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| Uvariopsis niangadoumae Couvreur & Dagallier, in Couvreur, Niangadouma, Nguimbit, Paradis, Dagallier, Baudoin-Huit, Collin, Haran et Droissart, 2025. |
Abstract
Background and aims – Gabon is a major centre of biodiversity. We describe a new species from the tropical plant family Annonaceae: Uvariopsis niangadoumae sp. nov., known from a single population in the Monts de Cristal National Park.
Material and methods – Field work was conducted to collect plant specimens and observe floral visitors. Pollen samples were collected and prepared for microscopic analysis. The phylogenetic tree of Uvariopsis was reconstructed using a maximum likelihood method and based on hundreds of nuclear markers. Pollination biology was studied using a DIY camera trap (PICT) placed near a female flower to record floral visitors and their behaviour for one full day. Several flower visitors were collected and identified using DNA barcoding.
Key results – Uvariopsis niangadoumae is a tree reaching five metres tall, characterized by strong-scented leaves, few-flowered cauliflorous foul-smelling flowers, and large pollen grains shed in tetrads. The species is endemic to a small area within the Monts de Cristal National Park. Phylogenetic analysis places U. niangadoumae within the “large-leaved clade” species complex with now five taxa. Pollination is diurnal, and the primary pollinator is a rove beetle (Staphylinidae), which uses the female flowers as a mating site, with males fighting for control of the flower. The rove beetles might be attracted by a chemical cue, the foul scent of the flowers, and visual cues, with the inner part of the petals resembling mushrooms.
Conclusion – These results emphasize once again the importance of the Monts de Cristal National Park for biodiversity and highlight conservation concerns for the newly described species. The new species is monitored regularly, especially for fruiting individuals, to support ex situ propagation. The Kinguélé Aval project maintains a conservation nursery with 56 species, including 20 individuals of this new species.
Keywords: camera trap, hydrological dam, IUCN conservation, plant-insect interactions, saprocantharophily, Staphylinidae
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Uvariopsis niangadoumae, detail of male and female flowers. A. Detail of inner side of female (left) and male (right) flowers, one petal removed. B. Detail of female flower, one petal removed. C. Detail of inner side of one female petal. D. Old female flower. E. Detail of sepals on male flower. F. Young male flower, not at anthesis yet. From Couvreur 1803. Photos by Thomas L.P. Couvreur. Scale bars: A–D = 0.5 cm. |
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| Uvariopsis niangadoumae, natural habit and vegetative characters. A. Habitat along a small stream. B. General view. C. Young leaves, light green, dropping. D. Detail of adaxial side of leaf base. E. Detail of abaxial side of leaf base. From Couvreur 1803. Photos by Thomas L.P. Couvreur. |
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| Uvariopsis niangadoumae, detail of fruits and flower visitors. A. One monocarp. B. Longitudinal section of a single monocarp showing the seeds. C. Male flower with small Diptera visitors. D. Female flower with one large Staphylinidae beetle. F. Upper side of male flower covered with Crematogaster sp. ants. F. Male flower with large Staphylinidae beetle emerging covered in pollen. From Couvreur 1803. Photos by Thomas L.P. Couvreur. Scale bars: A, B = 1 cm. |
Uvariopsis niangadoumae Couvreur & Dagallier, sp. nov.
Diagnosis: Uvariopsis niangadoumae resembles U. korupensis in the shape and dimensions of its leaves and the overall size of the flowers. It differs by having strong scented leaves versus no clear scent in U. korupensis. Furthermore, U. niangadoumae bears no more than two, few-flowered inflorescences on small protrusions at the base of the trunk, whereas in U. korupensis the base of the trunk is densely covered with inflorescences. Flowers of U. niangadoumae have free petals with a length:width ratio between 1.3 and 1.7 vs fused at base and a l:w ratio between 2.2 and 7 in U. korupensis. Uvariopsis niangadoumae also has fewer carpels than U. korupensis (20–25 vs 25–120).
Etymology: This species is dedicated to the Gabonese botanist Raoul Niangadouma who participated in the (long and arduous) botanical inventories that led to the official recognition of the Monts de Cristal National Park. Raoul Niangadouma is also one of the collectors of the type specimen of this species.
Thomas L.P. Couvreur, Raoul Niangadouma, Igor Nguimbit, Anne-Hélène Paradis, Léo-Paul M.J. Dagallier, Lola Baudoin-Huit, Myriam Collin, Julien M. Haran and Vincent Droissart. 2025. Passion and Combat on a Floral Stage: A New Species of Uvariopsis (Annonaceae) from Monts de Cristal, Gabon, with Notes on its Unique Pollination Ecology. Plant Ecology and Evolution. 158(2): 294-308. DOI: doi.org/10.5091/plecevo.152843
