Research Article |
Corresponding author: Lamarck Rocha ( lamarck.rocha@gmail.com ) Academic editor: Luciano de Queiroz
© 2022 Élvia Rodrigues de Souza, Priscilla Gomes C. de Almeida, Lamarck Rocha, Erik J.M. Koenen, Margoth Atahuachi Burgos, Gwilym P. Lewis, Colin E. Hughes.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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de Souza ÉR, de Almeida PGC, Rocha L, Koenen EJM, Burgos MA, Lewis GP, Hughes CE (2022) Boliviadendron, a new segregate genus of mimosoid legume (Leguminosae, Caesalpinioideae, mimosoid clade) narrowly endemic to the interior Andean valleys of Bolivia. In: Hughes CE, de Queiroz LP, Lewis GP (Eds) Advances in Legume Systematics 14. Classification of Caesalpinioideae Part 1: New generic delimitations. PhytoKeys 205: 439-452. https://doi.org/10.3897/phytokeys.205.82256
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Phylogenetic analyses of DNA sequence data sampling all species of Leucochloron alongside representatives of genera of the Inga and Albizia clades of the larger ingoid clade of mimosoid legumes (sensu
Fabaceae, generic delimitation, Leucochloron, monophyly, taxonomy
The genus Leucochloron Barneby & J.W. Grimes was established by
In May 2002, C.E. Hughes and collaborators collected material of an undescribed mimosoid legume tree from a single locality on the mid-elevation eastern flanks of the Bolivian Andes. A small number of additional collections from nearby localities have been made in subsequent years. This material shares the same combination of characters used by
This apparently morphologically commodious generic home for Leucochloron bolivianum has been brought into question by phylogenetic evidence from
Morpho-taxonomic analyses and sample selection for DNA extraction were based on field collections and herbarium specimens from BOLV, FHO, HUEFS, K, LPB, MBM, MEXU, NY, SP and VIC (acronyms follow
We sampled 47 accessions (40 of them newly sequenced here and seven using sequences from GenBank) in 19 genera, including all genera of the Albizia and Inga clades sensu
Total genomic DNA was extracted from silica-dried or herbarium leaf tissue using a modified 2 × CTAB protocol (
Polymerase Chain Reactions (PCR) were performed using TopTaq Master Mix Kit (QIAGEN GmbH, Hilden, Germany) according to the manufacturer’s protocol, in 10–15 μl of final reaction volume. For the nrITS and ETS amplifications, 1.0 M betaine and 2% DMSO (dimethylsulphoxide; 2% of the preparation volume) were added. PCR products were purified by enzymatic treatments with Exonuclease I and Shrimp alkaline phosphatase (kit ExoSapIT, GE Healthcare Buckinghamshire, U.K.). Sequencing reactions were performed using the same primers used for PCR and Big Dye Terminator kit v.3.1 (Applied Biosystems, Foster City, California, U.S.A.), on the ABI3130XL Analyzer (Applied BioSystems), at the Laboratório de Sistemática Molecular de Plantas (LAMOL), of the Universidade Estadual de Feira de Santana (UEFS), Bahia, Brazil.
Electropherograms were assembled in Geneious 5.3.6 (
Maximum Parsimony (MP) analyses were performed using PAUP v.4.0 (
Maximum Likelihood (ML) analyses were performed using RAxML v.8 (
Best-fitting substitution models for each data partition were selected using the Akaike Information Criterion (AIC) using MrModeltest v.2.3 (
While separate analyses of the nuclear ITS + ETS and plastid loci yielded gene trees that were, in many cases, poorly resolved (Suppl. material
Majority-rule (50%) consensus tree from Bayesian analysis of the combined nuclear (ITS, ETS) and plastid (psbA-trnH, rpL32, rps16, trnD-T, trnL-F) data for Boliviadendron and related genera. Values above branches are Bayesian Posterior Probabilities (PP), below are Bootstrap Support (BS) percentages from the maximum parsimony (left) and Maximum Likelihood analyses (right). Branches supported by PP ≥ 95% are in bold. Only BS values ≥ 50% are shown; - indicates BS ≤ 50%; * indicates PP = 1.0 or BS = 100%.
The non-monophyly of the genus Leucochloron is supported by two independent phylogenetic studies, one presented here sampling all five species currently assigned to the genus, based on a small set of widely-used nrDNA and plastid DNA sequence loci (Fig.
