Magalie Castelin

• PhD
• Professor (Assistant) at Muséum National d'Histoire Naturelle

Due to their life cycle shared between rivers and oceans, amphidromous organisms serve as intriguing models for studying biogeography. To investigate the implications of their unique life history, we examined the population structure of the amphidromous shrimp Caridina natalensis across its known range in the South Western Indian Ocean. A total of...

The calyptraeids Crepidula adunca and Crepidula norrisiarum, both direct developers, are abundant in the shallow waters of the northeastern Pacific. They have long been considered as two allopatric species that live on different hosts and differ in body size. In this study, we rigorously test this historical hypothesis by assessing molecular taxono...

In the ancillariid genus Amalda, the shell is character rich and 96 described species are currently treated as valid. Based on shell morphology, several subspecies have been recognized within Amalda hilgendorfi, with a combined range extending at depths of 150–750 m from Japan to the South-West Pacific. A molecular analysis of 78 specimens from thr...

Based on the specimens collected during three deep-sea cruises, and deposited at the Muséum National d’Histoire Naturelle (MNHN) in Paris, we analysed the diversity of benthic communities within the EEZ of French Polynesia. The literature and the MNHN database allowed us to inventory 471 species of invertebrates, among which 169 were newly describe...

Numerous specimens of a freshwater shrimp with small eggs belonging to the Caridina nilotica complex collected in the South Western Indian Ocean were studied and compared with recent and old collection specimens genetically (16S mitochondrial analysis for recent and type specimens) and morphologically. The results revealed that, in the Indian Ocean...

The Tonnoidea is a moderately diverse group of large, predatory gastropods with ∼360 valid species. Known for their ability to secrete sulfuric acid, they use it to prey on a diversity of invertebrates, primarily echinoderms. Tonnoideans currently are classified in seven accepted families: the comparatively well known, shallow water Bursidae, Cassi...

Bursa granularis (Röding, 1798) is a tonnoidean gastropod that is regarded as broadly distributed throughout the Indo-Pacific and tropical western Atlantic. Because of its variable shell it has received no less than thirteen names, now all synonymized under the name B. granularis. We sequenced a fragment of the cox1 gene for 82 specimens covering a...

The taxonomy of the freshwater shrimps Caridina (Atyidae) is very complex and confused mostly because the morphological characters that have traditionally been used for species delimitation and identification are highly plastic. There is thus a need for an integrative approach to their taxonomy. In total, 42 specimens belonging to either Caridina b...

Macrobrachium australe is an amphidromous prawn living in the insular freshwater systems of the Indo-Pacific. Because it possesses few informative morphological characters, that often vary from one habitat to another, M. australe has produced much taxonomic confusion and has historically been described under eight synonyms. Here, 53 specimens colle...

In shelled molluscs, assigning valid species names to independent evolutionary lineages can be a difficult task. Most original descriptions are based on empty shells and the high levels of variation in shape, color and pattern in some groups can make the shell a poor proxy for species-level identification. The deep-sea gastropod turbinid genus Bolm...

Molecular genetic approaches are playing an increasing role in conservation science by identifying biodiversity that may not be evident by morphology-based taxonomy and systematics. So-called cryptic species are particularly prevalent in freshwater environments, where isolation of dispersal-limited species, such as crayfishes, within dendritic rive...

Individual Bayesian phylogenetic trees for the Pacifastacus genus on 16S, COI, and GAPDH genes.

Improving our understanding of species responses to environmental changes is an important contribution ecologists can make to facilitate effective management decisions. Novel synthetic approaches to assessing biodiversity and ecosystem integrity are needed, ideally including all species living in a community and the dynamics defining their ecologic...

The genus Profundiconus Kuroda, 1956 is reviewed. The morphological characters of shell, radular tooth and internal anatomy of species in Profundiconus are discussed. In particular we studied Profundiconus material collected by dredging in deep-water during different scientific campaigns carried out in the Solomon Islands, Madagascar, Papua New Gui...

Invasion impacts on indigenous biodiversity are poorly understood, in part because ecosystem dynamics depend on complex and often unresolved networks of interacting species. Improved understanding of these systems and the impacts of invasive species requires novel synthetic approaches to biodiversity and ecology assessments that would, ideally, cap...

Human-induced disturbances generate strong selection pressures on the ecology and evolution of species, affecting community dynamics, ecosystem functioning, and global processes. In the marine environment, the taxonomy and distribution of most organisms are poorly known. As ecologists strive to understand increasingly complex processes, involving a...

Anthropogenic disturbances have generated selection pressures on ecology and evolution of species, affecting community dynamics, ecosystem functioning and global processes. As ecologists strive to understand increasingly complex processes, involving all species potentially interacting in natural communities, the development of reliable and accessib...

Connectivity among populations determines the dynamics and evolution of populations, and its assessment is essential in ecology in general and in conservation biology in particular. The robust basis of any ecological study is the accurate delimitation of evolutionary units, such as populations, meta-populations and species. Yet a disconnect still p...

Aquatic invasive species are transported via numerous human-mediated vectors and pose a significant risk to the Canadian economy and aquatic ecosystems. Early detection of new incursions can inform rapid response or other management interventions. Next generation sequencing technologies offer great promise for the early detection of invasive specie...

