Paracephaelis bardotiae De Block 2022, sp. nov.
Creators: name: Block, Petra De
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Gentianales
Rubiaceae
Paracephaelis
Paracephaelis bardotiae

description: Paracephaelis bardotiae De Block sp. nov.
urn:lsid:ipni.org:names:77260705-1
Figs 2F, 6
Diagnosis
Differing from Paracephaelis aristata sp. nov. by having reddish brown bark (vs pale greyish or fawnish), glabrous lower leaf surfaces (vs densely covered with long erect or spreading hairs), and densely pubescent inner calyx surfaces (vs glabrous).
Etymology
The species is named in honour of Ms Martine Bardot-Vaucoulon, who collected extensively in the tsingy of Ankarana.
Type material
MADAGASCAR – Antsiranana Province, Diana Region, Antsiranana II District • Anivorano Nord, Ankarana RS, Mahoro; 7 Nov. 1997; fr; Bardot-Vaucoulon & Andrianantoinina 933; holotype: P; isotypes: P.
Other material studied
MADAGASCAR – Antsiranana Province, Diana Region, Antsiranana II District • Ankarana, sentier botanique, ca 17 km NE of Mahamasina; 17 Jan. 2002; fl; De Block, Rakotonasolo & Randriamboavonjy 1280; BR, K, MO, P, TAN.
Description
Small tree, 2.5–5 m tall; pubescence tawny. Young shoots brown, densely covered with spreading or appressed hairs; older branches reddish brown, flaking, glabrous. Petioles 2–6 mm long, moderately to densely covered with appressed to spreading hairs. Leaf blades narrowly elliptic, narrowly obovate, elliptic, obovate or ovate, 3–8 × 1–2.5 cm, coriaceous, drying brown or blackish brown and not discolorous, upper surface glossy, both surfaces glabrous except for sparsely ciliate margin, midrib and sometimes secondary veins; base cuneate, obtuse or rounded; tip rounded and mucronate; ciliate pit domatia present; midrib moderately to densely covered with appressed hairs on both surfaces; 6–10 secondary veins on each side of midrib, inconspicuous on both surfaces, rarely sparsely covered with appressed hairs below; higher order venation inconspicuous on both surfaces. Stipules triangular with needle-like awn, outer surface moderately to densely covered with spreading or appressed hairs, inner surface glabrous with row of colleters interspaced with long appressed hairs at the base; sheath 1.5–2 mm long; awn 2–4.5 mm long. Inflorescences sessile, 1–2.5 × 1–2.5 cm, with 5–15 flowers; inflorescence parts densely covered with appressed or spreading hairs; first order axes 0.3–1.5 cm long; higher order bracts with stipular parts reduced or absent, foliar parts narrowly triangular and vaulted, 3–5 mm long, or, linear leaf-like, up to 10 mm long; bracteoles on pedicel just below ovary, opposite, stipular parts absent, foliar parts narrowly triangular, 2–3 mm long, tips acute. Flowers shortly pedicellate, pedicels 0.5–3 mm long when flowering, 0.5–7 mm long when fruiting. Calyx densely covered with appressed hairs outside (lobes less densely pubescent than tube), inner surface densely covered with long appressed hairs all over but most dense at the base; tube 1.2–1.5 mm long; lobes oblong or triangular, 2.5–3 mm long, tips obtuse. Mature corolla, stamens, style and stigma unknown. Ovary 1.5–2 mm long, faintly ribbed longitudinally (when dried), densely covered with appressed or spreading hairs (more densely pubescent than calyx); per locule 3–8 ovules arranged at periphery of placenta attached to middle of septum. Fruits ovoid or spherical, at least 0.6–0.8 cm in diam., faintly ribbed longitudinally and glossy (when dried), densely covered with appressed to spreading hairs; fruit wall thin, with sclerified vascular bundles; pyrenes hemispherical or hemi-ovoid, 5–6.5 × 4–5.5 mm, crustaceous, with rounded base, shortly acuminate tip, small adaxial opening somewhat below the middle and longitudinal central ridge running from the apex to the top of the adaxial opening. Seeds (1–)2–6(–10) per fruit, 3–4 × 2.5–3 mm.
Distribution
Only known from Ankarana National Park in Antsiranana II District, Diana Region (Antsiranana Province) (Fig. 23A).
Habitat and phenology
Low-elevation dry, deciduous or semi-deciduous forest; on limestone covered by sand or clay. Flowers: January; Fruits: November.
Provisional IUCN assessment
Critically Endangered: CR B2ab(iii). Since P. bardotiae sp. nov. is known from only two collections, it is impossible to estimate the EOO. The AOO of the species is estimated to be 8 km 2, which complies with the Critically Endangered category under criterion B2. The two specimens were collected in Ankarana Special Reserve in 1999 and 2002. The species thus occurs in a single location, which complies with the Critically Endangered category under sub criterion ‘a’ of criterion B2. The Ankarana Special Reserve was instated in 1956 and, legally, protection is complete (Nicoll & Langrand 1989). In reality, however, infringements into the reserve are common (Nicoll & Langrand 1989; Cardiff & Befourouack 2008). Forests in the Ankarana Special Reserve are destroyed by bushfires and are cleared for slash-and-burn agriculture. In the last 25 years, the reserve has experienced an enormous influx of migrant miners hunting for sapphires. The miners undercut the forest soil and set up semi-permanent camps inside the reserve. Furthermore, forests in the Ankarana Special Reserve are threatened by illegal logging for hardwood, firewood, and wood for the production of charcoal, by hunting, and by the selective collection of plant species for medicinal or subsistence use (Nicoll & Langrand 1989; Cardiff & Befourouack 2008; Fondation pour les Aires Protégées et la Biodiversité de Madagascar 2020). Because of these facts, a reduction in the extent and quality of the habitat of P. bardotiae sp. nov. is inferred. This threat, in combination with the low AOO and the single location, qualifies the species for Critically Endangered status.
Note
This species is only known from two collections. Mature flowers and fruits are still to be collected.
description: Published as part of Block, Petra De, 2022, Monograph of the western Indian Ocean genus Paracephaelis (Rubiaceae - Pavetteae), with description of thirteen new species, pp. 1-99 in European Journal of Taxonomy 801 on pages 25-27, DOI: 10.5852/ejt.2022.801.1685, http://zenodo.org/record/6358810