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Molecular perspective on the American transisthmian species of Macrobrachium (Caridea, Palaemonidae).

Pileggi LG, Rossi N, Wehrtmann IS, Mantelatto FL - Zookeys (2014)

Bottom Line: This relatively recent event was a trigger to diversification of various species in the Neotropics, nonetheless there are exemplars that do not show sufficient morphologic variability to separate them by traditional morphological tools.Our analysis corroborated the morphological proximity of the sibling species.Despite the high degree of morphological similarities and considerable genetic diversification encountered among the transisthmian sister species, our data support the conclusion that all species included in sibling groups studied herein are valid taxonomic entities, but not all pairs of siblings form natural groups.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratory of Bioecology and Crustacean Systematics (LBSC), Faculty of Philosophy, Science and Letters at Ribeirão Preto (FFCLRP), University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil.

ABSTRACT
The closure of the Isthmus of Panama (about 3.1 million years ago) separated previously continuous populations and created two groups of extant species, which live now in the Pacific and Atlantic drainage systems. This relatively recent event was a trigger to diversification of various species in the Neotropics, nonetheless there are exemplars that do not show sufficient morphologic variability to separate them by traditional morphological tools. About 60 years ago, some freshwater decapod species with high morphological similarity were separate by previous researchers, based on geographical distribution, in Pacific and Atlantic and considered as "sister species". However, the complete isolation of these prawns by this geographical barrier is questionable, and it has generated doubts about the status of the following transisthmian pairs of sibling species: Macrobrachiumoccidentale × Macrobrachiumheterochirus, Macrobrachiumamericanum × Macrobrachiumcarcinus, Macrobrachiumdigueti × Macrobrachiumolfersii, Macrobrachiumhancocki × Macrobrachiumcrenulatum, Macrobrachiumtenellum × Macrobrachiumacanthurus and Macrobrachiumpanamense × Macrobrachiumamazonicum. Here we evaluated the relation among these pairs of sibling species in a molecular phylogenetic context. We generated 95 new sequences: 26 sequences of 16S rDNA, 25 of COI mtDNA and 44 of 18S nDNA. In total, 181 sequences were analyzed by maximum likelihood phylogenetic method, including 12 Macrobrachium transisthmian species, as well as seven other American Macrobrachium species, and two other palaemonids. Our analysis corroborated the morphological proximity of the sibling species. Despite the high degree of morphological similarities and considerable genetic diversification encountered among the transisthmian sister species, our data support the conclusion that all species included in sibling groups studied herein are valid taxonomic entities, but not all pairs of siblings form natural groups.

No MeSH data available.


Phylogenetic tree obtained from concatenated maximum likelihood analysis of 16S, COI and 18S sequences for Macrobrachium sibling species. Numbers are significance values for 1000 bootstraps; values ≤ 50% are not shown. Abbreviations: ARG: Argentina; BR: Brazil; CH: Chile; CR: Costa Rica; MX: Mexico; PN: Panama; VZ: Venezuela. A: lateral view of the rostrum of Macrobrachiumamazonicum; B: lateral view of the rostrum of Macrobrachiumolfersii. C: lateral view of the rostrum of Macrobrachiumcarcinus.
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Figure 1: Phylogenetic tree obtained from concatenated maximum likelihood analysis of 16S, COI and 18S sequences for Macrobrachium sibling species. Numbers are significance values for 1000 bootstraps; values ≤ 50% are not shown. Abbreviations: ARG: Argentina; BR: Brazil; CH: Chile; CR: Costa Rica; MX: Mexico; PN: Panama; VZ: Venezuela. A: lateral view of the rostrum of Macrobrachiumamazonicum; B: lateral view of the rostrum of Macrobrachiumolfersii. C: lateral view of the rostrum of Macrobrachiumcarcinus.

Mentions: The topology obtained by maximum likelihood from concatenated genes (16S, 18S and COI) analyses confirmed that the transisthmian sibling species (Macrobrachiumheterochirus × Macrobrachiumoccidentale – Sibling 1, Macrobrachiumcarcinus × Macrobrachiumamericanum – Sibling 2, Macrobrachiumolfersii × Macrobrachiumdigueti – Sibling 3, Macrobrachiumcrenulatum × Macrobrachiumhancocki – Sibling 4, and Macrobrachiumacanthurus × Macrobrachiumtenellum – Sibling 5) are closely related by well-supported clades (Fig. 1). Sibling 6 (Macrobrachiumamazonicum × Macrobrachiumpanamense) did not form a separate sister clade despite being phylogenetically close. The position of Palaemonetesargentinus showed a stable condition in an external branch. However, the other outgroup (Cryphiopscaementarius) was maintained within the Macrobrachium clade in the phylogeny (Fig. 1). The results did not reveal geographical separation among populations of the same species inside each group (Siblings 1–5). Macrobrachiummichoacanus (see the arrow in the phylogeny) seems to be close related to Macrobrachiumhancocki in Sibling 4 group.