Devising a reproducible approach for species delimitation of hyperdiverse groups is an ongoing challenge in evolutionary biology. Speciation processes combine modes of passive and adaptive trait divergence requiring an integrative taxonomy approach to accurately generate robust species hypotheses. However, in light of the rapid decline of diversity...

Both present-day and past processes can shape connectivity of populations. Pleistocene vicariant events and dispersal have shaped the present distribution and connectivity patterns of aquatic species in the Indo-Pacific region. In particular, the processes that have shaped distribution of amphidromous goby species still remain unknown. Previous stu...

Elephantis, new genus, is established for Caridina natalensis Bouvier, 1925 hitherto known only from South Africa with one male specimen. Recently, three surveys by electric fishing (2004, 2008 and 2010) of some eastern rivers from Madagascar have permitted to discover numerous specimens of this species. Caridina natalensis is different from all ot...

Canada has the longest coastline in the world and the potential risks posed by aquatic invasive species (AIS) to the Canadian economy and ecosystems are immense. Prevention and early detection of new invasions are critical. DNA barcoding has the potential to be used for rapid, cost-effective, and accurate identification of AIS from complex environm...

Due to the sparse and unstable nature of insular freshwater habitats, marine larval dispersal of amphidromous species is considered a critical element of population persistence. We assessed population genetic structure of freshwater prawn Macrobrachium lar across its range that encompasses two biogeographic barriers: the vast open ocean separating...

Abstract Diadromous species undergo regular migration between fresh and marine waters. This behavior is found in many species, including fish, mollusks, and crustaceans, some of which are commercially valuable species. Several attempts to trace the evolution of this behavior have been made in Salmonidae and Galaxiidae, but ambiguous phylogenies and...

Characterizing speciation processes in the sea remains a highly contentious issue because geographic barriers to gene exchange, which are the initial conditions for the allopatric speciation model, are not obvious. Moreover, many benthic marine organisms have long-lived planktonic larvae that allow them to connect distant patches of habitats. We he...

Because they house large biodiversity collections and are also research centres with sequencing facilities, natural history museums are well placed to develop DNA barcoding best practices. The main difficulty is generally the vouchering system: it must ensure that all data produced remain attached to the corresponding specimen, from the field to pu...

Connectivité et mécanismes de spéciation en milieu marin: étude comparative des gastéropodes des monts sous-marins de la ZEE de Nouvelle Calédonie Magalie Castelin ATER Thèse soutenue en 2010 sous la direction de Sarah SAMADI UMR7138, Systématique, Adaptation et Evolution Dpt Systématique et Evolution

a b s t r a c t Seamounts were often considered as 'hotspots of diversity' and 'centers of endemism', but recently this opinion has been challenged. After 25 years of exploration and the work of numerous taxonomists, the Norfolk Ridge (Southwest Pacific) is probably one of the best-studied seamount chains worldwide. However, even in this intensivel...

Seamounts were often considered as 'hotspots of diversity' and 'centers of endemism', but recently this opinion has been challenged. After 25 years of exploration and the work of numerous taxonomists, the Norfolk Ridge (Southwest Pacific) is probably one of the best-studied seamount chains worldwide. However, even in this intensively explored area,...

Seamounts chains, which offer a set of fragmented habitats, are ideally suited to study the role of larval dispersal on the population genetic structure of benthic species. For this purpose, populations of the genus Nassaria, a deep-sea gastropod, were collected on the seamounts off New Caledonia. However, the lack of taxonomic knowledge seriously...

The seamounts chain offers a set of fragmented habitats in which species with poor dispersive ability may undergo divergence in allopatry. Such a scenario may explain the endemism often described on seamounts. In gastropods, it is possible to infer the mode of development of a species from the morphology of its larval shell. Accordingly, we examine...

Marine benthic invertebrates possess a species-specific mode of larval development. Species with planktotrophic development have larvae that spend an extended period of time in the water column, and it is commonly accepted that such species have higher levels of dispersal and gene flow than species with non-planktotrophic development. Because of th...

Species distribution and speciation processes in the deep-sea remain largely unknown. It has been suggested that seamounts, which vary greatly in their faunal assemblage and display many original species, may be center of speciation. Their spatial distribution represents a fragmented habitat which may locally increase speciation rate by breaking up...

The seamounts fauna is highly diversified and most studies underlined its singularity that was interpreted as endemism. It has been suggested that the spatial distribution of seamounts represents a fragmented habitat which may locally increase speciation rate by breaking up species in small isolated populations. However, recent studies emphasize th...

Marine benthic invertebrates possess a species-specific mode of larval development. Species with planktotrophic development have larvae that spend an extended period of time in the water column, and it is commonly accepted that such species have higher levels of dispersal and gene flow than species with non-planktotrophic development. Because of th...

As the example of oceanic islands, seamounts are a living laboratory of evolution currently considered as point of high potential endemism. To explain this apparent endemism, it has been hypothesized that both geographic isolation and hydrological phenomena such as Taylor Columns, which result from the interaction between oceanic circulation and to...

Previous studies have suggested that the high diversity associated with the Norfolk seamounts (Southwest Pacific) could reflect endemism resulting from limited dispersal due to hydrological phenomena. However in the case of the seamount benthic fauna, the extent of biodiversity is not well established and taxonomy remains poorly know. Majority of s...