Abstract
In this work, we describe Dialium heterophyllum, a new species for the largest genus in the diverse and morphologically unique legume subfamily Dialioideae. Dialium, with 32 species, has its highest diversity in tropical Africa and Asia, with four species accepted until now in the Neotropics. The fifth species described here reinforces the idea that a large portion of the Neotropical diversity, notably in the Amazon, is still unknown. Dialium heterophyllum is restricted to the south of the Amazon Basin in Brazil and Bolivia, areas under intense anthropic pressure in recent years. Due to its floral morphology, the species appears to be closely related to the other Neotropical species of the genus, differing by its reduced leaf rachis with unifoliolate to trifoliolate leaves, generally opposed to sub-opposed leaflets, the terminal leaflet much longer than the lateral ones (when present) and than the leaf rachis. We provide illustrations, distribution maps, a conservation risk assessment and an identification key.
References
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Thiers, B. (2018) Index Herbariorum: A global directory of public herbaria and associated staff. New York Botanical Garden’s Virtual Herbarium. Available from: <a href="http://sweetgum.nybg.org/science/ih/">http://sweetgum.nybg.org/science/ih/</a> (accessed 20 June 2020)
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<a href="https://doi.org/10.1016/j.sajb.2013.06.020">https://doi.org/10.1016/j.sajb.2013.06.020</a>
Zimmerman, E., Herendeen, P.S., Lewis, G.P. & Bruneau, A. (2017) Floral evolution and phylogeny of the Dialioideae, a diverse subfamily of tropical legumes. American Journal of Botany 104: 1019–1041.
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Beaune, D., Bretagnolle, F., Bollache, L., Hohmann, G., Surbeck, M., Bourson, C., & Fruth, B. (2013) The Bonobo–Dialium Positive Interactions: Seed Dispersal Mutualism. American Journal of Primatology 75 (4): 394–403.
<a href="https://doi.org/10.1002/ajp.22121">https://doi.org/10.1002/ajp.22121</a>
Bentham, G. & Hooker, J.D. (1867) Genera plantarum: ad exemplaria imprimis in Herberiis Kewensibus servata definite 1. Lovell Reeve and Williams and Norgate, London, 454 pp.
Bush, M.B. & Oliveira, P.E.D. (2006) The rise and fall of the Refugial Hypothesis of Amazonian speciation: a paleoecological perspective. Biota Neotrop 6 (1): 1–17.
<a href="https://doi.org/10.1590/S1676-06032006000100002">https://doi.org/10.1590/S1676-06032006000100002</a>
Breteler, F.J. (1994) Novitates gabonenses (14) Dialium lopense, a new Leguminosae-Caesalpinioideae from Central Gabon. Bulletin du Jardin botanique national de Belgique/Bulletin van de Nationale Plantentuin van Belgie 63: 201–204.
<a href="https://doi.org/10.2307/3668244">https://doi.org/10.2307/3668244</a>
Capuron, R. (1968) Contributions a L’Étude de la Flore Forestière de Madagascar. Adansonia 8 (2): 199–217.
Davidson, E.A., Araujo, A.C., Artaxo, P., Balch, J.K., Brown, I.F., Bustamante, M.M.C., Coe, M.T., DeFries, R.S., Keller, M., Longo, M., Munger, J.W., Schroeder, W., Soares-Filho, B.S., Souza, C.M. & Wofsy, S.C. (2012) The Amazon basin in transition. Nature 481: 321–328.
<a href="https://doi.org/10.1038/nature10717">https://doi.org/10.1038/nature10717</a>
Doyen, J.T. & Slobodchikoff, C.N. (1974) An operational approach to species classification. Systematic Biology 23 (2): 239–247.
<a href="https://doi.org/10.1093/sysbio/23.2.239">https://doi.org/10.1093/sysbio/23.2.239</a>
Falcão, M.J.A., Mansano, V.F. & Pinto, R.B. (2016) A taxonomic revision of the genus Dialium (Leguminosae: Dialiinae) in the neotropics. Phytotaxa 283 (2): 123–142.
<a href="https://doi.org/10.11646/phytotaxa.283.2.2">https://doi.org/10.11646/phytotaxa.283.2.2</a>
Falcão, M.J.A., Paulino, J.V., Kochanovski, F.J., Figueiredo, R.C., Basso-Alves, J.P. & Mansano, V.F. (2020) Development of inflorescences and flowers in Fabaceae subfamily Dialioideae: An evolutionary overview and complete ontogenetic series for Apuleia and Martiodendron. Botanical Journal of the Linnean Society 193: 19–46.
