Tsingya bemarana Capuron

Buerki, Sven, Doherty, Rebecca, Gautier, Laurent & Callmander, Martin W., 2014, Rediscovery of the genus Tsingya Capuron (Sapindaceae) and its phylogenetic position, Candollea 69 (2), pp. 195-200 : 196-199

Tsingya bemarana Capuron in Mém. Mus. Natl. Hist. Nat., sér. B, Bot. 19: 104. 1969.

( Fig. 2 ).

Typus: MADAGASCAR. Prov. Mahajunga: Plateau calcaire du Bemahara , aux env. de Tsiandro , [18°39’55”S 44°43’42”E], XI.1952, galled fl. & imm. fr., Service Forestier 6762 (holo-: P [ P00076184 ]! ; iso-: P [ P00076183 , P00214682 ] images seen, P [ P00363062 ]!, TEF [ TEF000597 ]!) .

Monoecious trees with platanoid bark exfoliating in plates, 13-25 m tall, 0.2-0.5 m in diam., young branches covered with dense fascicled-stellate pubescence. Leaves alternate, 15-25 × 20-23 cm, paripinnately compound, (4-)6-8- foliolate; leaflets ovate to elliptic, margin entire, petiolulate (2-7 mm), sub-membranous, (5-)9-12(-16) × (2.5-)3-4(-5) cm, discolor, dark green and shiny above and pale green below; base attenuate; apex acuminate; margin entire. Inflorescences axillary, racemose, 4-7 cm in length. Flowers small, 3-4 mm in diam., regular; sepals 5, valvate; petals absent; disc flattened, irregularly lobed, 2-2.5 mm in diameter, stellate pubescent; stamens 8-10, c. 4 mm in length, inserted into deep holes in the disc, filaments distinct; staminodia resembling short stamens; ovary 3-locular; style terminal, 3 mm in length, with stigmatic lines; ovule 1 per locule. Fruit indehiscent, pear-shaped berry, shortly apiculate, somehow asymmetrical, 3-3.5 × 2-2.5 cm, covered by stellate trichomes, 1-seeded by abortion, the seed surrounded by a fleshy, translucid arillode, and bearing a hilum scar the entire ventral length [adapted in part from CAPURON (1969) and SCHATZ (2001)].

Habitat and Ecology. – The recent collection of Tsingya bemarana came from sample site B020 of the forest study at Beanka, which was characterized by forest cover of 100% on exposed eroded limestone rock, and by the presence of: Pandanus flagellibracteatus Huynh (Pandanaceae) and Omphalea occidentalis Leandri (Euphorbiaceae) forest, with closed canopy and low emerging tree cover ( RAKOTOZAFY & al., 2013). This forest type has an average canopy of 12.5 m, and the tree collected formed part of the canopy. The species was listed by BOLLIGER (2014) as one of the 58 species of Beanka that are apparently exclusive to limestone. It would seem to be restricted to the dry deciduous forests on eroded limestone (“tsingy”) of western Madagascar in the Bemaraha and Beanka regions ( Fig. 3 ).

Conservation status. – Despite an intensive botanical inventory in the Beanka region, only one tree was found, and the species has not been collected from Bemaraha since 1952. Nevertheless, the forest of Behandrao, South of Tsiandro on the eastern slopes of Bemaraha ( Fig. 3 ), where the type has been collected, is under protection and very few collections have been made in this region since the 1950’s. This is also true for the Ambodiriana valley within the protected area to the west of Antsalova ( Fig. 3 ). With only two collections known and one reliable field observation ( LEANDRI, 1954), an “Extent of Occurrence” of 437 km 2, an “Area of Occupancy” (AOO) of 27 km 2 and three subpopulations (calculation following CALLMANDER & al., 2007), within a fully Protected Area (Bemaraha) and a Protected Area that holds temporary protection (Beanka), Tsingya bemarana is assigned a preliminary status of “Vulnerable” (VU D2) following IUCN Red List Categories and Criteria (2012). Despite the fact that all known populations are currently under protection, Tsingya bemarana is rare and known only from three locations.

Observations. – In CAPURON (1969: 85) ’s flower identification key to the Schleichereae , Tsingya keys out next to Beguea Capuron based on the absence of corolla. While working on a revision of Beguea for Madagascar, SCHATZ & LOWRY (pers. comm.) have therefore hypothesized that Tsingya may be conspecific with Beguea . In CAPURON (1969: 86) ’s fruit identification key, Tsingya keys out next to Plagioscyphus based on the hilum scar that runs on the entire ventral length of its seed. The phylogenetic inference is in agreement with the hypothesis that Tsingya is in fact closely related to Plagioscyphus in Madagascar (see above). The characters of the mature fruit of Tsingya recently discovered is in congruence with the phylogenetic evidence; Tsingya can easily be distinguished from Beguea by its pubescent pyriform fruits (vs. glabrous globular to ovoid) ( Fig. 2 ). Tsingya differs from Plagioscyphus by the type of indument on its fruit (stellate trichomes in Tsingya vs. simple in Plagioscyphus ) and the corolla (absent vs. present). The monoecious breeding system of Tsingya is also unique in the “ Macphersonia group” (all the other genera are dioecious or polygamous; BUERKI & al., 2010) and represents a good morphological synapomorphy for this genus.

Specimens examined. – MADAGASCAR. Prov. Mahajanga: Bemaraha, forêt de Behandrao , [18°49’37”S 44°52’25”E], 29.XI.1952, Leandri & al. 1969 (= Service Forestier 6762) ( P [ P00076181 , P00076182 ]) ; Beanka, Partie N, bord de la rivière Bokarano , 17°54’36”S 44°28’46”E, 222 m, 10.II.2012, fr., Hanitrarivo, Bolliger & Rakotozafy 167 ( G [ G00376555 ], K, L, MO, P, TEF).

Figures

Fig. 2. – Herbarium scan of Tsingya bemarana Capuron collected by Hanitrarivo, Bolliger & RakotozaFy 167 kept at G showing the pyriform fruit.

Fig. 3. – Detailed map of western Madagascar showing the distribution of Tsingya bemarana Capuron (herbarium collections: stars; observation: circle) in Bemaraha and Beanka, plotted on a map of forest cover in 2000 (grey) following HARPER & al. (2007).