Calycosiphonia or Kupeantha (Coffeeae, Rubiaceae)? A morphological and molecular study of a new species from the Albertine Rift

Keywords: Central Africa, Coffeeae, heterophylly, pollen, taxonomy

Abstract

Field work in the Kibira National Park (Burundi), located in the Kivu-Ruwenzori system of the Afromontane Region, revealed the existence of a new species clearly belonging to the Argocoffeopsis-Calycosiphonia clade (Coffeeae, Rubiaceae). The species shows striking heterophylly: the plagiotropous branches have several nodes bearing reduced or even scaly leaves. For the rest, it shares characters with Calycosiphonia and Kupeantha. Therefore, a morphological comparison with the clade is done, as well as molecular phylogenetic analyses. The morphology of the novelty is closer to Kupeantha than to Calycosiphonia, inter alia because the anthers have no transverse septa, in contrast to the multilocellate anthers of Calycosiphonia. However, the molecular data advocate for a position in Calycosiphonia – a result weakening the morphological distinction between Calycosiphonia and Kupeantha. The former genus is no longer restricted to species with transverse septa in the anthers and with placental outgrowths around the seed. The new species is formally described as Calycosiphonia albertina Ntore & Robbr. sp. nov. Nomenclaturally, this placement is also the most conservative option. A taxonomic treatment, illustrations, a geographical distribution map, and a preliminary conservation assessment are provided. The previous inclusion of Calycosiphonia pentamera in Kupeantha based on morphology is here corroborated by molecular analyses.

References

Ali S.J. & Robbrecht E. 1991. Remarks on the tropical Asian and Australian taxa included in Diplospora or Tricalysia (Rubiaceae-Ixoroideae-Gardenieae). Blumea 35: 279–305.

Alvarez-Aguirre M.G., Cheek M. & Sonké B. 2021. Kupeantha yabassi (Coffeeae-Rubiaceae), a new Critically Endangered shrub species of the Ebo Forest area, Littoral Region, Cameroon. Kew Bulletin 76: 735–743. https://doi.org/10.1007/s12225-021-09982-z

Andreasen K. & Bremer B. 1996. Phylogeny of the subfamily Ixoroideae (Rubiaceae). Opera Botanica Belgica 7: 119–138.

Andreasen K. & Bremer B. 2000. Combined phylogenetic analysis in the Rubiaceae-Ixoroideae: morphology, nuclear and chloroplast DNA data. American Journal of Botany 87 (11): 1731–1748. https://doi.org/10.2307/2656750

Andrews S. 2010. FastQC. A quality control tool for high throughput sequence data. Available from https://www.bioinformatics.babraham.ac.uk/projects/fastqc/ [accessed 7 Sep. 2023].

Arriola A.H., Davis A.P., Davies N.M., Meve U., Liede-Schumann S. & Alejandro G.J.D. 2018. Using multiple plastid DNA regions to construct the first phylogenetic tree for Asian genera of Coffeeae (Ixoroideae, Rubiaceae). Botanical Journal of the Linnean Society 188: 132–143. https://doi.org/10.1093/botlinnean/boy059

Aveling C. 2010. World Heritage in the Congo Basin. UNESCO World Heritage Centre, Paris.

Bachman S., Moat J., Hill A.W., de la Torre J. & Scott B. 2011 Supporting Red List threat assessments with GeoCAT: geospatial conservation assessment tool. ZooKeys 150: 117–126. https://doi.org/10.3897/zookeys.150.2109

Bridson D.M. & Verdcourt B. 2003. Rubiaceae. In: Pope G.V. (ed.) Flora Zambesiaca. Volume 5, part 3. Royal Botanic Gardens, Kew, Richmond.

Cheek M., Alvarez-Aguirre M.G., Grall A., Sonké B., Howes M.-J.R. & Larridon I. 2018. Kupeantha (Coffeeae, Rubiaceae), a new genus from Cameroon and Equatorial Guinea. PLoS ONE 13: e0199324. https://doi.org/10.1371/journal.pone.0199324

Cheek M. & Dawson S. 2000. A synoptic revision of Belonophora (Rubiaceae). Kew Bulletin 55: 63–80. https://doi.org/10.2307/4117761

Cheek M. & Tchiengué B. 2010. Argocoffeopsis fosimondi (Rubiaceae) a new cloud forest shrub species from Fosimondi, Cameroon. In: Harvey Y., Tchiengué B. & Cheek M. (eds) The Plants of the Lebialem Highlands, Cameroon: a Conservation Checklist. Royal Botanic Gardens, Kew, Richmond.

