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A molecular palaeobiological exploration of arthropod terrestrialization.

Lozano-Fernandez J, Carton R, Tanner AR, Puttick MN, Blaxter M, Vinther J, Olesen J, Giribet G, Edgecombe GD, Pisani D - Philos. Trans. R. Soc. Lond., B, Biol. Sci. (2016)

Bottom Line: Understanding animal terrestrialization, the process through which animals colonized the land, is crucial to clarify extant biodiversity and biological adaptation.While molecular divergence times for Arachnida are consistent with the fossil record, Myriapoda are inferred to have colonized land earlier, substantially predating trace or body fossil evidence.An estimated origin of myriapods by the Early Cambrian precedes the appearance of embryophytes and perhaps even terrestrial fungi, raising the possibility that terrestrialization had independent origins in crown-group myriapod lineages, consistent with morphological arguments for convergence in tracheal systems.This article is part of the themed issue 'Dating species divergences using rocks and clocks'.

View Article: PubMed Central - PubMed

Affiliation: School of Earth Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK.

No MeSH data available.


Results of the ancestral environment reconstruction analysis indicating that the last common total-group branchiopod ancestor was most likely a marine organism. The pie charts show the scaled marginal likelihoods of ancestral states for all nodes, with the scaled likelihoods of the total-group ancestor also shown in the text. Branch lengths are proportional to time.
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RSTB20150133F3: Results of the ancestral environment reconstruction analysis indicating that the last common total-group branchiopod ancestor was most likely a marine organism. The pie charts show the scaled marginal likelihoods of ancestral states for all nodes, with the scaled likelihoods of the total-group ancestor also shown in the text. Branch lengths are proportional to time.

Mentions: Our ancestral environmental reconstructions (figure 3) aimed to clarify whether the hexapods colonized the land through a freshwater route if their sister group is Branchiopoda rather than Remipedia (figure 1). We found that the last common ancestor of the stem-group Branchiopoda most likely inhabited a marine environment (p = 0.84; figure 3). A lower, but not negligible, probability is found for an ancestral freshwater habitat (p = 0.15), whereas a brackish ancestry for the total-group Branchiopoda can be confidently rejected (p = 0.002; figure 3). Note that these results used a topology where the marine Rehbachiella was considered the sister group of the extant branchiopods. As pointed out above, some studies suggested this fossil might instead be allied to cephalocarids [45,90]. If that were the case, given the sister group relationship between cephalocarids and branchiopods suggested in these studies, then a marine origin of Branchiopoda would be inevitable, thus not changing the results of our analyses.Figure 3.


A molecular palaeobiological exploration of arthropod terrestrialization.

Lozano-Fernandez J, Carton R, Tanner AR, Puttick MN, Blaxter M, Vinther J, Olesen J, Giribet G, Edgecombe GD, Pisani D - Philos. Trans. R. Soc. Lond., B, Biol. Sci. (2016)

Results of the ancestral environment reconstruction analysis indicating that the last common total-group branchiopod ancestor was most likely a marine organism. The pie charts show the scaled marginal likelihoods of ancestral states for all nodes, with the scaled likelihoods of the total-group ancestor also shown in the text. Branch lengths are proportional to time.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4920334&req=5

RSTB20150133F3: Results of the ancestral environment reconstruction analysis indicating that the last common total-group branchiopod ancestor was most likely a marine organism. The pie charts show the scaled marginal likelihoods of ancestral states for all nodes, with the scaled likelihoods of the total-group ancestor also shown in the text. Branch lengths are proportional to time.
Mentions: Our ancestral environmental reconstructions (figure 3) aimed to clarify whether the hexapods colonized the land through a freshwater route if their sister group is Branchiopoda rather than Remipedia (figure 1). We found that the last common ancestor of the stem-group Branchiopoda most likely inhabited a marine environment (p = 0.84; figure 3). A lower, but not negligible, probability is found for an ancestral freshwater habitat (p = 0.15), whereas a brackish ancestry for the total-group Branchiopoda can be confidently rejected (p = 0.002; figure 3). Note that these results used a topology where the marine Rehbachiella was considered the sister group of the extant branchiopods. As pointed out above, some studies suggested this fossil might instead be allied to cephalocarids [45,90]. If that were the case, given the sister group relationship between cephalocarids and branchiopods suggested in these studies, then a marine origin of Branchiopoda would be inevitable, thus not changing the results of our analyses.Figure 3.

Bottom Line: Understanding animal terrestrialization, the process through which animals colonized the land, is crucial to clarify extant biodiversity and biological adaptation.While molecular divergence times for Arachnida are consistent with the fossil record, Myriapoda are inferred to have colonized land earlier, substantially predating trace or body fossil evidence.An estimated origin of myriapods by the Early Cambrian precedes the appearance of embryophytes and perhaps even terrestrial fungi, raising the possibility that terrestrialization had independent origins in crown-group myriapod lineages, consistent with morphological arguments for convergence in tracheal systems.This article is part of the themed issue 'Dating species divergences using rocks and clocks'.

View Article: PubMed Central - PubMed

Affiliation: School of Earth Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK.

No MeSH data available.