@article {1982, title = {Evolutionary biogeography of the centipede genus Ethmostigmus from Peninsular India: testing an ancient vicariance hypothesis for Old World tropical diversity}, journal = {BMC Evolutionary Biology}, volume = {19}, year = {2019}, month = {14/02/2019}, pages = {1-10}, abstract = {

Background: Understanding the relative influence of vicariance and dispersal in shaping Old World tropical biodiversity remains a challenge. We aimed to infer the roles of these alternative biogeographic processes using a species time-tree for the centipede genus Ethmostigmus from the Old World tropics. Additionally, we explored fine-scale biogeographic patterns for an endemic radiation of Ethmostigmus from the peninsular Indian Plate (PIP), an area with complex geological and climatic history.

Results: Divergence time estimates suggest that Ethmostigmus began diversifying in the Late Cretaceous, 99 (\± 25) million years ago (Ma), its early biogeographic history shaped by vicariance. Members of Ethmostigmus in PIP form a monophyletic group that underwent endemic radiation in the Late Cretaceous, 72 (\± 25) Ma. In contrast, a new species of Ethmostigmus from north-east India formed a clade with African/Australian species. Fine-scale biogeographic analyses in PIP predict that Indian Ethmostigmus had an ancestor in southern-central parts of the Western Ghats. This was followed by four independent dispersal events from the southern-central Western Ghats to the Eastern Ghats, and between different parts of the Western Ghats in the Cenozoic.

Conclusions: Our results are consistent with Gondwanan break-up driving the early evolutionary history of the genus Ethmostigmus. Multiple dispersal events coinciding with geo-climatic events throughout the Cenozoic shaped diversification in PIP. Ethmostigmus species in PIP are restricted to wet forests and have retained that niche throughout their diversification.

Publication date remarks: The article was first published on 01/02/2019. The chosen publication date in Myriatrix is 14/02/2019, when a correction was issued and the original article updated.

}, keywords = {Gondwana biogeography, Palaeoclimate, Scolopendridae, Western and eastern Ghats}, issn = {1471-2148}, doi = {https://doi.org/10.1186/s12862-019-1367-6}, url = {https://bmcecolevol.biomedcentral.com/articles/10.1186/s12862-019-1367-6}, author = {Joshi, Jahnavi and Edgecombe, Gregory D.} } @article {1395, title = {Ancestral morphology of Ecdysozoa constrained by an early Cambrian stem group ecdysozoan}, journal = {BMC Evolutionary Biology}, volume = {20}, year = {2020}, month = {23/11/2020}, pages = {1-18}, type = {Research article}, abstract = {

Background: Ecdysozoa are the moulting protostomes, including arthropods, tardigrades, and nematodes. Both the molecular and fossil records indicate that Ecdysozoa is an ancient group originating in the terminal Proterozoic, and exceptional fossil biotas show their dominance and diversity at the beginning of the Phanerozoic. However, the nature of the ecdysozoan common ancestor has been difficult to ascertain due to the extreme morphological diversity of extant Ecdysozoa, and the lack of early diverging taxa in ancient fossil biotas.

Results: Here we re-describe Acosmia maotiania from the early Cambrian Chengjiang Biota of Yunnan Province, China and assign it to stem group Ecdysozoa. Acosmia features a two-part body, with an anterior proboscis bearing a terminal mouth and muscular pharynx, and a posterior annulated trunk with a through gut. Morphological phylogenetic analyses of the protostomes using parsimony, maximum likelihood and Bayesian inference, with coding informed by published experimental decay studies, each placed Acosmia as sister taxon to Cycloneuralia\ +\ Panarthropoda\—i.e. stem group Ecdysozoa. Ancestral state probabilities were calculated for key ecdysozoan nodes, in order to test characters inferred from fossils to be ancestral for Ecdysozoa. Results support an ancestor of crown group ecdysozoans sharing an annulated vermiform body with a terminal mouth like Acosmia, but also possessing the pharyngeal armature and circumoral structures characteristic of Cambrian cycloneuralians and lobopodians.

Conclusions: Acosmia is the first taxon placed in the ecdysozoan stem group and provides a constraint to test hypotheses on the early evolution of Ecdysozoa. Our study suggests acquisition of pharyngeal armature, and therefore a change in feeding strategy (e.g. predation), may have characterised the origin and radiation of crown group ecdysozoans from Acosmia-like ancestors.

}, keywords = {Cambrian, Cycloneuralia, Ecdysozoa, Palaeobiology, Panarthropoda, Phylogenetics}, issn = {1471-2148}, doi = {https://doi.org/10.1186/s12862-020-01720-6}, url = {https://bmcecolevol.biomedcentral.com/articles/10.1186/s12862-020-01720-6}, author = {Howard, Richard J. and Edgecombe, Gregory D. and Shi, Xiaomei and Hou, Xianguang and Ma, Xiaoya} } @article {419, title = {Four myriapod relatives {\textendash} but who are sisters? No end to debates on relationships among the four major myriapod subgroups}, journal = {BMC Evolutionary Biology}, volume = {20}, year = {2020}, month = {04/11/2020}, pages = {1-15}, abstract = {

Background: Phylogenetic relationships among the myriapod subgroups Chilopoda, Diplopoda, Symphyla and Pauropoda are still not robustly resolved. The first phylogenomic study covering all subgroups resolved phylogenetic relationships congruently to morphological evidence but is in conflict with most previously published phylogenetic trees based on diverse molecular data. Outgroup choice and long-branch attraction effects were stated as possible explanations for these incongruencies. In this study, we addressed these issues by extending the myriapod and outgroup taxon sampling using transcriptome data.

