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Molecular phylogeny of Myriapoda provides insights into evolutionary patterns of the mode in post-embryonic development.

Miyazawa H, Ueda C, Yahata K, Su ZH - Sci Rep (2014)

Bottom Line: Here we report the results of phylogenetic analyses and estimations of divergence time and ancestral state of myriapods.The results revealed that Symphyla whose phylogenetic position has long been debated is the sister lineage to all other myriapods, and that the interordinal relationships within classes were consistent with traditional classifications.Ancestral state estimation based on the tree topology suggests that myriapods evolved from an ancestral state that was characterized by a hemianamorphic mode of post-embryonic development and had a relatively low number of body segments and legs.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Biological Sciences, Graduate School of Science, Osaka University, Osaka 560-0043, Japan [2] JT Biohistory Research Hall, 1-1 Murasaki-cho, Takatsuki, Osaka 569-1125, Japan.

ABSTRACT
Myriapoda, a subphylum of Arthropoda, comprises four classes, Chilopoda, Diplopoda, Pauropoda, and Symphyla. While recent molecular evidence has shown that Myriapoda is monophyletic, the internal phylogeny, which is pivotal for understanding the evolutionary history of myriapods, remains unresolved. Here we report the results of phylogenetic analyses and estimations of divergence time and ancestral state of myriapods. Phylogenetic analyses were performed based on three nuclear protein-coding genes determined from 19 myriapods representing the four classes (17 orders) and 11 outgroup species. The results revealed that Symphyla whose phylogenetic position has long been debated is the sister lineage to all other myriapods, and that the interordinal relationships within classes were consistent with traditional classifications. Ancestral state estimation based on the tree topology suggests that myriapods evolved from an ancestral state that was characterized by a hemianamorphic mode of post-embryonic development and had a relatively low number of body segments and legs.

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Estimated divergence time of myriapod clades.Blue bars across nodes indicate 95% highest posterior density of the node estimate for divergence time (refer to Supplementary Fig. S2). Red circles at nodes indicate fossil calibration points.
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f4: Estimated divergence time of myriapod clades.Blue bars across nodes indicate 95% highest posterior density of the node estimate for divergence time (refer to Supplementary Fig. S2). Red circles at nodes indicate fossil calibration points.

Mentions: Divergence time was estimated using the BEAST33 with Bayesian inference based on data for four fossils. The tree topology was the same as the ML tree shown in Fig. 3, except for the relationships between the three colobognath diplopods (Fig. 4). The 95% highest posterior density (HPD) interval data for all nodes are shown in Supplementary Fig. S3. Divergence among the four myriapod classes was estimated to have occurred during the period from the early Cambrian to the early Ordovician. Divergence of the chilopod orders appears to have occurred some time between the Devonian and the early Permian (Fig. 4). Diversification of the Diplopoda dates back to the Ordovician, whereas the most closely related orders analyzed in this study separated in the middle of the Mesozoic. Interestingly, divergence between two families of Symphyla predates the divergence between orders of diplopods and chilopods (Fig. 4).


Molecular phylogeny of Myriapoda provides insights into evolutionary patterns of the mode in post-embryonic development.

Miyazawa H, Ueda C, Yahata K, Su ZH - Sci Rep (2014)

Estimated divergence time of myriapod clades.Blue bars across nodes indicate 95% highest posterior density of the node estimate for divergence time (refer to Supplementary Fig. S2). Red circles at nodes indicate fossil calibration points.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3927213&req=5

f4: Estimated divergence time of myriapod clades.Blue bars across nodes indicate 95% highest posterior density of the node estimate for divergence time (refer to Supplementary Fig. S2). Red circles at nodes indicate fossil calibration points.
Mentions: Divergence time was estimated using the BEAST33 with Bayesian inference based on data for four fossils. The tree topology was the same as the ML tree shown in Fig. 3, except for the relationships between the three colobognath diplopods (Fig. 4). The 95% highest posterior density (HPD) interval data for all nodes are shown in Supplementary Fig. S3. Divergence among the four myriapod classes was estimated to have occurred during the period from the early Cambrian to the early Ordovician. Divergence of the chilopod orders appears to have occurred some time between the Devonian and the early Permian (Fig. 4). Diversification of the Diplopoda dates back to the Ordovician, whereas the most closely related orders analyzed in this study separated in the middle of the Mesozoic. Interestingly, divergence between two families of Symphyla predates the divergence between orders of diplopods and chilopods (Fig. 4).

Bottom Line: Here we report the results of phylogenetic analyses and estimations of divergence time and ancestral state of myriapods.The results revealed that Symphyla whose phylogenetic position has long been debated is the sister lineage to all other myriapods, and that the interordinal relationships within classes were consistent with traditional classifications.Ancestral state estimation based on the tree topology suggests that myriapods evolved from an ancestral state that was characterized by a hemianamorphic mode of post-embryonic development and had a relatively low number of body segments and legs.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Biological Sciences, Graduate School of Science, Osaka University, Osaka 560-0043, Japan [2] JT Biohistory Research Hall, 1-1 Murasaki-cho, Takatsuki, Osaka 569-1125, Japan.

ABSTRACT
Myriapoda, a subphylum of Arthropoda, comprises four classes, Chilopoda, Diplopoda, Pauropoda, and Symphyla. While recent molecular evidence has shown that Myriapoda is monophyletic, the internal phylogeny, which is pivotal for understanding the evolutionary history of myriapods, remains unresolved. Here we report the results of phylogenetic analyses and estimations of divergence time and ancestral state of myriapods. Phylogenetic analyses were performed based on three nuclear protein-coding genes determined from 19 myriapods representing the four classes (17 orders) and 11 outgroup species. The results revealed that Symphyla whose phylogenetic position has long been debated is the sister lineage to all other myriapods, and that the interordinal relationships within classes were consistent with traditional classifications. Ancestral state estimation based on the tree topology suggests that myriapods evolved from an ancestral state that was characterized by a hemianamorphic mode of post-embryonic development and had a relatively low number of body segments and legs.

Show MeSH