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Molecular evidence of cryptic speciation in planktonic foraminifers and their relation to oceanic provinces.

ABSTRACT: The fossil record of planktonic foraminifers is a key source of data on the biodiversity and evolution of marine plankton. One of the most distinctive foraminiferal taxa, Orbulina universa, widely used as a stratigraphic and paleoclimatic index, has always been regarded as a single species. Here we present a phylogenetic analysis of Orbulina small subunit rDNA sequences from 25 pelagic stations covering 100 degrees latitude in the Atlantic Ocean. The genetic data reveal the presence of three cryptic species, whose distribution is clearly correlated to hydrographic provinces, and particularly to sea-surface total chlorophyll a concentration. Our results, together with previous studies, suggest that a considerable part of the diversity among planktonic foraminifers has been overlooked in morphological taxonomies. Our data also support the idea that planktonic foraminifers, even if adapted to particular hydrographic conditions, are high-dispersal organisms whose speciation may be similar to that of other high-dispersal taxa in which reproductive mechanisms and behavior, rather than just geographic barriers to dispersal, play key roles in species formation and maintenance.

SUBMITTER: de Vargas C

PROVIDER: S-EPMC15860 | biostudies-literature | 1999 Mar

REPOSITORIES: biostudies-literature

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Molecular evidence of cryptic speciation in planktonic foraminifers and their relation to oceanic provinces.

de Vargas C C Norris R R Zaninetti L L Gibb S W SW Pawlowski J J

Proceedings of the National Academy of Sciences of the United States of America 19990301 6

The fossil record of planktonic foraminifers is a key source of data on the biodiversity and evolution of marine plankton. One of the most distinctive foraminiferal taxa, Orbulina universa, widely used as a stratigraphic and paleoclimatic index, has always been regarded as a single species. Here we present a phylogenetic analysis of Orbulina small subunit rDNA sequences from 25 pelagic stations covering 100 degrees latitude in the Atlantic Ocean. The genetic data reveal the presence of three cry ...[more]

PMID: 10077602

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Project description:Cryptic species complexes are common among parasites, which tend to have large populations and are subject to rapid evolution. Such complexes may arise through host-parasite co-evolution and/or host switching. For parasites that reproduce directly on their host, there might be increased opportunities for sympatric speciation, either by exploiting different hosts or different micro-habitats within the same host. The genus Gyrodactylus is a specious group of viviparous monogeneans. These ectoparasites transfer between teleosts during social contact and cause significant host mortality. Their impact on the guppy (Poecilia reticulata), an iconic evolutionary and ecological model species, is well established and yet the population genetics and phylogenetics of these parasites remains understudied. Using mtDNA sequencing of the host and its parasites, we provide evidence of cryptic speciation in Gyrodactylus bullatarudis, G. poeciliae and G. turnbulli. For the COII gene, genetic divergence of lineages within each parasite species ranged between 5.7 and 17.2%, which is typical of the divergence observed between described species in this genus. Different lineages of G. turnbulli and G. poeciliae appear geographically isolated, which could imply allopatric speciation. In addition, for G. poeciliae, co-evolution with a different host species cannot be discarded due to its host range. This parasite was originally described on P. caucana, but for the first time here it is also recorded on the guppy. The two cryptic lineages of G. bullatarudis showed considerable geographic overlap. G. bullatarudis has a known wide host range and it can also utilize a killifish (Anablepsoides hartii) as a temporary host. This killifish is capable of migrating overland and it could act as a transmission vector between otherwise isolated populations. Additional genetic markers are needed to confirm the presence of these cryptic Gyrodactylus species complexes, potentially leading to more in-depth genetic, ecological and evolutionary analyses on this multi-host-parasite system.

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Dataset Information

Molecular evidence of cryptic speciation in planktonic foraminifers and their relation to oceanic provinces.

Publications

Molecular evidence of cryptic speciation in planktonic foraminifers and their relation to oceanic provinces.

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