Results: We generated new transcriptome data of 42 panarthropod species, including all four myriapod subgroups and additional outgroup taxa. Our taxon sampling was complemented by published transcriptome and genome data resulting in a supermatrix covering 59 species. We compiled two data sets, the first with a full coverage of genes per species (292 single-copy protein-coding genes), the second with a less stringent coverage (988 genes). We inferred phylogenetic relationships among myriapods using different data types, tree inference, and quartet computation approaches. Our results unambiguously support monophyletic Mandibulata and Myriapoda. Our analyses clearly showed that there is strong signal for a single unrooted topology, but a sensitivity of the position of the internal root on the choice of outgroups. However, we observe strong evidence for a clade Pauropoda+Symphyla, as well as for a clade Chilopoda+Diplopoda.

Conclusions: Our best quartet topology is incongruent with current morphological phylogenies which were supported in another phylogenomic study. AU tests and quartet mapping reject the quartet topology congruent to trees inferred with morphological characters. Moreover, quartet mapping shows that confounding signal present in the data set is sufficient to explain the weak signal for the quartet topology derived from morphological characters. Although outgroup choice affects results, our study could narrow possible trees to derivatives of a single quartet topology. For highly disputed relationships, we propose to apply a series of tests (AU and quartet mapping), since results of such tests allow to narrow down possible relationships and to rule out confounding signal.

}, keywords = {Arthropod phylogeny, conflict, Confounding signal, Internal rooting, Phylogenetics, phylogenomics, Quartet topology, RNA-Seq, Transcriptomes}, issn = {1471-2148}, doi = {10.1186/s12862-020-01699-0}, url = {https://bmcevolbiol.biomedcentral.com/articles/10.1186/s12862-020-01699-0}, author = {Szucsich, Nikolaus U. and Bartel, Daniela and Blanke, Alexander and B{\"o}hm, Alexander and Donath, Alexander and Fukui, Makiko and Grove, Simon and Liu, Shanlin and Macek, Oliver and Machida, Ryuichiro and Misof, Bernhard and Nakagaki, Yasutaka and Podsiadlowski, Lars and Sekiya, Kaoru and Tomizuka, Shigekazu and Von Reumont, Bj{\"o}rn M. and Waterhouse, Robert M. and Walzl, Manfred and Meng, Guanliang and Zhou, Xin and Pass, G{\"u}nther and Meusemann, Karen} } @article {68, title = {Towards a synthesis of the Caribbean biogeography of terrestrial arthropods}, journal = {BMC Evolutionary Biology}, volume = {20}, year = {2020}, month = {24/01/2020}, abstract = {

Background: The immense geologic and ecological complexity of the Caribbean has created a natural laboratory for interpreting when and how organisms disperse through time and space. However, competing hypotheses compounded with this complexity have resulted in a lack of unifying principles of biogeography for the region. Though new data concerning the timing of geologic events and dispersal events are emerging, powerful new analytical tools now allow for explicit hypothesis testing. Arthropods, with varying dispersal ability and high levels of endemism in the Caribbean, are an important, albeit understudied, biogeographic model system. Herein, we include a comprehensive analysis of every publicly available genetic dataset (at the time of writing) of terrestrial Caribbean arthropod groups using a statistically robust pipeline to explicitly test the current extent of biogeographic hypotheses for the region.

Results: Our findings indicate several important biogeographic generalizations for the region: the South American continent is the predominant origin of Caribbean arthropod fauna; GAARlandia played a role for some taxa in aiding dispersal from South America to the Greater Antilles; founder event dispersal explains the majority of dispersal events by terrestrial arthropods, and distance between landmasses is important for dispersal; most dispersal events occurred via island hopping; there is evidence of \‘reverse\’ dispersal from islands to the mainland; dispersal across the present-day Isthmus of Panama generally occurred prior to 3 mya; the Greater Antilles harbor more lineage diversity than the Lesser Antilles, and the larger Greater Antilles typically have greater lineage diversity than the smaller islands; basal Caribbean taxa are primarily distributed in the Greater Antilles, the basal-most being from Cuba, and derived taxa are mostly distributed in the Lesser Antilles; Jamaican taxa are usually endemic and monophyletic.

Conclusions: Given the diversity and deep history of terrestrial arthropods, incongruence of biogeographic patterns is expected, but focusing on both similarities and differences among divergent taxa with disparate life histories emphasizes the importance of particular qualities responsible for resulting diversification patterns. Furthermore, this study provides an analytical toolkit that can be used to guide researchers interested in answering questions pertaining to Caribbean biogeography using explicit hypothesis testing.

}, keywords = {Arachnids, BioGeoBEARS, biogeography, Central American seaway, insects, Islands, Isthmus of Panama, Probabilistic inference}, issn = {2730-7182}, doi = {https://doi.org/10.1186/s12862-019-1576-z}, url = {https://bmcevolbiol.biomedcentral.com/articles/10.1186/s12862-019-1576-z}, author = {Crews, Sarah C. and Esposito, Lauren A.} }