@ARTICLE{TreeBASE2Ref19163,
author = {Katharina Maria J?rger and Isabella St?ger and Yasunori Kano and Hiroshi Fukuda and Thomas Knebelsberger and Michael Schr?dl},
title = {On the origin of Acochlidia and other enigmatic euthyneuran gastropods, with implications for the systematics of Heterobranchia},
year = {2010},
keywords = {phylogeny, Euthyneura, Gastropoda, Aitengidae},
doi = {10.1186/1471-2148-10-323},
url = {http://},
pmid = {},
journal = {BMC Evolutionary Biology},
volume = {10},
number = {},
pages = {323},
abstract = {Background
A robust phylogenetic hypothesis of euthyneuran gastropods, as a basis to reconstructing their
evolutionary history, is still hindered by several groups of aberrant, more or less worm-like
slugs with unclear phylogenetic relationships. As a traditional ?order? in the Opisthobranchia,
the Acochlidia have a long history of controversial placements, among others influenced by
convergent adaptation to the mainly meiofaunal habitats. The present study includes six out of
seven acochlidian families in a comprehensive euthyneuran taxon sampling with special focus
on minute, aberrant slugs. Since there is no fossil record of tiny, shell-less gastropods, a
molecular clock was used to estimate divergence times within Euthyneura.
Results
Our multi-locus molecular study confirms Acochlidia in a pulmonate relationship, as sister to
Eupulmonata. Previous hypotheses of opisthobranch relations, or of a common origin with
other meiofaunal Euthyneura, are clearly rejected. The enigmatic amphibious and
insectivorous Aitengidae incerta sedis clusters within Acochlidia, as sister to meiofaunal and
brackish Pseudunelidae and limnic Acochlidiidae. Euthyneura, Opisthobranchia and
Pulmonata as traditionally defined are non-monophyletic. A relaxed molecular clock approach
indicates a late Paleozoic diversification of Euthyneura and a Mesozoic origin of the major
euthyneuran diversity, including Acochlidia.
Conclusions
The present study shows that the inclusion of small, enigmatic groups is necessary to solve
deep-level phylogenetic relationships, and underlines that ?pulmonate? and ?opisthobranch?
phylogeny, respectively, cannot be solved independently from each other. Our phylogenetic
hypothesis requires reinvestigation of the traditional classification of Euthyneura:
morphological synapomorphies of the traditionally defined Pulmonata and Opisthobranchia
are evaluated in light of the presented phylogeny, and a redefinition of major groups is
- 3 -
proposed. It is demonstrated that the invasion of the meiofaunal habitat has occurred several
times independently in various euthyneuran taxa, leading to convergent adaptations
previously misinterpreted as synapomorphies. The inclusion of Acochlidia extends the
structural and biological diversity in pulmonates, presenting a remarkable flexibility
concerning habitat choice.}
}
Matrices for Study 10811
Citation title: "On the origin of Acochlidia and other enigmatic euthyneuran gastropods, with implications for the systematics of Heterobranchia".
Study name: "On the origin of Acochlidia and other enigmatic euthyneuran gastropods, with implications for the systematics of Heterobranchia".
This study is part of submission 10801
(Status: Published).
Matrices
ID | Matrix Title | Description | Data type | NTAX | NCHAR | Taxa | ||||
---|---|---|---|---|---|---|---|---|---|---|
M767 | Hirsutella uncinata, ITS | Legacy TreeBASE Matrix ID = M1696 | Nucleic Acid | 16 | 570 | View Taxa |