This dataset was compiled as part of the first author's Master's thesis and the principal investigator's ongoing research. The main goal of the dataset is to establish a baseline of the biogeographic distribution of the three Abatus species. This baseline complements current research on the biogeography of the genus Abatus being carried out at the Laboratory of Molecular Ecology (LEM) at the University of Chile.

Some temporal and geographic records of Abatus species (Echinoidea, Schizasteridae) in Antarctic and Subantarctic environments

Fernando Moya, Claudia Maturana, Sebastian Rosenfeld, Melanie Delleuze, Guillaume Schwob, Camila Neder, Paul Brickle, Thomas Saucède, Léa Cabrol, Angie Díaz, Karin Gerard and Elie Poulin

The study area corresponds to shallow coastal waters in the subtidal zone of Antarctic and Subantarctic regions.

ANID-Programa Iniciativa Científica Milenio-ICN2021_002, FONDECYT Regular 1161358 and 1211672, IPEV project n°1044 PROTEKER, South Atlantic Environmental Research Institute (SAERI) and Fondecyt Postdoctoral project 3100139.

Samples were collected through various projects and expeditions in the Magellan Strait (Patagonia, South America), the Kerguelen Islands (several sites during the Proteker project campaigns 1, 5, 8 and 9), the Falkland/Malvinas Islands, South Georgia (with logistical support of the South Atlantic Environmental Research Institute) and the South Shetland Islands during Antarctic Scientific Expeditions (ECA), supported by the Chilean Antarctic Institute (2004–2024) (Fig. 1).

To sample the Abatus species, two complementary collection techniques were employed: 1) hand-picking in the infralittoral zone at low tide and 2) Self-Contained Underwater Breathing Apparatus (SCUBA) diving to sample subtidal habitat at depths of 1-20 m. Depending on the sampling campaign, collected specimens were transported to research vessels or scientific stations with in situ seawater. They were subsequently preserved in 95% ethanol in the onboard or station laboratories.

Through field surveys, accessible sites with specific environmental conditions (sediment type, grain size and protection from waves) were selected for sampling. Within each site, if the subtidal zone was shallow, samples were taken by hand at random points . If the subtidal zone was deep, SCUBA diving surveys were carried out systematically spaced at approximately 100 metres for Falkland/Malvinas Islands, Magellan Strait, South Shetlands Islands and South Georgia sites and 500 metre intervals for Kerguelen sites, ensuring methodical spatial coverage. After sampling, all specimens were preserved in 95% ethanol for both morphological and molecular analyses and were stored at room temperature. The GPS coordinates were recorded for each occurrence to ensure accurate georeferencing. To reduce any taxonomic misidentification, each urchin was revised by experts in the group and identified, based on diagnostic morphological characteristics following literature and the online taxonomic key "Antarctic Echinoidea".

The step-by-step methodology details of each project can be obtained from their respective researchers through the provided contact information (email) in the GBIF dataset.

This dataset encompasses records of Abatus species from five main regions across the Southern Ocean (Fig. 1). These include Possession Bay in the Magellan Strait (Patagonia; Fig. 1A); Canache area in the Falkland Islands/Malvinas (Fig. 1B); Stromness Bay in South Georgia (Fig. 1C); Port Aux Français, Fjords des Portes Noires, Anse du Halage, Haute, Port Matha, Ile Suhm and Port Couvreux in Kerguelen (Fig. 1D); and China Cove and Ardley Island in Fildes Bay (King George Island; South Shetland Islands) (Fig. 1E). The subantarctic zone (Patagonia, Kerguelen, Falkland/Malvinas and South Georgia) accounts for 62.1% of the recorded occurrences, whereas the Antarctic zone (South Shetland Islands) contributes the remaining 37.9% of occurrences (Fig. 2).

−64.876 and −48.935 Latitude; −69.478 and 70.219 Longitude.

