Capurodendron namorokense L. Gaut. & Boluda, 2022

Gautier, Laurent, Boluda, Carlos G., Randrianaivo, Richard & Naciri, Yamama, 2022, Two further new species in the highly-diverse Malagasy endemic genus Capurodendron (Sapotaceae), Candollea 77 (1), pp. 119-126 : 124

Capurodendron namorokense L. Gaut. & Boluda , sp. nov. ( Fig. 2F–G , 3 ).

Holotypus: MADAGASCAR. Reg. Melaky [Pro v. Mahajanga]: Tsingy de Namoroka , sur Tsingy, 16°27'39"S 45°16'35"E, 146 m, 25.X.2016, old fl., Gautier et al. 6276 ( G [ G0419383 ]!; iso-: P [ P00947295 ]!, MO!, S!, TAN!)

Capurodendron namorokense L. Gaut. & Boluda resembles C. antongiliense Aubrév. , C. birkinshawii L. Gaut. & Boluda and C. nodosum Aubrév. in its medium-sized leaves (blade 5.5–12 cm long) with 10–15 straight secondary veins that are regularly spaced and clearly raised on lower surface. It however differs from the latter three species by the lack of an obvious Aubréville branching pattern in terminal shoots and by its smaller outer calyx lobes (5.5 mm vs. 9–11 mm long). It further differs from C. birkinshawii by the acute leaf base (vs. broadly rounded to subcordate) and from both C. birkinshawii and C. antongiliense by its smaller stipules (<5 mm vs.> 6 mm long).

Tree, 11 m tall, 30 cm DBH, outer bark greyish, deeply fissured longitudinally, slash pink, with white latex; terminal twigs 2.5–4 mm in diam., glabrescent, with leaves clustered at the distal 1–2 cm, twig bark pale to medium grey, smooth to longitudinally wrinkled, profusely warted by the attachment of previous years’ leaves, later with short transversal cracks; brachyblasts absent; stipules triangular, 4 × 2 mm at base, felted outside, glabrous inside. Leaves chartaceous, caducous; petiole 9–17 × c. 1 mm, tomentose, terete proximally and semi-terete distally; leaf blade elliptic, 5.5–12 × 2.2–3.7 cm, base acute, apex obtuse, margin entire to slightly sinuous, frequently revolute, glabrous adaxially, whitish-tomentose abaxially, slightly bullate; midrib slightly prominent adaxially, very prominent abaxially, tomentose, 10–15 pairs of craspedodromous raised secondary veins spreading at 60–80°, straight, arching in the last millimetres to form a marginal vein, intersecondaries present, similar to the secondary veins but dissolving half-way to the margin, tertiary veins slightly conspicuous adaxially, inconspicuous abaxially, irregular, not forming well-delimited cells. Flowers solitary or in pairs, at the base of the current years’ shoots; pedicels 9–12 × 0.5–1 mm, tomentose. Sepals (old flowers) 5, quincuncial, two outers sub-triangular to ovato-lanceolate, 5.5 × 4 mm, apex subacute, sparsely tomentose inside except in the central portion, tomentose outside, three inners lanceolate, 4.8 × 4 mm, apex subacute, glabrous inside and densely pubescent with adpressed trichomes outside except at the overlapping margins. Corolla, stamens and staminodes unknown. Ovary (in late flowering state) with 5 uniovulate locules, densely hirsute with beige trichomes. Fruit unknown.

Etymology. – The specific epithet refers to the Tsingy de Namoroka, where the species was found.

Distribution, ecology and phenology. – Capurodendron namorokense is known only from northwestern Madagascar, thriving in dry deciduous forest on limestone outcrops (tsingy). The single known specimen has been collected in October, with old flowers.

Conservation status. – Capurodendron namorokense is known only from a single locality within the Tsingy de Namoroka Protected Area, only 800 m from its border. Its AOO is 4 km ² and its EOO is estimated to be less than 100 km ² (both qualifying for CR under criterion B). The species is documented in only one location with respect to the most probable threat which is selective logging. As most Capurodendron species are actively logged for their valuable timber, it has to be considered as threatened by selective logging despite the natural protection that the tsingy environment provides, and a population decline is projected. On this basis, the species is assessed as “Critically Endangered” [CR B1ab(i,ii,iii,v)+2ab(i,ii,iii,v)] ( IUCN, 2012).

Notes. – Capurodendron namorokense can be recognised by the characteristic venation pattern of its leaves, which is only slightly reminiscent of C. antongilense , C. birkinshawii , and C. nodosum . Genetically, it is retrieved with C. nanophyllum at the base of the “Arid Complex”, comprised of C. androyense , C. mandrarense , C. microphyllum , and C. mikearum ( BOLUDA et al., 2021) . The species of this clade are restricted to the southern half of the island whereas C. namorokense is known only from northwestern Madagascar.

Figures

Fig. 2. – Capurodendron mikearum L. Gaut.& Boluda:A. Habit; B. Twig; C. Slashed bark; D. Fascicles of flowers; E. Flowers. Capurodendron namorokense L. Gaut.& Boluda: F.Slashed bark; G. Twig with two old flowers in an early fruit development stage. [A: Gautier 6329; B–E: Gautier 6339; F–G: Gautier et al. 6276] [Photos: L. Gautier]

Fig. 3. – Capurodendron namorokense L. Gaut.& Boluda. A. Apex of branch; B. Branch; C. Old flower lacking corolla, dissected laterally; D. Old flower lacking corolla; E. Leaf, abaxial side; F. Leaf, adaxial side. [Gautier et al. 6276] [Drawing: G. Loza]