She sells seashells by the shore: Unraveling the biodiversity of intertidal limpets in Taiwan

Abstract

Intertidal limpets are among the most common grazers on Taiwan's rocky shores and play an important role in maintaining coastal ecosystems (Figure 1). However, their biodiversity remains poorly understood because species have traditionally been identified using only shell morphology, despite extensive intraspecific variation and the presence of cryptic species. We hypothesized that Taiwan's limpet diversity has been substantially underestimated and used an integrative taxonomic approach combining morphology and molecular data to provide a more accurate assessment of species diversity.

Between 2020 and 2023, we surveyed 86 coastal sites across Taiwan and its offshore islands, collecting over 500 specimens from both natural and artificial shores. Nearly 400 specimens were analyzed using DNA barcoding and phylogenetic methods. We identified 26 limpet species, including twelve previously undescribed species or new records for Taiwan, and revealed cryptic species complexes within widespread taxa.

Our results show that shell morphology alone is often insufficient for reliable species identification because genetically similar individuals can exhibit substantial morphological variation. This study provides the first comprehensive molecular reference for Taiwanese limpets, establishing a foundation for biodiversity research, ecological monitoring, and marine conservation.

Keywords: Integrative taxonomy; biodiversity; DNA barcoding; intertidal limpets; cryptic species, marine conservation

Methodology and Implementation Steps

To comprehensively assess intertidal limpet biodiversity in Taiwan, this study adopted an integrative taxonomic approach that combined extensive field surveys with morphological and molecular analyses. Between 2020 and 2023, systematic surveys were conducted at 86 coastal sites across Taiwan and its offshore islands, including Green Island, Orchid Island, Penghu, Kinmen, and Matsu (Figure 2). Sampling encompassed both natural rocky shores and artificial coastal habitats to capture limpet diversity across a broad range of environments.

More than 500 specimens were collected during low tide and initially identified based on shell morphology, including shell shape, coloration, surface sculpture, and other diagnostic characteristics. Representative specimens were photographed and catalogued to establish a morphological reference collection (Figure 3).

To evaluate species boundaries and validate morphological identifications, 394 specimens were selected for molecular analyses. DNA was extracted and mitochondrial COI and 16S rRNA markers were sequenced through DNA barcoding. Sequence data were compared with reference records from GenBank and analyzed using phylogenetic reconstruction and species delimitation methods.

Finally, morphological and molecular evidence were integrated to reassess species identities and distributions across Taiwan. Newly generated DNA sequences were deposited in the public GenBank database, creating an open-access reference resource to support future biodiversity research, ecological monitoring, and conservation.

Innovation and Cross-Disciplinary Collaboration

This study represents the first Taiwan-wide integrative taxonomic assessment of intertidal limpets, establishing a standardized framework for documenting marine biodiversity through the integration of classical taxonomy and molecular genetics. By integrating complementary lines of evidence rather than relying on a single identification method, morphological observations were validated using genetic evidence, establishing a more robust framework for species identification and biodiversity assessment. The project brought together expertise in taxonomy, molecular biology, phylogenetics, and marine ecology through collaboration between Academia Sinica and Kyoto University. The resulting DNA reference library and curated specimen database provide an open-access resource for future biodiversity research and species identification. Beyond academia, the findings have been translated into educational activities through collaborations with Taiwan's Ocean Conservation Administration, supporting coast ranger training and public outreach programs that promote marine biodiversity awareness.

Expected Results and Contributions

This study establishes the first comprehensive taxonomic baseline for intertidal limpets in Taiwan, providing an essential foundation for future ecological research, long-term biodiversity monitoring, and conservation planning.

The openly accessible DNA reference sequences and curated specimen records will facilitate accurate species identification, biodiversity surveys, environmental assessments, and future taxonomic studies. Together, these resources support both scientific research and biodiversity education through improved identification tools, coast ranger training, and public outreach initiatives. Beyond research, the project contributes to biodiversity education through improved identification resources, coast ranger training, and public outreach initiatives. More broadly, this study demonstrates the value of integrative taxonomy in revealing overlooked marine biodiversity and highlights the importance of continued baseline biodiversity surveys for conserving Taiwan's coastal ecosystems.