Capurodendron mikearum 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 : 120-122

Capurodendron mikearum L. Gaut. & Boluda , sp. nov. ( Fig. 1 , 2A–E ).

Holotypus: MADAGASCAR. Reg. Atsimo-Andrefana [Prov. Toliara]: Tuléar II , Belalanda, Ranobe , forêt de Ranobe PK32, 23°00'46"S 43°39'02"E, 101 m, 25.XI.2006, fl., Razaf indraibe et al. 165 ( G [ G00390469 ] !, iso-: MO-6427623 !, P, TAN!)

Capurodendron mikearum L. Gaut. & Boluda differs from its closest relative C. mandrarense Aubrév. by its glabrous lower leaf surface (vs. pubescent), with secondary nerves that are slightly raised (vs. conspicuously raised). It differs from the morphologically similar C. greveanum Aubrév. by its greyish pubescent young shoots (vs. green and glabrous), petioles with scattered trichomes (vs. glabrous), the presence of brachyblasts, and the very dense calyx indumentum (vs. sparse).

Tree, sometimes shrub, up to 18 m tall, 60 cm DBH, bark greyish, profoundly fissured longitudinally, outer wood pinkish, with white latex, inner wood light yellow; terminal twigs 2 mm in diam., at first densely brown-whitish curly pubescent, later glabrous, 2-year twigs pale to dark grey, longitudinally wrinkled, lenticels inconspicuous; brachyblasts present, 0.5–1(–3) cm long; stipules soon caducous, ovato-triangular, 1.5–2 mm long, densely pubescent on outer side. Leaves probably caducous; petioles 1.1–2.8 cm long, 0.8 mm in diam., with scattered thin whitish trichomes; blade oblanceolate to elliptical, rarely rounded, 2.2–5.5 × 1.4–3.2 cm, base cuneate to attenuate, apex rounded, sometimes acute, margin entire, with pubescent indumentum initially, soon becoming almost glabrous on both surfaces, except on the midrib of the lower surface that retains scattered yellowish to whitish trichomes, slightly discolorous in living plants (upper surface shiny, lower paler); midrib slightly prominent below, flat or slightly raised above, 8 –13 pairs of camptodromous secondary veins spreading at 30–45°, straight or arching towards the leaf apex, slightly raised on both surfaces, pale green or yellowish, intersecondaries absent or when present similar to the tertiaries, tertiary veins sparse, slightly raised on dried specimens, forming irregular cells that contains a quaternary venation forming isodiametric polygons. Flowers solitary to 6-fasciculate, 6– 9 × 5–7 mm, on last year shoots and brachyblasts, flowering sometimes profuse and packed; pedicels 3– 6 × 0.7 – 1 mm, enlarging distally below calyx, densely pubescent; sepals 5, quincuncial, ovate-lanceolate, apex slightly acute, two outers 4–6.5 × 3.2–3.9 mm (at base), densely golden pubescent inside and outside, three inners 3.4 –5 × 2.9–5.3 mm (at base), with scattered trichomes inside and densely pubescent outside except the margin; corolla gamopetalous, 5-lobed, pale yellowish or white, tube c. 3 mm long, lobes lanceolate, 3.5–5.3 × 1.1–1.9 mm, glabrous, erect, convex and enfolding the anther. Stamens 5, filaments cylindrical, 1.1–1.6 × 0.3–0.5 mm, same colour as the petals, glabrous, attached to the top of the corolla tube; anthers cream-coloured, lanceolate, 1.9–2.4 × 0.8–1 mm, medifixed, cordate at the base, extrorse, each theca lanceolate, 1.9–2.4 × c. 0.3 mm; connective hairy, prolonged into a 0.3 mm long mucro. Staminodes 5, alternate with respect to petals and stamens, ovate-triangular, same colour as the petals, 2.9–4.2 × 1–1.5 mm, with an arista 1.6 –2.7 mm long, carnose, glabrous except on the margins which are densely hirsute with trichomes that may bend and cover the complete outer surface, connivent and concealing the ovary at least during part of anthesis. Ovary slightly pentagonal, 1.4 × 1.4 mm, with 5 uniovulate locules, densely hirsute; style 5–7.5 × 0.4 mm, glabrous; stigma with 5 minute papillae. Fruit on a thickened pedicel 3 mm in diam., globose to ovoid, 14 –22 × 11–15 mm, apiculate, glabrescent, with a persistent enlarged (c. 2 ×) calyx; seeds one per fruit, 15–19 × 13 × 11 mm, testa shiny, scar basiventral, 11–13 × 6–8 mm.

Etymology. – This species is named after the Mikea ethnic group which inhabits the forests where the species is found.

Distribution, ecology and phenology. – Capurodendron mikearum is endemic to Madagascar where it is found in the Atsimo Andrefana region (part of the former Toliara Province) from Morombe southward to Toliara, at elevations between 10–135 m, never more than 20 km away from the coast. It occurs in forests on laterite sands in a transition zone between dry deciduous forest and dry spiny thicket. The flowering period extends from November to March and fruits were recorded in November and from February to April.

Conservation status. – The estimated EOO calculated with all available herbarium specimen data is 1,755 km ², and the minimum AOO is 76 km ² (both qualifying for EN under criterion B). The species thrives at only five locations with respect to the most important threat, which is habitat transformation for large scale agriculture. Other important threats include uncontrolled forest fires and very probably selective logging. It is known from 26 herbarium collections. Although the five locations are in protected areas or in their close vicinity, the pressures encountered by the dry forests in the southwestern Madagascar are so high that a projected continuing decline is inferred and justifies the assignment of this species to the category “Endangered” [EN B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v)] ( IUCN, 2012).

