@ARTICLE{TreeBASE2Ref18587,
author = {Lucas Leclere and Peter Schuchert and Corinne Cruaud and Arnaud Couloux and Micha?l Manuel},
title = {Molecular Phylogenetics of Thecata (Hydrozoa, Cnidaria) Reveals Long-Term Maintenance of Life History Traits Despite High Frequency of Recent Character Changes},
year = {2009},
keywords = {},
doi = {10.1093/sysbio/syp044},
url = {},
pmid = {},
journal = {Systematic Biology},
volume = {58},
number = {5},
pages = {509--526},
abstract = {Two fundamental life cycle types are recognized among hydrozoan cnidarians, the benthic (generally colonial) polyp stage either producing pelagic sexual medusae or directly releasing gametes elaborated from an attached gonophore. The existence of intermediate forms, with polyps producing simple medusoids, has been classically considered compelling evidence in favor of phyletic gradualism. In order to gain insights about the evolution of hydrozoan life history traits, we inferred phylogenetic relationships of 142 species of Thecata (= Leptothecata, Leptomedusae), the most species-rich hydrozoan group, using three different rRNA markers (16S, 18S, 28S). In conflict with morphology-derived classifications, most thecate species fell in two well-supported clades named here Statocysta and Macrocolonia. We inferred many independent medusa losses among Statocysta. Several instances of secondary regain of medusoids (but not of full medusa) from medusa-less ancestors were supported among Macrocolonia. Furthermore, life cycle character changes were significantly correlated with changes affecting colony shape. For both traits, changes did not reflect graded and progressive loss or gain of complexity, they were concentrated in recent branches, with intermediate character states being most probably relatively short-lived at a large evolutionary scale. This punctuational pattern supports the existence of two alternative stable evolutionary strategies: simple stolonal colonies with medusae (the ancestral strategy, seen in most Statocysta species) vs. large complex colonies with fixed gonophores (the derived strategy, seen in most Macrocolonia species). Hypotheses of species selection are proposed to explain the apparent long-term stability of these life history traits despite a high frequency of character change. Notably, maintenance of the medusa across geological time in Statocysta might be due to higher extinction rates for species that have lost this dispersive stage.}
}
Citation for Study 10096
Citation title:
"Molecular Phylogenetics of Thecata (Hydrozoa, Cnidaria) Reveals Long-Term Maintenance of Life History Traits Despite High Frequency of Recent Character Changes".
This study was previously identified under the legacy study ID S2436
(Status: Published).
Citation
Leclere L., Schuchert P., Cruaud C., Couloux A., & Manuel M. 2009. Molecular Phylogenetics of Thecata (Hydrozoa, Cnidaria) Reveals Long-Term Maintenance of Life History Traits Despite High Frequency of Recent Character Changes. Systematic Biology, 58(5): 509-526.
Authors
-
Leclere L.
-
Schuchert P.
-
Cruaud C.
-
Couloux A.
-
Manuel M.
Abstract
Two fundamental life cycle types are recognized among hydrozoan cnidarians, the benthic (generally colonial) polyp stage either producing pelagic sexual medusae or directly releasing gametes elaborated from an attached gonophore. The existence of intermediate forms, with polyps producing simple medusoids, has been classically considered compelling evidence in favor of phyletic gradualism. In order to gain insights about the evolution of hydrozoan life history traits, we inferred phylogenetic relationships of 142 species of Thecata (= Leptothecata, Leptomedusae), the most species-rich hydrozoan group, using three different rRNA markers (16S, 18S, 28S). In conflict with morphology-derived classifications, most thecate species fell in two well-supported clades named here Statocysta and Macrocolonia. We inferred many independent medusa losses among Statocysta. Several instances of secondary regain of medusoids (but not of full medusa) from medusa-less ancestors were supported among Macrocolonia. Furthermore, life cycle character changes were significantly correlated with changes affecting colony shape. For both traits, changes did not reflect graded and progressive loss or gain of complexity, they were concentrated in recent branches, with intermediate character states being most probably relatively short-lived at a large evolutionary scale. This punctuational pattern supports the existence of two alternative stable evolutionary strategies: simple stolonal colonies with medusae (the ancestral strategy, seen in most Statocysta species) vs. large complex colonies with fixed gonophores (the derived strategy, seen in most Macrocolonia species). Hypotheses of species selection are proposed to explain the apparent long-term stability of these life history traits despite a high frequency of character change. Notably, maintenance of the medusa across geological time in Statocysta might be due to higher extinction rates for species that have lost this dispersive stage.