Darriba D., Taboada G., Doallo R. & Posada D. 2012. jModelTest 2: more models, new heuristics and parallel computing. Nature Methods 9: 772. https://doi.org/10.1038/nmeth.2109

Davis A.P. 2010. Six species of Psilanthus transferred to Coffea (Coffeeae, Rubiaceae). Phytotaxa 10: 41–45. https://doi.org/10.11646/phytotaxa.10.1.6

Davis A.P. & Sonké B. 2008. A new Argocoffeopsis (Coffeeae, Rubiaceae) from southern Cameroon: Argocoffeopsis spathulata. Blumea 53: 527–532. https://doi.org/10.3767/000651908X607486

Davis A.P., Bridson D. & Rakotonasolo F. 2005. A reexamination of Coffea subgenus Baracoffea and comments on the morphology and classification of Coffea and Psilanthus (Rubiaceae-Coffeea). In: Keating R.C., Hollowell V.C. & Croat T.B. (eds) A Festschrift for William G. D’arcy: the Legacy of a Taxonomist: 399–420. Missouri Botanical Garden Press, St. Louis, Missouri.

Davis A.P., Chester M., Maurin O. & Fay M.F. 2007. Searching for relatives of Coffea (Rubiaceae, Ixoroideae): circumscription and phylogeny of Coffeeae based on plastid sequence data and morphology. American Journal of Botany 94: 313–329. https://doi.org/10.3732/ajb.94.3.313

Denoeud F., Carretero-Paulet L., Dereeper A., Droc G., Guyot R., Pietrella M., Zheng C., Alberti A., Anthony F., Aprea G., Aury J.-M., Bento P., Bernard M., Bocs S., Campa C., Cenci A., Combes M.-C., Crouzillat D., Da Silva C., Daddiego L., De Bellis F., Dussert S., Garsmeur O., Gayraud T., Guignon V., Jahn K., Jamilloux V., Joët T., Labadie K., Lan T., Leclercq J., Lepelley M., Leroy T., Li L.-T., Librado P., Lopez L., Muñoz A., Noel B., Pallavicini A., Perrotta G., Poncet V., Pot D., Priyono, Rigoreau M., Rouard M., Rozas J., Tranchant-Dubreuil C., VanBuren R., Zhang Q., Andrade A.C., Argout X., Bertrand B., de Kochko A., Graziosi G., Henry R.J., Jayarama, Ming R., Nagai C., Rounsley S., Sankoff D., Giuliano G., Albert V.A., Wincker P. & Lashermes P. 2014. The coffee genome provides insight into the convergent evolution of caffeine biosynthesis. Science 345: 1181–1184. https://doi.org/10.1126/science.1255274

Doyle J.J. & Doyle J.L. 1987. A rapid DNA isolation procedure for small quantities of fresh leaf tissue. Phytochemistry Bulletin 19: 11–15.

Fischer E., Killmann D. & Dhetchuvi J.-B.M.M. 2023. The family Zingiberaceae in Rwanda with description of two new species of Renealmia. Plant Ecology and Evolution 156 (2): 225–238. https://doi.org/10.5091/plecevo.99146

GBIF.org. 2023a. GBIF occurrence download of Argocoffeopsis. Available from https://doi.org/10.15468/dl.bceknq [accessed 24 May 2023].

GBIF.org. 2023b. GBIF occurrence download of Calycosiphonia. Available from https://doi.org/10.15468/dl.qsp43h [accessed 24 May 2023].

GBIF.org. 2023c. GBIF occurrence download of Kupeantha. Available from https://doi.org/10.15468/dl.ya4bgh [accessed 24 May 2023].

GBIF.org. 2023d. Impatiens mannii in GBIF Backbone Taxonomy. Available from https://www.gbif.org/species/4936432 [accessed 22 May 2023].