This robustly-supported non-monophyly is unexpected, given the close morphological similarities between L. bolivianum and the other four species of Leucochloron. Indeed, there appear to be very few qualitative morphological differences separating Boliviadendron (i.e., L. bolivianum) from Leucochloron, suggesting that the original combination of character states used by
Morphological characters which weakly separate Boliviadendron from Leucochloron s.s. are: (i) the leaflet base is more evidently asymmetrical in Boliviadendron than in the species of Leucochloron and the under-surface of Boliviadendron leaflets has 1–2 (–3) prominent primary veins, but otherwise the venation is not evident vs. the evident reticulate secondary and tertiary venation on the lower leaflet surface in Leucochloron species; (ii) in Boliviadendron, the upper leaflet surfaces are consistently blotched purple-black, while leaflets of Leucochloron s.s. species are strongly discolorous, with the upper surface drying dark brown and often glossy; (iii) the indumentum in Boliviadendron tends to be shorter and white, especially on the corollas and calyces which have fine white, appressed, silky trichomes vs. the generally more ferruginous and longer indumentum, occasionally with golden and/or white hairs intermixed, of Leucochloron species; (iv) the number of pollen grains per polyad is constant in Boliviadendron at 16 (counted on the isotype Hughes 2423 and Wood 21618 at K), while in Leucochloron s.s., it is variable (even within species) with 16, 18, 24 or 32 grains.
In the
Boliviadendron bolivianum (C.E. Hughes & Atahuachi) E.R. Souza & C.E. Hughes.
Boliviadendron
is similar in almost all respects to the genus Leucochloron and is segregated first and foremost because these two lineages are phylogenetically not closely related (Fig.
(modified from
The monospecific genus Boliviadendron occupies a narrowly restricted distribution endemic to Bolivia and has been recorded from just a small number of localities on the eastern flanks of the Andes at mid-elevations in interior Andean valleys in the Departments of La Paz, Cochabamba and Santa Cruz (Fig.
Locally common in fence-lines and remnant patches of subhumid or seasonally dry Yungas forest and secondary thickets of Baccharis dracunculifolia DC., Dasyphyllum brasiliense (Spreng.) Cabrera (both Asteraceae), Dodonaea viscosa Jacq. (Sapindaceae) and Tecoma stans Juss. (Bignoniaceae). Other associated species include Apurimacia michelii Harms., Coursetia brachyrhachis Harms., Erythrina falcata Benth., Mimosa boliviana Benth., M. woodii Atahuachi & C.E. Hughes, Parapiptadenia excelsa (Griseb.) Burkart (all Leguminosae), Schinopsis haenkeana Engl. (Anacardiaceae), Cordyline dracaenoides Kunth (Asparagaceae), Kageneckia lanceolata Ruiz & Pav. (Rosaceae) and Cleistocactus laniceps (K. Schum.) Rol.-Goss (Cactaceae). Boliviadendron is known only from the slopes of interior valleys of Bolivia between 2150 and 2770 m alt., around the transition from seasonally-dry tropical inter-Andean valley forests to more moist mid-elevation montane Ceja de Monte Yungeña vegetation. Most collections (apart from two outlying localities in Dept. Santa Cruz) come from two nearby tributaries of the upper Río Cotacajes, in Prov. Ayopaya, Cochabamba and Prov. Inquisivi, La Paz, Bolivia, an area with several other narrowly-endemic plants, including Justicia pluriformis Wash. & J.R.I. Wood (Acanthaceae), Philibertia fontellae (Murillo) Goyder (Apocynaceae), Solanum stellativelutinum Bitter and S. tunariense Kuntze (Solanaceae) and Mimosa woodii (Leguminosae). Boliviadendron (as Leucochloron bolivianum) was assigned an IUCN threat category of Endangered (EN) B1ab(iii,iv) in 2011 (
Boliviadendron is one of just two mimosoid legume genera known to be endemic to Bolivia (the other being Pseudosenegalia Seigler & Ebinger with two species) and that Bolivian endemism is highlighted here by the double-barrelled reference to that country in the name Boliviadendron bolivianum.
Leucochloron bolivianum C.E. Hughes & Atahuachi, Kew Bull. 61: 559. 2006, publ. 31 Jan 2007.
