Karin Gerard

• PhD
• Research Associate at University of Magallanes

Smooth-shelled mussels, Mytilus spp., have an antitropical distribution. In the Northern Hemisphere, the M. edulis complex of species is composed of three genetically well delineated taxa: M. edulis, M. galloprovincialis and M. trossulus. In the Southern Hemisphere, morphological characters, allozymes and intron length polymorphisms suggest that My...

The species of the genus Aequiyoldia Soot-Ryen, 1951, previously known as Yoldia, are common, soft-substratum, sareptid bivalves. In the Southern Ocean, Aequiyoldia eightsii (Jay, 1839) was originally described from the Antarctic Peninsula and has also been reported in southern South America. The species A. woodwardi (Hanley, 1960) was reported for...

Members of the trochoidean genus Margarella (Calliostomatidae) are broadly distributed across Antarctic and sub-Antarctic ecosystems. Here we used novel mitochondrial and nuclear gene sequences to clarify species boundaries and phylogenetic relationships among seven nominal species distributed on either side of the Antarctic Polar Front (APF). Mole...

Two species of scallop, Austrochlamys natans (“ Ostión del Sur ”) and Zygochlamys patagonica (“ Ostión patagonico ”) are presently exploited in the southern part of the Magallanes Province (MP). The lack of clarity in taxonomic identification and ecological aspects is generating both erroneous extraction statistics and an unperceived harvesting pre...

The potential for biological colonisation of Antarctic shores is an increasingly important topic in the context of anthropogenic warming. Successful Antarctic invasions until now have been recorded exclusively from terrestrial habitats. While non‐native marine species such as crabs, mussels and tunicates have already been reported from Antarctic co...

Conceptual biogeographic frameworks have proposed that the relative contribution of environmental and geographical factors on microbial distribution depends on several characteristics of the habitat (e.g. environmental heterogeneity, species diversity, proportion of specialist/generalist taxa), all of them defining the degree of habitat specificity...

Connectivity is a fundamental process of population dynamics in marine ecosystems. In the last decade, with the emergence of new methods, combining different approaches to understand the patterns of connectivity among populations and their regulation has become increasingly feasible. The Western Antarctic Peninsula (WAP) is characterized by complex...

Understanding the factors that sculpt fish gut microbiome is challenging, especially in natural populations characterized by high environmental and host genomic complexity. However, closely related hosts are valuable models for deciphering the contribution of host evolutionary history to microbiome assembly, through the underscoring of phylosymbios...

How the near-shore marine benthic communities survived Quaternary glaciations in Antarctica is a major question for Southern Ocean biogeographers. Several hypotheses that consider life-history traits, such as bathymetric ranges and developmental modes, have been proposed. Near-shore species with high dispersive potential are expected to show star-l...

Abstract Sea stars are a diverse and important component of the Southern Ocean benthos. However, scarce information is available regarding their diversity, distribution, evolution, and taxonomic uncertainties persist for multiple taxa. The Magellanic Region (south of Chile) remains under-sampled despite its pivotal location for species distributio...

This database compiles occurrences of different taxa of marine and freshwater invertebrate species recorded from 2008 to 2023 in the Subantarctic regions, including the Magellanic region, the Cape Horn Reserve Biosphere, the sub-Antarctic islands of South Georgia and Kerguelen, the west and east coasts of the Antarctic Peninsula, the South Shetland...

Understanding the factors that sculpt fish gut microbiome is challenging, especially in natural populations characterized by high environmental and host genomic complexity. Yet, closely related hosts are valuable models for deciphering the contribution of host evolutionary history to microbiome assembly, through the underscoring of phylosymbiosis a...

It has been observed in high-latitude marine environments of the Southern Hemisphere that the variability in the ecological patterns of macrobenthic communities show variations at different spatial scales (i.e. cm to km), mainly influenced by environmental stress gradients. We examined macrobenthic communities of intertidal and subtidal habitats in...

Reticulated evolution -i.e. secondary introgression / admixture between sister taxa-is increasingly recognized as playing a key role in structuring infra-specific genetic variation and revealing cryptic genetic connectivity patterns. When admixture zones coincide with ecological transitions, the connectivity patterns often follow environmental vari...

The Diego Ramírez archipelago is the last point of the South-America continent, located in the Drake Passage 112 km SW of Cape Horn. Due to its difficult access, information on the marine biodiversity that inhabits its coasts is still limited. This study presents the first report of the assemblage of coastal marine mollusks in this archipelago. Sam...

