Systematics of Ditaxinae and Related Lineages within the Subfamily Acalyphoideae (Euphorbiaceae) Based on Molecular Phylogenetics

Simple Summary This study represents the most comprehensive phylogenetic reconstruction of the plant subtribe Ditaxinae and related taxa within Acalyphoideae (Euphorbiaceae). The taxonomy of this group, mainly based in morphology, has long been controversial. Here, we present a new taxonomic classification at the genus and tribe ranks using a solid phylogenetic framework. We also provide key morphological synapomorphies supporting the main recovered clades. Abstract The subtribe Ditaxinae in the plant family Euphorbiaceae is composed of five genera (Argythamnia, Caperonia, Chiropetalum, Ditaxis and Philyra) and approximately 120 species of perennial herbs (rarely annual) to treelets. The subtribe is distributed throughout the Americas, with the exception of Caperonia, which also occurs in tropical Africa and Madagascar. Under the current classification, Ditaxinae includes genera with a questionable morphology-based taxonomy, especially Argythamnia, Chiropetalum and Ditaxis. Moreover, phylogenetic relationships among genera are largely unexplored, with previous works sampling <10% of taxa, showing Ditaxinae as paraphyletic. In this study, we inferred the phylogenetic relationships within Ditaxinae and related taxa using a dataset of nuclear (ETS, ITS) and plastid (petD, trnLF, trnTL) DNA sequences and a wide taxon sampling (60%). We confirmed the paraphyly of Ditaxinae and Ditaxis, both with high support. Following our phylogenetic results, we combined Ditaxis in Argythamnia and upgraded Ditaxinae to the tribe level (Ditaxeae). We also established and described the tribe Caperonieae based on Caperonia, and transferred Philyra to the tribe Adelieae, along with Adelia, Garciadelia, Lasiocroton and Leucocroton. Finally, we discuss the main morphological synapomorphies for the genera and tribes and provide a taxonomic treatment, including all species recognized under each genus.

[1]  J. F. Baumgratz,et al.  New species and occurrences of Caperonia (Euphorbiaceae) for South America , 2021, Phytotaxa.

[2]  I. Sanmartín,et al.  Skipping the Dry Diagonal: spatio-temporal evolution of Croton section Cleodora (Euphorbiaceae) in the Neotropics , 2021, Botanical Journal of the Linnean Society.

[3]  Ann Lette,et al.  Toolkit , 2010, Food Urbanism.

[4]  F. Schweingruber,et al.  Euphorbiaceae , 2022, Anatomic Atlas of Aquatic and Wetland Plant Stems.

[5]  J. F. Baumgratz,et al.  Ditaxis (Euphorbiaceae) from the Brazilian Caatinga, including a new species , 2020 .

[6]  M. Suchard,et al.  Posterior summarisation in Bayesian phylogenetics using Tracer , 2022 .

[7]  T. Borsch,et al.  Successive arrivals since the Miocene shaped the diversity of the Caribbean Acalyphoideae (Euphorbiaceae) , 2016 .

[8]  Yocupitzia Ramírez-Amezcua,et al.  Revisión taxonómica de Argythamnia subgénero Ditaxis (Euphorbiaceae) en México , 2013 .

[9]  J. Morawetz,et al.  A worldwide molecular phylogeny and classification of the leafy spurges, Euphorbia subgenus Esula (Euphorbiaceae) , 2013 .

[10]  J. Morawetz,et al.  Molecular phylogenetics and classification of Euphorbia subgenus Chamaesyce (Euphorbiaceae) , 2012 .

[11]  Ramón Doallo,et al.  CircadiOmics: integrating circadian genomics, transcriptomics, proteomics and metabolomics , 2012, Nature Methods.

[12]  Olga Golosova,et al.  Unipro UGENE: a unified bioinformatics toolkit , 2012, Bioinform..

[13]  J. Francisco‐Ortega,et al.  Islands within islands: a molecular phylogenetic study of the Leucocroton alliance (Euphorbiaceae) across the Caribbean Islands and within the serpentinite archipelago of Cuba , 2012 .

[14]  Maxim Teslenko,et al.  MrBayes 3.2: Efficient Bayesian Phylogenetic Inference and Model Choice Across a Large Model Space , 2012, Systematic biology.

[15]  A. C. Pscheidt,et al.  Sinopse da tribo Hippomaneae (Euphorbiaceae) no Estado de São Paulo, Brasil , 2012 .