Hallé F., Oldeman R.A.A. & Tomlinson P.B. 1978. Tropical Trees and Forests: an Architectural Analysis. Springer, Berlin. https://doi.org/10.1007/978-3-642-81190-6

Hoang D.T., Chernomor O., von Haeseler A., Minh B.Q., Vinh L.S. 2018. UFBoot2: improving the ultrafast bootstrap approximation. Molecular Biology and Evolution 35 (2): 518–522. https://doi.org/10.1093/molbev/msx281

IUCN Standards and Petitions Subcommittee. 2022. Guidelines for using the IUCN Red List categories and criteria. Version 15.1. Prepared by the Standards and Petitions Subcommittee.

Kainulainen K., Razafimandimbison S.G., Wikström N. & Bremer B. 2017. Island hopping, long-distance dispersal and species radiation in the Western Indian Ocean: historical biogeography of the Coffeeae alliance (Rubiaceae). Journal of Biogeography 44: 1966–1979. https://doi.org/10.1111/jbi.12981

Katoh K. & Standley D.M. 2013. MAFFT Multiple sequence alignment software version 7: improvements in performance and usability. Molecular Biology and Evolution 30 (4): 772–780. https://doi.org/10.1093/molbev/mst010

Kilian A., Wenzl P., Huttner E., Carling J., Xia L., Blois H., Caig V., Heller-Uszynska K., Jaccoud D., Hopper C., Aschenbrenner-Kilian M., Evers M., Peng K., Cayla C., Hok P. & Uszynski G. 2012. Diversity arrays technology: a generic genome profiling technology on open platforms. In: Pompanon F. & Bonin A. (eds) Data Production and Analysis in Population Genomics. Methods in Molecular Biology 888: 67–89. Humana Press, Totowa. https://doi.org/10.1007/978-1-61779-870-2_5

Lebrun J. 1941. Recherches morphologiques et systématiques sur les caféiers du Congo. Institut Royal Colonial Belge, Section des Sciences Naturelles et Médicales, Mémoires 11 (3): 1–184.

Li H. & Durbin R. 2009. Fast and accurate short read alignment with Burrows-Wheeler transform. Bioinformatics 25 (14): 1754–1760. https://doi.org/10.1093/bioinformatics/btp324

Martin M. 2011. Cutadapt removes adapter sequences from high-throughput sequencing reads. EMBnet.journal 17 (1): 10–12. https://doi.org/10.14806/ej.17.1.200

McKenna A., Hanna M., Banks E., Sivachenko A., Cibulskis K., Kernytsky A., Garimella K., Altshuler D., Gabriel S., Daly M. & DePristo M.A. 2010. The Genome Analysis Toolkit: a MapReduce framework for analyzing next-generation DNA sequencing data. Genome Research 20: 1297–1303. https://doi.org/10.1101/gr.107524.110

Minh B.Q., Schmidt H.A., Chernomor O., Schrempf D., Woodhams M.D., von Haeseler A. & Lanfear R. 2020. IQ-TREE 2: new models and efficient methods for phylogenetic inference in the genomic era. Molecular Biology and Evolution 37 (5): 1530–1534 https://doi.org/10.1093/molbev/msaa015

Moens P. 1962. La place systématique du Coffea lebruniana Germain et Kesler. Bulletin du Jardin botanique de l’État à Bruxelles 32: 129–131. https://doi.org/10.2307/3667319

Ntore S., Fischer E. & Sosef S.M. 2018. Red List of the endemic and range-restricted vascular plants of Burundi. Scripta Botanica Belgica 58: 1–215.

Persson C. 2000. Phylogeny of the Neotropical Alibertia group (Rubiaceae), with emphasis on the genus Alibertia, inferred from ITS and 5S ribosomal DNA sequences. American Journal of Botany 87 (7): 1018–1028. https://doi.org/10.2307/2657002

POWO 2023. Plants of the World Online. Facilitated by the Royal Botanic Gardens, Kew. Available from http://www.plantsoftheworldonline.org [accessed 7 Sep. 2023].

Rambaut A. 2018. FigTree ver. 1.4.4. Available from https://github.com/rambaut/figtree [accessed 7 Sep. 2023].