<a href="https://doi.org/10.1093/botlinnean/boz098">https://doi.org/10.1093/botlinnean/boz098</a>
Fourrier, M.S. (2013) The spatial and temporal ecology of seed dispersal by gorillas in Lopé National Park, Gabon: linking patterns of disperser behavior and recruitment in an Afrotropical forest. All Theses and Dissertations (ETDs): 1043.
Frey, J.K. (1993) Modes of peripheral isolate formation and speciation. Systematic Biology 42 (3): 373–381.
<a href="https://doi.org/10.1093/sysbio/42.3.373">https://doi.org/10.1093/sysbio/42.3.373</a>
Ghalambor, C.K., Huey, R.B., Martin, P.R., Tewksbury, J.J. & Wang, G. (2006) Are mountain passes higher in the tropics? Janzen’s hypothesis revisited. Integrative and comparative biology 46 (1): 5–17.
<a href="https://doi.org/10.1093/icb/icj003">https://doi.org/10.1093/icb/icj003</a>
Giray, E.F. (1976) An integrated biological approach to the species problem. The British Journal for the Philosophy of Science 27 (4): 317–328.
<a href="https://doi.org/10.1093/bjps/27.4.317">https://doi.org/10.1093/bjps/27.4.317</a>
Haffer, J. (2008) Hypotheses to explain the origin of species in Amazonia. Brazilian Journal of Biology 68 (4): 917–947.
<a href="https://doi.org/10.1590/S1519-69842008000500003">https://doi.org/10.1590/S1519-69842008000500003</a>
Harms, H. (1915) Leguminosae Africanae VIII. Botanische Jahrbücher für Systematik, Pflanzengeschichte und Pflanzengeographie 53: 455–476.
Harris, J.G. & Harris, M.W. (2001) Plant identification terminology: an illustrated glossary. Spring Lake Publishing. Spring Lake, Utah, USA, 206 pp.
INPE (National Institute for Space Research, Brazil) (2020) Earth Observation General Coordination (OBT). Satellite Monitoring of the Brazilian Amazon and Other Biomes Alerts – Amazon Biome – Available from: <a href="http://terrabrasilis.dpi.inpe.br/downloads/">http://terrabrasilis.dpi.inpe.br/downloads/</a> (accessed 22 May 2020)
Irwin, H.S. & Barneby, R.C. (1981) Cassieae. In Polhill RM, Raven PH, eds. Advances in legume systematics 1: 97–106.
IUCN Standards and Petitions Committee (2019) Guidelines for Using the IUCN Red List Categories and Criteria. Version 14. Prepared by the Standards and Petitions Committee. Available from: <a href="http://www.iucnredlist.org/documents/RedListGuidelines.pdf">http://www.iucnredlist.org/documents/RedListGuidelines.pdf</a> (accessed 26 September 2020)
Legume Phylogeny Working Group (2017) A new subfamily classification of the Leguminosae based on a taxonomically comprehensive phylogeny. Taxon 66: 44–77.
<a href="https://doi.org/10.12705/661.3">https://doi.org/10.12705/661.3</a>
Linnaeus, C.V. (1767) Systema Naturae. 12 ed. Holmiae: Impensis Direct. Lautentii Salvii, Stockholm, 736 pp.
Liu, J.Q. (2016) The integrative species concept and species on the speciation way’. Biodiversity Science 24 (9): 1004–1008.
<a href="https://doi.org/10.17520/biods.2016222">https://doi.org/10.17520/biods.2016222</a>
Masi, S., Cipolletta, C. & Robbins, M.M. (2009) Western lowland gorillas (Gorilla gorilla gorilla) change their activity patterns in response to frugivory. American Journal of Primatology: Official Journal of the American Society of Primatologists 71 (2): 91–100.
<a href="https://doi.org/10.1002/ajp.20629">https://doi.org/10.1002/ajp.20629</a>
Montibeller, B., Kmoch, A., Virro, H., Mander, U. & Uuemaa, E. (2020) Increasing fragmentation of forest cover in Brazil’s Legal Amazon from 2001 to 2017. Scientific Reports 10 (1): 5803.
<a href="https://doi.org/10.1038/s41598-020-62591-x">https://doi.org/10.1038/s41598-020-62591-x</a>
Pijl, L. van der (1982) Principles of dispersal in higher plants. 3rd. ed. Berlin, Heidelberg and New York, Springer-Verlag.
