Pandanus kalobinonensis Callm., Razakamal. & Luino, 2020

Callmander, Martin W., Razakamalala, Richard, Luino, Iacopo, Andriamarisoa, Roger Lala & Buerki, Sven, 2020, Novelties from the Northern Mountains Complex of Madagascar V: A new threatened Pandanus (Pandanaceae) from the Kalobinono massif, Candollea 75 (1), pp. 99-105 : 100-103

Pandanus kalobinonensis Callm., Razakamal. & Luino , sp. nov.

( Fig. 2 , 3 ).

Holotypus: MADAGASCAR. Reg. DIANA [Prov. Antsiranana]: Fkt. Anketrabe-Belinta , massif du Kalobinono , 13°38'42"S 48°40'29"E, 740 m, 16.X.2015, fr., Luino & Razakamalala 106 ( G [ G00341880 ]!; iso-: TAN!) .

Haec species ab omnibus congeneris syncarpio parvo globoso solitario brevipedunculato atque drupis monocarpellatis in stigma spiniforme adaxialiter sulcatum desinentibus differt.

Treelet to 3–4 m tall; stem prickly, up to 5 cm dbh. Leaves 125–160 cm long, 2–3 cm wide in the middle, 3 cm wide near the sheath, gradually attenuate in the upper third, and tapering to a flagellate apex in the distal 5 cm, coriaceous; longitudinal and transverse veins visible on both surfaces; prickles white in vivo; marginal prickles beginning at (4–) 5–6 cm above the base and extending to the apex, antrorse, 2–4 mm and placed 2–8 mm apart in the lower third, to 2 mm and 5–10 mm apart in the middle third; to <1 mm and 2– 4 mm apart in the distal third; midrib armed below in the upper 2/3, prickles small (<1 mm), irregularly disposed (5–10 mm); sheath 5 cm long, c. 3.5 cm wide at apex c. 4–4.5 cm large at base. Infrutescence terminal, a solitary syncarp subtended by naviculate bracts, borne on a straight short peduncle; syncarp 50 × 60–70 mm, globose to ovoïd; peduncle straight, short, 65 mm long, c. 9 mm in diam at apex, trigonous, 3– 4 remaining bracts, c. 5– 7.5 cm long, positioned near the base of the syncarp, boat-shaped at base and becoming flagellate in the distal part.

Drupes c. 65–140 per syncarp, (15–)20(–25) mm high, 5–7 mm wide, (3–) 4–6 mm thick, 4–6 angled; carpel 1, free in the upper fourth, tapering to the base; pileus pyramidal, somewhat rounded at apex. Stigma 1, erect or curved, spiniform, on the centre of the apical face of the pileus, brown in vivo, 3–5 mm in length, stigmatic groove abaxial, covering c. 2/3 of the length of the stigma. Endocarp 10–13 mm long in the centre, <1 mm wide, 4–6 mm away from stigma base; seed locule oblong, 10 – 12 × 3– 5 mm, superior and inferior mesocarp fibrous. Staminate plant unknown.

Etymology. – The species epithet refers to the Kalobinono massif and its eroded landscape of Isalo Sandstone dominated by a pair of distinctly shaped domes (fig. 1). The literal translation from the Sakalava dialect means “princess with large breasts”. Similarly, the name Galoko refers to a local king. The two summits are sacred for the local Sakalava. According to the legend, the queen embodied in the Kalobinono massif gave birth to the nearby Manongarivo massif, fathered by the king at Galoko (SOLO et al., 2008).

Distribution and ecology. – Pandanus kalobinonensis is currently only known from the lowland moist evergreen forest in the Kalobinono massif (northwestern Madagascar) between 420 to 740 m elevation.

Conservation status. – Pandanus kalobinonensis is known from 2 locations from the Galoko-Kalobinono Protected Area collected at a distance of c. 1 km in lowland moist evergreen forests. The holotype collection is located well within the intact forest at 740 m, but the paratype is located at 425 m and was made only a hundred meters from recently cleared forest. This latter location could be projected to disappear in a relatively near future. Lowland moist evergreen forests were highly threatened in the

massifs where Tsimihety immigrants have established settlements for several decades and are practicing slash and burn agriculture (SOLO et al., 2008) ( Fig. 1 ). The loss of moist evergreen forest area between 2006 to 2016 has reached 1408 ha, which represents 15% of the total cover of the PA (RABENANDRASANA et al., 2018). Since mid 2018, slash and burn agriculture is restricted within the strict conservation zone, but the risk of uncontrolled pasture fire is still a threat (P. Ranirison, pers. comm.). With an area of occupancy (AOO) of 4 km ², and despite that both collections ocur within limits of the protected area, P. kalobinonensis is therefore assigned a preliminary conservation status of “Endangered” [EN B1ab(ii,iii,iv,v)+2ab(ii,iii,iv,v)] using IUCN Red List Categories and Criteria ( IUCN, 2012).

Notes. – Pandanus kalobinonensis is morphologically distinct among Malagasy species of Pandanus . Its small globose solitary syncarp bearing monocarpellate drupes topped by a spiniform stigma ( Fig. 2 , 3 ) resembles several Southeast Asian Pandanus species. Several species in Madagascar were hypothesized to have morphological Indo-Malaysian affinities (STONE 1974; CALLMANDER & LAIVAO, 2003). Pandanus platyphyllus Martelli was for example placed by STONE (1974) in the Malaysian Pandanus subgenus Rykia (Vrise) B.C. Stone before staminate plants were studied by HUYNH (1977) and confirmed to belong to the Afro-Malagasy subgenus Vinsonia (Warb.) B.C. Stone. Phylogenetic analyses further demonstrated that those latter morphological affinities were most likely the result of convergent evolution since all Malagasy species of Pandanus subgenus Vinsonia formed a monophyletic clade ( BUERKI et al., 2012). In this context, Pandanus kalobinonensis is therefore classified in Pandanus subgenus Vinsonia . The sectional placement of this species remains to be established, like other recently discovered morphologically isolated species in Madagascar (see CALLMANDER et al., 2008, 2009b, 2013).

Paratypus. – MADAGASCAR. Reg. DIANA [Prov. Antsiranana]: Beramanja , Anketrabe Belinta , massif du Kalobinono , 13°38'16"S 48°40'21"E, 425 m, 29.IX.2013, fr., Razakamalala et al. 7586 (TAN) .

Figures

Fig. 2. – Pandanus kalobinonensis Callm., Razakamal. & Luino. A. Fruiting branch; B. Detail of the syncarp; C. Drupe; D. Cross section of a drupe; E. Basal section of a leaf; F. Mid section of a leaf; G. Apex section of a leaf. [A–D: Razakamalala et al. 7586, TAN; E–G: Luino & Razakamalala 106, TAN] [Drawing: R.L. Andriamiarisoa]

Fig. 3. – Photograph of Pandanus kalobinonensis Callm., Razakamal. & Luino. [Luino & Razakamalala et al. 106] [Photo: I. Luino]

Fig. 1. – The Galoko mountain range with the Galoko summit on the left, the distinctly shaped domes of the Kalobinono on the right and rice plantations in the foothills. [Photo: S. Wohlhauser]