Rambaut A., Drummond A.J., Xie D., Baele G. & Suchard M.A. 2018. Posterior summarisation in Bayesian phylogenetics using Tracer 1.7. Systematic Biology 67 (5): 901–904. https://doi.org/10.1093/sysbio/syy032

Ranarivelo-Randriamboavonjy T., Robbrecht E., Rabakonandrianina E. & De Block P. 2007. Revision of the Malagasy species of the genus Tricalysia (Rubiaceae). Botanical Journal of the Linnean Society 155: 83–126. https://doi.org/10.1111/j.1095-8339.2007.00688.x

Robbrecht E. 1978. Sericanthe, a new African genus of Rubiaceae (Coffeeae). Bulletin du Jardin botanique national de Belgique / Bulletin van de Nationale Plantentuin van België 48: 3–78. https://doi.org/10.2307/3667918

Robbrecht E. 1979. The African genus Tricalysia A. Rich. (Rubiaceae-Coffeeae). 1. A revision of the species of subgenus Empogona. Bulletin du Jardin botanique national de Belgique / Bulletin van de Nationale Plantentuin van België 49: 239–360. https://doi.org/10.2307/3668089

Robbrecht E. 1980. Bijdragen tot de Classificatie van de Ixoroideae en tot de revisie van Tricalysia s.l. (Rubiaceae), Part 3. PhD thesis, Ghent University, Belgium.

Robbrecht E. 1981a. Studies in tropical African Rubiaceae (I). Bulletin du Jardin botanique national de Belgique / Bulletin van de Nationale Plantentuin van België 51: 165–189. https://doi.org/10.2307/3667740

Robbrecht E. 1981b. Studies in tropical African Rubiaceae (II). Bulletin du Jardin botanique national de Belgique / Bulletin van de Nationale Plantentuin van België 51: 359–378. https://doi.org/10.2307/3668069

Robbrecht E. 1982. Rubiaceae. Distributiones Plantarum Africanarum 22: maps 757–758.

Robbrecht E. 1983. The African genus Tricalysia A. Rich. (Rubiaceae). 3. Probletostemon revived as a section of subgenus Tricalysia. Bulletin du Jardin botanique national de Belgique / Bulletin van de National Plantentuin van België 53: 299–320. https://doi.org/10.2307/3667793

Robbrecht E. 1986. Studies in tropical African Rubiaceae (7–12). Bulletin du Jardin botanique national de Belgique / Bulletin van de Nationale Plantentuin van België 56: 145–162. https://doi.org/10.2307/3667762

Robbrecht E. 1987. The African genus Tricalysia A. Rich. (Rubiaceae). 4. A revision of the species of sectio Tricalysia and sectio Rosea. Bulletin du Jardin botanique national de Belgique / Bulletin van de Nationale Plantentuin van België 57: 39–208. https://doi.org/10.2307/3668317

Robbrecht E. 1988. Tropical woody Rubiaceae. Characteristic features and progressions. Contributions to a new subfamilial classification. Opera Botanica Belgica 1: 1–270.

Robbrecht E. 1996. Geography of African Rubiaceae with reference to glacial rain forest refuges. In: van der Maesen L.J.G., van der Burgt X.M. & van Medenbach de Rooy J.M. (eds) The Biodiversity of African Plants: 564–581. Springer Netherlands, Dordrecht. https://doi.org/10.1007/978-94-009-0285-5_71

Robbrecht E. & Manen J.-F. 2006. The major evolutionary lineages of the coffee family (Rubiaceae, angiosperms). Combined analysis (nDNA and cpDNA) to infer the position of Coptosapelta and Luculia, and supertree construction based on rbcL, rps16, trnL-trnF and atpB-rbcL data. A new classification in two subfamilies, Cinchonoideae and Rubioideae. Systematics and Geography of Plants 76: 85–145.

Robbrecht E. & Puff C. 1986. A survey of the Gardenieae and related tribes. Botanische Jahrbücher für Systematik, Pflanzengeschichte und Pflanzengeographie 108: 63–137.

