Terminalia carinata Sabatier & J.Engel, 2020

Engel, Julien & Sabatier, Daniel, 2020, Terminalia carinata Sabatier & J. Engel, sp. nov. (Combretaceae), a new large tree species from the Guiana shield revealed by re-examination of material previously identified as T. guyanensis Eichler, Adansonia (3) 42 (16), pp. 261-271 : 262-266

Terminalia carinata Sabatier & J.Engel , sp. nov.

( Figs 1 , 2 , 3 , 4 )

TYPUS. — French Guiana. Montagnes Plomb , inv. code PG18-63A 3, 355 m, 4°59’N, 52°59’W, fr., 18.X.2004, Sabatier et al. 4891 (holo-, CAY ([ CAY182887 !]); iso-, P ([ P01155925 !], K!).

DIAGNOSIS. — The new species differs from other neotropical Terminalia by its papillose, palish-gray and slightly pubescent leaf undersurface, its quite long petioles (usually> 2 cm) and its 2-winged fruits with wings wider than fruits central body that is distinctly keeled on one face and flat on the other one.

ETYMOLOGY. — The specific epithet refers to the fruit central body which is keeled (or carinate) on one face and flat on the other one. DISTRIBUTION. — Consulted specimens come mainly from French Guiana, only two from Suriname. One fruiting specimen, collected in the Brazilian state of Para by Kuhlmann and identified as Terminalia cf. mameluco Pickel by Stace in 2002, looks alike T. carinata Sabatier & J.Engel , sp. nov. However, the authors would need to physically study this herbarium sheet to be completely sure of the determination in T. carinata Sabatier & J.Engel , sp. nov.

HABITAT. — T. carinata Sabatier & J.Engel , sp. nov. occurs in terra-firme forest from sea-level to 630 m a.s.l. This species grows preferentially on well-drained soil in high, irregular canopy forests ( Gond et al. 2011).

PHENOLOGY. — Mature flowers have been recorded in August during leafless stage, fruits in January, July, October and November.

CONSERVATION STATUS. — According to herbarium sheets and inventory data from GUYAFOR and GUYADIV networks ( Engel 2015), T. carinata Sabatier & J.Engel , sp. nov. is known from 16 localities in French Guiana and two localities in Suriname. The Extent of occurrence (EOO) calculated is 58 090 km² and the area of occupancy (AOO) 80 km ², and the localities where this species is encountered are not threatened by human activities. According to the IUCN Red List criteria ( IUCN 2012), T. carinata Sabatier & J.Engel , sp. nov. is thus classified as Least Concern (LC). However, and even if the number of individuals encountered in the GUYAFOR and GUYADIV plots is greater than those of T. guyanensis (52 vs 12), it remains an uncommon tree species with unknown ecological requirements and whose consequences of climate change on its regeneration cannot be predicted (Esquivel-Muelbert et al. 2018). AFFINITIES. — Among other neotropical Terminalia , seven species have fruits with two wings longer than 1 cm and a body keeled or ridged on one side and flat on the other ( T. arbuscula Sw. , T. bucidoides Standl. & L.O. Williams , T. chicharronia C. Wright , T. eriostachya A. Rich. , T. mameluco Pickel , T. oblonga (Ruiz & Pav.) Steud. , and T. valverdeae A.H. Gentry ). Terminalia carinata Sabatier & J.Engel , sp. nov. differs from these species by its leaf undersurface palish-gray and slightly pubescent, its venation weakly brochidodromous and its petioles usually longer than 2 cm. Vegetatively, the leaves of T. carinata Sabatier & J.Engel , sp.nov. closely resemble those of T. argentea Mart. & Zucc. , which is a small tree species typically found in savannah-like ecosystems like the Brazilian cerrado. But their fruits are different, those of T. argentea have a central body swollen on both sides and rounded (although sometimes with a slight ridge), whereas T. carinata Sabatier & J.Engel , sp. nov. fruits have a central body keeled on one side and flat on the other side with larger, more elongated wings.