This dataset includes three species of the genus Abatus (order Spatangoida; family Schizasteridae) of the eleven species currently recognised in this genus (David et al. 2005). Each of the three recorded species is associated with a specific geographic range: Abatus agassizii (Fig. 3A) occurs in the South Shetland Islands, Abatus cordatus (Fig. 3B) occurs in the Kerguelen Islands (both have the highest number of records in this dataset, with 11 occurrences per species) and Abatus cavernosus (Fig. 3C) occurs in the Subantarctic Region of South America (Patagonia), primarily in the eastern Magellan Strait with five occurrences. The dataset also includes one occurrence in the Falkland/Malvinas Islands (Fig. 3D) and one in South Georgia (Fig. 3E), which represent an Abatus species that have not been identified due to some overlapping characters (e.g. type of pedicellariae and test shape) which limits a reliable identification.

This dataset includes occurrence records of Abatus species from 2004 to 2024. The Antarctic Scientific Expeditions (ECAs) allowed sampling of A. agassizii in the Antarctic sector during 2004, 2006, 2009, 2010, 2011, 2017, 2020 and 2024. The PROTEKER campaigns provided samples of A. cordatus in different areas of the Kerguelen Islands during 2011, 2019 and 2021. Expeditions to the Magellan Strait during 2022, 2023 and 2024 allowed the collection of the species A. cavernosus. Finally, occurrences from South Georgia and the Falkland/Malvinas Islands were recorded only in 2021 and 2022, respectively (Fig. 4).

Colección de Invertebrados del Laboratorio de Ecología Molecular de la Universidad de Chile

urn:BASE:LEM:Inv:Ech:Echi:Aba

95% Ethanol.

Other

This work is licensed under a Creative Commons Attribution (CC-BY 4.0) Licence.

Some temporal and geographic records of Abatus species (Echinoidea, Schizasteridae) in Antarctic and Subantarctic environments

https://doi.org/10.15468/gmsy5y

https://www.gbif.org/dataset/57d14cdb-47c9-49ac-99f9-d0796c8eec80

1

This work consolidates two decades (2004–2024) of georeferenced occurrences for three Abatus species across five sectors of the Southern Ocean from various Antarctic and Subantarctic research campaigns, providing a brief, but explicit spatio-temporal baseline for future ecological, biogeographic and conservation analyses (Moya et al. 2024a). While unequal sampling does not allow us to infer abundance trends, the repeated detections of A. cordatus in the Kerguelen Islands and A. agassizii in Fildes Bay (King George Island) in multiple expeditions throughout different years show a persistent local presence, suggesting a temporary maintenance of the patches in those sites, consistent with the species' short generation times (around 5 years) and brooding life history (Mesphoulhé and David 1992). Notably, A. agassizii appears highly localised within the South Shetlands/Antarctic Peninsula Region, where it is most reliably encountered in the protected, ice-free embayments of Fildes Bay. Conversely, A. cordatus is endemic to the Kerguelen Plateau and widespread in shallow soft-bottom habitats there. These patterns align with prior work emphasising the restricted ranges of A. agassizii and the endemism of A. cordatus in the Kerguelen Islands (Mesphoulhé and David 1992, Palma et al. 2006, Diaz et al. 2012, Arnould-Pétré et al. 2021).

However, unresolved phylogenetic relationships and morphological similarities amongst Abatus species have led to erroneous identifications and problems in the taxonomic accuracy within this genus (David et al. 2016, GBIF 2023), limiting the accurate mapping of species distribution ranges. For instance, records from the Falkland/Malvinas Islands, which typically share fauna with Patagonia (Koubbi et al. 2014), highlight taxonomic uncertainty by documenting the presence of A. agassizii or potentially A. philippii (GBIF 2023), instead of the expected A. cavernosus, which is found in the Magellan Strait as well as in locations on the southern coast of Argentina (e.g. Puerto Deseado; see Gil et al. (2009), Gil et al. (2020)). Similarly, published syntheses of the Scotia Arc report occurrences of multiple species, such as A. agassizii, A. bidens, A. cavernosus and A. philippii (David et al. 2016, GBIF 2023). In Antarctic areas (South Shetland and Antarctic Peninsula), problems between species are evident as well, such as A. cavernosus and A. bidens for the sector of Maritime Antarctica (GBIF 2023). These discrepancies show the importance of accurate occurrence data and robust taxonomic resolution and specimen-vouchered datasets and integrative taxonomy (targeted barcoding, diagnostic morphology and ecological specificity) are most valuable for these purposes. We therefore flag Falkland/Malvinas/South Georgia Abatus occurrences as priorities for DNA sequencing and standardised re-identification to resolve whether they belong to A. cavernosus, A. philippii or an undescribed unit.