Notes. – Specimens attributed to this species have alternatively been identified as Capurodendron mandrarense or C. greveanum , as they share character states with both. The new species differs from its closest relative C. mandrarense by its glabrous lower leaf surface (vs. pubescent), with secondary nerves that are slightly raised (vs. conspicuously raised). It differs from the morphologically similar C. greveanum by its greyish pubescent young shoots (vs. green and glabrous), petioles with scattered trichomes (vs. glabrous), the presence of brachyblasts, and the very dense calyx indumentum (vs. sparse).

The three species occur in southwestern Madagascar and Capurodendron greveanum is even sympatric in the northernmost part of C. mikearum distribution. The hypothesised hybrid origin of this taxon has not been validated by the genetic studies we conducted, which indeed revealed that the new species was quite far from C. greveanum . It is however closely related to C. mandrarense . Together with the very distinctive C. androyense , these three species form the core of what has been referred as the “Arid Complex” ( BOLUDA et al., 2021, 2022).

Additional specimens examined – MADAGASCAR. Reg. Atsimo-Andrefana [Prov. Toliara]: Belalanda, Ranobe, 23°04'S 43°42'E, 110 m, 16.III.2006, fl. & old fl., Andrianjafy 1669 (G, MO, P, TAN); ibid. loco, 23°01'S 43°39'E, 100 m, 16.III.2006, fr. & old fl., Andrianjafy et al. 1679 (G, MO, P, TAN); Belakana, embouchure sur Fiherenana, [23°18'S 43°39'E], XI.1956, bud, Bosser 10408 (P, TEF); 12 km N of Tulear on road to Morombe , [23°15'S 43°38'E], c. 0 m, 5.II.1975, Croat 30799 (MO, TAN); 16–18 km N of Tulear along road to Morombe , [23°12'S 43°37'E], c. 0 m, 6.II.1975, Croat 30885 (MO, TAN); Ranobe PK 32, partie W, 15 km à l’ESE d’Ankilimalinika, 23°01'S 43°42'E, 130 m, 17.II.2017, old fl. & imm. fr., Gautier et al. 6329 (G, MO, P, TAN); ibid. loco, bud, Gautier et al. 6331 (G, TAN); ibid. loco, old fl., Gautier et al. 6332 (G, MO, P, TAN), 6333 (G, K, MO, P, S, TAN); Mikea, partie sud, 11 km à l’W d’Ankililoloaka, 22°47'S 43°31'E, 120 m, 18.II.2017, old fl., Gautier et al. 6336 (G, MO, P, TAN); ibid. loco, 120 m, 18.II.2017, ster., Gautier et al. 6337 (G, TAN); ibid. loco, 13.5 km à l’W d’Ankililoloaka, 22°47'S 43°29'E, 130 m, 18.II.2017, fl., Gautier et al. 6339 (G, K, MO, P, S, TAN); ibid. loco, ster., Gautier et al. 6340 (G, TAN); Ifaty, dans l’arboretum, 23°07'S 43°37'E, 10 m, 18.II.2017, ster., Gautier et al. 6341 (G, MO, P, TAN); Songaritelo, [23°14'S 43°37'E], 23.IX.1967, ster., Koechlin 44 (P); N of Toliara, forêt de Mikea, c. 18 road-km W of Vorehe, [22°16'S 43°26'E], 50 m, 8.II.1998, old fl., McPherson et al. 17358 (G, MO); Mikea Forest , 22°47'S 43°31'E, 130 m, 20.XI.2002, fl., Phillipson 5603 (G, MO, P); Ifaty, 23°09'S 43°37'E, 14.I.1994, old fl. & fl., Rabesandratana 4192 (P); Tulear II, Belalanda, forêt de Ranobe, 23°18'S 43°39'E, 35 m, 18.XI.2002, fr., Ranaivojaona 459 (G, MO, P, TAN); Toliara II, Ankilimalinika, forêt de Ranobe, 23°00'S 43°41'E, 100 m, 24.IV.2005, fr., Randrianaivo & Randrianarivelo 1187 (G, MO, P, TAN); 35 km N of Toliara, along coast road, 23°4'S 43°35'E, 20 m, 12.XII.1988, fl. & old fl., Schatz & Miller 2477 (MO, P, S, TAN); au bord d’un chemin qui mène vers Mambo, Ankazomanga Tosimitro, [23°16'S 43°43'E], 19.VI.1954, old fl., Service Forestier 10220 (P); rte de Tuléar à Sarodrano, au pied des falaises du plateau calcaire, [23°29'S 43°46'E], 16.III.1961, fr., Service Forestier 20178 (P, TEF); Sarodrano et environs, [23°32'S 43°45'E], XII.1961, fl., Service Forestier 20831 (MO, P, TEF); sables littoraux au S de Morombe, [21°48'S 43°21'E], 1.XII.1969, fl., Service Forestier 28965 (MO, P, TEF).

Figures

Fig. 1. – Capurodendron mikearum L. Gaut.& Boluda. A. Corolla, seen from inside; B. Corolla, seen from outside; C. Flower; D. Leaf, abaxial side; E. Leaf, adaxial side; F. Flower, dissected laterally; G. Flowering branch; H. Fruit; I. Seed. [A–G: Gautier 6339; H–I: Andrianjafy 1679] [Drawing: G. Loza]

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]