Bolivia. La Paz, Prov. Inquisivi, 6 km N of Inquisivi, rd towards Cajuata, Circuata and Miguillas, 16°53'42"S, 67°08'23"W, 2385 m alt., 12 Dec 2003, C.E. Hughes, T. Ortuño & M. Mendoza 2423 (holotype: LPB; isotypes: BOLV, FHO, K [K000532854], USZ).
Bolivia. Cochabamba, Prov. Ayopaya, 1 km S of Independencia on rd to Pongo, 17°05'03"S, 66°48'53"W, 2630 m alt., 15 May 2002 (unripe fr.), C.E. Hughes, J.R.I. Wood & R. Forrest 2287 (FHO!, K! [2 specimens], LPB!). Cochabamba, Ayopaya, 1 km above Independencia on road to Sailapata and La Mina, 17°04'S, 66°48'W, 2770 m, 18 Dec 2002 (fl.), J.R.I. Wood, M. Mercado & M. Mendoza 18731 (K!). La Paz, Prov. Inquisivi, ca. 10 km N of Inquisivi, rd to Licoma and Circuata, 16°53'71"S, 67°08'35"W, 2300 m alt., 27 March 2007 (unripe fr.), C.E. Hughes, T. Särkinen, A. Wortley & P. Duchen 2608 (FHO!, K! [2 specimens], LPB). La Paz, Prov. Inquisivi, 6 km N of Inquisivi, rd towards Cajuata, 16°53'43"S, 67°08'23"W, 2379 m alt., 12 Feb 2005 (ripe fr.), J.R.I. Wood, M. Atahuachi & T. Ortuño 21607 (BOLV, FHO!, K! [2 specimens], LPB). La Paz, Prov. Inquisivi, 0.5 km above Sica rd from Inquisivi to Cajuata, 16°52'32"S, 67°08'04"W, 2565 m alt., 12 Feb 2005 (fl.), J.R.I. Wood, M. Atahuachi & T. Ortuño 21618 (BOLV, FHO!, K! [2 specimens], LPB). La Paz, Prov. Inquisivi, 13 km from Inquisivi towards Licoma, crossing the Río Quime, 2150 m alt., 24 April 1992 (unripe fr.), St.G. Beck 21125 (K! [2 specimens]). La Paz, Prov. Inquisivi, along slopes E of Communidad Micayani to the Rio Khokhoni more or less to the junction with a fork flowing down from Communidad Yamora and following the Rio Khokhoni upstream 1 km from this point, ca. 4 km SE from Inquisivi, 16°55'S, 67°06'W, 2650 m alt., 14 Jan 1989 (fl.), M. Lewis 35094 (K!, LPB, MO). Santa Cruz, Prov. M. Caballero, ascending from Comarapa towards Cerro Bravo, 17°52'25"S, 64°31'32"W, 20 Nov 2005 (fl.), J.R.I. Wood & M. Mendoza 22081 (BOLV, FHO!, K! [2 specimens], LPB). Santa Cruz, Prov. Valle Grande, 14.2 km on the gravel road towards Moro Moro from the highway in the Trigal / Muyurina valley, 18°21'00"S, 64°14'27"W, 2335 m alt., 1 Jan 2011 (fl.), M. Nee & J.M. Mendoza F 57498 (NY!).
We thank the Laboratório de Sistemática Molecular de Plantas (LAMOL-UEFS) and the Jodrell Laboratory of the Royal Botanic Gardens, Kew staff for support with laboratory procedures and all the colleagues who kindly provided samples for DNA extraction. This work was supported by the FAPESB (grants: PTX0004/2016 and APP0096/2016), SISBIOTA (563084/2010-3) and the Swiss National Science Foundation through grants 310003A_156140 and 31003A_182453/1 to Colin Hughes and an Early.Postdoc.Mobility fellowship P2ZHP3_199693 to Erik Koenen. We are grateful to curators of all herbaria cited for providing access to their collections and to João Iganci and Luciano de Queiroz for comments and careful revision of the text.
Table S1–S3
Data type: Tables
Explanation note: Includes voucher information, primers and protocols and summary of phylogenetic analyses.
Figures S1–S9
Data type: Individual phylogenetic analyzes
Explanation note: Includes all trees derived from the BI, MP and ML with combined nuclear + plastidial loci, and individual analyses from nuclear, and plastidial loci.