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The more we search, the more we find: discovery of a new lineage and a new species complex in the genus Asparagopsis.

Dijoux L, Viard F, Payri C - PLoS ONE (2014)

Bottom Line: This clade was found only in Western Australia, Tasmania and New Zealand, and is thus restricted to a subregional biogeographic unit.These results illustrate the difficulty in accurately defining cosmopolitan species.Our findings also highlight the need for targeted (i.e., in poorly studied areas) and geographically extensive sampling efforts when studying taxa that have been introduced globally and that are likely to hide species complexes.

View Article: PubMed Central - PubMed

Affiliation: Institut de Recherche pour le Développement (IRD), UR227 CoRéUs-LabEx-CORAIL, Noumea, New Caledonia; Sorbonne Universités, Université Pierre et Marie Curie (UPMC) Univ Paris 06, UMR 7144, Station Biologique de Roscoff, Roscoff, France; Centre National de la Recherche Scientifique (CNRS), UMR 7144, Divco team, Station Biologique de Roscoff, Roscoff, France.

ABSTRACT
In the past few decades, in the marine realm in particular, the use of molecular tools has led to the discovery of hidden taxonomic diversity, revealing complexes of sister species. A good example is the red algal genus Asparagopsis. The two species (A. armata and A. taxiformis) recognized in this genus have been introduced in many places around the world. Within the nominal species A. taxiformis, previous molecular analyses have uncovered several lineages, suggesting the existence of sister species or subspecies. Although the genus has been well studied in some regions (e.g., the Mediterranean Sea and Hawaii), it remains poorly investigated in others (e.g., South Pacific). Our study mainly focused on these latter areas to clarify lineages and better determine lineage status (i.e., native vs. introduced). A total of 188 specimens were collected from 61 sites, 58 of which had never been sampled before. We sequenced the DNA from samples for three markers and obtained 112 sequences for the chloroplastic RuBisCo spacer, 118 sequences for the nuclear LSU rRNA gene, and 174 for the mitochondrial spacer cox2-3. Phylogenetic analyses using all three markers suggested the existence of two cryptic sister species with the discovery of a new clade within A. armata. This clade was found only in Western Australia, Tasmania and New Zealand, and is thus restricted to a subregional biogeographic unit. We also discovered a new, fifth lineage for A. taxiformis restricted to the South Pacific and Western Australia. Except for this newly described lineage, all other lineages showed a global distribution influenced by introduction events. These results illustrate the difficulty in accurately defining cosmopolitan species. Our findings also highlight the need for targeted (i.e., in poorly studied areas) and geographically extensive sampling efforts when studying taxa that have been introduced globally and that are likely to hide species complexes.

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Present-day reported distribution of the currently recognized species (A) A. armata (A) and (B) A. taxiformis.Black symbols stand for morphological identification alone. Colored symbols are used to indicate different mitochondrial molecular lineages when known. Blank triangles report bibliographic data and filled circles indicate data obtained from the present study [3], [13].
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pone-0103826-g001: Present-day reported distribution of the currently recognized species (A) A. armata (A) and (B) A. taxiformis.Black symbols stand for morphological identification alone. Colored symbols are used to indicate different mitochondrial molecular lineages when known. Blank triangles report bibliographic data and filled circles indicate data obtained from the present study [3], [13].

Mentions: Figures 1a and 1b depict present-day reports of the taxa described as A. taxiformis and A. armata. Some of these reports are not associated with taxonomic studies and misidentification between the two taxa may have occurred. Despite existing inventories and previous detailed studies (Figure 1, see Table S1 for details and references), only a limited amount of molecular data is available. Data tend to be restricted to some regions with very little information on the Indo-Pacific region, even though this region has been recognized as a likely diversification center [38]–[40]. The maps in Figure 1 show that some areas were overlooked. In particular, in New Caledonia only one individual has been sampled in the Southwest lagoon (2002, Passe Mato). Also, in a number of cases, reports from the Indo-Pacific are not associated with molecular identification, so that doubts persist as to the taxa and lineages currently present in the area. For example, Catala reported in 1950 the presence of A. armata in New Caledonia based on Valerie May's identification [41], but in the absence of herbarium vouchers, this identification cannot be confirmed. Likewise, in the southwestern Indian Ocean where A. taxiformis has been reported [22], morphological or molecular data are lacking.