[16]  P. Berry,et al.  A revised infrageneric classification and molecular phylogeny of New World Croton (Euphorbiaceae) , 2011 .

[17]  Yocupitzia Ramírez Amezcua.  Relaciones filogenéticas en Argythamnia(Euphorbiaceae) sensu lato , 2011 .

[18]  Mark A. Miller,et al.  Creating the CIPRES Science Gateway for inference of large phylogenetic trees , 2010, 2010 Gateway Computing Environments Workshop (GCE).

[19]  J. Francisco‐Ortega,et al.  Generic delimitation in the Antillean Adelieae (Euphorbiaceae) with description of the Hispaniolan endemic genus Garciadelia , 2010 .

[20]  Fredrik Ronquist,et al.  Bayesian phylogenetics and its influence on insect systematics. , 2010, Annual review of entomology.

[21]  C. Davis,et al.  Malpighiales phylogenetics: Gaining ground on one of the most recalcitrant clades in the angiosperm tree of life. , 2009, American journal of botany.

[22]  B. Thiers,et al.  Index Herbariorum: a global directory of public herbaria and associated staff. New York Botanical Garden's Virtual Herbarium. , 2009 .

[23]  J. Rougemont,et al.  A rapid bootstrap algorithm for the RAxML Web servers. , 2008, Systematic biology.

[24]  J. Francisco‐Ortega,et al.  Lasiocroton trelawniensis (Euphorbiaceae), a Critically Endangered Species from the Cockpit Country of Jamaica, Belongs to Bernardia (Euphorbiaceae) , 2008, The Botanical Review.

[25]  A. Rambaut,et al.  BEAST: Bayesian evolutionary analysis by sampling trees , 2007, BMC Evolutionary Biology.

[26]  V. Sosa,et al.  Phylogeny and generic delimitation of Adelia (Euphorbiaceae) inferred from molecular and morphological data , 2007 .

[27]  Toru Tokuoka.  Molecular phylogenetic analysis of Euphorbiaceae sensu stricto based on plastid and nuclear DNA sequences and ovule and seed character evolution , 2007, Journal of Plant Research.

[28]  K. Wurdack,et al.  Phylogenetic Relationships and the Description of a New Species of Enriquebeltrania (Euphorbiaceae s.s.): An Enigmatic Genus Endemic to Mexico , 2006 .

[29]  M. Chase,et al.  Molecular phylogenetic analysis of uniovulate Euphorbiaceae (Euphorbiaceae sensu stricto) using plastid RBCL and TRNL-F DNA sequences. , 2005, American journal of botany.

[30]  M. Chase,et al.  Molecular phylogenetic analysis of Phyllanthaceae (Phyllanthoideae pro parte, Euphorbiaceae sensu lato) using plastid RBCL DNA sequences. , 2004, American journal of botany.

[31]  J. Lundberg,et al.  An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants : APG II THE ANGIOSPERM PHYLOGENY GROUP * , 2003 .

[32]  O. Gascuel,et al.  A simple, fast, and accurate algorithm to estimate large phylogenies by maximum likelihood. , 2003, Systematic biology.

[33]  F. Lutzoni,et al.  Bayes or bootstrap? A simulation study comparing the performance of Bayesian Markov chain Monte Carlo sampling and bootstrapping in assessing phylogenetic confidence. , 2003, Molecular biology and evolution.

[34]  M. Chase,et al.  When in doubt, put it in Flacourtiaceae: a molecular phylogenetic analysis based on plastid rbcL DNA sequences , 2002 .

[35]  Noel H. Holmgren,et al.  Index Herbariorum: A global directory of public herbaria and associated staff , 1998 .

[36]  F. Pax,et al.  Euphorbiaceae-Acalypheae-Chrozophorinae , 1994 .

[37]  J. Doyle.  DNA Protocols for Plants , 1991 .

[38]  Andrew W. B. Johnston,et al.  Molecular Techniques in Taxonomy , 1991, NATO ASI Series.

[39]  A. Borhidi.  Taxonomic revision of genus Leucocroton (Euphorbiaceae). , 1990 .

[40]  G. Webster.  CONSPECTUS OF A NEW CLASSIFICATION OF THE EUPHORBIACEAE , 1975 .

[41]  H. Akaike.  A new look at the statistical model identification , 1974 .

[42]  J. Ingram.  New Names in Argythamnia Subgenus ditaxis , 1957 .