This data is in the framework of the following entitled paper: "Unveiling the unknown phylogenetic position of the scallop Austrochlamys natans and its implications for marine stewardship in the Magallanes Province"

The Diego Ramírez archipelago is the last point of the South-America continent, located in the Drake Passage 112 km SW of Cape Horn. Due to its difficult access, information on the marine biodiversity that inhabits its coasts is still limited. This study presents the first report of the assemblage of coastal marine mollusks in this archipelago. Sam...

During a 2007 expedition dedicated to study kelp diversity within the Magellanic region, specimens of Lessonia Bory with corrugate, yellowish blades were found along the Beagle Channel. This type of corrugated Lessonia is uncommon, with exception of two species from New Zealand. Three possible hypotheses for its origin were explored in this study:...

The generitype Lessonia flavicans Bory is an endemic and important kelp from Sub-Antarctic Magellanic ecoregion that shows affinity to extreme salinity, temperature, and photoperiod conditions. Genomic analysis of L. flavicans from Rinconada Bulnes, Punta Arenas, Chile, resulted in the assembly of its organellar genomes. The L. flavicans complete m...

Biological connection between sub-Antarctic and Antarctic regions through two crustaceans: Boeckella poppei and Halicarcinus planatus

La separación de la fauna antártica y subantártica es profunda, antigua y afectó a la mayoría de los organismos acuáticos. Existe un aislamiento de varios millones de años entre poblaciones de especies de algas e invertebrados marinos codistribuidas en ambos lados del paso Drake. Sin embargo, aún existen vestigios de esa antigua conexión. En los úl...

Animal mitochondria are usually inherited through the maternal lineage. The excep- tional system allowing fathers to transmit their mitochondria to the offspring exists in some bivalves. Its taxonomic spread is poorly understood and new mitogenomic data are needed to fill the gap. Here, we present for the first time the two divergent mitogenomes fr...

PCR primers for Perimytilus purpuratus used in this study.

Length, base composition and sequence divergence of M and F rRNA and protein genes of Perumytilus purpuratu s from two mitogenomes sampled from the northern population (individual LCP1).

Length, base composition and sequence divergence of M and F rRNA and protein genes of Perumytilus purpuratu s from two mitogenomes sampled from the south-eastern population (individual BRP4).

One of the most relevant characteristics of the extant Southern Ocean fauna is its resiliency to survive glacial processes of the Quaternary. These climatic events produced catastrophic habitat reductions and forced some marine benthic species to move, adapt or go extinct. The marine benthic species inhabiting the Antarctic upper continental shelf...

Number of private alleles by locus for locality. (DOCX)

Bayesian analysis results of Sterechinus neumayeri from structure. A) Boxplot for the assignment of individual genotypes for K = 1 to K = 5; B) Graph that shows the variation of the mean Ln probability of data. (TIF)

Interactions between algae and herbivores can be affected by various factors, such as seasonality and habitat structure. Among herbivores inhabiting marine systems, species of the order Patellogastropoda are considered key organisms in many rocky coasts of the world. Nacella species are one of the most dominant macroherbivores on the rocky shores o...

Reticulated evolution-i.e. secondary introgression/admixture between sister taxa-is increasingly recognized as a key evolutionary process that may play a role in promoting adaptation. Mytilus spp. is an ideal system to assess its importance, because these marine mussels form semi-isolated species that remain reproductively compatible over large tim...

Broadcasting is the predominant spawning behavior among benthic marine invertebrates, mainly associated with planktotrophic and planktonic lecitotrophic development. Broadcasting allows genetic mixing that should contribute to increase the genetic diversity of a female clutch. Conversely, in brooding species characterized by protected development,...

The biogeography of the Southern Ocean is the result of the complex interaction of different macroevolutionary forces over its particular biota in space and time. Plate tectonics processes derived in the separation of the continents, together with the establishment of the Antarctic Circumpolar Current and the gradual cooling of the region since the...

Glacial episodes of the Quaternary, and particularly the Last Glacial Maximum (LGM) drastically altered the distribution of the Southern-Hemisphere biota, principally at higher latitudes. The irregular coastline of Patagonia expanding for more than 84.000 km constitutes a remarkable area to evaluate the effect of Quaternary landscape and seascape s...

Table S1.Molecular markers: locus name, source, primer sequence, annealing temperature (T°C) and fragment length (L) in base pairs. Table S2. Kerguelen blue mussels.