The life-history of Abatus (direct development, maternal brooding and absence of pelagic larvae) constrains dispersal and gene flow, favouring fine-scale spatial genetic structure and demographic sensitivity to habitat fragmentation (Poulin and Féral 1996, Ledoux et al. 2012). Empirical studies document a long brooding cycle, limited mobility and significant micro-spatial genetic variation in Abatus species. Additionally, individual-based simulations indicate that these populations are vulnerable to local disturbances, as supported by multiple studies (Ledoux et al. 2012, Maturana et al. 2016, Fabri‐Ruiz et al. 2020, Arnould-Pétré et al. 2021, Pascal et al. 2021, Delleuze et al. 2024). Recent morphological and microbiological analyses further confirm this fragility, especially in response to metal contamination (Moya et al. 2025). Our multi-campaign occurrence series, thus, offers a needed baseline to detect future range contractions or shifts under environmental change, especially for brooders whose realised dispersal is intrinsically low (Schatt and Feral 1991, Arnould-Pétré et al. 2021).

Methodologically, open biodiversity aggregators (OBIS, GBIF) are indispensable to contextualise Southern Ocean biodiversity, but exhibit strong spatial, temporal and taxonomic biases due to remoteness, logistics and route-based sampling. We therefore advocate routine occurrence-data QA/QC (e.g. CoordinateCleaner pipelines for georeferencing artefacts; depth/land–sea mismatch checks and institutional centroid filters) before downstream analyses (e.g. Species Distribution Models, range metrics). At the Southern Ocean scale, Species Distribution Models for benthic taxa should be constructed with careful bias correction and environmental realism (substrate, bathymetry, near-bottom climatologies) (Zizka et al. 2019, Bonnet-Lebrun et al. 2023), as recent echinoid-focused assessments caution that model robustness otherwise suffers (Fabri‐Ruiz et al. 2020). Our curated, vouchered occurrences provide a high-quality backbone for such analyses, while making explicit where data gaps remain. From a conservation standpoint, shallow Antarctic and Subantarctic soft-bottom communities are exposed to multiple, interacting drivers (ocean warming and marine heatwaves, sea-ice and iceberg-scour dynamics, acidification, pollution and fisheries) whose effects are magnified for brooders with limited dispersal and narrow depth/temperature envelopes. Building on our baseline, future assessments should quantify Extent of Occurrence (EOO) and Area of Occupancy (AOO) following current IUCN Red List guidance, explicitly accounting for sampling bias and taxonomic uncertainty (IUCN 2025). Region-specific ecoregionalisations, based on echinoid distributions, can help translate occurrence baselines into spatial priorities (e.g. Marine protected areas design/updates) under Intergovernmental Panel on Climate Change (IPCC) consistent scenarios.

Taken together, our dataset: (i) documents persistent populations at key localities for A. cordatus and A. agassizii; (ii) highlights taxonomic uncertainty in the Falkland/Malvinas Islands and South Georgia where integrative work is needed; (iii) provides curated inputs for bias-aware SDMs and future monitoring; and (iv) establishes a reproducible baseline against which to test hypotheses about brooder vulnerability, range dynamics and conservation status across the Southern Ocean (Griffiths 2010). Therefore, this dataset not only addresses existing knowledge gaps, but also establishes a valuable baseline for future biogeographic, ecological and genetic studies aimed at understanding the resilience and evolutionary potential of Abatus species in the face of global environmental change.