External links
About this resource
- Canonical resource URI:
http://purl.org/phylo/treebase/phylows/study/TB2:S10096
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@ARTICLE{TreeBASE2Ref18587,
author = {Lucas Leclere and Peter Schuchert and Corinne Cruaud and Arnaud Couloux and Micha?l Manuel},
title = {Molecular Phylogenetics of Thecata (Hydrozoa, Cnidaria) Reveals Long-Term Maintenance of Life History Traits Despite High Frequency of Recent Character Changes},
year = {2009},
keywords = {},
doi = {10.1093/sysbio/syp044},
url = {},
pmid = {},
journal = {Systematic Biology},
volume = {58},
number = {5},
pages = {509--526},
abstract = {Two fundamental life cycle types are recognized among hydrozoan cnidarians, the benthic (generally colonial) polyp stage either producing pelagic sexual medusae or directly releasing gametes elaborated from an attached gonophore. The existence of intermediate forms, with polyps producing simple medusoids, has been classically considered compelling evidence in favor of phyletic gradualism. In order to gain insights about the evolution of hydrozoan life history traits, we inferred phylogenetic relationships of 142 species of Thecata (= Leptothecata, Leptomedusae), the most species-rich hydrozoan group, using three different rRNA markers (16S, 18S, 28S). In conflict with morphology-derived classifications, most thecate species fell in two well-supported clades named here Statocysta and Macrocolonia. We inferred many independent medusa losses among Statocysta. Several instances of secondary regain of medusoids (but not of full medusa) from medusa-less ancestors were supported among Macrocolonia. Furthermore, life cycle character changes were significantly correlated with changes affecting colony shape. For both traits, changes did not reflect graded and progressive loss or gain of complexity, they were concentrated in recent branches, with intermediate character states being most probably relatively short-lived at a large evolutionary scale. This punctuational pattern supports the existence of two alternative stable evolutionary strategies: simple stolonal colonies with medusae (the ancestral strategy, seen in most Statocysta species) vs. large complex colonies with fixed gonophores (the derived strategy, seen in most Macrocolonia species). Hypotheses of species selection are proposed to explain the apparent long-term stability of these life history traits despite a high frequency of character change. Notably, maintenance of the medusa across geological time in Statocysta might be due to higher extinction rates for species that have lost this dispersive stage.}
}
- Show RIS reference
TY - JOUR
ID - 18587
AU - Leclere,Lucas
AU - Schuchert,Peter
AU - Cruaud,Corinne
AU - Couloux,Arnaud
AU - Manuel,Micha?l
T1 - Molecular Phylogenetics of Thecata (Hydrozoa, Cnidaria) Reveals Long-Term Maintenance of Life History Traits Despite High Frequency of Recent Character Changes
PY - 2009
UR - http://dx.doi.org/10.1093/sysbio/syp044
N2 - Two fundamental life cycle types are recognized among hydrozoan cnidarians, the benthic (generally colonial) polyp stage either producing pelagic sexual medusae or directly releasing gametes elaborated from an attached gonophore. The existence of intermediate forms, with polyps producing simple medusoids, has been classically considered compelling evidence in favor of phyletic gradualism. In order to gain insights about the evolution of hydrozoan life history traits, we inferred phylogenetic relationships of 142 species of Thecata (= Leptothecata, Leptomedusae), the most species-rich hydrozoan group, using three different rRNA markers (16S, 18S, 28S). In conflict with morphology-derived classifications, most thecate species fell in two well-supported clades named here Statocysta and Macrocolonia. We inferred many independent medusa losses among Statocysta. Several instances of secondary regain of medusoids (but not of full medusa) from medusa-less ancestors were supported among Macrocolonia. Furthermore, life cycle character changes were significantly correlated with changes affecting colony shape. For both traits, changes did not reflect graded and progressive loss or gain of complexity, they were concentrated in recent branches, with intermediate character states being most probably relatively short-lived at a large evolutionary scale. This punctuational pattern supports the existence of two alternative stable evolutionary strategies: simple stolonal colonies with medusae (the ancestral strategy, seen in most Statocysta species) vs. large complex colonies with fixed gonophores (the derived strategy, seen in most Macrocolonia species). Hypotheses of species selection are proposed to explain the apparent long-term stability of these life history traits despite a high frequency of character change. Notably, maintenance of the medusa across geological time in Statocysta might be due to higher extinction rates for species that have lost this dispersive stage.
L3 - 10.1093/sysbio/syp044
JF - Systematic Biology
VL - 58
IS - 5
SP - 509
EP - 526
ER -