The montane trees of the Cameroon Highlands, West-Central Africa, with Deinbollia onanae sp. nov. (Sapindaceae), a new primate-dispersed, Endangered species

Abstract

We test the hypothesis that the tree species previously known as Deinbollia sp. 2. is a new species for science. We formally characterise and name this species as Deinbollia onanae (Sapindaceae-Litchi clade) and we discuss it in the context of the assemblage of montane tree species in the Cameroon Highlands of West-Central Africa. The new species is a shade-bearing, non-pioneer understorey forest tree species reaching 15 m high and a trunk diameter that can attain over 40 cm at 1.3 m above the ground. Seed dispersal has been recorded by chimpanzees (Pan troglodytes ellioti) and by putty-nose monkeys (Cercopithecus nictitans) and the species is used by chimpanzees for nesting. Cameroon has the highest species-diversity and species endemism known in this African-Western Indian Ocean genus of 42, mainly lowland species. Deinbollia onanae is an infrequent tree species known from six locations in surviving islands of montane (sometimes also upper submontane) forest along the line of the Cameroon Highlands, including one at Ngel Nyaki in Mambilla, Nigeria. Deinbollia onanae is here assessed as Endangered according to the IUCN 2012 standard, threatened by severe fragmentation of its mountain forest habitat due to extensive and ongoing clearance for agriculture. The majority of the 28 tree species of montane forest (above 2000 m alt.) in the Cameroon Highlands are also widespread in East African mountains (i.e. are Afromontane wide). Deinbollia onanae is one of only seven species known to be endemic (globally restricted to) these highlands. It is postulated that this new species is morphologically closest to Deinbollia oreophila, a frequent species at a lower (submontane) altitudinal band of the same range. Detailed ecological data on Deinbollia onanae from the Nigerian location, Ngel Nyaki, where it has been known under the name Deinbollia “pinnata”, is reviewed.

The endemic plant species of Bali Ngemba Forest Reserve, Bamenda Highlands Cameroon, with a new Endangered cloud-forest tree speciesVepris onanae(Rutaceae)

“…Evidence for seed dispersal by primates (chimpanzees) was recently presented for another new species of Vepris (Langat et al . 2021a) for which traversal of human created habitat is known to be problematic (Cheek et al 2021a). While the second Vepris species at Bali-Ngemba, Vepris bali occurred at higher altitude and is considered likely to be extinct (Cheek et al .…”

“…He led field teams of YA staff working with those of K that resulted in the collection of numerous specimens during these surveys and personally collected the type specimen and only known female specimen of this species in the field ( Onana 2006, K, YA). Ledermanniella onanae Cheek (Cheek 2003), Diospyros onanae Gosline (Gosline 2009), Psychotria onanae O.Lachenaud (Lachenaud 2019) and Deinbollia onanae Cheek (Cheek et al . 2021a) are also named for him.…”

“…The species might be considered severely fragmented since the three forests in which it survives have become separated from each other due to clearance for agriculture. Evidence for seed dispersal by primates (chimpanzees) was recently presented for another new species of Vepris (Langat et al 2021a) for which traversal of human created habitat is known to be problematic (Cheek et al 2021a). While the second Vepris species at Bali-Ngemba, Vepris bali occurred at higher altitude and is considered likely to be extinct (Cheek et al 2018a), we consider it likely that Vepris onanae survives there at present since it was found to be relatively frequent in our surveys of 2000 -2004, witness the number of specimens cited.…”

Taxonomic Monograph ofSaxicolella(Podostemaceae), African waterfall plants highly threatened by Hydro-Electric projects, with five new species

“…Kniphofia reflexa Hutch. ex Codd (Hepper 1968), Scleria cheekii Bauters (Bauters et al 2018), Deinbollia onanae Cheek (Cheek et al 2021b) Saxicolella marginalis is genuinely rare in Cameroon, since the first author has targeted searches for it at other falls and rapids in the Mt Oku area and not found it, although two other species of Podostemaceae have been found . Near-comprehensive botanical surveys in other locations S, W and E of Kilum-Ijim have failed to find additional locations although they brought to light several other species of Podostemaceae (see references above under Saxicolella ijim).…”

Impatiens banensp. nov. &I. etugeisp. nov. (Balsaminaceae), threatened lowland species of the Cross-Sanaga Interval, Cameroon

“…New species to science from Cameroon are being published steadily, from herbs of waterfalls, forest shrubs to canopy trees (Achoundong et al 2021;Alvarez-Aguirre et al 2021;Cheek & Onana 2021;2021b;in press;Gosline et al 2022). Many of these species, including those described in this paper, were collected as part of a programme to produce a series of conservation checklists (see below) for areas of intact natural habitat ranging over much of the Cross-Sanaga interval (Cheek et al 2001).…”