foundation for that work – and, ultimately, for understanding the diversity and evolutionary history of one of the most species-rich groups of marine snails.
Zoological Journal of the Linnean Society
Data/statistical analysis
Animals
Phylogeny, classification, and evolutionary history of Neogastropoda.
26-Jul-2026