Robbrecht E., Puff C. & Igersheim A. 1991. The genera Mitchella and Damnacanthus. Evidence for their close alliance; comments on the campylotropy in the Rubiaceae and the circumscription of the Morindeae. Blumea 35: 307–345. Available from https://repository.naturalis.nl/pub/525774 [accessed 14 Apr. 2023].

Robbrecht E., De Block P., Dessein S. & Lachenaud O. 2020. Rubiaceae, Introduction. In: Sosef M.S.M. (ed.) Flore d’Afrique centrale, nouvelle série, Spermatophyta. Jardin botanique de Meise, Meise.

Ronquist F. & Huelsenbeck J.P. 2003. MrBayes 3: Bayesian phylogenetic inference under mixed models. Bioinformatics 19: 1572–1574. https://doi.org/10.1093/bioinformatics/btg180

Schaumont D. 2020. GBprocesS: genotyping-by-sequencing data processing toolkit. Available from https://gitlab.com/ilvo/GBprocesS [accessed 7 Sep. 2023].

Sonké B., Djuikouo M.-N. & Robbrecht E. 2007. Calycosiphonia pentamera sp. nov. (afrotropical Rubiaceae) from the ‘Lower Guinea’ area. Nordic Journal of Botany 25: 275–280. https://doi.org/10.1111/j.0107-055X.2007.00141.x

Stoffelen P., Robbrecht E. & Smets E. 1997. Pollen morphology of Coffea and Psilanthus (Rubiaceae‐Coffeeae), mainly from Africa. Grana 36: 313–327. https://doi.org/10.1080/00173139709362625

Taylor C.M., Razafimandimbison S.G., Barrabé L., Jardim J.G. & Barbosa M.R.V. 2017. Eumachia expanded, a pantropical genus distinct from Psychotria (Rubiaceae, Palicoureeae). Candollea 72: 289–318. https://doi.org/10.15553/c2017v722a6

Thiers B. 2023. Index herbariorum. A global directory of public herbaria and associated staff. New York Botanical Garden’s Virtual Herbarium. Available from https://sweetgum.nybg.org/science/ih/ [accessed 7 Sep. 2023].

Tosh J., Davis A.P., Dessein S., De Block P., Huysmans S., Fay M.F., Smets E. & Robbrecht E. 2009. Phylogeny of Tricalysia (Rubiaceae) and its relationships with allied genera based on plastid DNA data: resurrection of the genus Empogona. Annals of the Missouri Botanical Garden 96: 194–213. https://doi.org/10.3417/2006202

UNESCO. 2021. State of Conservation: Kahuzi-Biega National Park (Democratic Republic of the Congo). Available from https://whc.unesco.org/en/soc/4029 [accessed 7 Sep. 2023].

Verdcourt B. 1977. A synopsis of the genus Chazaliella (Rubiaceae-Psychotrieae). Kew Bulletin 31: 785–818. https://doi.org/10.2307/4109551

von Teichman I. & van Wyk A.E. 1994. Structural aspects and trends in the evolution of recalcitrant seeds in dicotyledons. Seed Science Research 4 (2): 225–239. https://doi.org/10.1017/S096025850000221X

White F. 1978. The Afromontane Region. In: Werger M.J.A. (ed.) Biogeography and Ecology of Southern Africa. Monographiae Biologicae. Volume 31. Springer, Dordrecht. https://doi.org/10.1007/978-94-009-9951-0_11

Wickham H. 2016. ggplot2: Elegant Graphics for Data Analysis. Springer-Verlag, New York. https://doi.org/10.1007/978-3-319-24277-4_9

Zhang C., Rabiee M., Sayyari E. & Mirarab S. 2018. ASTRAL-III: polynomial time species tree reconstruction from partially resolved gene trees. BMC Bioinformatics 19 (Suppl 6): 153. https://doi.org/10.1186/s12859-018-2129-y

Published
2024-05-17
How to Cite
Ntore, S., Nkengurutse, J., de Backer, S., Sonké, B., De Block, P., Janssens, S. B., Verstraete, B., & Robbrecht, E. (2024). Calycosiphonia or Kupeantha (Coffeeae, Rubiaceae)? A morphological and molecular study of a new species from the Albertine Rift. European Journal of Taxonomy, 935(1), 1–28. https://doi.org/10.5852/ejt.2024.935.2539
Section
Research article