OTHER MATERIAL STUDIED. — French Guiana. St-Élie, Réserve naturelle des Montagnes de la Trinité , Plateau Tabulaire, 400-630 m, 4°35’N, 53°21’W, fr., VII.1999, Poncy & Crozier 1415 ( CAY [ CAY114758 !]) ; Gobaya Soula, Bassin du Maroni , 230 m, 3°37’N, 53°58’W, fr., 31.I.1989, De Granville et al. 10958 ( B, CAY [ CAY 010133 !], P, U, US [ US 00601847 ], NY) ; Saül, Mont la Fumée , 200-400 m, 3°37’N, 53°12’W, fr., 21.X.1982, Mori & Boom 15121 ( CAY [ CAY 170310 !], LTR, NY, P [ P 04877940 !]) ; Saül, Mont Galbao trail , between village and entrance to Grand Boeuf Mort trail, 200-250 m, fl., 6.VIII.87, Mori & Gracie 18653 ( CAY [ CAY 170302 !], LTR, NY) ; Saül, Mont la Fumée , 200-400 m, 3°37’N, 53°12’W, st., 15.X.1982, Boom & Mori 2134 ( CAY [ CAY 170308 !], LTR, NY) ; ibid., 21.X.1982, Boom & Mori 2237 ( CAY [ CAY 170303 !], LTR, NY) ; ibid., 13.X.1982, Boom & Mori 2028 ( CAY [ CAY 170309 !]) ; Saül and vicinity: Boeuf-Mort trail, less than 1 km from entrance at Route de Bélizon , st., 13.IX.1994, Mori et al. 23905 ( CAY [ CAY 170307 !], NY [ NY 1365060 ]) ; Centre Orstom, Île de Cayenne , 5 m, 4°56’N, 52°19’W, st., 26.XI.1990, De Granville 11158 ( CAY [ CAY 170305 , CAY 170306 !], K, P [ P 04717178 !], U) ; Roche Dachine , st., 15.XII.1999, Chareyre 1035 ( CAY [ CAY 019647 !]) ; Massif Dékou Dékou, région Paul Isnard , 300 m, 4°42’N, 53°56’W, st., 27.XI.2000, Dutreve 608 ( CAY [ CAY 046309 !]) ; Montagne La Fumée, région de Saül , 3°38’N, 53°12’W, st., 21.XI.1988, Sabatier 2298 ( CAY [ CAY 010140 !], LTR) ; Commune de Saül , 3°37’N, 53°13’W, st., 24.XI.1988, Sabatier 2309 ( CAY [ CAY 010139 !], P, NY, MO, U) ; Plateau de la Douane, environ 3 km de Saül sur le tracé Carbet Maïs , st., 16.XII.1970, Oldeman 3190 ( CAY [ CAY 170311 , CAY 170312 !], NY, P [ P 04878224 ], U [ U 0175056 ]) ; Saut Pararé , st., 29.IX.1983, Sabatier 575 ( CAY [ CAY 170313 !]) ; Saut Pararé, riv. Arataye affluent Approuague , 70 km SW Régina, st., 9.III.1987, Villiers 3833 ( CAY [ CAY 070672 !]) ; idid., 2.III.1988, Villiers 4409 ( CAY [ CAY 099763 !]) ; ibid., 11.III.1988, Villiers 4505 ( CAY [ CAY 099693 !]) ; Camp Pararé, Station de l’Arataye, Bassin de l’Approuague , 200 m, st., 13.III.1983, Barrier 2755 ( CAY [ CAY 099694 !]) ; ibid., 7.IX.1983, Barrier 4165 ( B, CAY [ CAY 083661 !], COL, IAN, K, MO, NY, U, US, VEN) ; station des Nouragues, Grand Plateau , inv. code NL110027, 4°4’58”N, 52°41’W, st., 30.XI.2007, Baraloto 3067 ( CAY [ CAY 182886 !]) ; ibid., inv. code NL110099, Baraloto 3077 ( CAY [ CAY 182885 !]) ; Nouragues Nature Réserve , c. 100 km SSW of Cayenne and 40 km SW of Régina, Grand Plateau , 4°5’N, 52°41’W, st., 17.XI.2006, Mori et al. 26498 ( CAY [ CAY 080491 !], NY) ; Saint-Georges, Régina , entre pk 30,6 et 31,85, st., 5.XI.1998, Grenand 3065 ( CAY [ CAY 000288 !]) . Suriname. Mts Bakhuis , concession BMS: zone 4, sud-ouest, 170 m, fr., 4.X.2005, Bordenave et al. 8144 ( BBS, CAY [ CAY 065001 !]) ; Area of Kabalebo dam project, distr. Nickerie, c. 22 km SW of Avanavero dam site, fr., 15.XI.1976, Heyde & Lindeman 89 ( F [ V 0188958 F], K, MO, NY, U [ U 0248638 ]) .

DOUBTFUL SPECIMEN. — Brazil. Estado do Para :rodovia Belèm-Brasilia km 92, fr., 30.IX.1959, Kuhlmann & Jimbo 318, ( US [ US 1891248 ]) .

DESCRIPTION

Deciduous canopy tree up to 65 m tall, with large plank to thick buttresses to 2-6 m high. Diameter up to 120 cm. Bark brown-yellow, scaly, inner bark pale yellow-green.Twigs pubescent, becoming glabrous; terminal buds densely pubescent. Leaves alternate, spirally arranged, usually clustered at branchlet tips; blades chartaceous, elliptic-obovate to obovate, 5-12 × 2-6.5 cm; apex acuminate; base cuneate or attenuate-cuneate; margin entire, revolute at very base; densely pubescent-sericeous on both faces when young; mature with adaxial surface sparse-pubescent mainly along main veins, abaxial surface slightly pubescent, palish-gray (sometimes not obvious on dried material); lateral veins 6-8, uniformly pinnate, weakly brochidodromous, slightly raised on both surfaces, lower venation random reticulate, visible on both surfaces; petioles 1.4-4 cm, slightly pubescent or glabrous, often with a pair of small glands toward apex (more obvious on fresh material).