The more we search, the more we find: discovery of a new lineage and a new species complex in the genus Asparagopsis.

Dijoux L, Viard F, Payri C - PLoS ONE (2014)

Present-day reported distribution of the currently recognized species (A) A. armata (A) and (B) A. taxiformis.Black symbols stand for morphological identification alone. Colored symbols are used to indicate different mitochondrial molecular lineages when known. Blank triangles report bibliographic data and filled circles indicate data obtained from the present study [3], [13].
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4116237&req=5

pone-0103826-g001: Present-day reported distribution of the currently recognized species (A) A. armata (A) and (B) A. taxiformis.Black symbols stand for morphological identification alone. Colored symbols are used to indicate different mitochondrial molecular lineages when known. Blank triangles report bibliographic data and filled circles indicate data obtained from the present study [3], [13].
Mentions: Figures 1a and 1b depict present-day reports of the taxa described as A. taxiformis and A. armata. Some of these reports are not associated with taxonomic studies and misidentification between the two taxa may have occurred. Despite existing inventories and previous detailed studies (Figure 1, see Table S1 for details and references), only a limited amount of molecular data is available. Data tend to be restricted to some regions with very little information on the Indo-Pacific region, even though this region has been recognized as a likely diversification center [38]–[40]. The maps in Figure 1 show that some areas were overlooked. In particular, in New Caledonia only one individual has been sampled in the Southwest lagoon (2002, Passe Mato). Also, in a number of cases, reports from the Indo-Pacific are not associated with molecular identification, so that doubts persist as to the taxa and lineages currently present in the area. For example, Catala reported in 1950 the presence of A. armata in New Caledonia based on Valerie May's identification [41], but in the absence of herbarium vouchers, this identification cannot be confirmed. Likewise, in the southwestern Indian Ocean where A. taxiformis has been reported [22], morphological or molecular data are lacking.

Bottom Line: This clade was found only in Western Australia, Tasmania and New Zealand, and is thus restricted to a subregional biogeographic unit.These results illustrate the difficulty in accurately defining cosmopolitan species.Our findings also highlight the need for targeted (i.e., in poorly studied areas) and geographically extensive sampling efforts when studying taxa that have been introduced globally and that are likely to hide species complexes.

View Article: PubMed Central - PubMed

Affiliation: Institut de Recherche pour le Développement (IRD), UR227 CoRéUs-LabEx-CORAIL, Noumea, New Caledonia; Sorbonne Universités, Université Pierre et Marie Curie (UPMC) Univ Paris 06, UMR 7144, Station Biologique de Roscoff, Roscoff, France; Centre National de la Recherche Scientifique (CNRS), UMR 7144, Divco team, Station Biologique de Roscoff, Roscoff, France.

ABSTRACT
In the past few decades, in the marine realm in particular, the use of molecular tools has led to the discovery of hidden taxonomic diversity, revealing complexes of sister species. A good example is the red algal genus Asparagopsis. The two species (A. armata and A. taxiformis) recognized in this genus have been introduced in many places around the world. Within the nominal species A. taxiformis, previous molecular analyses have uncovered several lineages, suggesting the existence of sister species or subspecies. Although the genus has been well studied in some regions (e.g., the Mediterranean Sea and Hawaii), it remains poorly investigated in others (e.g., South Pacific). Our study mainly focused on these latter areas to clarify lineages and better determine lineage status (i.e., native vs. introduced). A total of 188 specimens were collected from 61 sites, 58 of which had never been sampled before. We sequenced the DNA from samples for three markers and obtained 112 sequences for the chloroplastic RuBisCo spacer, 118 sequences for the nuclear LSU rRNA gene, and 174 for the mitochondrial spacer cox2-3. Phylogenetic analyses using all three markers suggested the existence of two cryptic sister species with the discovery of a new clade within A. armata. This clade was found only in Western Australia, Tasmania and New Zealand, and is thus restricted to a subregional biogeographic unit. We also discovered a new, fifth lineage for A. taxiformis restricted to the South Pacific and Western Australia. Except for this newly described lineage, all other lineages showed a global distribution influenced by introduction events. These results illustrate the difficulty in accurately defining cosmopolitan species. Our findings also highlight the need for targeted (i.e., in poorly studied areas) and geographically extensive sampling efforts when studying taxa that have been introduced globally and that are likely to hide species complexes.

Show MeSH