Potapov, P., Hansen, M.C., Laestadius, L., Turubanova, S., Yaroshenk, A., Thies, C., Smith, W., Zhuravleva, I., Komarova, A., Minnemeyer, S. & Esipova, E. (2017) The last frontiers of wilderness: tracking loss of intact forest landscapes from 2000 to 2013. Science Advances 3 (1): e1600821.
<a href="https://doi.org/10.1126/sciadv.1600821">https://doi.org/10.1126/sciadv.1600821</a>
REFLORA (2020) Flora do Brasil 2020 em construção. Jardim Botânico do Rio de Janeiro. Available from: <a href="http://floradobrasil.jbrj.gov.br/">http://floradobrasil.jbrj.gov.br/</a> (accessed 26 September 2020)
Ridley, H.N. (1930) The dispersal of plants throughout the world. Ashford, Kent, Reeve.
Rojo, J.P. (1982) Studies in the genus Dialium (Cassieae–Caesalpinioideae). University of Oxford, Oxford. UK.
Species Link (2020) Sistema de Informação Distribuído para Coleções Biológicas. INCT-Herbário Virtual da Flora e dos Fungos. Brasil, Available from: <a href="http://inct.splink.org.br/">http://inct.splink.org.br/</a> (accessed 26 September 2020)
Spjut, R.W. (1994) A systematic treatment of fruit types. Memoirs of the New York Botanical Garden 70: 1–182.
Steinbauer, M.J., Field, R., Grytnes, J.A., Trigas, P., Ah., Peng, C., Attorre, F., Birks, H.J.B., Borges, P.A.V., Cardoso, P., Chou, C.-H., De Sanctis, M., de Sequeira, M.M., Duarte, M.C., Elias, R.B., Fernández?Palacios, J.M., Gabriel, R., Gereau, R.E., Gillespie, R.G., Greimler, J., Harter, D.E.V., Huang, T.-J., Irl, S.D.H., Jeanmonod, D., Jentsch, A., Jump, A.S., Kueffer, C., Nogué, S., Otto, R., Price, J., Romeiras, M.M., Strasberg, D., Stuessy, T., Svenning, J.-C., Vetaas, O.R. & De Sanctis, M. (2016) Topography-driven isolation, speciation and a global increase of endemism with elevation. Global Ecology and Biogeography 25 (9): 1097–1107.
<a href="https://doi.org/10.1111/geb.12469">https://doi.org/10.1111/geb.12469</a>
Steyaert, R.L. (1951) Contribution à l’étude du genre Dialium. Bulletin de la Société Botanique de Belgique 84 (38): 29–45.
Stuessy, T.F. (2009) Plant taxonomy: the systematic evaluation of comparative data. Columbia University Press.
Thiers, B. (2018) Index Herbariorum: A global directory of public herbaria and associated staff. New York Botanical Garden’s Virtual Herbarium. Available from: <a href="http://sweetgum.nybg.org/science/ih/">http://sweetgum.nybg.org/science/ih/</a> (accessed 20 June 2020)
Turland, N.J., Wiersema, J.H., Barrie, F.R., Greuter, W., Hawksworth, D.L., Herendeen, P.S., Knapp, S., Kusber, W.-H., Li, D.-Z., Marhold, K., May, T.W., McNeill, J., Monro, A.M., Prado, J., Price, M.J. & Smith, G.F. (2018) International Code of Nomenclature for algae, fungi, and plants (Shenzhen Code). Adopted by the Nineteenth International Botanical Congress Shenzhen, China, July 2017.
<a href="https://doi.org/10.12705/Code.2018">https://doi.org/10.12705/Code.2018</a>
Zimmerman, E., Prenner, G. & Bruneau, A. (2013) Floral ontogeny in Dialiinae (Caesalpinioideae: Cassieae), a study in organ loss and instability. South African Journal of Botany 89: 188–209.
<a href="https://doi.org/10.1016/j.sajb.2013.06.020">https://doi.org/10.1016/j.sajb.2013.06.020</a>
Zimmerman, E., Herendeen, P.S., Lewis, G.P. & Bruneau, A. (2017) Floral evolution and phylogeny of the Dialioideae, a diverse subfamily of tropical legumes. American Journal of Botany 104: 1019–1041.
<a href="https://doi.org/10.3732/ajb.1600436">https://doi.org/10.3732/ajb.1600436</a>