The Kerguelen archipelago, isolated in the Southern Ocean, shelters a blue mussel Mytilus metapopulation far from any influence of continental populations or any known hybrid zone. The finely carved coast leads to a highly heterogeneous habitat. We investigated the impact of the environment on the genetic structure in those Kerguelen blue mussels b...

Divergence time estimations and contrasting patterns of genetic diversity between Antarctic and southern South America benthic invertebrates Estimaciones de los tiempos de divergencia y patrones contrastantes de diversidad genética entre invertebrados bentónicos de Antártica y el extremo austral de Sudamérica ABSTRACT Diversity, abundance and compo...

Restricted geographic distribution and low genetic diversity of the brooding sea urchin Abatus agassizii (Spatangoidea: Schizasteridae) in the South Shetland Islands: A bridgehead population before the spread to the northern Antarctic Peninsula? Distribución geográfi ca restringida y baja diversidad genética en el erizo incubante Abatus agassizii (...

Diversity, abundance and composition of taxonomic groups in the Southern Ocean differ from elsewhere in the planet, since the biogeography in this region reflects the complex interactions of tectonics, oceanography, climate and biological elements since the Eocene. Several groups of marine benthic organisms exhibit high levels of genetic divergence...

Understanding the limits and population dynamics of closely related sibling species in the marine realm is particularly relevant in organisms that require management. The crown-of-thorns starfish Acanthaster planci, recently shown to be a species complex of at least four closely related species, is a coral predator infamous for its outbreaks that h...

NeighborNet analyses of the (a) Northern and (b) Southern Indian Ocean sister-species. The two main clades within each species are highlighted, and the central Cocos Keeling Island haplotypes in the ESIO clade are surrounded by a grey box. (PDF)

Run conditions for the Migrate analyses (Control Region dataset) for the Northern (NIO) and Southern Indian Ocean (SIO) sister-species. (PDF)

Current direction and velocity during the peak of (a) the Southwest Monsoon (January mean from 1993 to 2009) and (b) the Northeast Monsoon (July mean from 1993 to 2009). Arrow colour indicates direction of flow (westward: blue, eastward: red), arrow length and plot background colour indicate current velocity in meters per second. Data obtained from...

Areas of primary productivity higher than 130 gC/m−2. In grey; modified from Reid et al., 2006, data for 1998–99 [not an El Niño year] after NASA SeaWiFS. (PDF)

Bayesian skyline plots for the (a) Northern and (b) Southern Indian Ocean sister-species. Black lines are an estimate of effective population size as a function of time, grey lines indicate the 95% upper and lower highest posterior probability interval. (PDF)

Genetic distance ΦST/(1−ΦST) as a function of the natural logarithm of geographic distance (in km) for the (a) Northern and (b) Southern Indian Ocean sister-species. (PDF)

Run conditions for the BEAST Bayesian Skyline analysis for both the Northern and the Southern Indian Ocean sister-species. (PDF)

Sampling locations of crown-of-thorns starfish individuals. With coordinates (decimal degrees), collector or reference, number of Control Region (CR) sequences (nCR) and of Cytochrome Oxidase I (COI) sequences (nCOI) per clade and location, and EMBL accession numbers (in grey are EMBL accession numbers from Vogler et al. (2008)). Locations preceded...

Pairwise ΦST values for the (a) Northern and (b) Southern Indian Ocean sister-species. (PDF)

The Southern Ocean benthic communities are characterized by their levels of endemism and their diversity of invertebrate brooding species. Overall, biological processes acting within these species remain poorly understood despite their importance to understand impacts of ongoing global change. We take part in filling this gap by studying the geneti...

Restricted geographic distribution and low genetic diversity of the brooding sea urchin Abatus agassizii (Spatangoidea: Schizasteridae) in the South Shetland Islands: A bridgehead population before the spread to the northern Antarctic Peninsula? Distribución geográfi ca restringida y baja diversidad genética en el erizo incubante Abatus agassizii (...

Population outbreaks of the coral-eating starfish, Acanthaster planci, are hypothesized to spread to many localities in the Indo-Pacific Ocean through dispersal of planktonic larvae. To elucidate the gene flow of A. planci across the Indo-Pacific in relation to ocean currents and to test the larval dispersal hypothesis, the genetic structure among...

Acanthaster planci (L.) is one of the major threats to coral reefs, whose genetic diversity has been mainly studied with allozymes. Allozymes revealed the low genetic differentiation between A. planci populations in the Indo-Pacific area. We obtained sequences of A. planci from Kenya, Mayotte and Madagascar at the three loci cytochrome oxydase subu...