Molecular perspective on the American transisthmian species of Macrobrachium (Caridea, Palaemonidae).

Pileggi LG, Rossi N, Wehrtmann IS, Mantelatto FL - Zookeys (2014)

Phylogenetic tree obtained from concatenated maximum likelihood analysis of 16S, COI and 18S sequences for Macrobrachium sibling species. Numbers are significance values for 1000 bootstraps; values ≤ 50% are not shown. Abbreviations: ARG: Argentina; BR: Brazil; CH: Chile; CR: Costa Rica; MX: Mexico; PN: Panama; VZ: Venezuela. A: lateral view of the rostrum of Macrobrachiumamazonicum; B: lateral view of the rostrum of Macrobrachiumolfersii. C: lateral view of the rostrum of Macrobrachiumcarcinus.
© Copyright Policy - creative-commons-attribution
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4283367&req=5

Figure 1: Phylogenetic tree obtained from concatenated maximum likelihood analysis of 16S, COI and 18S sequences for Macrobrachium sibling species. Numbers are significance values for 1000 bootstraps; values ≤ 50% are not shown. Abbreviations: ARG: Argentina; BR: Brazil; CH: Chile; CR: Costa Rica; MX: Mexico; PN: Panama; VZ: Venezuela. A: lateral view of the rostrum of Macrobrachiumamazonicum; B: lateral view of the rostrum of Macrobrachiumolfersii. C: lateral view of the rostrum of Macrobrachiumcarcinus.
Mentions: The topology obtained by maximum likelihood from concatenated genes (16S, 18S and COI) analyses confirmed that the transisthmian sibling species (Macrobrachiumheterochirus × Macrobrachiumoccidentale – Sibling 1, Macrobrachiumcarcinus × Macrobrachiumamericanum – Sibling 2, Macrobrachiumolfersii × Macrobrachiumdigueti – Sibling 3, Macrobrachiumcrenulatum × Macrobrachiumhancocki – Sibling 4, and Macrobrachiumacanthurus × Macrobrachiumtenellum – Sibling 5) are closely related by well-supported clades (Fig. 1). Sibling 6 (Macrobrachiumamazonicum × Macrobrachiumpanamense) did not form a separate sister clade despite being phylogenetically close. The position of Palaemonetesargentinus showed a stable condition in an external branch. However, the other outgroup (Cryphiopscaementarius) was maintained within the Macrobrachium clade in the phylogeny (Fig. 1). The results did not reveal geographical separation among populations of the same species inside each group (Siblings 1–5). Macrobrachiummichoacanus (see the arrow in the phylogeny) seems to be close related to Macrobrachiumhancocki in Sibling 4 group.

Bottom Line: This relatively recent event was a trigger to diversification of various species in the Neotropics, nonetheless there are exemplars that do not show sufficient morphologic variability to separate them by traditional morphological tools.Our analysis corroborated the morphological proximity of the sibling species.Despite the high degree of morphological similarities and considerable genetic diversification encountered among the transisthmian sister species, our data support the conclusion that all species included in sibling groups studied herein are valid taxonomic entities, but not all pairs of siblings form natural groups.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratory of Bioecology and Crustacean Systematics (LBSC), Faculty of Philosophy, Science and Letters at Ribeirão Preto (FFCLRP), University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil.

ABSTRACT
The closure of the Isthmus of Panama (about 3.1 million years ago) separated previously continuous populations and created two groups of extant species, which live now in the Pacific and Atlantic drainage systems. This relatively recent event was a trigger to diversification of various species in the Neotropics, nonetheless there are exemplars that do not show sufficient morphologic variability to separate them by traditional morphological tools. About 60 years ago, some freshwater decapod species with high morphological similarity were separate by previous researchers, based on geographical distribution, in Pacific and Atlantic and considered as "sister species". However, the complete isolation of these prawns by this geographical barrier is questionable, and it has generated doubts about the status of the following transisthmian pairs of sibling species: Macrobrachiumoccidentale × Macrobrachiumheterochirus, Macrobrachiumamericanum × Macrobrachiumcarcinus, Macrobrachiumdigueti × Macrobrachiumolfersii, Macrobrachiumhancocki × Macrobrachiumcrenulatum, Macrobrachiumtenellum × Macrobrachiumacanthurus and Macrobrachiumpanamense × Macrobrachiumamazonicum. Here we evaluated the relation among these pairs of sibling species in a molecular phylogenetic context. We generated 95 new sequences: 26 sequences of 16S rDNA, 25 of COI mtDNA and 44 of 18S nDNA. In total, 181 sequences were analyzed by maximum likelihood phylogenetic method, including 12 Macrobrachium transisthmian species, as well as seven other American Macrobrachium species, and two other palaemonids. Our analysis corroborated the morphological proximity of the sibling species. Despite the high degree of morphological similarities and considerable genetic diversification encountered among the transisthmian sister species, our data support the conclusion that all species included in sibling groups studied herein are valid taxonomic entities, but not all pairs of siblings form natural groups.

No MeSH data available.