Inflorescences axillary, clustered in about 10 spikes at mostly leafless branchlet-ends, c. 4-5 cm long, densely pubescent, c. 25-30-flowered;peduncle 0.7-1.7cm long; bracts inconspicuous and caducous. Flowers bisexual, pale greenish, actinomorphic, 2.6-3.9 × 1.9-2.7 mm; lower hypanthium extended into a short “neck” surrounding the ovary, 1.2-1.9 mm long, densely pubescent, upper hypanthium cupuliform to campanulate, 1.5- 1.9 mm long, pubescent on the external surface, densely lanate with much longer trichomes on the inner surface; calyx lobes 5, 0.8-1.2 mm long, pubescent on the external surface, lanate with much longer trichomes on the inner surface; petals 0; stamens 10, exserted, white, glabrous, 1.9-4.2 mm, anthers versatile, 0.4- 0.5 mm long; intrastaminal disk lanate, 0.9-1.9 mm width;ovary inferior, unilocular, with two pendulous ovules, style exserted, 2.5-3.3 mm long, lanate over most of its length. Infrutescence with1-2 fruits,peduncle and rachis slightly pubescent to glabrous. Fruits 2-winged, dry, glabrous, dull green pruinose becoming shiny, 6.8-8.6 × 1.6-3.2 cm, apex flat to slightly emarginated, base obtuse; wings stiff, (sub)equal, 3.2-4 cm long, narrowly to very narrowly rounded; body c. 0.5-0.9 cm width, c. 4-5 mm high, keeled on one side and flat on the other.

NOTE

T. carinata Sabatier & J.Engel , sp. nov. was previously identified as T. guyanensis in CAY , while the ‘true’ T. guyanensis , as originally described by Eichler ( Martius & Eichler 1867), was considered as an unknown morpho-species in CAY. This confusion is visible in Mori et al. (2005), where the illustration of T. guyanensis is in fact an illustration of T. carinata Sabatier & J.Engel , sp. nov. And in the last review of the genus Terminalia ( Stace 2010) , specimens of T. carinata Sabatier & J.Engel , sp. nov. and T. guyanensis were merged together as T. guyanensis . Here, we propose to revert to the original protologue of T. guyanensis by Eichler ( Martius & Eichler 1867), and we introduce T. carinata Sabatier & J.Engel , sp. nov. as a new species according to the description above. The circumscription of T. guyanensis is therefore clarified and this species can be distinguished from T. carinata Sabatier & J.Engel , sp. nov. by its fruit central body bulging on both faces while T. carinata Sabatier & J.Engel , sp. nov. fruit central body is flat on one face and keeled on the other one. In addition, T. guyanensis leaves are glabrous whereas those of T. carinata Sabatier & J.Engel , sp. nov. are slightly pubescent and palish-gray abaxially with longer petioles (usually> 2 cm). In scanning electron microscope, we observe that this distinctive undersurface of T. carinata Sabatier & J.Engel , sp. nov. is made up of a very high density of papillae that are absent from the surface of the leaves of T. guyanensis ( Fig. 3 ). Trichomes are similar in T. carinata Sabatier & J.Engel , sp. nov. and in T. guyanensis : pointed at base and widen at top to a rounded head with a cavity, but much less abundant in T. guyanensis whose lamina appears almost completely hairless at glance.

Figures

FIG. 1. — Terminalia carinata Sabatier & J.Engel, sp. nov.: A, stem with leaves; B, detail of abaxial leaf surface; C, inflorescences with a young shoot of leaves; D, flower; E, longitudinal section of flower; F, three views of stamens; G, fruits; H, transverse section of fruit; A, B, Boom & Mori 2134 (CAY); C-F, Mori & Gracie 18653 (CAY); G, H, Mori & Boom 15121 (CAY). Drawn by Laurence Ramon. Scale bars: A, C, G, H, 1 cm; B, D, E, 1 mm; F, 0.5 mm.

FIG. 2. — Terminalia carinata Sabatier & J.Engel, sp. nov.: A, B, inflorescences; C, fruiting branch (note fruit keeled on one side and flat on the other); D, stem with leaves; note: i) the typical Terminalia arrangement of leaves clustered at twig tips; and ii) the leaf margin revolute at very base; E, trunk; F, trunk slash; A, B, Mori & Gracie 18653; C, Sabatier et al. 4891 (type specimen); D, Sabatier 2309. A, B, Photographs by Carol Gracie; C, D, photographs by Daniel Sabatier; E, F, photographs by Julien Engel.

FIG. 3. — Leaf abaxial surface in SEM:A-D, Terminalia carinata Sabatier & J.Engel, sp.nov.; note the hidden stomata; E, F, Terminalia guyanensis Eichler;A, B, Sabatier et al. 4891; D, E, De Granville et al. 10958; E, F, Sabatier et al. 6018. Scale bars: A, C, E, 200 µm; B, D, F, 100 µm.

FIG. 4. — Distribution of Terminalia guyanensis Eichler and Terminalia carinata Sabatier & J.Engel, sp. nov.: (·) T. guyanensis and (▲) T. carinata Sabatier & J.Engel, sp. nov., herbarium specimens; () T. guyanensis and () T. carinata Sabatier & J.Engel, sp. nov., observations (no voucher) from the GUYADIV and GUYAFOR networks (Engel 2015).